{ "page": { "file": "05-20", "title": "Mars games", "folder": "05", "facts_file": "05-20-mars-games.json", "version": "1.9", "status": "Active", "last_updated": "10 October 2026", "about": "Facts file for 05-20 Mars games. It owns the home page's games section: its headline, the three game cards (Mars or Earth?, Fact or Fiction?, The Mars Quiz), the moving preview on each card, their pictures and what a card says while its game is still being built. All three games are built (games/); their plan and the question bank are in thinking/active/mars-quiz.", "one_line": "Three quick games on the home page: tell Mars from Earth in a photo, swipe fact or fiction, and take the Mars Quiz.", "shelf_life": "Re-check when a game is built: give its card an href so the card opens the game instead of turning over to say it is opening soon.", "header": { "purpose": "Give the home page one slim, eye-catching section that makes people want to play, and keep every word it shows in one place.", "why": "The owner wants games on the home page to drive play and sharing (9 and 10 October 2026). It does not matter how good a game is if nobody taps through to it, so the section's only job is to make the first tap irresistible.", "when": "Changing the games section on the home page, adding a game, or opening a game when it is ready.", "change": "Edit this facts file (numbers.home), then build. The home page draws the section from games/library.json." }, "sections": [ { "id": "1.1", "title": "The three games" }, { "id": "1.2", "title": "The home page section" }, { "id": "1.3", "title": "Mars or Earth?: the photos and what they show" }, { "id": "1.4", "title": "Fact or Fiction?: the statements and the facts behind them" }, { "id": "1.5", "title": "The Mars Quiz: the questions and the facts behind them" } ], "facts": [ { "id": "F-01", "section": "1.3", "text": "Curiosity took this from a ridge, looking back across the crater floor where it landed in 2012. The far hills are the rim of Gale Crater.", "sources": [ "nasa_pia22209" ] }, { "id": "F-02", "section": "1.3", "text": "The top of this rock tower stands about 5 metres above the rover: about as high as a two-storey house.", "sources": [ "nasa_pia20843" ] }, { "id": "F-03", "section": "1.3", "text": "These stripes are old sand dunes turned to stone. Wind piled the sand up billions of years ago, then the dunes hardened into rock.", "sources": [ "nasa_pia21043" ] }, { "id": "F-04", "section": "1.3", "text": "The haze is dust hanging in the air. Through it you can just make out the rim of Gale Crater, many kilometres away.", "sources": [ "nasa_pia21041" ] }, { "id": "F-05", "section": "1.3", "text": "Rock towers like these are all that is left of a sheet of sandstone. Wind has worn away the rock around them.", "sources": [ "nasa_pia21042" ] }, { "id": "F-06", "section": "1.3", "text": "Mount Sharp, the mountain Curiosity is climbing, is about 5 km tall: more than half the height of Everest.", "sources": [ "nasa_pia25733" ] }, { "id": "F-07", "section": "1.3", "text": "The dark band is a field of moving dunes. Curiosity was the first craft ever to study a moving dune on another planet.", "sources": [ "nasa_dunes_2015" ] }, { "id": "F-08", "section": "1.3", "text": "Mars has two sizes of sand ripple. The small ones look like a beach on Earth; the big ones, metres apart, are a kind Earth does not have.", "sources": [ "nasa_ripples_2017" ] }, { "id": "F-09", "section": "1.3", "text": "Floods of water and rock once rushed down this channel, piling boulders into mounds.", "sources": [ "nasa_pia26367" ] }, { "id": "F-10", "section": "1.3", "text": "The pile of boulders in the middle may have been swept here by flowing water billions of years ago.", "sources": [ "nasa_pia25733" ] }, { "id": "F-11", "section": "1.3", "text": "These clouds are made of ice. Curiosity caught them just after sunset, drifting over a cliff it was studying.", "sources": [ "nasa_pia24622" ] }, { "id": "F-12", "section": "1.3", "text": "On Mars the sunset glows blue. Fine dust lets blue light through towards the Sun, the reverse of Earth's red sky.", "sources": [ "nasa_pia19400" ] }, { "id": "F-13", "section": "1.3", "text": "Curiosity took 32 photos of this cliff, then rolled 4 metres sideways and took them all again, to see its layers in 3D.", "sources": [ "nasa_pia24266" ] }, { "id": "F-14", "section": "1.3", "text": "Mount Sharp is built of layer on layer of old rock, like the pages of a book. Curiosity is climbing it to read Mars's past.", "sources": [ "nasa_msl" ] }, { "id": "F-15", "section": "1.3", "text": "Many Mars photos are colour-balanced to Earth's daylight so geologists can read the rocks. That is why this sky looks pale blue.", "sources": [ "nasa_pia25414" ] }, { "id": "F-16", "section": "1.3", "text": "Spirit took this from the top of Husband Hill in 2005. It was built to last 90 days and kept working for six years.", "sources": [ "nasa_spirit" ] }, { "id": "F-17", "section": "1.3", "text": "The flat pale stones are nicknamed paving stones. Perseverance picked this kind of rock for its first sample to bring home to Earth.", "sources": [ "nasa_pia24765" ] }, { "id": "F-18", "section": "1.3", "text": "These boulders lie on the floor of Jezero Crater, where a lake once stood. Perseverance is collecting rocks here to send to Earth.", "sources": [ "nasa_pia25172" ] }, { "id": "F-19", "section": "1.3", "text": "Curiosity took 340 photos in half an hour around midday to make this one view.", "sources": [ "nasa_pia26471" ] }, { "id": "F-20", "section": "1.3", "text": "Three years after landing, this was Curiosity's view of the slopes it was about to climb.", "sources": [ "nasa_pia19803" ] }, { "id": "F-21", "section": "1.3", "text": "The Atacama Desert stretches about 1,000 km along the coast of Chile, about the length of Great Britain.", "sources": [ "eso_atacama" ] }, { "id": "F-22", "section": "1.3", "text": "The air here is so dry and clear that two of the world's great observatories stand on these hills.", "sources": [ "eso_atacama_iced" ] }, { "id": "F-23", "section": "1.3", "text": "NASA tests rovers and drills in the Atacama, because its dry soil is about as close to Mars as Earth gets.", "sources": [ "nasa_arads" ] }, { "id": "F-24", "section": "1.3", "text": "This is Boa Vista, an island off West Africa. A desert of bare stones like this is called a hamada.", "sources": [ "wiki_hamada" ] }, { "id": "F-25", "section": "1.3", "text": "Egypt's Western Desert covers about two thirds of the country.", "sources": [ "wiki_western_desert" ] }, { "id": "F-26", "section": "1.3", "text": "The Sahara is about as big as the United States.", "sources": [ "wiki_sahara" ] }, { "id": "F-27", "section": "1.3", "text": "Satellites have measured the ground here at over 70 °C, one of the hottest surfaces ever recorded on Earth.", "sources": [ "nasa_lut" ] }, { "id": "F-28", "section": "1.3", "text": "Wind carved these ridges, called yardangs, out of old lake mud. Mars has yardangs too, in whole fields.", "sources": [ "wiki_yardang" ] }, { "id": "F-29", "section": "1.3", "text": "Mars has wind-carved ridges just like these. Orbiting spacecraft see whole fields of them near the Martian equator.", "sources": [ "wiki_yardang" ] }, { "id": "F-30", "section": "1.3", "text": "The Lut Desert is a World Heritage Site, listed in 2016 for its wind-carved landscape.", "sources": [ "unesco_lut" ] }, { "id": "F-31", "section": "1.3", "text": "Wadi Rum has played Mars on film, including in The Martian.", "sources": [ "wiki_wadi_rum" ] }, { "id": "F-32", "section": "1.3", "text": "Wadi Rum has been a World Heritage Site since 2011.", "sources": [ "unesco_wadi_rum" ] }, { "id": "F-33", "section": "1.3", "text": "Its rock is mostly sandstone, the same kind of rock Curiosity found in rock towers on Mars.", "sources": [ "wiki_wadi_rum" ] }, { "id": "F-34", "section": "1.3", "text": "This rock is called the Seven Pillars of Wisdom, after T. E. Lawrence's book.", "sources": [ "wiki_wadi_rum" ] }, { "id": "F-35", "section": "1.3", "text": "Factory Butte is in Utah, a short drive from the Mars Desert Research Station, where crews practise living on Mars.", "sources": [ "wiki_mdrs" ] }, { "id": "F-36", "section": "1.3", "text": "The Bisti wilderness covers about 170 square km: bigger than the city of Manchester.", "sources": [ "blm_bisti" ] }, { "id": "F-37", "section": "1.3", "text": "The rock towers here are called hoodoos: soft rock worn away from under a harder cap.", "sources": [ "wiki_hoodoo" ] }, { "id": "F-38", "section": "1.3", "text": "Death Valley holds the record for the hottest air ever measured on Earth: 56.7 °C, in 1913.", "sources": [ "wiki_death_valley" ] }, { "id": "F-39", "section": "1.3", "text": "Goblin Valley has played another planet on film, in the comedy Galaxy Quest.", "sources": [ "wiki_goblin_valley" ] }, { "id": "F-40", "section": "1.3", "text": "Iron in the rock paints these colours: the same metal that, rusted, turns Mars red.", "sources": [ "wiki_painted_desert" ] }, { "id": "F-41", "section": "1.3", "text": "It rains here more than in many forests, but acid rain from the volcano keeps plants away.", "sources": [ "nps_kau" ] }, { "id": "F-42", "section": "1.3", "text": "NASA scientists studied dry stream beds like this one to recognise the same pebbles on Mars, where Curiosity found them.", "sources": [ "nasa_pia16191" ] }, { "id": "F-43", "section": "1.3", "text": "Near here Spirit's stuck wheel dug up soil that is almost pure silica, the kind of deposit hot springs leave behind on Earth.", "sources": [ "nasa_silica_2007" ] }, { "id": "F-44", "section": "1.4", "text": "The Face on Mars, photographed by Viking 1 in 1976, is an ordinary hill: sharper photos from 1998 on show it plainly. Seeing faces in shapes is called pareidolia.", "sources": [ "wiki_cydonia" ] }, { "id": "F-45", "section": "1.4", "text": "An email claiming Mars will look as big as the full Moon has gone round every August since 2003. Even at its closest, the Moon looks about 70 times wider than Mars.", "sources": [ "wiki_mars_hoax" ] }, { "id": "F-46", "section": "1.4", "text": "No person has been to Mars. NASA calls it the only planet known to be inhabited entirely by robots.", "sources": [ "nasa_mars" ] }, { "id": "F-48", "section": "1.4", "text": "On average over time, Mercury is the closest planet to Earth, and to every other planet, because it never strays far from the Sun.", "sources": [ "pt_mercury" ] }, { "id": "F-49", "section": "1.4", "text": "NASA's InSight lander tracked Mars's spin by radio and found it speeding up very slightly each year, by a fraction of a millisecond, so its day is getting shorter.", "sources": [ "jpl_insight_spin" ] }, { "id": "F-50", "section": "1.4", "text": "A survey on the night of the 1938 War of the Worlds broadcast found only about 2% of homes listening; newspapers exaggerated the panic.", "sources": [ "wiki_wotw" ] }, { "id": "F-51", "section": "1.4", "text": "Jonathan Swift's Gulliver's Travels (1726) gave Mars two moons, 151 years before Asaph Hall found them in 1877: a lucky guess.", "sources": [ "wiki_moons" ] }, { "id": "F-52", "section": "1.4", "text": "The Mars bar is named after the Mars family. Forrest Mars first made it in Slough, England, in 1932.", "sources": [ "wiki_mars_bar" ] }, { "id": "F-53", "section": "1.4", "text": "March is named after Martius, the month of Mars, the Roman god of war.", "sources": [ "wiki_march" ] }, { "id": "F-54", "section": "1.4", "text": "The Meteoritical Society counts 401 meteorites from Mars found on Earth, each blasted off Mars by an impact.", "sources": [ "scripps_meteorite" ] }, { "id": "F-55", "section": "1.4", "text": "NASA's InSight lander detected 1,319 marsquakes. The biggest, magnitude 4.7 on 4 May 2022, kept the planet ringing for hours.", "sources": [ "ls_marsquake" ] }, { "id": "F-56", "section": "1.4", "text": "Phobos and Deimos, Fear and Dread, are the sons of the war god Ares in Greek myth; Mars is the Roman Ares.", "sources": [ "wiki_moons" ] }, { "id": "F-57", "section": "1.5", "text": "In 1877 Giovanni Schiaparelli mapped 'canali' on Mars, Italian for channels; translated as 'canals', it started about 90 years of stories about Martian engineers.", "sources": [ "wiki_canals" ] }, { "id": "F-58", "section": "1.5", "text": "The 1993 video game Doom begins on Phobos, a real moon of Mars.", "sources": [ "wiki_doom" ] }, { "id": "F-59", "section": "1.5", "text": "NASA's InSight lander tracked Mars's spin by radio and found it speeding up very slightly every year, by a fraction of a millisecond.", "sources": [ "bank_qz009" ], "owner_to_be": "02-01" }, { "id": "F-60", "section": "1.5", "text": "A trick question. Venus and Mars swing very close, then very far away. Mercury never strays far from the Sun, so on average it is nearest to every planet, Earth included.", "sources": [ "bank_qz010" ], "owner_to_be": "02-01" }, { "id": "F-61", "section": "1.5", "text": "It came within 55.8 million km, the closest in about 59,600 years. Mars will not come that close again until 2287.", "sources": [ "bank_qz011" ], "owner_to_be": "02-01" }, { "id": "F-62", "section": "1.5", "text": "InSight heard 1,319 marsquakes. The biggest, magnitude 4.7 on 4 May 2022, kept the planet ringing for hours.", "sources": [ "bank_qz012" ], "owner_to_be": "02-01" }, { "id": "F-63", "section": "1.5", "text": "Sunlight shines through clear sheets of dry ice and warms the dark ground underneath. Trapped gas bursts out and carves branching channels. NASA recreated them in a lab in 2024.", "sources": [ "bank_qz031" ], "owner_to_be": "02-02" }, { "id": "F-64", "section": "1.5", "text": "Mars's last ice age ran from about 2.1 million to 400,000 years ago, when ice spread about a third of the way to its equator.", "sources": [ "bank_qz087" ], "owner_to_be": "02-02" }, { "id": "F-65", "section": "1.5", "text": "Its radar found layers sloping like sand on a seashore, about 3 billion years old: one of the strongest signs of an old northern ocean.", "sources": [ "bank_qz088" ], "owner_to_be": "02-04" }, { "id": "F-66", "section": "1.5", "text": "It arrived during a planet-wide dust storm, waited for it to clear, then mapped 85% of Mars.", "sources": [ "bank_qz121" ], "owner_to_be": "01-05" }, { "id": "F-67", "section": "1.5", "text": "Mars 2 crashed on 27 November 1971. Days later Mars 3 landed, then fell silent within seconds.", "sources": [ "bank_qz122" ], "owner_to_be": "01-02" }, { "id": "F-68", "section": "1.5", "text": "PrOP-M weighed 4.5 kg and was meant to ski along on a 15 m cable. Nobody knows if it ever got the chance.", "sources": [ "bank_qz123" ], "owner_to_be": "03-05" }, { "id": "F-69", "section": "1.5", "text": "The letters of NASA's Jet Propulsion Laboratory. The pattern also helps engineers measure how far it has driven.", "sources": [ "bank_qz127" ], "owner_to_be": "03-05" }, { "id": "F-70", "section": "1.5", "text": "Geologists often put a coin in their photos for scale. Curiosity carries one on its camera calibration target.", "sources": [ "bank_qz128" ], "owner_to_be": "03-05" }, { "id": "F-71", "section": "1.5", "text": "One piece of software worked in pound-force, another expected newtons. The $327.6 million craft skimmed far too low into Mars's air.", "sources": [ "bank_qz129" ], "owner_to_be": "01-02" }, { "id": "F-72", "section": "1.5", "text": "About $73 million. India's prime minister made the comparison himself. India was the first Asian nation to reach Mars orbit.", "sources": [ "bank_qz130" ], "owner_to_be": "01-01" }, { "id": "F-73", "section": "1.5", "text": "Its camera test chart was painted by Damien Hirst. It landed in 2003 but never called home: photos found in 2015 showed its solar panels had not all opened.", "sources": [ "bank_qz131" ], "owner_to_be": "01-02" }, { "id": "F-74", "section": "1.5", "text": "Sofi Collis won NASA's naming contest in 2003. Children have named Sojourner, Curiosity and Perseverance too.", "sources": [ "bank_qz134" ], "owner_to_be": "01-05" }, { "id": "F-75", "section": "1.5", "text": "A slice of the Sayh al Uhaymir 008 meteorite, loaned by the Natural History Museum, used to check one of its instruments. A Mars rock, home again.", "sources": [ "bank_qz135" ], "owner_to_be": "02-08" }, { "id": "F-76", "section": "1.5", "text": "Tianwen-1 landed in May 2021. Its rover Zhurong drove 1.9 km.", "sources": [ "bank_qz136" ], "owner_to_be": "01-01" }, { "id": "F-77", "section": "1.5", "text": "Arthur C. Clarke gave his blessing. Since 2010 it has been the longest-serving spacecraft at Mars.", "sources": [ "bank_qz138" ], "owner_to_be": "01-05" }, { "id": "F-78", "section": "1.5", "text": "The first pure sulphur ever found on Mars. Scientists had not expected it there at all.", "sources": [ "bank_qz139" ], "owner_to_be": "02-03" }, { "id": "F-79", "section": "1.5", "text": "Fourteen years after landing, and still climbing Mount Sharp.", "sources": [ "bank_qz140" ], "owner_to_be": "02-08" }, { "id": "F-80", "section": "1.5", "text": "Many cultures named it for its colour: Egypt called it 'the Red Horus', and Babylon named it after its god of fire and war.", "sources": [ "bank_qz190" ], "owner_to_be": "new file: Mars in human culture" }, { "id": "F-81", "section": "1.5", "text": "March comes from Martius. Tuesday is mardi in French and martes in Spanish: Mars's day. English swapped in another war god, Tiw.", "sources": [ "bank_qz191" ], "owner_to_be": "new file: Mars in human culture" }, { "id": "F-82", "section": "1.5", "text": "Alchemists also used it for iron, which happens to be what makes Mars red.", "sources": [ "bank_qz192" ], "owner_to_be": "new file: Mars in human culture" }, { "id": "F-83", "section": "1.5", "text": "Worth it: Mars showed him that planets travel in ellipses, not circles, one of the great discoveries in science.", "sources": [ "bank_qz193" ], "owner_to_be": "02-01" }, { "id": "F-84", "section": "1.5", "text": "Jonathan Swift wrote it in 1726. The moons were found in 1877. A lucky guess, not a secret.", "sources": [ "bank_qz194" ], "owner_to_be": "02-07" }, { "id": "F-85", "section": "1.5", "text": "Asaph Hall found the moons in 1877. He said he might have stopped searching but for Angeline Stickney's encouragement. Its biggest crater carries her name.", "sources": [ "bank_qz195" ], "owner_to_be": "02-07" }, { "id": "F-86", "section": "1.5", "text": "Henry Madan, an Eton science master, picked Phobos and Deimos. In 1930 his great-niece Venetia Burney, aged 11, suggested the name Pluto.", "sources": [ "bank_qz196" ], "owner_to_be": "02-07" }, { "id": "F-87", "section": "1.5", "text": "Clyde Tombaugh found Pluto there in 1930.", "sources": [ "bank_qz198" ], "owner_to_be": "new file: Mars in human culture" }, { "id": "F-88", "section": "1.5", "text": "He said 24 hours 40 minutes. Not bad for 360 years ago.", "sources": [ "bank_qz199" ], "owner_to_be": "02-01" }, { "id": "F-89", "section": "1.5", "text": "It appears in the comic Watchmen.", "sources": [ "bank_qz200" ], "owner_to_be": "02-04" }, { "id": "F-90", "section": "1.5", "text": "Forrest Mars first made it in Slough, England, in 1932.", "sources": [ "bank_qz201" ], "owner_to_be": "new file: Mars in human culture" }, { "id": "F-91", "section": "1.5", "text": "One house further down the street than Earth, which is third.", "sources": [ "bank_qz014" ], "owner_to_be": "02-01" }, { "id": "F-92", "section": "1.5", "text": "Only Mercury is smaller. Mars is about half as wide as Earth.", "sources": [ "bank_qz015" ], "owner_to_be": "02-01" }, { "id": "F-93", "section": "1.5", "text": "It formed at about the same time as Earth. 13.8 billion years is the age of the whole universe.", "sources": [ "bank_qz017" ], "owner_to_be": "02-01" }, { "id": "F-94", "section": "1.5", "text": "Big worlds pull themselves into spheres. Phobos is only about 26 km long, too small to do that.", "sources": [ "bank_qz052" ], "owner_to_be": "02-07" }, { "id": "F-95", "section": "1.5", "text": "Mount Sharp is about two thirds of Everest's height, sitting in Gale crater, which is about 154 km wide.", "sources": [ "bank_qz070" ], "owner_to_be": "02-04" }, { "id": "F-96", "section": "1.5", "text": "An 82 km bowl of ice that never melts. Cold air sinks into the crater and sits over the ice like a lid, keeping it frozen.", "sources": [ "bank_qz089" ], "owner_to_be": "02-03" }, { "id": "F-97", "section": "1.5", "text": "Almost a marathon's distance. It also dug up boulders of buried ice, and NASA's InSight lander felt the ground shake.", "sources": [ "bank_qz091" ], "owner_to_be": "02-03" }, { "id": "F-98", "section": "1.5", "text": "83 Martian days in 1997, nearly twelve times its plan. And it weighed about 11 kg, less than a checked suitcase.", "sources": [ "bank_qz141" ], "owner_to_be": "03-05" }, { "id": "F-99", "section": "1.5", "text": "It hit the ground wrapped in airbags and bounced along like a beach ball before rolling to a stop. Spirit and Opportunity landed the same way.", "sources": [ "bank_qz142" ], "owner_to_be": "01-02" }, { "id": "F-100", "section": "1.5", "text": "Cameras for driving, for science and to film its own landing. More cameras than most people have in their whole house.", "sources": [ "bank_qz143" ], "owner_to_be": "02-08" }, { "id": "F-101", "section": "1.5", "text": "Curiosity and Perseverance. Mars is the only planet we know of that is lived on entirely by robots.", "sources": [ "bank_qz144" ], "owner_to_be": "01-05" }, { "id": "F-102", "section": "1.5", "text": "The first time anyone matched a crater on Mars to the shaking it made. The impact was on Christmas Eve.", "sources": [ "bank_qz145" ], "owner_to_be": "02-03" }, { "id": "F-103", "section": "1.5", "text": "Including tomatoes, peas, radish and rocket. They used Earth air and added compost, so this is a first step, not a Martian allotment.", "sources": [ "bank_qz159" ], "owner_to_be": "03-10" }, { "id": "F-104", "section": "1.5", "text": "Growing crops together, as gardeners do on Earth, may help the first Mars farms. The test ran in a greenhouse on Earth.", "sources": [ "bank_qz160" ], "owner_to_be": "03-10" }, { "id": "F-105", "section": "1.5", "text": "The official rule: villages with fewer than 100,000 people. Bigger craters honour people who studied or wrote about Mars.", "sources": [ "bank_qz202" ], "owner_to_be": "02-04" }, { "id": "F-106", "section": "1.5", "text": "Small valleys are named after rivers on Earth. Mars's map is written in languages from all over our planet.", "sources": [ "bank_qz203" ], "owner_to_be": "02-04" }, { "id": "F-107", "section": "1.5", "text": "Written in 1914 in a pounding 5/4 rhythm, and finished before the First World War began.", "sources": [ "bank_qz206" ], "owner_to_be": "new file: Mars in human culture" }, { "id": "F-108", "section": "1.5", "text": "A 24.7 kg meteorite found in the Sahara, sold by Sotheby's in New York. It is about 70% bigger than the next-largest piece of Mars we have.", "sources": [ "bank_qz207" ], "owner_to_be": "02-09" }, { "id": "F-109", "section": "1.5", "text": "The Meteoritical Society counts 401, the first one recorded in 1815. Each was blasted off Mars by an impact and drifted here through space.", "sources": [ "bank_qz208" ], "owner_to_be": "02-09" }, { "id": "F-110", "section": "1.5", "text": "37% in a YouGov poll. Young people were far more hopeful: 60% of 18 to 24-year-olds, against 22% of over-65s.", "sources": [ "bank_qz209" ], "owner_to_be": "05-09" } ], "numbers": { "home": { "title": "Think you know", "title_accent": "Mars?", "back_label": "Back", "soon_title": "Opening soon", "soon_line": "This game is being built right now.", "cards": [ { "id": "mars-or-earth", "n": "01", "kind": "Photo game", "title": "Mars or Earth?", "hook": "One photo. Two buttons. Can you tell the planets apart?", "meta": "Endless streak", "cta": "Play", "accent": "#E0825E", "preview": "split", "pictures": { "left": "games/art/mars.webp", "left_sm": "games/art/mars-sm.webp", "right": "games/art/earth.webp", "right_sm": "games/art/earth-sm.webp" }, "labels": { "left": "Mars", "right": "Earth" }, "alt": "One desert seen twice and split down the middle: on the left under a butterscotch Martian sky, on the right under a blue Earth sky", "how": "We show you a photo. You tap Mars or Earth. One wrong answer ends your streak.", "href": "games/mars-or-earth/", "store": "moe", "best": "Your best: {n} in a row" }, { "id": "fact-or-fiction", "n": "02", "kind": "Swipe game", "title": "Fact or Fiction?", "hook": "The strangest claims about Mars. Swipe on your gut.", "meta": "Quick-fire", "cta": "Play", "accent": "#8DB8F2", "preview": "swipe", "pictures": { "main": "games/art/sunset.webp", "main_sm": "games/art/sunset-sm.webp" }, "statement": "Sunsets on Mars are blue", "labels": { "left": "Fiction?", "right": "Fact?" }, "alt": "A small white Sun setting behind a crater rim on Mars, wrapped in a cool blue glow", "how": "A card says something about Mars. Swipe right for fact, left for fiction. You have three lives.", "href": "games/fact-or-fiction/", "store": "fof", "best": "Your best: {n} right" }, { "id": "mars-quiz", "n": "03", "kind": "Quiz", "title": "The Mars Quiz", "hook": "Seven questions. Four answers each. A new quiz every day.", "meta": "New every day", "cta": "Play", "accent": "#E9C28E", "preview": "quiz", "pictures": { "main": "games/art/olympus.webp", "main_sm": "games/art/olympus-sm.webp" }, "question": "How many Everests tall is {olympus}?", "options": [ "About 1", "About 2½", "About 5", "About 10" ], "alt": "Olympus Mons from high above at dawn: a vast shield volcano with a nested crater on top and a towering cliff at its edge", "how": "Seven questions with four answers each. Every answer shows you the real thing, to scale.", "href": "games/mars-quiz/", "store": "quiz", "best": "Your best: {n} out of 7" } ], "share_tag": "Play it at wakeuponmars.com" }, "mars_or_earth": { "words": { "title": "Mars or Earth?", "line": "Rovers took some of these photos on Mars. People took the rest on Earth. Can you tell which is which?", "rules": [ { "icon": "eye", "text": "Look at the photo" }, { "icon": "tap", "text": "Tap Mars or Earth" }, { "icon": "flame", "text": "One slip ends your run" } ], "play": "Play", "again": "Play again", "mars": "Mars", "earth": "Earth", "streak": "In a row", "best": "Best", "photo_n": "Photo {n}", "right": [ "Spot on.", "Sharp eyes.", "Nailed it.", "Right again.", "Exactly.", "Good call." ], "wrong": "Not this time.", "taken_on": { "mars": "Taken on Mars", "earth": "Taken on Earth" }, "on_planet": { "mars": "Mars", "earth": "Earth" }, "did_you_know": "Did you know?", "next": "Next photo", "see_run": "See your run", "end_title": "{n} in a row", "end_title_one": "1 in a row", "got_you": "This one got you", "your_run": "Your run", "all_title": "Every photo, named", "all_line": "You named all {n}. Nothing fools you.", "new_best": "New best", "share": "Share your score", "challenge": "Challenge a friend", "copied": "Link copied", "share_text": "I named {n} photos in a row in Mars or Earth? Can you beat me?", "share_card": "{n} in a row", "share_card_line": "Can you tell Mars from Earth?", "beat_banner": "A friend named {n} in a row. Can you beat it?", "beat_won": "You beat your friend's {n}.", "home": "Home", "sound": "Sound", "keys": "Keys: ← Mars · → Earth", "more_title": "More games", "soon": "Opening soon", "share_fooled": "This one fooled me. Would it fool you?", "end_title_zero": "Fooled by the very first photo", "levels": [ "Easy", "Medium", "Hard" ], "rank_up": "New rank", "streak_milestone": "{n} in a row!", "go_on": "Opens in a new tab, so your run keeps going" }, "ranks": [ { "min": 0, "title": "Tourist", "line": "Mars hides well. Have another look." }, { "min": 3, "title": "Rover driver", "line": "You are getting a feel for the place." }, { "min": 6, "title": "Field geologist", "line": "You read rocks like a map." }, { "min": 10, "title": "Mars veteran", "line": "You have done this before, haven't you?" }, { "min": 15, "title": "Mission scientist", "line": "NASA would like a word." }, { "min": 25, "title": "Born on Mars", "line": "You could do this in your sleep." } ], "photos": [ { "id": "gale-vista", "planet": "mars", "level": 3, "nasa": "PIA22209", "crop": [ 0.05, 0.1, 0.66, 0.8 ], "spot": "View from Vera Rubin Ridge", "place": "curiosity", "by": "Curiosity rover, 2018", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-01", "plain": "Looking back across a giant crater" }, { "id": "murray-butte", "planet": "mars", "level": 2, "nasa": "PIA20843", "crop": [ 0.22, 0.25, 0.97, 0.85 ], "spot": "Murray Buttes", "place": "curiosity", "by": "Curiosity rover, 2016", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-02", "plain": "A rock tower made of old sand" }, { "id": "murray-layers", "planet": "mars", "level": 2, "nasa": "PIA21043", "spot": "Murray Buttes", "place": "curiosity", "by": "Curiosity rover, 2016", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-03", "plain": "Sand dunes turned to stone" }, { "id": "murray-haze", "planet": "mars", "level": 2, "nasa": "PIA21041", "spot": "Murray Buttes", "place": "curiosity", "by": "Curiosity rover, 2016", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-04", "plain": "Dust hanging in the air" }, { "id": "murray-gap", "planet": "mars", "level": 2, "nasa": "PIA21042", "spot": "Murray Buttes", "place": "curiosity", "by": "Curiosity rover, 2016", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-05", "plain": "A gap between two rock towers" }, { "id": "murray-cliff", "planet": "mars", "level": 1, "nasa": "PIA21045", "spot": "Murray Buttes", "place": "curiosity", "by": "Curiosity rover, 2016", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-06", "plain": "A cliff of layered rock" }, { "id": "bagnold-edge", "planet": "mars", "level": 3, "nasa": "PIA19929", "crop": [ 0.04, 0.06, 0.96, 0.86 ], "spot": "Bagnold Dunes and Mount Sharp", "place": "curiosity", "by": "Curiosity rover, 2015", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-07", "plain": "A field of dark, moving dunes" }, { "id": "ripples", "planet": "mars", "level": 2, "nasa": "PIA11242", "spot": "Bagnold Dunes", "place": "curiosity", "by": "Curiosity rover, 2017", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-08", "plain": "Ripples in Martian sand" }, { "id": "gediz-channel", "planet": "mars", "level": 2, "nasa": "PIA26367", "crop": [ 0.03, 0.24, 0.8, 0.8 ], "spot": "Gediz Vallis channel", "place": "curiosity", "by": "Curiosity rover, 2024", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-09", "plain": "An old flood channel" }, { "id": "gediz-valley", "planet": "mars", "level": 2, "nasa": "PIA25733", "crop": [ 0.5, 0.3, 0.8, 0.78 ], "spot": "Gediz Vallis", "place": "curiosity", "by": "Curiosity rover, 2022", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-10", "plain": "Boulders left by ancient floods" }, { "id": "mercou-clouds", "planet": "mars", "level": 3, "nasa": "PIA24622", "spot": "Mont Mercou at dusk", "place": "curiosity", "by": "Curiosity rover, 2021", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-11", "plain": "Ice clouds at dusk" }, { "id": "blue-sunset", "planet": "mars", "level": 3, "nasa": "PIA19400", "crop": [ 0, 0.05, 1, 0.92 ], "spot": "Sunset over the crater rim", "place": "curiosity", "by": "Curiosity rover, 2015", "credit": "Photo: NASA/JPL-Caltech/MSSS/Texas A&M Univ.", "fact": "F-12", "plain": "A blue sunset" }, { "id": "mont-mercou", "planet": "mars", "level": 2, "nasa": "PIA24266", "crop": [ 0.1, 0, 0.75, 1 ], "spot": "Mont Mercou", "place": "curiosity", "by": "Curiosity rover, 2021", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-13", "plain": "A wall of rock layers" }, { "id": "sharp-hills", "planet": "mars", "level": 3, "nasa": "PIA19912", "spot": "Lower slopes of Mount Sharp", "place": "curiosity", "by": "Curiosity rover, 2015", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-14", "plain": "The foothills of a giant mountain" }, { "id": "bolivar", "planet": "mars", "level": 3, "nasa": "PIA25414", "crop": [ 0.1, 0.26, 0.9, 0.82 ], "spot": "Bolívar and its sand ridges", "place": "curiosity", "by": "Curiosity rover, 2022", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-15", "plain": "Wind-swept sand ridges" }, { "id": "husband-hill", "planet": "mars", "level": 1, "nasa": "PIA17760", "spot": "Top of Husband Hill", "place": "spirit", "by": "Spirit rover, 2005", "credit": "Photo: NASA/JPL-Caltech/Cornell Univ.", "fact": "F-16", "plain": "The view from a hilltop" }, { "id": "first-drill", "planet": "mars", "level": 1, "nasa": "PIA24765", "crop": [ 0.03, 0.06, 0.97, 0.94 ], "spot": "Perseverance's first drill site", "place": "jezero", "by": "Perseverance rover, 2021", "credit": "Photo: NASA/JPL-Caltech/ASU/MSSS", "fact": "F-17", "plain": "Where Perseverance first drilled" }, { "id": "santa-cruz", "planet": "mars", "level": 2, "nasa": "PIA25172", "crop": [ 0.3, 0.05, 0.65, 1 ], "spot": "Boulders before Santa Cruz", "place": "jezero", "by": "Perseverance rover, 2022", "credit": "Photo: NASA/JPL-Caltech/ASU/MSSS", "fact": "F-18", "plain": "Boulders on an old lake floor" }, { "id": "tracks-west", "planet": "mars", "level": 1, "nasa": "PIA26471", "crop": [ 0.03, 0.22, 0.33, 0.84 ], "spot": "West of Gediz Vallis", "place": "curiosity", "by": "Curiosity rover, 2024", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-19", "plain": "Cracked plates of rock" }, { "id": "geology-ahead", "planet": "mars", "level": 3, "nasa": "PIA19803", "crop": [ 0.15, 0.1, 0.62, 1 ], "spot": "Looking up Mount Sharp", "place": "curiosity", "by": "Curiosity rover, 2015", "credit": "Photo: NASA/JPL-Caltech/MSSS", "fact": "F-20", "plain": "The slopes Curiosity was about to climb" }, { "id": "home-plate", "planet": "mars", "level": 1, "nasa": "PIA02688", "crop": [ 0.58, 0.0, 0.97, 0.66 ], "spot": "Inside Home Plate", "place": "home_plate", "by": "Spirit rover, 2006", "credit": "Photo: NASA/JPL-Caltech/USGS/Cornell Univ.", "fact": "F-43", "plain": "Rock from an ancient hot spring" }, { "id": "atacama-sunset", "planet": "earth", "level": 3, "commons": "Desert landscape (malin 2709).jpg", "licence": "CC BY 4.0", "spot": "Atacama Desert", "where": "Chile", "lat": -24.63, "lon": -70.4, "credit": "Photo: ESO/C. Malin, CC BY 4.0", "fact": "F-21" }, { "id": "atacama-hills", "planet": "earth", "level": 2, "commons": "Atacama Desert Landscape (iced moment 870-CC).jpg", "licence": "CC BY 4.0", "crop": [ 0.25, 0.05, 1, 0.52 ], "spot": "Atacama Desert", "where": "Chile", "lat": -24.62, "lon": -70.41, "credit": "Photo: L. Honnorat/ESO, CC BY 4.0", "fact": "F-22" }, { "id": "atacama-plain", "planet": "earth", "level": 2, "commons": "Atacama Desert Panorama (img 2303).jpg", "licence": "CC BY 4.0", "crop": [ 0.3, 0.05, 0.85, 1 ], "spot": "Atacama Desert", "where": "Chile", "lat": -23.9, "lon": -69.6, "credit": "Photo: D. Schreiner and S. Degezelle/ESO, CC BY 4.0", "fact": "F-23" }, { "id": "atacama-stream", "planet": "earth", "level": 3, "nasa": "PIA16191", "crop": [ 0, 0.3, 1, 1 ], "spot": "Dry stream bed, Atacama Desert", "where": "Chile", "lat": -22.9, "lon": -69.9, "credit": "NASA/UC Berkeley", "fact": "F-42" }, { "id": "boa-vista", "planet": "earth", "level": 3, "commons": "260 Boa Vista.jpg", "licence": "Public domain", "spot": "Boa Vista", "where": "Cape Verde", "lat": 16.1, "lon": -22.85, "credit": "Photo: Ingo Wölbern, Public domain", "fact": "F-24" }, { "id": "western-desert", "planet": "earth", "level": 3, "commons": "Western Desert, Sahara Desert, Egypt.jpg", "licence": "CC BY 4.0", "spot": "Western Desert", "where": "Egypt", "lat": 25.5, "lon": 27.5, "credit": "Photo: Vyacheslav Argenberg, CC BY 4.0", "fact": "F-25" }, { "id": "libyan-desert", "planet": "earth", "level": 3, "commons": "Western Desert, Sahara Desert, Libyan Desert, Egypt.jpg", "licence": "CC BY 4.0", "spot": "Sahara", "where": "Egypt", "lat": 25.4, "lon": 27.4, "credit": "Photo: Vyacheslav Argenberg, CC BY 4.0", "fact": "F-26" }, { "id": "lut-plain", "planet": "earth", "level": 2, "commons": "2020-01-01 Iran, Kerman, Dasht-e Lut DSC 9214 DxO.jpg", "licence": "CC BY 4.0", "spot": "Lut Desert", "where": "Iran", "lat": 30.6035, "lon": 57.8534, "credit": "Photo: Lrkrol, CC BY 4.0", "fact": "F-27" }, { "id": "lut-kaluts", "planet": "earth", "level": 2, "commons": "2020-01-02 Iran, Kerman, Dasht-e Lut DSC 9870 DxO 1-1.jpg", "licence": "CC BY 4.0", "spot": "Shahdad Kaluts, Lut Desert", "where": "Iran", "lat": 30.787, "lon": 57.7837, "credit": "Photo: Lrkrol, CC BY 4.0", "fact": "F-28" }, { "id": "lut-ridges", "planet": "earth", "level": 2, "commons": "2020-01-02 Iran, Kerman, Dasht-e Lut DSC 9872 DxO PS.jpg", "licence": "CC BY 4.0", "spot": "Shahdad Kaluts, Lut Desert", "where": "Iran", "lat": 30.787, "lon": 57.7837, "credit": "Photo: Lrkrol, CC BY 4.0", "fact": "F-29" }, { "id": "lut-ravine", "planet": "earth", "level": 1, "commons": "2020-01-02 Iran, Kerman, Dasht-e Lut DSC 9676 DxO.jpg", "licence": "CC BY 4.0", "spot": "Lut Desert", "where": "Iran", "lat": 31.0002, "lon": 57.6413, "credit": "Photo: Lrkrol, CC BY 4.0", "fact": "F-30" }, { "id": "wadi-rum", "planet": "earth", "level": 2, "commons": "Jordan, Wadi Rum Desert, Infinite Spaces.jpg", "licence": "CC BY 4.0", "spot": "Wadi Rum", "where": "Jordan", "lat": 29.58, "lon": 35.42, "credit": "Photo: Vyacheslav Argenberg, CC BY 4.0", "fact": "F-31" }, { "id": "wadi-rum-haze", "planet": "earth", "level": 3, "commons": "Jordan, Wadi Rum Desert, Infinite Spaces 2.jpg", "licence": "CC BY 4.0", "spot": "Wadi Rum", "where": "Jordan", "lat": 29.57, "lon": 35.43, "credit": "Photo: Vyacheslav Argenberg, CC BY 4.0", "fact": "F-32" }, { "id": "wadi-rum-cliffs", "planet": "earth", "level": 2, "commons": "Wadi Rum Desert, Jordan, Infinite spaces.jpg", "licence": "CC BY 4.0", "spot": "Wadi Rum", "where": "Jordan", "lat": 29.56, "lon": 35.41, "credit": "Photo: Vyacheslav Argenberg, CC BY 4.0", "fact": "F-33" }, { "id": "seven-pillars", "planet": "earth", "level": 1, "commons": "Wadi Rum Desert, Jordan, The \"Seven Pillars of Wisdom\".jpg", "licence": "CC BY 4.0", "spot": "Wadi Rum", "where": "Jordan", "lat": 29.6, "lon": 35.43, "credit": "Photo: Vyacheslav Argenberg, CC BY 4.0", "fact": "F-34" }, { "id": "factory-butte", "planet": "earth", "level": 2, "commons": "Factory Butte (28162446462).jpg", "licence": "Public domain", "spot": "Factory Butte", "where": "Utah, USA", "lat": 38.42, "lon": -110.89, "credit": "Photo: Bureau of Land Management, Public domain", "fact": "F-35" }, { "id": "bisti", "planet": "earth", "level": 1, "commons": "Bisti-De-Na-Zin Wilderness (9440579733).jpg", "licence": "Public domain", "spot": "Bisti/De-Na-Zin Wilderness", "where": "New Mexico, USA", "lat": 36.27, "lon": -108.25, "credit": "Photo: Bureau of Land Management, Public domain", "fact": "F-36" }, { "id": "bisti-hoodoos", "planet": "earth", "level": 1, "commons": "Bisti-De-Na-Zin Wilderness (9443461966).jpg", "licence": "Public domain", "spot": "Bisti/De-Na-Zin Wilderness", "where": "New Mexico, USA", "lat": 36.26, "lon": -108.24, "credit": "Photo: Bureau of Land Management, Public domain", "fact": "F-37" }, { "id": "zabriskie", "planet": "earth", "level": 1, "commons": "Zabriskie Point, Death Valley, California, panorama.jpg", "licence": "CC BY 2.5", "crop": [ 0.15, 0, 0.72, 1 ], "spot": "Zabriskie Point, Death Valley", "where": "California, USA", "lat": 36.42, "lon": -116.81, "credit": "Photo: Jlkramer, CC BY 2.5", "fact": "F-38" }, { "id": "goblin-valley", "planet": "earth", "level": 2, "commons": "Goblin Valley State Park - 53646807382.jpg", "licence": "CC BY 2.0", "crop": [ 0, 0.3, 1, 1 ], "spot": "Goblin Valley", "where": "Utah, USA", "lat": 38.57, "lon": -110.7, "credit": "Photo: A J Cole, CC BY 2.0", "fact": "F-39" }, { "id": "painted-desert", "planet": "earth", "level": 1, "commons": "Colorful Painted Desert.jpg", "licence": "CC BY 2.0", "spot": "Painted Desert", "where": "Arizona, USA", "lat": 35.1446, "lon": -109.6806, "credit": "Photo: katsrcool, CC BY 2.0", "fact": "F-40" }, { "id": "kau-desert", "planet": "earth", "level": 3, "commons": "Ka‘ū Desert from Jaggar Museum.jpg", "licence": "Public domain", "spot": "Kaʻū Desert", "where": "Hawaii, USA", "lat": 19.35, "lon": -155.3, "credit": "Photo: National Park Service, Public domain", "fact": "F-41" } ], "links": { "curiosity": { "href": "atlas/#curiosity", "text": "Find this spot on the Mars atlas" }, "spirit": { "href": "atlas/#spirit", "text": "Find this spot on the Mars atlas" }, "home_plate": { "href": "atlas/#home_plate", "text": "Find this spot on the Mars atlas" }, "jezero": { "href": "stand-in-jezero/", "text": "Stand in this crater, then and now" }, "earth": { "href": "mars-through-time/", "text": "Now explore the real Mars" } } }, "fact_or_fiction": { "words": { "title": "Fact or Fiction?", "line": "The strangest things people say about Mars. Some are true. Some are not. Trust your gut.", "rules": [ { "icon": "read", "text": "Read the card" }, { "icon": "swipe", "text": "Swipe right for fact, left for fiction" }, { "icon": "heart", "text": "Three slips and the run is over" } ], "play": "Play", "again": "Play again", "fact": "Fact", "fiction": "Fiction", "streak": "Right", "best": "Best", "card_n": "Card {n}", "right": [ "Spot on.", "Sharp.", "Nailed it.", "Right again.", "Exactly.", "Good call." ], "wrong": "Not this time.", "it_is": { "fact": "It's a fact", "fiction": "It's fiction" }, "next": "Next card", "see_run": "See your run", "end_title": "{n} right", "end_title_one": "1 right", "got_you": "These got you", "your_run": "Your run", "all_title": "Every card, called", "all_line": "You called all {n}. Nothing gets past you.", "new_best": "New best", "share": "Share your score", "challenge": "Challenge a friend", "copied": "Link copied", "share_text": "I called {n} Mars claims right in Fact or Fiction? Can you beat me?", "share_card": "{n} right", "share_card_line": "Fact or fiction? Can you tell?", "share_fooled": "This one fooled me:", "beat_banner": "A friend called {n} right. Can you beat it?", "beat_won": "You beat your friend's {n}.", "home": "Home", "sound": "Sound", "keys": "Keys: ← Fiction · → Fact", "hint": "Drag the card, or tap a button", "more_title": "More games", "soon": "Opening soon", "end_title_zero": "Fooled by the very first card", "levels": [ "Easy", "Medium", "Hard" ], "rank_up": "New rank", "streak_milestone": "{n} in a row!", "lives": "Lives left", "life_lost": "One life gone", "last_life": "Last life", "got_you_one": "This one got you", "proof": "The proof" }, "ranks": [ { "min": 0, "title": "Easily fooled", "line": "Mars is full of surprises. Have another go." }, { "min": 3, "title": "Myth spotter", "line": "You can smell a tall tale." }, { "min": 6, "title": "Science reporter", "line": "Facts in, fiction out." }, { "min": 10, "title": "Fact checker", "line": "You would make a fine sceptic." }, { "min": 15, "title": "Mission scientist", "line": "NASA would like a word." }, { "min": 25, "title": "Myth buster", "line": "Nothing gets past you." }, { "min": 40, "title": "Mars oracle", "line": "You could write the textbook." } ], "statements": [ { "id": "blue-sunset", "answer": "fact", "level": 1, "says": "Sunsets on Mars are blue.", "reveal": "Fact. Mars turns the sunset inside out.", "why": "By day the dusty sky is butterscotch. At sunset fine dust lets blue light through towards the Sun: the reverse of Earth.", "cite": "02-01 F-16", "picture": "blue-sunset" }, { "id": "weight", "answer": "fact", "level": 1, "says": "On Mars you would weigh about a third of what you weigh on Earth.", "reveal": "Fact. Hello, slow-motion leaps.", "why": "Mars pulls with {grav_pct}% of Earth's gravity. You keep all your muscle and lose almost two thirds of your weight.", "cite": "02-01 F-01", "picture": "murray-haze" }, { "id": "day-length", "answer": "fact", "level": 1, "says": "A day on Mars is almost exactly as long as a day on Earth.", "reveal": "Fact. Close enough to set your watch by, nearly.", "why": "A Mars day lasts {sol_hm}, so a Mars clock only falls about {drift_min} minutes a day behind an Earth one.", "cite": "02-01 F-17", "picture": "gale-vista" }, { "id": "year-length", "answer": "fact", "level": 1, "says": "A year on Mars is almost twice as long as ours.", "reveal": "Fact. Birthdays are rare here.", "why": "A Mars year lasts {mars_year} Earth days, so a birthday comes round about every {year_months} months.", "cite": "02-01 F-18", "picture": "sharp-hills" }, { "id": "seasons", "answer": "fact", "level": 1, "says": "Mars has seasons, just like Earth.", "reveal": "Fact. Spring, summer, autumn and winter.", "why": "Mars leans over by {mars_tilt}°, almost exactly like Earth's {earth_tilt}°, so it gets seasons too. Each one lasts about twice as long.", "cite": "02-01 F-19", "picture": "murray-gap", "proof": "p-north-cap" }, { "id": "red-through", "answer": "fiction", "level": 1, "says": "Mars is red all the way through.", "reveal": "Fiction. Mars is only red skin-deep.", "why": "The red is a thin coat of rusty dust. Underneath, the rock is grey, as Curiosity's very first drill hole showed.", "cite": "02-03 F-38", "picture": "tracks-west", "proof": "p-drill" }, { "id": "no-water", "answer": "fiction", "level": 2, "says": "There is no water on Mars at all.", "reveal": "Fiction. It is hiding underground.", "why": "Buried ice lies under roughly a third of Mars. The first city will drill for it.", "cite": "02-03 F-01", "picture": "gediz-channel", "proof": "p-young-ice" }, { "id": "snow", "answer": "fact", "level": 2, "says": "Snow falls on Mars.", "reveal": "Fact. Phoenix watched it fall.", "why": "In 2008 NASA's Phoenix lander saw water-ice snow falling from about {phoenix_snow} km up. Most of it turned to vapour before it landed.", "cite": "02-02 F-29", "picture": "mercou-clouds" }, { "id": "storm-rocket", "answer": "fiction", "level": 1, "says": "A Mars dust storm could knock over a rocket, like in the film The Martian.", "reveal": "Fiction. Great film, wrong wind.", "why": "Mars's air is only {air_pct}% as thick as Earth's, so even the strongest storm winds push like a light breeze.", "cite": "02-01 F-34", "picture": "murray-haze" }, { "id": "meteors", "answer": "fact", "level": 2, "says": "Mars has shooting stars.", "reveal": "Fact. Make a wish on Mars.", "why": "In 2004 Spirit caught a meteor streaking across the Martian sky: the first ever seen from another planet.", "cite": "02-07 F-28", "picture": "blue-sunset" }, { "id": "two-moons", "answer": "fact", "level": 1, "says": "Mars has two moons.", "reveal": "Fact. Two little ones.", "why": "Phobos and Deimos are lumpy rocks just {phobos_km} km and {deimos_km} km across. Our Moon could swallow them many times over.", "cite": "02-01 F-42", "picture": "gale-vista", "proof": "p-phobos" }, { "id": "backwards-moon", "answer": "fact", "level": 3, "says": "One of Mars's moons rises in the west and sets in the east.", "reveal": "Fact. Phobos runs the wrong way.", "why": "Phobos laps Mars about three times while the ground turns once, so from the surface it crosses the sky backwards.", "cite": "02-07 F-07", "picture": "mercou-clouds", "proof": "p-phobos-transit" }, { "id": "rings", "answer": "fiction", "level": 1, "says": "Mars has rings, like Saturn.", "reveal": "Fiction. Not yet, anyway.", "why": "Phobos is falling about {phobos_fall} m closer every century. In {break_lo} to {break_hi} million years it may break up and become a ring.", "cite": "02-07 F-12", "picture": "sharp-hills" }, { "id": "small-sun", "answer": "fact", "level": 2, "says": "From Mars, the Sun looks smaller than it does from Earth.", "reveal": "Fact. A bright coin, not a blazing disc.", "why": "Mars is half as far again from the Sun, so it gets only {sun_pct}% of the sunlight Earth does.", "cite": "02-01 F-15", "picture": "blue-sunset", "proof": "p-sunset" }, { "id": "see-earth", "answer": "fact", "level": 1, "says": "You can see Earth from Mars.", "reveal": "Fact. As the evening star.", "why": "Earth shows up as the brightest star in the Martian sky. Curiosity photographed Earth and the Moon from {earth_photo} million km away.", "cite": "02-01 F-45", "picture": "blue-sunset" }, { "id": "aurora", "answer": "fact", "level": 3, "says": "Mars has auroras, like the northern lights.", "reveal": "Fact. Green ones, too.", "why": "In 2024 Perseverance saw a faint green glow across the whole night sky: the first aurora ever seen from another planet's surface.", "cite": "02-07 F-26", "picture": "mercou-clouds" }, { "id": "north-star", "answer": "fiction", "level": 3, "says": "There is a North Star on Mars.", "reveal": "Fiction. Martian sailors would be lost.", "why": "Mars's north pole points at an empty patch of the Swan, Cygnus, well away from any bright star.", "cite": "02-07 F-22", "picture": "mercou-clouds" }, { "id": "olympus", "answer": "fact", "level": 1, "says": "Mars's biggest volcano is more than twice as tall as Everest.", "reveal": "Fact. The giant of the solar system.", "why": "Olympus Mons is {oly_ev} times the height of Everest, the tallest volcano anywhere around the Sun.", "cite": "02-01 F-48", "picture": "sharp-hills", "proof": "p-olympus" }, { "id": "gentle-climb", "answer": "fact", "level": 3, "says": "You could walk up Mars's tallest mountain and barely notice you were climbing.", "reveal": "Fact. Its drama is all at the edge.", "why": "Olympus Mons slopes so gently a walker would barely notice. But its edge is a cliff up to {oly_scarp} km tall.", "cite": "02-01 F-49", "picture": "murray-butte" }, { "id": "canyon", "answer": "fact", "level": 2, "says": "Mars has a canyon that would stretch across the United States.", "reveal": "Fact. Coast to coast.", "why": "Valles Marineris runs about {valles_km} km, roughly from California to New York.", "cite": "02-01 F-51", "picture": "gediz-valley", "proof": "p-valles" }, { "id": "sound", "answer": "fiction", "level": 2, "says": "On Mars you could hear a friend talking 50 metres away.", "reveal": "Fiction. Stand close.", "why": "Sound fades out after about {carry_m} m in Mars's thin air, against about {carry_e} m on Earth.", "cite": "02-01 F-11", "picture": "murray-gap" }, { "id": "two-speeds", "answer": "fact", "level": 3, "says": "On Mars, high notes travel faster than low notes.", "reveal": "Fact. Mars has two speeds of sound.", "why": "Perseverance's microphone heard high notes travel at about {snd_hi} metres a second and low ones at {snd_lo}. On Earth every note travels at {snd_e}.", "cite": "02-01 F-10", "picture": "first-drill" }, { "id": "no-suit", "answer": "fiction", "level": 2, "says": "Without a spacesuit on Mars, you would stay awake for about a minute.", "reveal": "Fiction. Much less.", "why": "More like {conscious} seconds: about the time oxygen-starved blood takes to travel from your lungs to your brain.", "cite": "02-01 F-08", "picture": "murray-cliff" }, { "id": "co2-air", "answer": "fact", "level": 1, "says": "Mars's air is mostly carbon dioxide.", "reveal": "Fact. Don't take a deep breath.", "why": "It is {co2}% carbon dioxide. Oxygen is just {o2}%.", "cite": "02-01 F-06", "picture": "gale-vista" }, { "id": "dust-devils", "answer": "fact", "level": 2, "says": "Dust devils on Mars can be taller than Everest.", "reveal": "Fact. Much taller.", "why": "The tallest one photographed was about {dd_km} km high, {dd_ev} times Everest's height, yet only about {dd_w} m wide.", "cite": "02-02 F-25", "picture": "bolivar", "proof": "p-devil-orbit" }, { "id": "sparks", "answer": "fact", "level": 3, "says": "Dust devils on Mars crackle with tiny electric sparks.", "reveal": "Fact. Perseverance heard them.", "why": "Its microphone has recorded {sparks} little snaps inside passing dust devils: static shocks, not lightning.", "cite": "02-02 F-26", "picture": "bolivar", "proof": "p-devil-ground" }, { "id": "dry-ice-snow", "answer": "fact", "level": 3, "says": "Some snow on Mars is made of dry ice.", "reveal": "Fact. The only snow like it known anywhere.", "why": "In the south polar winter, carbon dioxide snow falls. It needs about {dry_ice}°C to form.", "cite": "02-02 F-08", "picture": "ripples" }, { "id": "air-freezes", "answer": "fact", "level": 3, "says": "Every winter, part of Mars's air freezes solid onto its pole.", "reveal": "Fact. The whole planet breathes.", "why": "As much as a third of the carbon dioxide air freezes onto the winter pole, so the atmosphere swells and shrinks by about {atm_swing}% every year.", "cite": "02-02 F-04", "picture": "ripples" }, { "id": "life-found", "answer": "fiction", "level": 1, "says": "Life has been found on Mars.", "reveal": "Fiction, so far.", "why": "Nothing living or fossil has been confirmed. But there are exciting clues, and three missions are on the hunt.", "cite": "02-09 F-01", "picture": "home-plate", "proof": "p-tubes" }, { "id": "methane", "answer": "fiction", "level": 2, "says": "Finding methane gas on Mars proves there is life there.", "reveal": "Fiction. Rocks can make it too.", "why": "Curiosity smells methane that comes and goes with the seasons, but rock and water can make it without any life at all.", "cite": "02-09 F-05", "picture": "sharp-hills" }, { "id": "face", "answer": "fiction", "level": 1, "says": "There is a giant carved face on Mars.", "reveal": "Fiction. It is just a hill.", "why": "The Face on Mars, photographed by Viking in 1976, turned out to be an ordinary hill in sharper photos. Seeing faces in shapes is called pareidolia.", "cite": "F-44", "picture": "murray-butte" }, { "id": "august-moon", "answer": "fiction", "level": 2, "says": "Every August, Mars looks as big as the full Moon.", "reveal": "Fiction. A hoax that keeps coming back.", "why": "The claim has gone round by email since 2003. Even at its closest, Mars is a bright dot: the Moon looks about 70 times wider.", "cite": "F-45", "picture": "blue-sunset" }, { "id": "walked", "answer": "fiction", "level": 1, "says": "People have already walked on Mars.", "reveal": "Fiction. Not yet.", "why": "Every visitor so far has been a robot. Mars is the only planet we know of that is lived on entirely by robots.", "cite": "F-46", "picture": "tracks-west" }, { "id": "rivers", "answer": "fiction", "level": 1, "says": "Rivers flow on Mars today.", "reveal": "Fiction. Long, long ago.", "why": "Mars has no seas, lakes, rivers or rain today: the air is too thin for liquid water to last. Its riverbeds are billions of years old.", "cite": "02-01 F-12", "picture": "gediz-channel" }, { "id": "blue-sky-photo", "answer": "fact", "level": 2, "says": "The first colour photo from Mars's surface showed a blue sky.", "reveal": "Fact, at first.", "why": "Viking 1's first colour picture was released with a blue sky. Once its colours were corrected, the sky turned out dusty butterscotch.", "cite": "02-07 F-01", "picture": "murray-gap", "proof": "p-viking-colour" }, { "id": "helicopter", "answer": "fact", "level": 1, "says": "A helicopter has flown on Mars.", "reveal": "Fact. Ingenuity took off.", "why": "NASA's little Ingenuity helicopter was meant to make a few test hops. It kept flying, dozens of times, for almost three years.", "cite": "02-08 F-13", "picture": "santa-cruz", "proof": "p-ingenuity" }, { "id": "closest", "answer": "fiction", "level": 3, "says": "Mars is the closest planet to Earth, on average.", "reveal": "Fiction. It is Mercury.", "why": "Venus and Mars swing close, then very far away. Mercury never strays far from the Sun, so on average it is nearest to every planet.", "cite": "F-48", "picture": "gale-vista" }, { "id": "faster-spin", "answer": "fact", "level": 3, "says": "Mars's day is getting very slightly shorter.", "reveal": "Fact. Mars is speeding up.", "why": "NASA's InSight lander tracked Mars's spin by radio and found it speeding up, by a tiny fraction of a millisecond each year.", "cite": "F-49", "picture": "sharp-hills" }, { "id": "war-worlds", "answer": "fiction", "level": 2, "says": "The 1938 War of the Worlds radio play caused panic across America.", "reveal": "Fiction, mostly.", "why": "A survey that night found only about 2% of homes were even listening. Newspapers blew up the panic story.", "cite": "F-50", "picture": "mercou-clouds" }, { "id": "gulliver", "answer": "fact", "level": 3, "says": "Gulliver's Travels described Mars's two moons before anyone had seen them.", "reveal": "Fact. A lucky guess.", "why": "Jonathan Swift wrote it in 1726. The moons were found in 1877, more than 150 years later.", "cite": "F-51", "picture": "blue-sunset" }, { "id": "mars-bar", "answer": "fiction", "level": 2, "says": "The Mars bar is named after the planet.", "reveal": "Fiction. It is named after a family.", "why": "Forrest Mars, of the Mars family, first made it in Slough, England, in 1932.", "cite": "F-52", "picture": "murray-layers" }, { "id": "march", "answer": "fact", "level": 1, "says": "The month of March is named after Mars.", "reveal": "Fact. The war god's month.", "why": "March comes from Martius, the month of Mars, the Roman god of war the planet is named after.", "cite": "F-53", "picture": "murray-cliff" }, { "id": "meteorites", "answer": "fact", "level": 2, "says": "Pieces of Mars have landed on Earth.", "reveal": "Fact. About 400 of them.", "why": "Space rocks blasted off Mars by impacts drift here through space. Scientists count about 400 found so far.", "cite": "F-54", "picture": "murray-layers", "proof": "p-alh84001" }, { "id": "friction", "answer": "fiction", "level": 3, "says": "Spacecraft heat up coming into Mars's air because of friction.", "reveal": "Fiction. It is squeezing, not rubbing.", "why": "The heat comes from air squeezed in the shock wave in front of the ship, like a bicycle pump warming as you pump.", "cite": "01-02 F-38", "picture": "gale-vista" }, { "id": "warm-feet", "answer": "fact", "level": 3, "says": "On Mars's equator at noon, your feet could be warm while your head is freezing.", "reveal": "Fact. Bring a hat.", "why": "The thin air holds little heat: NASA says it could feel like {feet_c}°C at your feet and {head_c}°C at your head.", "cite": "02-01 F-22", "picture": "first-drill" }, { "id": "quakes", "answer": "fact", "level": 1, "says": "Mars has earthquakes.", "reveal": "Fact. Marsquakes.", "why": "NASA's InSight lander felt more than 1,300 marsquakes. The biggest kept the planet ringing for hours.", "cite": "F-55", "picture": "murray-butte", "proof": "p-seismometer" }, { "id": "magnetic", "answer": "fiction", "level": 2, "says": "Mars has a magnetic field like Earth's.", "reveal": "Fiction. It lost it long ago.", "why": "Mars lost its global magnetic field billions of years ago. Only patches of magnetised old rock remain.", "cite": "02-01 F-24", "picture": "geology-ahead", "proof": "p-magnet" }, { "id": "land", "answer": "fact", "level": 2, "says": "Mars has about as much dry land as Earth.", "reveal": "Fact. Half the width, the same land.", "why": "Mars is about half as wide as Earth, but with no oceans its ground adds up to almost exactly as much as all Earth's continents.", "cite": "02-01 F-46", "picture": "gale-vista" }, { "id": "instant-call", "answer": "fiction", "level": 1, "says": "A radio message reaches Mars almost instantly.", "reveal": "Fiction. No video calls home.", "why": "Radio travels at the speed of light, but Mars is so far away that a message takes between {lt_min} and {lt_max} minutes to arrive.", "cite": "02-01 F-39", "picture": "blue-sunset" }, { "id": "fear-dread", "answer": "fact", "level": 2, "says": "Mars's two moons are named Fear and Dread.", "reveal": "Fact. Very on brand.", "why": "Phobos and Deimos are the sons of the Greek war god Ares, who rode into battle with him. Mars is the Roman name for Ares.", "cite": "F-56", "picture": "mercou-clouds" }, { "id": "closer-sun", "answer": "fiction", "level": 1, "says": "Mars is closer to the Sun than Earth is.", "reveal": "Fiction. It is further out.", "why": "Mars is about half as far again from the Sun as Earth, and gets only {sun_pct}% of our sunlight.", "cite": "02-01 F-15", "picture": "gale-vista" }, { "id": "blue-day", "answer": "fiction", "level": 2, "says": "The daytime sky on Mars is blue, like ours.", "reveal": "Fiction. It is butterscotch.", "why": "Fine dust colours the Martian sky yellow to orange by day. Only around the setting Sun does it turn blue.", "cite": "02-01 F-16", "picture": "murray-gap" }, { "id": "bigger", "answer": "fiction", "level": 1, "says": "Mars is bigger than Earth.", "reveal": "Fiction. About half as wide.", "why": "Mars is about half as wide as Earth. Only Mercury is a smaller planet.", "cite": "02-01 F-46", "picture": "sharp-hills" }, { "id": "hot-red", "answer": "fiction", "level": 1, "says": "Mars is hot, because it is red.", "reveal": "Fiction. It is freezing.", "why": "Mars averages about {mean_c}°C, as cold as the South Pole in midwinter. The red is rust, not heat.", "cite": "02-01 F-20", "picture": "murray-haze" }, { "id": "phobos-away", "answer": "fiction", "level": 3, "says": "Phobos is drifting away from Mars, just as our Moon is drifting away from Earth.", "reveal": "Fiction. Phobos is falling in.", "why": "Mars's gravity draws Phobos about {phobos_fall} m closer every century. One day it will break apart.", "cite": "02-07 F-12", "picture": "mercou-clouds" }, { "id": "lava-caves", "answer": "fact", "level": 2, "says": "Caves on Mars could be far bigger than any on Earth.", "reveal": "Fact. Low gravity lets giant caves stand.", "why": "Earth's widest lava tubes are about {q_0203_earth_tube_m_1} m across. Mars's may reach about {q_0203_mars_tube_m_1} m.", "cite": "02-03 F-28", "picture": "murray-cliff" }, { "id": "soil-water", "answer": "fact", "level": 2, "says": "Ordinary Martian soil has water locked inside it.", "reveal": "Fact. Bake it and it steams.", "why": "Heat a box of soil 30 cm on each side and about a litre of water comes out.", "cite": "02-03 F-11", "picture": "ripples" }, { "id": "ice-boulders", "answer": "fact", "level": 3, "says": "A space rock that hit Mars in 2021 threw up boulders of ice.", "reveal": "Fact. Ice was hiding just under the dust.", "why": "The crash dug up blocks of buried ice the size of boulders, much nearer the equator than anyone expected.", "cite": "02-03 F-07", "picture": "bagnold-edge", "proof": "p-ice-blocks" }, { "id": "ice-age", "answer": "fiction", "level": 3, "says": "Mars is in an ice age right now.", "reveal": "Fiction. It came out of one.", "why": "Mars's last ice age ended about 400,000 years ago, as its tilt changed.", "cite": "05-20 F-64", "picture": "mercou-clouds" }, { "id": "beach", "answer": "fact", "level": 3, "says": "A rover has found an ancient beach buried under the Martian plains.", "reveal": "Fact. Sand that once met the waves.", "why": "China's Zhurong rover used radar to find sloping beach layers 10 to 35 m underground.", "cite": "05-20 F-65", "picture": "gediz-valley" }, { "id": "leopard", "answer": "fact", "level": 2, "says": "NASA's best clue to ancient life on Mars is a rock with leopard spots.", "reveal": "Fact. The spots are tiny.", "why": "On Earth, spots like these are often left by microbes. Each is about the size of a grain of sand.", "cite": "02-08 F-14", "picture": "home-plate" }, { "id": "first-orbit", "answer": "fact", "level": 2, "says": "The first spacecraft ever to orbit another planet went to Mars.", "reveal": "Fact. Mariner 9, in 1971.", "why": "It arrived during a dust storm that hid the whole planet, waited, and then mapped Mars as the dust cleared.", "cite": "05-20 F-66", "picture": "murray-haze" }, { "id": "skis", "answer": "fact", "level": 3, "says": "The first rover ever sent to Mars was built to move on skis.", "reveal": "Fact. Soviet skis, in 1971.", "why": "It rode on the Mars 3 lander, which fell silent within seconds of landing. Nobody knows if it ever moved.", "cite": "05-20 F-68", "picture": "tracks-west" }, { "id": "morse", "answer": "fact", "level": 2, "says": "Curiosity's wheels print a message in Morse code as it drives.", "reveal": "Fact. It spells JPL.", "why": "The holes in its wheels spell the lab that built it, and the pattern helps engineers measure how far it has gone.", "cite": "05-20 F-69", "picture": "tracks-west" }, { "id": "penny", "answer": "fact", "level": 3, "says": "There is a coin on Mars.", "reveal": "Fact. A 1909 US penny.", "why": "Curiosity carries it on the target its camera uses to check its colours.", "cite": "05-20 F-70", "picture": "first-drill", "proof": "p-selfie" }, { "id": "units", "answer": "fact", "level": 1, "says": "A NASA spacecraft was lost because one team used imperial units and another used metric.", "reveal": "Fact. A very costly mix-up.", "why": "Mars Climate Orbiter skimmed far too low into the air of Mars in 1999 and was lost.", "cite": "05-20 F-71", "picture": "murray-haze" }, { "id": "gravity-film", "answer": "fact", "level": 2, "says": "India's first Mars mission cost less than the film Gravity.", "reveal": "Fact. Mars on a budget.", "why": "India's prime minister made the comparison himself. India was the first Asian nation to reach Mars orbit.", "cite": "05-20 F-72", "picture": "sharp-hills" }, { "id": "blur", "answer": "fact", "level": 3, "says": "A British Mars lander was going to call home with a tune by the band Blur.", "reveal": "Fact. Beagle 2's call sign.", "why": "It landed in 2003 but never called home. Photos found in 2015 showed its solar panels had not all opened.", "cite": "05-20 F-73", "picture": "gale-vista" }, { "id": "spirit-stuck", "answer": "fact", "level": 2, "says": "A Mars rover got stuck in sand and was never freed.", "reveal": "Fact. Spirit's last stop.", "why": "A month of driving in 2010 moved it just 33 cm. It never got free.", "cite": "03-05 F-22", "picture": "husband-hill" }, { "id": "most-crash", "answer": "fiction", "level": 2, "says": "Most spacecraft that try to land on Mars crash.", "reveal": "Fiction, just.", "why": "Ten of the 16 that have tried made it down safely. Landing on Mars is still one of the hardest things in spaceflight.", "cite": "01-02 F-33", "picture": "murray-butte" }, { "id": "named-by-girl", "answer": "fact", "level": 2, "says": "The rovers Spirit and Opportunity were named by a 9-year-old girl.", "reveal": "Fact. She won a contest.", "why": "Children have named Sojourner, Curiosity and Perseverance too.", "cite": "05-20 F-74", "picture": "husband-hill" }, { "id": "china-all", "answer": "fact", "level": 2, "says": "China's first Mars mission orbited, landed and drove a rover all at once.", "reveal": "Fact. A first try, all in one.", "why": "Its rover Zhurong drove 1.9 km across the plain of Utopia.", "cite": "05-20 F-76", "picture": "gediz-valley" }, { "id": "viking-apollo", "answer": "fact", "level": 2, "says": "The first lasting landing on Mars came seven years to the day after the first Moon landing.", "reveal": "Fact. 20 July, twice.", "why": "Apollo 11 landed on the Moon on 20 July 1969. Viking 1 landed on Mars on 20 July 1976.", "cite": "02-04 F-18", "picture": "murray-layers", "proof": "p-viking-colour" }, { "id": "odyssey-film", "answer": "fact", "level": 2, "says": "A spacecraft at Mars is named after the film 2001: A Space Odyssey.", "reveal": "Fact. Mars Odyssey.", "why": "Arthur C. Clarke gave his blessing. Since 2010 it has been the longest-serving spacecraft at Mars.", "cite": "05-20 F-77", "picture": "gale-vista" }, { "id": "sulphur", "answer": "fact", "level": 3, "says": "Curiosity drove over a rock and cracked it open to find yellow crystals inside.", "reveal": "Fact. Pure sulphur.", "why": "It happened in 2024. Scientists had not expected pure sulphur there at all.", "cite": "05-20 F-78", "picture": "first-drill" }, { "id": "heaviest", "answer": "fiction", "level": 1, "says": "People have already landed a ship on Mars heavier than a lorry.", "reveal": "Fiction. No one has landed there yet.", "why": "The heaviest thing ever landed on Mars is the Perseverance rover, about {q_0102_perse_rover_kg} kg: about the weight of a small car.", "cite": "01-02 F-36", "picture": "santa-cruz" }, { "id": "taller", "answer": "fact", "level": 1, "says": "Astronauts grow taller in space.", "reveal": "Fact. By up to about {ff_taller_cm} cm.", "why": "With no weight pressing on it, the spine stretches out. The height goes again a few months after landing.", "cite": "01-02 F-16", "picture": "murray-cliff" }, { "id": "moon-smell", "answer": "fact", "level": 2, "says": "Moon dust smells like burnt gunpowder.", "reveal": "Fact. Every moonwalker noticed.", "why": "All {q_0206_numbers_moonwalkers} people who walked on the Moon smelled it in their cabin. Mars dust will need the same care.", "cite": "02-06 F-21", "picture": "ripples" }, { "id": "flashes", "answer": "fact", "level": 3, "says": "Astronauts see flashes of light even with their eyes shut.", "reveal": "Fact. Cosmic rays.", "why": "Tiny particles from space pass straight through their eyes. A crew going to Mars will see them too.", "cite": "01-02 F-24", "picture": "blue-sunset" }, { "id": "moxie", "answer": "fact", "level": 2, "says": "A machine on Mars has already made oxygen out of the Martian air.", "reveal": "Fact. Its name was MOXIE.", "why": "Riding on Perseverance, it made {q_0203_numbers_moxie_g} g of oxygen in {q_0203_numbers_moxie_runs} runs: a first small step to air and rocket fuel made on Mars.", "cite": "02-03 F-14", "picture": "santa-cruz" }, { "id": "mars-time", "answer": "fact", "level": 3, "says": "People on Earth have lived on Mars time, starting work later every day.", "reveal": "Fact. For 11 weeks.", "why": "A NASA team in 2008 lived by the Mars day, which is about {drift_min} minutes longer than ours, so their working day kept sliding later.", "cite": "02-06 F-30", "picture": "gale-vista" }, { "id": "fire-star", "answer": "fact", "level": 2, "says": "In Chinese, Mars is called the fire star.", "reveal": "Fact. 火星.", "why": "The name is ancient, and it suits the planet's glow in the night sky.", "cite": "05-20 F-80", "picture": "blue-sunset" }, { "id": "tuesday", "answer": "fiction", "level": 3, "says": "The English word Tuesday is named after Mars.", "reveal": "Fiction, almost.", "why": "In French it is mardi and in Spanish martes: Mars's day. English swapped in another war god, Tiw.", "cite": "05-20 F-81", "picture": "murray-layers" }, { "id": "male-sign", "answer": "fact", "level": 2, "says": "The ♂ sign for male began as the war god Mars's shield and spear.", "reveal": "Fact. A shield and a spear.", "why": "The same sign stands for the planet Mars in old star charts.", "cite": "05-20 F-82", "picture": "murray-butte" }, { "id": "kepler", "answer": "fiction", "level": 3, "says": "Johannes Kepler worked out Mars's path round the Sun in the eight days he promised.", "reveal": "Fiction. It took about eight years.", "why": "Mars's stretched orbit kept beating him, until he realised planets move in ovals, not circles.", "cite": "05-20 F-83", "picture": "sharp-hills" }, { "id": "stickney", "answer": "fact", "level": 3, "says": "The biggest crater on Phobos is named after the astronomer's wife.", "reveal": "Fact. Stickney crater.", "why": "Asaph Hall said he might have given up looking for the moons without Angeline Stickney's encouragement.", "cite": "05-20 F-85", "picture": "mercou-clouds", "proof": "p-phobos-close" }, { "id": "pluto-family", "answer": "fact", "level": 3, "says": "The family that named Mars's two moons also named Pluto.", "reveal": "Fact. Two generations apart.", "why": "In 1930 Venetia Burney, aged 11, suggested the name Pluto. Her great-uncle had named Phobos and Deimos.", "cite": "05-20 F-86", "picture": "blue-sunset" }, { "id": "smiley", "answer": "fact", "level": 1, "says": "There is a giant smiley face on Mars.", "reveal": "Fact. Galle crater.", "why": "Hills and frost inside a crater 230 km wide make a perfect grin. It is pure chance, not a message.", "cite": "05-20 F-89", "picture": "sharp-hills", "proof": "p-happy-face" }, { "id": "third", "answer": "fiction", "level": 1, "says": "Mars is the third planet from the Sun.", "reveal": "Fiction. It is the fourth.", "why": "Mercury, Venus and Earth come first. Mars is next, then the giants.", "cite": "05-20 F-91", "picture": "gale-vista" }, { "id": "second-smallest", "answer": "fact", "level": 2, "says": "Mars is the second smallest planet.", "reveal": "Fact. Only Mercury is smaller.", "why": "Mars is about half as wide as Earth.", "cite": "05-20 F-92", "picture": "murray-gap" }, { "id": "nitrogen", "answer": "fact", "level": 2, "says": "The second most common gas in Mars's air is nitrogen.", "reveal": "Fact. A long way second.", "why": "Mars's air is {co2}% carbon dioxide. Nitrogen comes next, the same gas that makes up most of the air we breathe.", "cite": "02-01 F-06", "picture": "murray-haze" }, { "id": "long-cloud", "answer": "fact", "level": 3, "says": "A cloud about {q_0207_clouds_amec_km} km long grows beside a Mars volcano on spring mornings.", "reveal": "Fact. And it is fast.", "why": "It races west at over {q_0207_clouds_amec_kmh} km/h, then fades away within a few hours.", "cite": "02-07 F-34", "picture": "mercou-clouds" }, { "id": "potato-moons", "answer": "fact", "level": 1, "says": "Mars's moons are shaped like potatoes.", "reveal": "Fact. Lumpy, not round.", "why": "Phobos is only about {phobos_km} km long, too small for its own gravity to pull it into a ball.", "cite": "05-20 F-94", "picture": "sharp-hills", "proof": "p-phobos-close" }, { "id": "korolev", "answer": "fact", "level": 2, "says": "There is a crater on Mars full of ice all year round.", "reveal": "Fact. Korolev crater.", "why": "Cold air sinks into the crater and sits over the ice like a lid, keeping it frozen.", "cite": "05-20 F-96", "picture": "bagnold-edge" }, { "id": "sojourner", "answer": "fact", "level": 2, "says": "The first rover to drive on Mars weighed less than a checked suitcase.", "reveal": "Fact. Sojourner, in 1997.", "why": "It weighed about 11 kg. It was planned to last a week and kept going for about 12.", "cite": "05-20 F-98", "picture": "murray-butte" }, { "id": "airbags", "answer": "fact", "level": 2, "says": "Some Mars landers bounced down inside giant airbags.", "reveal": "Fact. Boing.", "why": "Mars Pathfinder bounced across the ground in 1997. Spirit and Opportunity landed the same way.", "cite": "05-20 F-99", "picture": "husband-hill" }, { "id": "robots-only", "answer": "fact", "level": 1, "says": "Mars is the only planet we know of where only robots live.", "reveal": "Fact. A world of robots.", "why": "NASA has two rovers driving there now, with spacecraft circling overhead.", "cite": "05-20 F-101", "picture": "santa-cruz", "proof": "p-selfie" }, { "id": "crops", "answer": "fact", "level": 2, "says": "Scientists have grown food in fake Mars soil.", "reveal": "Fact. Ten crops in 2016.", "why": "They used Earth air and added compost, so it is a first step, not a Martian allotment yet.", "cite": "05-20 F-103", "picture": "ripples" }, { "id": "village-craters", "answer": "fact", "level": 3, "says": "Many small craters on Mars are named after villages on Earth.", "reveal": "Fact. Big ones honour people.", "why": "Bigger craters are named after people who studied or wrote about Mars.", "cite": "05-20 F-105", "picture": "gale-vista" }, { "id": "auction", "answer": "fact", "level": 3, "says": "A rock from Mars sold at auction for about $5 million.", "reveal": "Fact. In 2025.", "why": "It is the biggest piece of Mars ever found on Earth, about 70% bigger than the next.", "cite": "05-20 F-108", "picture": "murray-layers" }, { "id": "eridania", "answer": "fact", "level": 3, "says": "One ancient Mars sea held more water than all its other lakes put together.", "reveal": "Fact. The Eridania sea.", "why": "It covered about {q_0209_eridania_area_million_km2} million square kilometres, about {q_0209_eridania_age_bn} billion years ago.", "cite": "02-09 F-13", "picture": "gediz-channel" }, { "id": "horizon", "answer": "fact", "level": 2, "says": "On Mars, the horizon is closer than on Earth.", "reveal": "Fact. Mars is smaller and curves away faster.", "why": "Stand on flat ground and the edge of the world is only about 3.4 km away: about a 40-minute walk.", "cite": "02-01 F-47", "picture": "bagnold-edge" }, { "id": "feather", "answer": "fiction", "level": 1, "says": "Drop a spanner on Mars and it floats down like a feather.", "reveal": "Fiction. It still falls.", "why": "Mars pulls with {grav_pct}% of Earth's gravity, so things fall more slowly, but a spanner dropped from head height lands in about a second.", "cite": "02-01 F-02", "picture": "murray-cliff" }, { "id": "twilight", "answer": "fact", "level": 3, "says": "Twilight on Mars can last up to {ff_twilight_h} hours after sunset.", "reveal": "Fact. A long, slow fade.", "why": "Dust high in the air keeps catching sunlight long after the Sun has gone.", "cite": "02-07 F-04", "picture": "blue-sunset", "proof": "p-twilight" }, { "id": "short-eclipse", "answer": "fact", "level": 2, "says": "An eclipse of the Sun on Mars lasts less than a minute.", "reveal": "Fact. About {q_0207_phobos_eclipse_s} seconds.", "why": "Phobos is too small to cover the Sun. It takes a potato-shaped bite out of it and hurries on.", "cite": "02-07 F-11", "picture": "blue-sunset", "proof": "p-phobos-eclipse" }, { "id": "spiders", "answer": "fact", "level": 2, "says": "Every spring, giant spider shapes appear near Mars's south pole.", "reveal": "Fact. Carved by gas.", "why": "Gas trapped under dry ice bursts out as the Sun returns and carves branching channels up to 1 km across.", "cite": "05-20 F-63", "picture": "ripples", "proof": "p-spiders" }, { "id": "close-2003", "answer": "fact", "level": 3, "says": "In 2003 Mars came closer to Earth than it had for about 60,000 years.", "reveal": "Fact. A very close pass.", "why": "Mars will not come that close again until 2287.", "cite": "05-20 F-61", "picture": "blue-sunset" }, { "id": "long-stay", "answer": "fact", "level": 3, "says": "One person has stayed in space for more than a year in one go.", "reveal": "Fact. {q_0102_mind_polyakov_days} days.", "why": "Valeri Polyakov flew it to test a Mars-length trip, then walked from his capsule to show a crew could work after landing.", "cite": "01-02 F-23", "picture": "murray-gap" }, { "id": "dozens-rovers", "answer": "fiction", "level": 1, "says": "Dozens of robots are driving on Mars right now.", "reveal": "Fiction. Just two.", "why": "NASA's Curiosity and Perseverance are the rovers still driving.", "cite": "05-20 F-101", "picture": "tracks-west" }, { "id": "mars500", "answer": "fact", "level": 3, "says": "Six men once lived sealed inside a pretend spaceship for {q_0103_days_mars500} days.", "reveal": "Fact. Mars-500, in Moscow.", "why": "It was as long as a real trip to Mars and back. They clashed with mission control far more than with each other.", "cite": "01-03 F-14", "picture": "murray-layers" }, { "id": "night-sky-earth", "answer": "fiction", "level": 2, "says": "From Mars, Earth looks like a big blue ball in the sky.", "reveal": "Fiction. A bright star.", "why": "From Mars, Earth is just a bright blue-white point of light, best seen just after sunset or before sunrise.", "cite": "02-01 F-45", "picture": "blue-sunset" }, { "id": "no-air", "answer": "fiction", "level": 1, "says": "Mars has no air at all.", "reveal": "Fiction. It has a little.", "why": "Mars's air is only about {air_pct}% as thick as Earth's, and almost all of it is carbon dioxide. Thin, but enough to carry dust storms and clouds.", "cite": "02-01 F-04", "picture": "murray-haze" }, { "id": "breathe-warm", "answer": "fiction", "level": 2, "says": "If Mars were warmer, you could breathe its air.", "reveal": "Fiction. Warmth would not help.", "why": "Mars's air is {co2}% carbon dioxide and just {o2}% oxygen. Settlers will make their own air.", "cite": "02-01 F-06", "picture": "gale-vista" }, { "id": "jump-house", "answer": "fiction", "level": 1, "says": "On Mars you could jump over a house.", "reveal": "Fiction. Higher, but not that high.", "why": "Mars pulls with {grav_pct}% of Earth's gravity, so you would jump about {ff_jump_x} times as high as you can here. Impressive, but nowhere near a house.", "cite": "02-01 F-01", "picture": "murray-gap" }, { "id": "black-sky", "answer": "fiction", "level": 1, "says": "The sky on Mars is black, like space.", "reveal": "Fiction. It is butterscotch.", "why": "Fine dust hangs in the air and turns the daytime sky yellow to orange. Only around the setting Sun does it glow blue.", "cite": "02-01 F-16", "picture": "murray-butte", "proof": "p-sunset" }, { "id": "faster-sound", "answer": "fiction", "level": 2, "says": "Sound travels faster on Mars than on Earth.", "reveal": "Fiction. It is slower.", "why": "In Mars's cold, thin air sound crawls along at about {snd_lo} metres a second. On Earth it travels at {snd_e}.", "cite": "02-01 F-10", "picture": "bagnold-edge" }, { "id": "hours-message", "answer": "fiction", "level": 2, "says": "A message from Mars takes hours to reach Earth.", "reveal": "Fiction. Minutes, not hours.", "why": "Radio travels at the speed of light, so a message takes between {lt_min} and {lt_max} minutes, depending on where the two planets are.", "cite": "02-01 F-39", "picture": "blue-sunset" }, { "id": "joystick", "answer": "fiction", "level": 2, "says": "Mars rovers are driven live with a joystick from Earth.", "reveal": "Fiction. The delay is too long.", "why": "Each signal takes {lt_min} to {lt_max} minutes to arrive, so drivers send a plan for the day and the rover carries it out by itself.", "cite": "02-01 F-39", "picture": "tracks-west" }, { "id": "thunder", "answer": "fiction", "level": 2, "says": "Mars has thunderstorms with huge bolts of lightning.", "reveal": "Fiction. Only tiny sparks.", "why": "Perseverance's microphone has heard {sparks} little electric snaps inside dust devils and dust storms. Nothing like a lightning bolt.", "cite": "02-02 F-26", "picture": "bolivar", "proof": "p-devil-ground" }, { "id": "no-clouds", "answer": "fiction", "level": 1, "says": "There are no clouds on Mars.", "reveal": "Fiction. Mars has clouds.", "why": "Most are thin clouds of water ice, floating up to about {ff_cloud_km} km high. Curiosity has even photographed clouds glowing after sunset.", "cite": "02-07 F-31", "picture": "mercou-clouds", "proof": "p-twilight" }, { "id": "storm-century", "answer": "fiction", "level": 3, "says": "A storm that covers the whole of Mars comes only once a century.", "reveal": "Fiction. Far more often.", "why": "A planet-wide dust storm comes about once every {global_every} Mars years, though never on a timetable.", "cite": "02-02 F-13", "picture": "murray-haze" }, { "id": "quick-clear", "answer": "fiction", "level": 2, "says": "After a big dust storm on Mars, the sky clears in a day or two.", "reveal": "Fiction. It takes much longer.", "why": "The fine dust takes weeks to months to settle back out of the air.", "cite": "02-02 F-21", "picture": "murray-haze" }, { "id": "dry-ice-caps", "answer": "fiction", "level": 3, "says": "Mars's polar ice caps are made only of dry ice.", "reveal": "Fiction. There is real water ice.", "why": "The north cap is mostly water ice. Melted and spread over the whole planet, the ice layers under it would make a layer of water about {q_0203_npld_global_m} m deep.", "cite": "02-03 F-12", "picture": "bagnold-edge", "proof": "p-north-cap" }, { "id": "same-halves", "answer": "fiction", "level": 3, "says": "The north and south of Mars look much the same.", "reveal": "Fiction. Mars has two faces.", "why": "The north is low and smooth, {ff_dich_lo} to {ff_dich_hi} km lower than the south, which is high and covered in craters.", "cite": "02-04 F-06", "picture": "sharp-hills" }, { "id": "river-canyon", "answer": "fiction", "level": 2, "says": "Mars's great canyon was carved by a river, like the Grand Canyon.", "reveal": "Fiction. The ground split apart.", "why": "Valles Marineris is mostly a rift: Mars's crust pulled apart as its giant volcanoes grew, then collapse and erosion widened it.", "cite": "02-04 F-30", "picture": "gediz-valley", "proof": "p-valles" }, { "id": "always-dry", "answer": "fiction", "level": 1, "says": "Mars has always been a dry desert.", "reveal": "Fiction. It once had lakes.", "why": "Billions of years ago a river flowed into Jezero crater and filled it with a lake. Perseverance is driving across the old lake bed now.", "cite": "02-08 F-03", "picture": "santa-cruz" }, { "id": "fish-plants", "answer": "fiction", "level": 2, "says": "If anything ever lived on Mars, it was probably fish and plants.", "reveal": "Fiction. Think tiny.", "why": "On Earth, life stayed too small to see for about 3 billion years before the first big animals appeared. That is why scientists hunt Mars for microbes, not fossil fish.", "cite": "02-09 F-23", "picture": "home-plate" }, { "id": "grow-straight", "answer": "fiction", "level": 2, "says": "You could grow food in Martian soil straight away.", "reveal": "Fiction. It needs cleaning first.", "why": "The soil holds perchlorate salts, which harm the thyroid gland. Martian farms will have to get rid of them before anything is eaten.", "cite": "02-01 F-32", "picture": "ripples" }, { "id": "deimos-bigger", "answer": "fiction", "level": 2, "says": "Deimos is the bigger of Mars's two moons.", "reveal": "Fiction. Phobos is bigger.", "why": "Phobos is about {phobos_km} km across. Deimos is only about {deimos_km} km.", "cite": "02-01 F-42", "picture": "mercou-clouds", "proof": "p-phobos" }, { "id": "moon-sized", "answer": "fiction", "level": 1, "says": "Mars's moons are about as big as our Moon.", "reveal": "Fiction. They are tiny.", "why": "Our Moon is about {moon_phobos} times wider than Phobos, the bigger of Mars's two moons.", "cite": "02-01 F-42", "picture": "sharp-hills", "proof": "p-phobos-close" }, { "id": "any-day", "answer": "fiction", "level": 2, "says": "A rocket can set off for Mars on any day of the year.", "reveal": "Fiction. You have to wait for the window.", "why": "Earth and Mars line up for the best trip only about once every {window_mo} months. Miss it and you wait for the next one.", "cite": "01-01 F-15", "picture": "gale-vista" }, { "id": "few-days", "answer": "fiction", "level": 1, "says": "Flying to Mars takes a few days, like going to the Moon.", "reveal": "Fiction. Months, not days.", "why": "With today's rockets the trip takes about {trip_mo} months.", "cite": "01-01 F-15", "picture": "murray-gap" }, { "id": "easy-landing", "answer": "fiction", "level": 3, "says": "Landing on Mars is easy because its air is so thin.", "reveal": "Fiction. The thin air makes it harder.", "why": "The air is thick enough to heat a spacecraft red hot, but too thin for parachutes alone to slow a heavy one down. Rockets have to do the rest.", "cite": "01-02 F-36", "picture": "murray-cliff" }, { "id": "samples-home", "answer": "fiction", "level": 2, "says": "Rocks collected by NASA's Mars rover have already been flown back to Earth.", "reveal": "Fiction. They are still waiting.", "why": "Perseverance has sealed more than 30 rock samples, but the mission to bring them home was cancelled in January 2026. For now they stay on Mars.", "cite": "01-01 F-26", "picture": "first-drill" }, { "id": "all-solar", "answer": "fiction", "level": 2, "says": "Every rover on Mars has run on solar panels.", "reveal": "Fiction. Two run on nuclear power.", "why": "Curiosity and Perseverance carry small nuclear power packs, so dust on the panels and long winters cannot stop them.", "cite": "03-03 F-12", "picture": "geology-ahead", "proof": "p-selfie" }, { "id": "ninety-days", "answer": "fiction", "level": 2, "says": "Opportunity stopped working after the 90 days it was built for.", "reveal": "Fiction. It kept going and going.", "why": "It lasted about {opp_x} times longer than planned, until a planet-wide dust storm blotted out its Sun in 2018.", "cite": "02-02 F-18", "picture": "husband-hill" }, { "id": "one-hop", "answer": "fiction", "level": 1, "says": "NASA's Mars helicopter only managed one short hop.", "reveal": "Fiction. It flew and flew.", "why": "Ingenuity was meant for a few test flights. It flew dozens of times over almost three years.", "cite": "02-08 F-13", "picture": "santa-cruz", "proof": "p-ingenuity" }, { "id": "first-photo-2000s", "answer": "fiction", "level": 2, "says": "The first photos from the ground on Mars were taken this century.", "reveal": "Fiction. It was 1976.", "why": "Viking 1 landed on 20 July 1976 and sent back pictures within minutes.", "cite": "02-04 F-18", "picture": "murray-layers", "proof": "p-viking-colour" }, { "id": "starship-landed", "answer": "fiction", "level": 1, "says": "A SpaceX Starship has already landed on Mars.", "reveal": "Fiction. Not yet.", "why": "Starship is still flying test flights from Texas. No ship has been sent to Mars so far.", "cite": "01-01 F-14", "picture": "gale-vista" }, { "id": "same-distance", "answer": "fiction", "level": 2, "says": "Mars is always the same distance from Earth.", "reveal": "Fiction. It swings near and far.", "why": "The two planets come close about once every {window_mo} months, then drift apart to opposite sides of the Sun. In 2003 Mars came the closest in about 60,000 years.", "cite": "05-20 F-61", "picture": "blue-sunset" }, { "id": "moon-photo", "answer": "fact", "level": 2, "says": "A rover on Mars has photographed Earth and our Moon together.", "reveal": "Fact. Home, from Mars.", "why": "Curiosity caught them as two bright dots in the evening sky, {earth_photo} million km away.", "cite": "02-01 F-45", "picture": "blue-sunset" } ], "lives": 3, "proofs": [ { "id": "p-phobos-eclipse", "nasa": "PIA25179", "crop": [ 0, 0.18, 1, 0.82 ], "caption": "Phobos crossing the Sun, filmed by Perseverance in 2022.", "credit": "Photo: NASA/JPL-Caltech/ASU/MSSS/SSI" }, { "id": "p-phobos", "nasa": "PIA10368", "caption": "Phobos, photographed by Mars Reconnaissance Orbiter in 2008.", "credit": "Photo: NASA/JPL-Caltech/University of Arizona" }, { "id": "p-phobos-close", "nasa": "PIA10369", "caption": "Phobos up close: about the size of a city, and lumpy.", "credit": "Photo: NASA/JPL-Caltech/University of Arizona" }, { "id": "p-phobos-transit", "nasa": "PIA26248", "caption": "Phobos passing in front of the Sun, seen by Perseverance in 2024.", "credit": "Photo: NASA/JPL-Caltech/ASU/MSSS" }, { "id": "p-sunset", "nasa": "PIA19400", "caption": "The Sun setting over Gale crater, seen by Curiosity in 2015.", "credit": "Photo: NASA/JPL-Caltech/MSSS/Texas A&M Univ." }, { "id": "p-ingenuity", "nasa": "PIA25970", "caption": "Ingenuity in the air on its 54th flight, filmed by Perseverance in 2023.", "credit": "Photo: NASA/JPL-Caltech/ASU/MSSS" }, { "id": "p-devil-orbit", "nasa": "PIA23736", "caption": "A dust devil and its long shadow, seen from orbit in 2020.", "credit": "Photo: NASA/JPL-Caltech/University of Arizona" }, { "id": "p-devil-ground", "nasa": "PIA20012", "crop": [ 0, 0.1, 1, 0.75 ], "caption": "A dust devil twisting through the valley below Opportunity, 2016.", "credit": "Photo: NASA/JPL-Caltech" }, { "id": "p-seismometer", "nasa": "PIA22956", "crop": [ 0, 0.2, 1, 0.85 ], "caption": "InSight's quake detector, set down on Mars in 2018.", "credit": "Photo: NASA/JPL-Caltech" }, { "id": "p-alh84001", "nasa": "PIA00289", "caption": "ALH84001, a rock from Mars found in Antarctica in 1984.", "credit": "Photo: NASA/JSC" }, { "id": "p-tubes", "nasa": "PIA00288", "caption": "The tiny tubes found in that rock in 1996. Most scientists now think rock, not life, made them.", "credit": "Photo: NASA/JSC" }, { "id": "p-olympus", "nasa": "PIA02982", "crop": [ 0, 0.05, 1, 0.85 ], "caption": "Olympus Mons from above, by Viking 1 Orbiter in 1978.", "credit": "Photo: NASA/JPL" }, { "id": "p-valles", "nasa": "PIA00003", "crop": [ 0, 0.22, 1, 0.78 ], "caption": "The great canyon across the face of Mars, from 102 Viking pictures.", "credit": "Photo: NASA/JPL/USGS" }, { "id": "p-viking-colour", "nasa": "PIA00563", "crop": [ 0, 0.1, 1, 0.9 ], "caption": "Viking 1's first colour view from the ground, 1976.", "credit": "Photo: NASA/JPL" }, { "id": "p-north-cap", "nasa": "PIA02800", "crop": [ 0, 0.15, 1, 0.8 ], "caption": "Mars's north polar cap in early summer, 1999.", "credit": "Photo: NASA/JPL/MSSS" }, { "id": "p-magnet", "nasa": "PIA02819", "crop": [ 0, 0, 1, 0.8 ], "caption": "The patches of magnetised rock left in Mars's crust, mapped by Mars Global Surveyor.", "credit": "Picture: NASA/GSFC" }, { "id": "p-drill", "nasa": "PIA16726", "caption": "Curiosity's first drill hole, 2013: grey rock under the red dust.", "credit": "Photo: NASA/JPL-Caltech/MSSS" }, { "id": "p-young-ice", "nasa": "PIA26321", "caption": "A fresh crater on Mars, with bright buried ice thrown out around it.", "credit": "Photo: NASA/JPL-Caltech/University of Arizona" }, { "id": "p-ice-blocks", "nasa": "PIA25583", "caption": "The 2021 crater, ringed by boulders of ice.", "credit": "Photo: NASA/JPL-Caltech/University of Arizona" }, { "id": "p-happy-face", "nasa": "PIA02325", "crop": [ 0, 0.06, 1, 0.94 ], "caption": "Galle crater, 230 km wide, nicknamed Happy Face.", "credit": "Photo: NASA/JPL/MSSS" }, { "id": "p-spiders", "nasa": "PIA22587", "caption": "Spring 'spiders' near Mars's south pole, 2018.", "credit": "Photo: NASA/JPL-Caltech/University of Arizona" }, { "id": "p-selfie", "nasa": "PIA24173", "crop": [ 0, 0.2, 1, 0.75 ], "caption": "Curiosity's selfie at Mary Anning, 2020.", "credit": "Photo: NASA/JPL-Caltech/MSSS" }, { "id": "p-twilight", "nasa": "PIA24646", "caption": "Clouds lit up after sunset, seen by Curiosity in 2021.", "credit": "Photo: NASA/JPL-Caltech" } ] }, "mars_quiz": { "words": { "title": "The Mars Quiz", "line": "Seven questions about Mars. Four answers each. Every answer shows you the real thing, to scale.", "daily": "Today's quiz", "daily_n": "Mars Quiz #{n}", "daily_line": "The same seven questions for everyone today.", "random": "Play a random round", "rules": [ { "icon": "seven", "text": "Seven questions" }, { "icon": "four", "text": "Four answers each" }, { "icon": "scale", "text": "The real thing, to scale" } ], "play": "Play today's quiz", "again": "Play a random round", "q_n": "Question {n} of {t}", "right": [ "Spot on.", "Sharp.", "Nailed it.", "Right.", "Exactly.", "Good call." ], "wrong": "Not quite.", "answer_was": "The answer: {a}", "next": "Next question", "finish": "See your score", "did_you_know": "Did you know?", "to_scale": "To scale", "score": "{s} out of {t}", "done_today": "You've played today's quiz", "come_back": "A new quiz every day.", "share": "Share your score", "challenge": "Challenge a friend", "copied": "Copied", "share_text": "Mars Quiz #{n}: {s}/{t}", "share_text_random": "The Mars Quiz: {s}/{t}", "share_line": "Can you beat me?", "beat_banner": "A friend scored {n} out of 7. Can you beat it?", "beat_won": "You beat your friend's {n}.", "home": "Home", "sound": "Sound", "keys": "Keys: 1 to 4 to answer · Enter for the next question", "more_title": "More games", "soon": "Opening soon", "first_day": "2026-10-10", "levels": [ "Easy", "Medium", "Hard" ], "next_quiz": "Next quiz in {t}", "day_streak": "{n} days in a row", "day_streak_one": "Day 1 of your streak", "streak_line": "Play every day to keep it going." }, "ranks": [ { "min": 0, "title": "Tourist", "line": "Mars is a strange place. Have another go." }, { "min": 2, "title": "Space cadet", "line": "You know your way round the red planet." }, { "min": 4, "title": "Mars explorer", "line": "You'd do well on the first ship." }, { "min": 6, "title": "Mission scientist", "line": "NASA would like a word." }, { "min": 7, "title": "Martian", "line": "A perfect round. You must live there." } ], "round": { "easy": 2, "medium": 2, "picture": 1, "hard": 2 }, "questions": [ { "id": "weigh", "level": 1, "picture": "murray-haze", "q": "On Mars, an 80 kg adult would weigh the same as what on Earth?", "options": [ "A {mars_80kg} kg child", "A 60 kg teenager", "An 80 kg adult", "A 5 kg cat" ], "reveal": "You'd weigh about a third as much.", "big": "{grav_pct}%", "big_sub": "of Earth's gravity", "why": "You keep all your muscle and lose almost two thirds of your weight, so every step becomes a small bound.", "cite": "02-01 F-01", "compare": { "kind": "lengths", "unit": "kg", "items": [ [ "Weighing 80 kg on Earth", 80, "earth" ], [ "The same person on Mars", "@mars_80kg", "mars" ] ] } }, { "id": "day", "level": 1, "picture": "gale-vista", "q": "How long is a day on Mars?", "options": [ "{sol_hm}", "12 hours", "37 hours", "6 Earth days" ], "reveal": "Almost exactly like ours.", "big": "{sol_hm}", "big_sub": "one day on Mars", "why": "A Mars clock only falls about {drift_min} minutes a day behind an Earth one. Mission teams on Mars time start work a little later every day.", "cite": "02-01 F-17", "compare": { "kind": "lengths", "unit": "h", "items": [ [ "A day on Earth", 24, "earth" ], [ "A day on Mars", "@sol_h", "mars" ] ] } }, { "id": "birthdays", "level": 2, "picture": "sharp-hills", "q": "You are 40 years old. How many Mars birthdays would you have had?", "options": [ "{mars_bdays}", "10", "40", "80" ], "reveal": "Birthdays come round only about every {year_months} months.", "big": "{mars_bdays}", "big_sub": "Mars birthdays by age 40", "why": "A Mars year lasts {mars_year} Earth days, almost twice as long as ours.", "cite": "02-01 F-18", "compare": { "kind": "lengths", "unit": "days", "items": [ [ "A year on Earth", "@earth_year", "earth" ], [ "A year on Mars", "@mars_year", "mars" ] ] } }, { "id": "land", "level": 2, "picture": "gale-vista", "q": "Mars is only about half as wide as Earth. How does its land compare with all of Earth's dry land?", "options": [ "About the same", "A tenth as much", "Half as much", "Twice as much" ], "reveal": "Half the width, the same land.", "big": "Same", "big_sub": "as all Earth's continents", "why": "Mars has no oceans, so its ground adds up to almost exactly as much as every continent on Earth put together.", "cite": "02-01 F-46" }, { "id": "thin-air", "level": 2, "picture": "murray-gap", "q": "How thick is Mars's air compared with Earth's?", "options": [ "Less than 1%", "About half", "About a tenth", "Twice as thick" ], "reveal": "Thinner than the top of Everest.", "big": "{air_pct}%", "big_sub": "of Earth's air pressure", "why": "That's why even the fiercest Martian storm pushes like a light breeze, and why water can't sit in pools on the ground.", "cite": "02-01 F-04", "compare": { "kind": "lengths", "unit": "Pa", "items": [ [ "Air pressure on Earth", "@earth_pa", "earth" ], [ "Air pressure on Mars", "@mars_pa", "mars" ] ] } }, { "id": "co2", "level": 1, "picture": "gale-vista", "q": "What is Mars's air mostly made of?", "options": [ "Carbon dioxide", "Oxygen", "Nitrogen", "Methane" ], "reveal": "Don't take a deep breath.", "big": "{co2}%", "big_sub": "carbon dioxide", "why": "Oxygen is just {o2}% of Mars's air. Settlers will make their own from ice and from the air itself.", "cite": "02-01 F-06", "compare": { "kind": "lengths", "unit": "% oxygen", "items": [ [ "Oxygen in Earth's air", "@earth_o2", "earth" ], [ "Oxygen in Mars's air", "@o2", "mars" ] ] } }, { "id": "sunset", "level": 1, "picture": "blue-sunset", "q": "What colour is a sunset on Mars?", "options": [ "Blue", "Red", "Green", "Purple" ], "reveal": "The reverse of Earth.", "big": "Blue", "big_sub": "sunsets on Mars", "why": "By day the dusty sky is butterscotch. At sunset fine dust lets blue light through towards the Sun. Curiosity took this very photo.", "cite": "02-01 F-16" }, { "id": "dust-devil", "level": 2, "picture": "bolivar", "q": "The tallest dust devil photographed on Mars was about how high?", "options": [ "20 km", "200 m", "2 km", "200 km" ], "reveal": "Taller than two Everests.", "big": "{dd_km} km", "big_sub": "the tallest Martian dust devil", "why": "Yet it was only about {dd_w} m wide: a thread of dust reaching into the sky.", "cite": "02-02 F-25", "compare": { "kind": "heights", "unit": "km", "items": [ [ "Everest", "@everest_km", "earth" ], [ "Mars's tallest dust devil", "@dd_km", "mars" ] ] } }, { "id": "hear", "level": 2, "picture": "murray-gap", "q": "Standing on Mars, how far away could you still hear a friend talking normally?", "options": [ "About {carry_m} m", "About 65 m", "About 300 m", "About 1 km" ], "reveal": "Stand close.", "big": "{carry_m} m", "big_sub": "how far a voice carries on Mars", "why": "On Earth the same voice carries about {carry_e} m. Two people 5 m apart on Mars would struggle to chat.", "cite": "02-01 F-11", "compare": { "kind": "people", "unit": "m", "items": [ [ "A voice carries on Earth", "@carry_e", "earth" ], [ "A voice carries on Mars", "@carry_m", "mars" ] ] } }, { "id": "two-speeds", "level": 3, "picture": "first-drill", "q": "Perseverance's microphone found something strange about sound on Mars. What?", "options": [ "High notes arrive before low notes", "Sound travels faster than on Earth", "There's no sound at all", "Every sound echoes twice" ], "reveal": "Mars has two speeds of sound.", "big": "2", "big_sub": "speeds of sound on Mars", "why": "High notes travel at about {snd_hi} metres a second, low ones at {snd_lo}. On Earth every note travels at {snd_e}, so on Mars a distant song would reach you high notes first.", "cite": "02-01 F-10" }, { "id": "moons", "level": 1, "picture": "mercou-clouds", "q": "How many moons does Mars have?", "options": [ "2", "0", "1", "4" ], "reveal": "Two little ones.", "big": "2", "big_sub": "Phobos and Deimos", "why": "Phobos is {phobos_km} km across and Deimos {deimos_km} km. Our Moon is {moon_phobos} times wider than Phobos.", "cite": "02-01 F-42", "compare": { "kind": "circles", "unit": "km", "items": [ [ "Our Moon", "@moon_km", "earth" ], [ "Phobos", "@phobos_km", "mars" ], [ "Deimos", "@deimos_km", "mars" ] ] } }, { "id": "backwards", "level": 3, "picture": "mercou-clouds", "q": "Phobos does something our Moon never does. What?", "options": [ "It rises in the west and sets in the east", "It glows in the dark", "It stays still in the sky", "It changes colour every night" ], "reveal": "Phobos runs the wrong way.", "big": "3×", "big_sub": "round Mars every Mars day", "why": "Phobos laps the planet about three times while the ground turns once, so from the surface it crosses the sky backwards.", "cite": "02-07 F-07" }, { "id": "phobos-fate", "level": 3, "picture": "sharp-hills", "q": "What will eventually happen to Phobos?", "options": [ "Mars's gravity will tear it apart", "It will drift away into space", "It will crash into Deimos", "Nothing: it will orbit for ever" ], "reveal": "Phobos is falling.", "big": "{phobos_fall} m", "big_sub": "closer every century", "why": "In {break_lo} to {break_hi} million years it will be pulled apart, and may leave Mars with a ring.", "cite": "02-07 F-12" }, { "id": "sun-size", "level": 3, "picture": "blue-sunset", "q": "From Mars, how big does the Sun look?", "options": [ "About two thirds as wide as from Earth", "Exactly the same", "Twice as wide", "A tiny dot, like a star" ], "reveal": "A bright coin, not a blazing disc.", "big": "{sun_w}%", "big_sub": "as wide as from Earth", "why": "Mars is half as far again from the Sun, so it gets only {sun_pct}% of Earth's sunlight.", "cite": "02-01 F-15", "compare": { "kind": "circles", "unit": "%", "items": [ [ "The Sun from Earth", 100, "earth" ], [ "The Sun from Mars", "@sun_w", "mars" ] ] } }, { "id": "evening-star", "level": 2, "picture": "blue-sunset", "q": "On a Martian evening, which bright 'star' could you see, with a faint dot right beside it?", "options": [ "Earth, with our Moon", "Saturn, with its rings", "Venus, with its moon", "The Pole Star" ], "reveal": "Home, as an evening star.", "big": "{earth_photo}m km", "big_sub": "Curiosity's photo of Earth and the Moon", "why": "Earth is the brightest star in the Martian evening or morning sky, with our Moon a faint dot beside it.", "cite": "02-01 F-45" }, { "id": "aurora", "level": 3, "picture": "mercou-clouds", "q": "In 2024 Perseverance saw something never seen before from another planet's surface. What?", "options": [ "A green aurora", "A rainbow", "A lightning storm", "A tornado of ice" ], "reveal": "Northern lights, Martian style.", "big": "Green", "big_sub": "the colour of Mars's aurora", "why": "It is the same green oxygen glow as Earth's northern lights, spread faintly across the whole sky.", "cite": "02-07 F-26" }, { "id": "olympus", "level": 1, "picture": "sharp-hills", "q": "Olympus Mons, Mars's biggest volcano, is about how many times as tall as Everest?", "options": [ "About 2½", "About 1", "About 5", "About 10" ], "reveal": "The giant of the solar system.", "big": "{oly_ev}×", "big_sub": "the height of Everest", "why": "No volcano anywhere around the Sun is taller.", "cite": "02-01 F-48", "place": "olympus" }, { "id": "olympus-base", "level": 2, "picture": "sharp-hills", "q": "The base of Olympus Mons would cover which country?", "options": [ "Italy", "Belgium", "Iceland", "Australia" ], "reveal": "A volcano the size of a country.", "big": "Italy", "big_sub": "under one volcano", "why": "Its slopes are so gentle that a walker would barely notice the climb.", "cite": "02-01 F-48" }, { "id": "cliff", "level": 2, "picture": "murray-cliff", "q": "How tall is the cliff around the edge of Olympus Mons?", "options": [ "Up to {oly_scarp} km", "8 m", "80 m", "800 m" ], "reveal": "Almost an Everest of sheer rock.", "big": "{oly_scarp} km", "big_sub": "of cliff at its edge", "why": "The mountain's gentle slopes end in a wall taller than most mountains on Earth.", "cite": "02-01 F-49", "compare": { "kind": "heights", "unit": "km", "items": [ [ "Everest", "@everest_km", "earth" ], [ "Olympus Mons's cliff", "@oly_scarp", "mars" ] ] } }, { "id": "valles", "level": 2, "picture": "gediz-valley", "q": "Mars's great canyon, Valles Marineris, is about as long as a trip from...", "options": [ "California to New York", "London to Paris", "One end of Britain to the other", "Round the whole Earth" ], "reveal": "Coast to coast.", "big": "{valles_km} km", "big_sub": "of canyon", "why": "The Grand Canyon would fit in one of its side valleys.", "cite": "02-01 F-51", "compare": { "kind": "lengths", "unit": "km", "items": [ [ "London to New York", "@ldn_ny", "earth" ], [ "Valles Marineris", "@valles_km", "mars" ] ] } }, { "id": "hellas", "level": 3, "picture": "gale-vista", "q": "The floor of Hellas, the deepest crater on Mars, lies how far below the planet's average level?", "options": [ "About {hellas_km} km", "70 m", "700 m", "70 km" ], "reveal": "Deeper than Earth's oceans.", "big": "{hellas_km} km", "big_sub": "down", "why": "The air is thickest down there, the closest Mars gets to holding liquid water.", "cite": "02-01 F-50", "place": "hellas" }, { "id": "water-now", "level": 1, "picture": "gediz-channel", "q": "How much of Mars's surface is covered by liquid water today?", "options": [ "None", "About a tenth", "About a third", "About 70%" ], "reveal": "Not a drop.", "big": "0%", "big_sub": "liquid water on the surface", "why": "The air is too thin for water to last: it boils or freezes. Earth is {earth_water}% water.", "cite": "02-01 F-12", "compare": { "kind": "lengths", "unit": "% covered", "items": [ [ "Earth's surface under water", "@earth_water", "earth" ], [ "Mars's surface under water", 0, "mars" ] ] } }, { "id": "ice", "level": 2, "picture": "gediz-channel", "q": "Buried ice lies under roughly how much of Mars?", "options": [ "About a third", "None of it", "About a hundredth", "All of it" ], "reveal": "Water, hiding underground.", "big": "⅓", "big_sub": "of Mars has ice beneath it", "why": "Roughly one step in three across Mars would be over hidden ice. The first city will drill for it.", "cite": "02-03 F-01" }, { "id": "jezero", "level": 2, "picture": "santa-cruz", "q": "Jezero Crater, where Perseverance landed, once held what?", "options": [ "A lake", "A volcano", "A glacier", "A sea of lava" ], "reveal": "A lake, fed by a river.", "big": "Lake", "big_sub": "Jezero, billions of years ago", "why": "Perseverance is collecting rocks from where an old river once flowed in to send back to Earth.", "cite": "02-08 F-04", "place": "jezero" }, { "id": "grey", "level": 1, "picture": "tracks-west", "q": "Curiosity drilled into a rock on Mars. What colour was the powder that came up?", "options": [ "Grey", "Red", "White", "Black" ], "reveal": "Mars is red skin-deep.", "big": "Grey", "big_sub": "under the rust", "why": "The red is a thin coat of rusty dust. Underneath, the rock is grey.", "cite": "02-03 F-38" }, { "id": "ingenuity", "level": 1, "picture": "santa-cruz", "q": "Ingenuity was the first machine to do what on another planet?", "options": [ "Fly", "Drill a hole", "Swim", "Dig a tunnel" ], "reveal": "A helicopter on Mars.", "big": "Fly", "big_sub": "in air 1% as thick as ours", "why": "Meant for a few test hops, it kept flying for almost three years.", "cite": "02-08 F-13" }, { "id": "radio", "level": 2, "picture": "blue-sunset", "q": "A radio message from Mars takes how long to reach Earth?", "options": [ "{lt_min} to {lt_max} minutes", "Under a second", "{lt_min} to {lt_max} hours", "About a week" ], "reveal": "No video calls home.", "big": "{lt_max} min", "big_sub": "at the farthest", "why": "It depends where the two planets are. A question and its answer can take up to twice as long.", "cite": "02-01 F-39", "compare": { "kind": "lengths", "unit": "min", "items": [ [ "When the planets are closest", "@lt_min", "mars" ], [ "When they are farthest apart", "@lt_max", "mars" ] ] } }, { "id": "conscious", "level": 2, "picture": "murray-cliff", "q": "Without a spacesuit on Mars, how long would you stay conscious?", "options": [ "About {conscious} seconds", "About 2 minutes", "About 10 minutes", "About an hour" ], "reveal": "Barely time to say hello.", "big": "{conscious} s", "big_sub": "before you black out", "why": "About the time oxygen-starved blood takes to travel from your lungs to your brain.", "cite": "02-01 F-08" }, { "id": "radiation", "level": 2, "picture": "gale-vista", "q": "A day on Mars's surface gives you about as much radiation as how many chest X-rays?", "options": [ "About {xrays}", "Less than one", "About 60", "About 600" ], "reveal": "That's why homes are buried.", "big": "{xrays}", "big_sub": "chest X-rays a day", "why": "The thin air and no magnetic field let space radiation through. {cover_m} metres of soil overhead brings it down to Earth-like levels.", "cite": "02-01 F-29" }, { "id": "co2-snow", "level": 3, "picture": "ripples", "q": "What kind of snow falls at Mars's south pole in winter?", "options": [ "Dry ice: frozen carbon dioxide", "Ordinary water snow only", "Frozen methane", "Salt crystals" ], "reveal": "Snow made of air.", "big": "{dry_ice}°C", "big_sub": "to make carbon dioxide snow", "why": "It is the only carbon dioxide snow known anywhere.", "cite": "02-02 F-08" }, { "id": "air-freeze", "level": 3, "picture": "ripples", "q": "Every winter, how much of Mars's air freezes solid onto its pole?", "options": [ "Up to about a third", "None", "About a hundredth", "All of it" ], "reveal": "The planet breathes.", "big": "{atm_swing}%", "big_sub": "swing in air every year", "why": "The whole atmosphere swells and shrinks as the poles freeze and thaw.", "cite": "02-02 F-04" }, { "id": "global-storm", "level": 2, "picture": "murray-haze", "q": "How often does a dust storm wrap around the whole of Mars?", "options": [ "About once every {global_every} Mars years", "Every few days", "Once a century", "Never" ], "reveal": "Planet-wide, now and then.", "big": "{global_every}", "big_sub": "Mars years between global storms, on average", "why": "Never on a schedule, though. The 2018 storm ended the Opportunity rover's mission.", "cite": "02-02 F-13" }, { "id": "cold", "level": 2, "picture": "murray-haze", "q": "Mars's average temperature, about {mean_c}°C, is closest to what?", "options": [ "The South Pole in midwinter", "A London winter", "A home freezer", "A ski slope in the Alps" ], "reveal": "Bring a very warm coat.", "big": "{mean_c}°C", "big_sub": "on average", "why": "That is the average everywhere, all year round. A summer noon on the equator can still feel warm at your feet.", "cite": "02-01 F-20" }, { "id": "mariner4", "level": 2, "picture": "gale-vista", "q": "In 1965 Mariner 4 sent the first close-up photos of Mars. Roughly how long did each photo take to send?", "options": [ "About {m4_h} hours", "About 1 second", "About 1 minute", "About 10 days" ], "reveal": "Slow, but history.", "big": "{m4_h} h", "big_sub": "per photo", "why": "It sent a few bits a second. Staff were so impatient they coloured in the first picture's numbers by hand.", "cite": "01-05 F-17" }, { "id": "seven-minutes", "level": 3, "picture": "santa-cruz", "q": "When Earth first heard that Perseverance had started its 7-minute landing, where was the rover?", "options": [ "Already on the ground", "Still in space", "Halfway down", "Bouncing on airbags" ], "reveal": "It was all over already.", "big": "{perse_min} min", "big_sub": "for the signal to reach Earth", "why": "The landing finished before anyone on Earth knew it had started.", "cite": "01-05 F-03", "compare": { "kind": "lengths", "unit": "min", "items": [ [ "The landing", 7, "mars" ], [ "The signal's trip to Earth", "@perse_min", "earth" ] ] } }, { "id": "opportunity", "level": 2, "picture": "murray-butte", "q": "NASA's Opportunity rover was built to last 90 days. How long did it keep working?", "options": [ "Over 14 years", "91 days", "About a year", "About 5 years" ], "reveal": "The rover that wouldn't quit.", "big": "{opp_x}×", "big_sub": "its planned 90 days", "why": "Its last message came in 2018, as a planet-wide dust storm blotted out the Sun.", "cite": "02-02 F-18", "compare": { "kind": "lengths", "unit": "× planned", "items": [ [ "The life it was built for", 1, "earth" ], [ "The life it really had", "@opp_x", "mars" ] ] } }, { "id": "trip", "level": 1, "picture": "blue-sunset", "q": "Roughly how long does the trip from Earth to Mars take today?", "options": [ "About {trip_mo} months", "About 3 days", "About 7 weeks", "About 7 years" ], "reveal": "Pack for half a year.", "big": "{trip_mo}", "big_sub": "months in space", "why": "Perseverance took just under seven months in 2020 and 2021.", "cite": "01-01 F-16", "compare": { "kind": "lengths", "unit": "months", "items": [ [ "The trip itself", "@trip_mo", "mars" ], [ "The wait between launch windows", "@window_mo", "earth" ] ] } }, { "id": "window", "level": 2, "picture": "blue-sunset", "q": "Earth and Mars line up for the cheapest trip how often?", "options": [ "About every {window_mo} months", "Every month", "Every year", "Every 10 years" ], "reveal": "Like a bus every two years.", "big": "{window_mo}", "big_sub": "months between windows", "why": "Miss the window and you wait more than two years for the next.", "cite": "01-01 F-15", "compare": { "kind": "lengths", "unit": "months", "items": [ [ "The trip itself", "@trip_mo", "mars" ], [ "The wait between launch windows", "@window_mo", "earth" ] ] } }, { "id": "starship", "level": 2, "picture": "gale-vista", "q": "Starship, the rocket SpaceX plans to send to Mars, stands about how tall?", "options": [ "About {ss_h} m", "About 12 m", "About 1.2 km", "About 30 m" ], "reveal": "Taller than Big Ben's tower.", "big": "{ss_h} m", "big_sub": "booster and ship together", "why": "The tallest, most powerful rocket ever flown.", "cite": "01-01 F-01", "compare": { "kind": "towers", "unit": "m", "items": [ [ "Big Ben's tower", "@qz_tower_m", "earth" ], [ "Starship", "@ss_h", "mars" ] ] } }, { "id": "fear-dread", "level": 2, "picture": "mercou-clouds", "q": "What do the names of Mars's moons, Phobos and Deimos, mean?", "options": [ "Fear and Dread", "Night and Day", "Fire and Ice", "Hope and Glory" ], "reveal": "Very on brand.", "big": "Fear", "big_sub": "and Dread", "why": "They are the sons of the Greek war god Ares, who rode into battle with him. Mars is the Roman name for Ares.", "cite": "05-20 F-56" }, { "id": "canali", "level": 2, "picture": "gediz-channel", "q": "In 1877 an Italian astronomer mapped 'canali' on Mars. What did he actually mean?", "options": [ "Natural channels", "Canals built by Martians", "Rivers of lava", "Roads" ], "reveal": "Lost in translation.", "big": "90", "big_sub": "years of Martian canal stories", "why": "English turned canali into 'canals', which sounded built. One translation started generations of stories about Martian engineers.", "cite": "05-20 F-57" }, { "id": "doom", "level": 1, "picture": "murray-layers", "q": "Where does the famous 1993 video game Doom begin?", "options": [ "On Mars's moon Phobos", "On the Moon", "On Venus", "In Atlantis" ], "reveal": "A real moon of Mars.", "big": "Phobos", "big_sub": "where Doom begins", "why": "One of gaming's best-known starting points is a real place you can see from Mars.", "cite": "05-20 F-58" }, { "id": "the-martian", "level": 1, "picture": "wadi-rum", "q": "Which real desert played Mars in the film The Martian?", "options": [ "Wadi Rum, Jordan", "Death Valley, USA", "The Sahara, Egypt", "The Atacama, Chile" ], "reveal": "This very desert.", "big": "Jordan", "big_sub": "stood in for Mars", "why": "Wadi Rum's red sand and towering sandstone made it the obvious choice. This photo was taken there.", "cite": "05-20 F-31" }, { "id": "pcr", "level": 3, "picture": "home-plate", "q": "A microbe found in a Yellowstone hot spring in 1966 made which modern test possible?", "options": [ "The PCR test, used for COVID-19", "The pregnancy test", "Blood typing", "X-rays" ], "reveal": "Hot springs changed medicine.", "big": "PCR", "big_sub": "from a hot-spring microbe", "why": "Something inside it survives boiling, and that made the PCR test work. It won a Nobel Prize. Mars has hot-spring deposits too, like here at Home Plate.", "cite": "02-09 F-29" }, { "id": "bacteria", "level": 2, "picture": "home-plate", "q": "Most bacteria are so small that roughly how many would fit across one human hair?", "options": [ "About 140", "About 2", "About 14,000", "About a million" ], "reveal": "Any life on old Mars was this small.", "big": "140", "big_sub": "bacteria across one hair", "why": "That's why scientists hunt for microbes on Mars, not fossil fish.", "cite": "02-09 F-20" }, { "id": "b002", "level": 2, "picture": "gale-vista", "q": "Drop a spanner from head height on Mars. How long until it hits the ground?", "options": [ "About 1 second", "About half a second", "About 3 seconds", "About 10 seconds" ], "reveal": "About a second on Mars, against about two thirds of a second on Earth.", "big": "", "big_sub": "", "why": "Everything falls as if in slow motion.", "cite": "02-01 F-02", "bank": "QZ-002" }, { "id": "b006", "level": 3, "picture": "sharp-hills", "q": "Stand on flat ground on Mars. How far away is the horizon?", "options": [ "About 3.4 km", "About 1 km", "About 4.7 km", "About 12 km" ], "reveal": "A smaller planet curves away sooner.", "big": "About 3.4 km", "big_sub": "", "why": "The edge of the world is about a 40-minute walk away. On an Earth beach you can see a good deal further.", "cite": "02-01 F-47", "bank": "QZ-006" }, { "id": "b009", "level": 3, "picture": "bolivar", "q": "Is a day on Mars getting longer or shorter?", "options": [ "Shorter: Mars is spinning faster", "Longer: Mars is slowing down", "Neither: it never changes", "Nobody can measure it" ], "reveal": "NASA's InSight lander tracked Mars's spin by radio and found it speeding up very slightly every year, by a fraction of a millisecond.", "big": "", "big_sub": "", "why": "", "cite": "05-20 F-59", "bank": "QZ-009" }, { "id": "b010", "level": 2, "picture": "gale-vista", "q": "On average over the years, which planet is closest to Earth?", "options": [ "Mercury", "Mars", "Venus", "Jupiter" ], "reveal": "A trick question.", "big": "Mercury", "big_sub": "", "why": "Venus and Mars swing very close, then very far away. Mercury never strays far from the Sun, so on average it is nearest to every planet, Earth included.", "cite": "05-20 F-60", "bank": "QZ-010" }, { "id": "b011", "level": 3, "picture": "sharp-hills", "q": "In August 2003 Mars came closer to Earth than it had for how long?", "options": [ "About 60,000 years", "About 100 years", "About 1,000 years", "About 1 million years" ], "reveal": "It came within 55.8 million km, the closest in about 59,600 years.", "big": "", "big_sub": "", "why": "Mars will not come that close again until 2287.", "cite": "05-20 F-61", "bank": "QZ-011" }, { "id": "b012", "level": 2, "picture": "bolivar", "q": "Mars has quakes too. For how long did the biggest one NASA's InSight lander ever felt keep Mars shaking?", "options": [ "Hours", "A split second", "About a minute", "A whole year" ], "reveal": "InSight heard 1,319 marsquakes.", "big": "Hours", "big_sub": "", "why": "The biggest, magnitude 4.7 on 4 May 2022, kept the planet ringing for hours.", "cite": "05-20 F-62", "bank": "QZ-012" }, { "id": "b029", "level": 2, "picture": "murray-haze", "q": "What has Perseverance's microphone heard crackling inside Martian dust devils?", "options": [ "Tiny electric sparks", "Thunder", "Hailstones", "Nothing at all" ], "reveal": "{q_0202_sparks_0} small discharges since 2021: the snap of a static shock, not lightning.", "big": "", "big_sub": "", "why": "", "cite": "02-02 F-26", "bank": "QZ-029" }, { "id": "b031", "level": 2, "picture": "bolivar", "q": "What carves giant 'spiders', up to 1 km across, into the ground near Mars's south pole each spring?", "options": [ "Jets of gas bursting through dry ice", "Real giant spiders", "Meteorites", "Underground rivers" ], "reveal": "Sunlight shines through clear sheets of dry ice and warms the dark ground underneath.", "big": "", "big_sub": "", "why": "Trapped gas bursts out and carves branching channels. NASA recreated them in a lab in 2024.", "cite": "05-20 F-63", "bank": "QZ-031" }, { "id": "b048", "level": 3, "picture": "blue-sunset", "q": "When Phobos passes in front of the Sun, how long does the eclipse last?", "options": [ "About {q_0207_phobos_eclipse_s} seconds", "About 2 hours", "About 10 minutes", "About 2 seconds" ], "reveal": "Perseverance filmed one in 2022.", "big": "", "big_sub": "", "why": "Phobos is too small to cover the Sun: it looks like a potato-shaped bite.", "cite": "02-07 F-11", "bank": "QZ-048" }, { "id": "b049", "level": 3, "picture": "mercou-clouds", "q": "Is there a North Star on Mars?", "options": [ "No: there is no bright star at Mars's north pole", "Yes, Polaris, the same as ours", "Yes, Earth", "Yes, the Sun at midnight" ], "reveal": "Mars's north pole points at Cygnus, the Swan.", "big": "", "big_sub": "", "why": "The nearest bright star, Deneb, is about 9° away.", "cite": "02-07 F-22", "bank": "QZ-049" }, { "id": "b050", "level": 3, "picture": "blue-sunset", "q": "After sunset on Mars, how long can the twilight glow linger?", "options": [ "Up to about 2 hours", "It goes dark instantly", "About 10 minutes", "All night" ], "reveal": "Dust high in the air scatters sunlight round to the night side.", "big": "", "big_sub": "", "why": "", "cite": "02-07 F-04", "bank": "QZ-050" }, { "id": "b066", "level": 3, "picture": "sharp-hills", "q": "Mars is split in two. What is different about its two halves?", "options": [ "The north is low and smooth, the south is high and cratered", "The east is hot, the west is frozen", "One half always faces the Sun", "The north is red, the south is blue" ], "reveal": "The northern lowlands, about a third of Mars, sit 1 to 3 km lower than the southern highlands.", "big": "", "big_sub": "", "why": "Some scientists think an ocean once filled them.", "cite": "02-04 F-06", "bank": "QZ-066" }, { "id": "b067", "level": 3, "picture": "gediz-valley", "q": "Lava tubes on Mars could be up to how much bigger than Earth's?", "options": [ "About 80 times", "Exactly the same", "Twice", "A million times" ], "reveal": "Earth's are usually {q_0203_earth_tube_m_0} to {q_0203_earth_tube_m_1} m across.", "big": "", "big_sub": "", "why": "Mars's may reach about {q_0203_mars_tube_m_1} m wide, because low gravity lets bigger caves stand.", "cite": "02-03 F-28", "bank": "QZ-067", "compare": { "kind": "lengths", "unit": "m", "items": [ [ "Earth's widest lava tubes", "@q_0203_earth_tube_m_1", "earth" ], [ "Mars's may reach", "@q_0203_mars_tube_m_1", "mars" ] ] } }, { "id": "b068", "level": 3, "picture": "murray-butte", "q": "Noctis Labyrinthus, a maze of canyons on Mars, means what in Latin?", "options": [ "Labyrinth of the night", "Valley of kings", "River of fire", "Maze of the dead" ], "reveal": "About {q_0204_canyon_noctis_km} km across: roughly London to Madrid.", "big": "", "big_sub": "", "why": "", "cite": "02-04 F-19", "bank": "QZ-068", "compare": { "kind": "lengths", "unit": "km", "items": [ [ "London to New York", "@ldn_ny", "earth" ], [ "Noctis Labyrinthus", "@q_0204_canyon_noctis_km", "mars" ] ] } }, { "id": "b069", "level": 3, "picture": "sharp-hills", "q": "Ophir Chasma, part of Mars's great canyon, is named after...", "options": [ "The land of King Solomon's gold", "A Roman emperor", "An astronaut", "A Greek sea monster" ], "reveal": "About {q_0204_canyon_ophir_km} km long, a little shorter than London to Paris.", "big": "", "big_sub": "", "why": "", "cite": "02-04 F-24", "bank": "QZ-069", "compare": { "kind": "lengths", "unit": "km", "items": [ [ "London to New York", "@ldn_ny", "earth" ], [ "Ophir Chasma", "@q_0204_canyon_ophir_km", "mars" ] ] } }, { "id": "b082", "level": 2, "picture": "gediz-channel", "q": "Heat a box of ordinary Martian soil, 30 cm on each side. How much water comes out?", "options": [ "About a litre", "None", "A teaspoon", "A bathful" ], "reveal": "About 2% of the soil is water.", "big": "", "big_sub": "", "why": "NASA's Laurie Leshin put it as 'two pints' per cubic foot.", "cite": "02-03 F-11", "bank": "QZ-082" }, { "id": "b084", "level": 3, "picture": "santa-cruz", "q": "If the buried ice layers under Mars's north pole melted, how deep would the water be, spread over the whole planet?", "options": [ "About up to your shoulders", "Ankle deep", "Over a house", "Deeper than Everest" ], "reveal": "At least {q_0203_npld_global_m} m deep, all over Mars.", "big": "", "big_sub": "", "why": "And that is only the third-largest water store.", "cite": "02-03 F-12", "bank": "QZ-084", "compare": { "kind": "wade", "unit": "m", "items": [ [ "A person", "@q_0102_body_taller_m", "earth" ], [ "Water from the north pole's ice", "@q_0203_npld_global_m", "mars" ] ] } }, { "id": "b086", "level": 3, "picture": "gediz-valley", "q": "In 2021 a space rock smashed into Mars. What did it throw up?", "options": [ "Boulders of ice", "Liquid water", "Gold", "Lava" ], "reveal": "It left a crater {q_0203_numbers_ce_width_m} m wide and showed ice much closer to the equator than anyone had seen it before.", "big": "", "big_sub": "", "why": "", "cite": "02-03 F-07", "bank": "QZ-086" }, { "id": "b087", "level": 2, "picture": "gediz-channel", "q": "Is Mars in an ice age right now?", "options": [ "No: it came out of one about 400,000 years ago", "Yes, the deepest ever", "It has never had one", "It is one big ice ball" ], "reveal": "Mars's last ice age ran from about 2.1 million to 400,000 years ago, when ice spread about a third of the way to its equator.", "big": "", "big_sub": "", "why": "", "cite": "05-20 F-64", "bank": "QZ-087" }, { "id": "b088", "level": 3, "picture": "santa-cruz", "q": "China's Zhurong rover found what buried 10 to 35 m under the Martian plains?", "options": [ "An ancient beach", "A frozen lake", "A cave", "A meteorite" ], "reveal": "Its radar found layers sloping like sand on a seashore, about 3 billion years old: one of the strongest signs of an old northern ocean.", "big": "", "big_sub": "", "why": "", "cite": "05-20 F-65", "bank": "QZ-088" }, { "id": "b101", "level": 2, "picture": "home-plate", "q": "NASA's best candidate yet for signs of ancient life on Mars is a rock with markings like what?", "options": [ "Leopard spots", "Tiger stripes", "Fingerprints", "Footprints" ], "reveal": "Perseverance found Cheyava Falls in 2024.", "big": "", "big_sub": "", "why": "On Earth, spots like these are often left by microbes. Each is about the size of a grain of sand.", "cite": "02-08 F-14", "bank": "QZ-101" }, { "id": "b102", "level": 2, "picture": "santa-cruz", "q": "Mars's ancient Eridania sea held how much water?", "options": [ "More than all its other lakes put together", "A puddle's worth", "Exactly as much as Lake Jezero", "More than all of Earth's oceans" ], "reveal": "It covered about {q_0209_eridania_area_million_km2} million km², roughly the area of Egypt, with hot water venting through its floor {q_0209_eridania_age_bn} billion years ago.", "big": "", "big_sub": "", "why": "", "cite": "02-09 F-13", "bank": "QZ-102" }, { "id": "b104", "level": 3, "picture": "home-plate", "q": "On Earth, how long after the first life did the first big animals appear?", "options": [ "About 3 billion years", "About 1 million years", "About 100 years", "About 10,000 years" ], "reveal": "About 2.9 billion years.", "big": "", "big_sub": "", "why": "That is why we look for microbes on Mars, not fossil fish.", "cite": "02-09 F-23", "bank": "QZ-104" }, { "id": "b105", "level": 2, "picture": "santa-cruz", "q": "In 1977 a submarine found life thriving where sunlight never reaches. Where?", "options": [ "Around hot vents on the deep sea floor", "Inside a volcano", "Under Antarctic ice", "In a cave on the Moon" ], "reveal": "It overturned the idea that all life needs the Sun, and gave us one of the best places to look on Mars.", "big": "", "big_sub": "", "why": "", "cite": "02-09 F-26", "bank": "QZ-105" }, { "id": "b106", "level": 3, "picture": "home-plate", "q": "Lake Hillier in Australia is bubble-gum pink. Why?", "options": [ "Tiny salt-loving microbes", "Pink sand", "Dye from a factory", "Reflected sunset" ], "reveal": "Microbes like these may once have lived in Mars's last salty pools as its lakes dried up.", "big": "", "big_sub": "", "why": "", "cite": "02-09 F-36", "bank": "QZ-106" }, { "id": "b121", "level": 2, "picture": "first-drill", "q": "Which was the first spacecraft ever to orbit another planet?", "options": [ "Mariner 9, at Mars in 1971", "Voyager 1, at Jupiter", "Sputnik, at Venus", "Apollo 8, at Mars" ], "reveal": "It arrived during a planet-wide dust storm, waited for it to clear, then mapped 85% of Mars.", "big": "", "big_sub": "", "why": "", "cite": "05-20 F-66", "bank": "QZ-121" }, { "id": "b122", "level": 3, "picture": "tracks-west", "q": "What was the first object from Earth to touch the surface of Mars?", "options": [ "A Soviet lander that crashed, in 1971", "NASA's Viking 1", "Britain's Beagle 2", "A meteorite from Earth" ], "reveal": "Mars 2 crashed on 27 November 1971.", "big": "", "big_sub": "", "why": "Days later Mars 3 landed, then fell silent within seconds.", "cite": "05-20 F-67", "bank": "QZ-122" }, { "id": "b123", "level": 3, "picture": "santa-cruz", "q": "The first Mars rover ever, sent by the Soviet Union in 1971, was designed to move on what?", "options": [ "Skis", "Legs", "Tank tracks", "A tiny hovercraft cushion" ], "reveal": "PrOP-M weighed 4.5 kg and was meant to ski along on a 15 m cable.", "big": "Skis", "big_sub": "", "why": "Nobody knows if it ever got the chance.", "cite": "05-20 F-68", "bank": "QZ-123" }, { "id": "b126", "level": 2, "picture": "husband-hill", "q": "Which rover ran the first marathon on another world?", "options": [ "Opportunity", "Curiosity", "Sojourner", "Zhurong" ], "reveal": "{q_0305_opportunity_km} km, finished in March 2015 after {q_0305_opportunity_years} years: about 10 m a day.", "big": "Opportunity", "big_sub": "", "why": "", "cite": "03-05 F-23", "bank": "QZ-126" }, { "id": "b127", "level": 2, "picture": "first-drill", "q": "Curiosity's wheels print a secret message in Morse code in every track. What does it say?", "options": [ "JPL", "HELLO", "SOS", "MARS" ], "reveal": "The letters of NASA's Jet Propulsion Laboratory.", "big": "JPL", "big_sub": "", "why": "The pattern also helps engineers measure how far it has driven.", "cite": "05-20 F-69", "bank": "QZ-127" }, { "id": "b128", "level": 3, "picture": "tracks-west", "q": "Which coin is fixed to the Curiosity rover on Mars?", "options": [ "A 1909 US penny", "A gold sovereign", "A Roman denarius", "A 2012 euro" ], "reveal": "Geologists often put a coin in their photos for scale.", "big": "", "big_sub": "", "why": "Curiosity carries one on its camera calibration target.", "cite": "05-20 F-70", "bank": "QZ-128" }, { "id": "b129", "level": 1, "picture": "santa-cruz", "q": "NASA's Mars Climate Orbiter was lost in 1999. What went wrong?", "options": [ "One team used imperial units, another used metric", "It was hit by a meteor", "Martians shot it down", "It ran out of fuel" ], "reveal": "One piece of software worked in pound-force, another expected newtons.", "big": "", "big_sub": "", "why": "The $327.6 million craft skimmed far too low into Mars's air.", "cite": "05-20 F-71", "bank": "QZ-129" }, { "id": "b130", "level": 2, "picture": "husband-hill", "q": "India's first Mars mission, in 2014, famously cost less than what?", "options": [ "The Hollywood film Gravity", "A new car", "A London flat", "The Olympics opening ceremony" ], "reveal": "About $73 million.", "big": "", "big_sub": "", "why": "India's prime minister made the comparison himself. India was the first Asian nation to reach Mars orbit.", "cite": "05-20 F-72", "bank": "QZ-130" }, { "id": "b131", "level": 2, "picture": "first-drill", "q": "Britain's Beagle 2 lander was going to announce its arrival with a call sign written by which band?", "options": [ "Blur", "Oasis", "Coldplay", "The Beatles" ], "reveal": "Its camera test chart was painted by Damien Hirst.", "big": "Blur", "big_sub": "", "why": "It landed in 2003 but never called home: photos found in 2015 showed its solar panels had not all opened.", "cite": "05-20 F-73", "bank": "QZ-131" }, { "id": "b132", "level": 3, "picture": "tracks-west", "q": "What finally trapped the Spirit rover?", "options": [ "Soft sand under a crust", "A Martian ice storm", "A rockfall", "A broken radio" ], "reveal": "It broke through a crust in 2009.", "big": "", "big_sub": "", "why": "A month of driving in 2010 moved it just 33 cm. It never got free.", "cite": "03-05 F-22", "bank": "QZ-132" }, { "id": "b133", "level": 2, "picture": "santa-cruz", "q": "How many of the 16 spacecraft that have tried to land on Mars succeeded?", "options": [ "10", "2", "8", "16" ], "reveal": "About 38% of attempts have failed.", "big": "10", "big_sub": "", "why": "Landing on Mars is still one of the hardest things in spaceflight.", "cite": "01-02 F-33", "bank": "QZ-133" }, { "id": "b134", "level": 2, "picture": "husband-hill", "q": "Who named the rovers Spirit and Opportunity?", "options": [ "A 9-year-old girl", "NASA's director", "A famous author", "A computer" ], "reveal": "Sofi Collis won NASA's naming contest in 2003.", "big": "", "big_sub": "", "why": "Children have named Sojourner, Curiosity and Perseverance too.", "cite": "05-20 F-74", "bank": "QZ-134" }, { "id": "b135", "level": 3, "picture": "first-drill", "q": "Perseverance carried a rock from London to Mars. What was it?", "options": [ "A meteorite that had come from Mars", "A piece of Stonehenge", "A brick from Big Ben", "A fossil from the Jurassic Coast" ], "reveal": "A slice of the Sayh al Uhaymir 008 meteorite, loaned by the Natural History Museum, used to check one of its instruments.", "big": "", "big_sub": "", "why": "A Mars rock, home again.", "cite": "05-20 F-75", "bank": "QZ-135" }, { "id": "b136", "level": 3, "picture": "tracks-west", "q": "Which country's very first Mars mission managed to orbit, land and drive a rover all at once?", "options": [ "China", "USA", "Russia", "India" ], "reveal": "Tianwen-1 landed in May 2021.", "big": "China", "big_sub": "", "why": "Its rover Zhurong drove 1.9 km.", "cite": "05-20 F-76", "bank": "QZ-136" }, { "id": "b137", "level": 2, "picture": "santa-cruz", "q": "Viking 1 landed on Mars on 20 July 1976. What happened on 20 July seven years earlier?", "options": [ "Apollo 11 landed on the Moon", "Sputnik launched", "The first man went to space", "Pluto was discovered" ], "reveal": "The first long-lived Mars lander touched down on the Moon landing's anniversary.", "big": "", "big_sub": "", "why": "", "cite": "02-04 F-18", "bank": "QZ-137" }, { "id": "b138", "level": 3, "picture": "husband-hill", "q": "NASA's Mars Odyssey orbiter, still working after 25 years, is named after which film?", "options": [ "2001: A Space Odyssey", "The Martian", "Star Wars", "Apollo 13" ], "reveal": "Arthur C.", "big": "", "big_sub": "", "why": "Clarke gave his blessing. Since 2010 it has been the longest-serving spacecraft at Mars.", "cite": "05-20 F-77", "bank": "QZ-138" }, { "id": "b139", "level": 3, "picture": "first-drill", "q": "In 2024 Curiosity drove over a rock and cracked it open. What was inside?", "options": [ "Pure yellow sulphur crystals", "Liquid water", "A fossil", "Diamonds" ], "reveal": "The first pure sulphur ever found on Mars.", "big": "", "big_sub": "", "why": "Scientists had not expected it there at all.", "cite": "05-20 F-78", "bank": "QZ-139" }, { "id": "b140", "level": 3, "picture": "tracks-west", "q": "Curiosity was planned to work for one Mars year. In August 2026 it reached which milestone?", "options": [ "5,000 days on Mars", "100 days on Mars", "Its return to Earth", "The top of Olympus Mons" ], "reveal": "Fourteen years after landing, and still climbing Mount Sharp.", "big": "", "big_sub": "", "why": "", "cite": "05-20 F-79", "bank": "QZ-140" }, { "id": "b154", "level": 3, "picture": "gale-vista", "q": "How fast was Perseverance going when it hit the top of Mars's air?", "options": [ "About {q_0102_perse_entry_kmh} km/h", "About 200 km/h", "About 1,950 km/h", "About 195,000 km/h" ], "reveal": "Its heat shield reached about {q_0102_perse_peak_c}°C.", "big": "", "big_sub": "", "why": "Seven minutes later a sky crane lowered it gently onto the ground on cables.", "cite": "01-02 F-27", "bank": "QZ-154" }, { "id": "b156", "level": 3, "picture": "gale-vista", "q": "What is the heaviest thing ever landed on Mars?", "options": [ "The Perseverance rover", "A crashed Soviet probe", "An astronaut's boot", "A Starship" ], "reveal": "About {q_0102_perse_rover_kg} kg, the weight of a small car.", "big": "", "big_sub": "", "why": "A crewed ship would be many times heavier.", "cite": "01-02 F-36", "bank": "QZ-156" }, { "id": "b157", "level": 2, "picture": "gale-vista", "q": "How many people applied to join NASA's astronaut class of 2017?", "options": [ "More than 18,000, for {q_0103_y2017_selected} places", "About 50", "About 500", "About 2 million" ], "reveal": "A record.", "big": "", "big_sub": "", "why": "About 55 times harder to get into than Harvard.", "cite": "01-03 F-03", "bank": "QZ-157" }, { "id": "b158", "level": 3, "picture": "gale-vista", "q": "In the Mars-500 experiment, six men lived sealed in a mock spaceship in Moscow for how long?", "options": [ "{q_0103_days_mars500} days", "5 days", "52 days", "5 years" ], "reveal": "The length of a real Mars trip.", "big": "{q_0103_days_mars500} days", "big_sub": "", "why": "They had {q_0103_mars500_control_conflicts} clashes with mission control, and only 8 with each other.", "cite": "01-03 F-14", "bank": "QZ-158", "compare": { "kind": "lengths", "unit": "days", "items": [ [ "Mars-500, sealed in Moscow", "@q_0103_days_mars500", "earth" ], [ "Polyakov's year in space", "@q_0102_mind_polyakov_days", "earth" ], [ "One year on Mars", "@mars_year", "mars" ] ] } }, { "id": "b172", "level": 2, "picture": "murray-cliff", "q": "Astronauts get taller in space. By up to how much?", "options": [ "About 5 cm", "About 5 mm", "About 50 cm", "They shrink" ], "reveal": "Without gravity squeezing the spine, a {q_0102_body_taller_m} m person can grow up to 3%.", "big": "About 5 cm", "big_sub": "", "why": "It goes again a few months after landing.", "cite": "01-02 F-16", "bank": "QZ-172" }, { "id": "b173", "level": 3, "picture": "murray-gap", "q": "In weightlessness, an astronaut's hip bone loses about as much in one month as an older person on Earth loses in...", "options": [ "Over a year", "A day", "A week", "Ten years" ], "reveal": "About {q_0206_numbers_esa_hip_pct_month}% a month, roughly ten times the rate of osteoporosis.", "big": "Over a year", "big_sub": "", "why": "That is why crews exercise 2 hours a day.", "cite": "02-06 F-11", "bank": "QZ-173" }, { "id": "b174", "level": 3, "picture": "murray-cliff", "q": "All {q_0206_numbers_moonwalkers} people who walked on the Moon noticed the dust smelled like what?", "options": [ "Burnt gunpowder", "Strawberries", "Wet dog", "Nothing at all" ], "reveal": "They also sneezed: 'lunar hay fever'.", "big": "", "big_sub": "", "why": "Mars dust will need the same care, and NASA set its first Mars dust limit in 2026.", "cite": "02-06 F-21", "bank": "QZ-174" }, { "id": "b175", "level": 3, "picture": "murray-gap", "q": "Apollo astronauts saw flashes of light even with their eyes closed. What caused them?", "options": [ "Cosmic rays passing through their eyes", "Tiredness", "The Sun through their eyelids", "Moon dust" ], "reveal": "Radiation made visible: about one flash every {q_0102_mind_flash_min} minutes in the dark.", "big": "", "big_sub": "", "why": "", "cite": "01-02 F-24", "bank": "QZ-175" }, { "id": "b176", "level": 2, "picture": "murray-cliff", "q": "NASA's MOXIE machine made oxygen from Mars's air. How much did it make, compared with a dog?", "options": [ "What a small dog breathes in about 10 hours", "Enough for a city", "Not a single breath", "Enough for an elephant for a year" ], "reveal": "{q_0203_numbers_moxie_g} g over {q_0203_numbers_moxie_runs} runs, from 2021 to 2023: small, but proof that you can make air on Mars.", "big": "", "big_sub": "", "why": "", "cite": "02-03 F-14", "bank": "QZ-176" }, { "id": "b177", "level": 3, "picture": "murray-gap", "q": "In 2008 a NASA team lived on Mars time for {q_0206_phoenix_weeks} weeks. What did that mean for their working day?", "options": [ "It started about 40 minutes later every day", "They never slept", "They worked only at night", "Nothing changed" ], "reveal": "Their shift went right round the clock about every 36 days.", "big": "", "big_sub": "", "why": "With blue-light lamps most kept in step.", "cite": "02-06 F-30", "bank": "QZ-177" }, { "id": "b178", "level": 3, "picture": "murray-cliff", "q": "Who holds the record for the longest single stay in space, flown to test a Mars-length trip?", "options": [ "Valeri Polyakov, {q_0102_mind_polyakov_days} days", "Neil Armstrong, 21 days", "Tim Peake, 186 days", "Scott Kelly, 340 days" ], "reveal": "On Mir, 1994 to 1995.", "big": "", "big_sub": "", "why": "At the end he walked from his capsule to prove a crew could work after landing on Mars.", "cite": "01-02 F-23", "bank": "QZ-178", "compare": { "kind": "lengths", "unit": "days", "items": [ [ "Polyakov's year in space", "@q_0102_mind_polyakov_days", "earth" ], [ "Mars-500, sealed in Moscow", "@q_0103_days_mars500", "earth" ], [ "One year on Mars", "@mars_year", "mars" ] ] } }, { "id": "b190", "level": 1, "picture": "gale-vista", "q": "The Chinese name for Mars, 火星, means what?", "options": [ "Fire star", "Red king", "War moon", "Blood planet" ], "reveal": "Many cultures named it for its colour: Egypt called it 'the Red Horus', and Babylon named it after its god of fire and war.", "big": "Fire star", "big_sub": "", "why": "", "cite": "05-20 F-80", "bank": "QZ-190" }, { "id": "b191", "level": 2, "picture": "gale-vista", "q": "Which month and which day of the week are named after Mars?", "options": [ "March and Tuesday", "May and Monday", "August and Friday", "January and Sunday" ], "reveal": "March comes from Martius.", "big": "", "big_sub": "", "why": "Tuesday is mardi in French and martes in Spanish: Mars's day. English swapped in another war god, Tiw.", "cite": "05-20 F-81", "bank": "QZ-191" }, { "id": "b192", "level": 2, "picture": "gale-vista", "q": "The ♂ symbol used for 'male' started life as what?", "options": [ "The war god Mars's shield and spear", "An arrow for hunting", "A key", "A compass" ], "reveal": "Alchemists also used it for iron, which happens to be what makes Mars red.", "big": "", "big_sub": "", "why": "", "cite": "05-20 F-82", "bank": "QZ-192" }, { "id": "b193", "level": 3, "picture": "gale-vista", "q": "Johannes Kepler boasted he would work out Mars's orbit in 8 days. How long did it really take?", "options": [ "About 8 years", "8 hours", "8 weeks", "He never managed it" ], "reveal": "Worth it: Mars showed him that planets travel in ellipses, not circles, one of the great discoveries in science.", "big": "", "big_sub": "", "why": "", "cite": "05-20 F-83", "bank": "QZ-193" }, { "id": "b194", "level": 2, "picture": "gale-vista", "q": "Which novel described Mars's two moons 151 years before anyone saw them?", "options": [ "Gulliver's Travels", "The War of the Worlds", "Frankenstein", "Robinson Crusoe" ], "reveal": "Jonathan Swift wrote it in 1726.", "big": "", "big_sub": "", "why": "The moons were found in 1877. A lucky guess, not a secret.", "cite": "05-20 F-84", "bank": "QZ-194" }, { "id": "b195", "level": 3, "picture": "gale-vista", "q": "The biggest crater on Phobos is named after whom?", "options": [ "The astronomer's wife, who told him not to give up", "The astronomer himself", "A Greek god", "A NASA engineer" ], "reveal": "Asaph Hall found the moons in 1877.", "big": "", "big_sub": "", "why": "He said he might have stopped searching but for Angeline Stickney's encouragement. Its biggest crater carries her name.", "cite": "05-20 F-85", "bank": "QZ-195" }, { "id": "b196", "level": 3, "picture": "gale-vista", "q": "One English family named Mars's two moons and which other world?", "options": [ "Pluto", "Neptune", "The Moon", "Uranus" ], "reveal": "Henry Madan, an Eton science master, picked Phobos and Deimos.", "big": "Pluto", "big_sub": "", "why": "In 1930 his great-niece Venetia Burney, aged 11, suggested the name Pluto.", "cite": "05-20 F-86", "bank": "QZ-196" }, { "id": "b198", "level": 3, "picture": "gale-vista", "q": "Percival Lowell built an observatory to study Martian canals. What did it find instead?", "options": [ "Pluto", "Life on Mars", "A new moon of Mars", "Halley's comet" ], "reveal": "Clyde Tombaugh found Pluto there in 1930.", "big": "Pluto", "big_sub": "", "why": "", "cite": "05-20 F-87", "bank": "QZ-198" }, { "id": "b199", "level": 3, "picture": "gale-vista", "q": "In 1666 Giovanni Cassini timed a Mars day with a 17th-century telescope. How close did he get?", "options": [ "Within about 3 minutes", "Within a second", "About 2 hours out", "About a day out" ], "reveal": "He said 24 hours 40 minutes.", "big": "", "big_sub": "", "why": "Not bad for 360 years ago.", "cite": "05-20 F-88", "bank": "QZ-199" }, { "id": "b200", "level": 3, "picture": "gale-vista", "q": "Galle crater on Mars, 230 km wide, looks like what?", "options": [ "A smiley face", "A heart", "A footprint", "A rabbit" ], "reveal": "It appears in the comic Watchmen.", "big": "", "big_sub": "", "why": "", "cite": "05-20 F-89", "bank": "QZ-200" }, { "id": "b201", "level": 2, "picture": "gale-vista", "q": "The Mars bar is named after...", "options": [ "The Mars family who made it", "The planet", "The Roman god", "A racehorse" ], "reveal": "Forrest Mars first made it in Slough, England, in 1932.", "big": "", "big_sub": "", "why": "", "cite": "05-20 F-90", "bank": "QZ-201" }, { "id": "b014", "level": 1, "picture": "gale-vista", "q": "Counting out from the Sun, which planet is Mars?", "options": [ "Fourth", "Third", "Fifth", "Sixth" ], "reveal": "One house further down the street than Earth, which is third.", "big": "Fourth", "big_sub": "", "why": "", "cite": "05-20 F-91", "bank": "QZ-014" }, { "id": "b015", "level": 1, "picture": "sharp-hills", "q": "Of the eight planets, how does Mars rank by size?", "options": [ "Second smallest", "Largest", "Middle of the pack", "Smallest" ], "reveal": "Only Mercury is smaller.", "big": "", "big_sub": "", "why": "Mars is about half as wide as Earth.", "cite": "05-20 F-92", "bank": "QZ-015" }, { "id": "b017", "level": 1, "picture": "bolivar", "q": "Roughly how old is Mars?", "options": [ "About 4.5 billion years", "About 6,000 years", "About 45 million years", "About 13.8 billion years" ], "reveal": "It formed at about the same time as Earth.", "big": "", "big_sub": "", "why": "13.8 billion years is the age of the whole universe.", "cite": "05-20 F-93", "bank": "QZ-017" }, { "id": "b032", "level": 2, "picture": "ripples", "q": "After carbon dioxide, which gas is the next most common in Mars's air?", "options": [ "Nitrogen", "Oxygen", "Helium", "Methane" ], "reveal": "Only about 2.6%, though.", "big": "Nitrogen", "big_sub": "", "why": "On Earth, nitrogen makes up most of the air we breathe.", "cite": "02-01 F-06", "bank": "QZ-032" }, { "id": "b033", "level": 1, "picture": "murray-haze", "q": "A giant cloud grows beside the volcano Arsia Mons on spring mornings. What is it made of?", "options": [ "Water ice", "Volcanic smoke", "Dust", "Ash" ], "reveal": "It looks like an eruption, but the volcano has been quiet for millions of years.", "big": "Water ice", "big_sub": "", "why": "It is an ice cloud, like the clouds that cling to mountains on Earth.", "cite": "02-07 F-34", "bank": "QZ-033" }, { "id": "b034", "level": 1, "picture": "bolivar", "q": "How long can that Arsia Mons cloud stretch?", "options": [ "About {q_0207_clouds_amec_km} km", "About 18 km", "About 180 km", "About 18,000 km" ], "reveal": "Further than London to Madrid.", "big": "", "big_sub": "", "why": "It races west at over {q_0207_clouds_amec_kmh} km/h, then fades away within a few hours.", "cite": "02-07 F-34", "bank": "QZ-034", "compare": { "kind": "lengths", "unit": "km", "items": [ [ "London to New York", "@ldn_ny", "earth" ], [ "The Arsia Mons cloud", "@q_0207_clouds_amec_km", "mars" ] ] } }, { "id": "b052", "level": 1, "picture": "mercou-clouds", "q": "Why are Mars's two moons shaped like potatoes instead of balls?", "options": [ "They are too small for their gravity to pull them round", "Mars squashed them", "They are hollow", "Meteors chipped them square" ], "reveal": "Big worlds pull themselves into spheres.", "big": "", "big_sub": "", "why": "Phobos is only about 26 km long, too small to do that.", "cite": "05-20 F-94", "bank": "QZ-052" }, { "id": "b053", "level": 1, "picture": "blue-sunset", "q": "Earth has a magnetic field that shields us from space radiation. Does Mars?", "options": [ "No, only small patches in its rocks", "Yes, a stronger one", "Yes, exactly the same", "Only at night" ], "reveal": "Mars lost its global field billions of years ago.", "big": "", "big_sub": "", "why": "Magnetised rocks in the south are the fossil of the one it had.", "cite": "02-01 F-24", "bank": "QZ-053" }, { "id": "b070", "level": 1, "picture": "gediz-valley", "q": "Curiosity is exploring a mountain that rises from the middle of a crater. How tall is it?", "options": [ "About 5.5 km", "About 55 m", "About 550 m", "About 55 km" ], "reveal": "Mount Sharp is about two thirds of Everest's height, sitting in Gale crater, which is about 154 km wide.", "big": "About 5.5 km", "big_sub": "", "why": "", "cite": "05-20 F-95", "bank": "QZ-070" }, { "id": "b089", "level": 1, "picture": "gediz-valley", "q": "Korolev crater, near Mars's north pole, is famous for being filled with what?", "options": [ "Ice, all year round", "Lava", "Sand dunes", "Liquid water" ], "reveal": "An 82 km bowl of ice that never melts.", "big": "", "big_sub": "", "why": "Cold air sinks into the crater and sits over the ice like a lid, keeping it frozen.", "cite": "05-20 F-96", "bank": "QZ-089" }, { "id": "b090", "level": 2, "picture": "gediz-channel", "q": "At its thickest, how deep is the ice in Korolev crater?", "options": [ "About 1.8 km", "About 1.8 m", "About 18 m", "About 18 km" ], "reveal": "About a fifth of the height of Everest, in solid ice, inside a crater 82 km wide.", "big": "About 1.8 km", "big_sub": "", "why": "", "cite": "02-01 F-48", "bank": "QZ-090" }, { "id": "b091", "level": 2, "picture": "santa-cruz", "q": "When a space rock hit Mars on Christmas Eve 2021, how far did it throw debris?", "options": [ "About 37 km", "About 37 m", "About 370 m", "About 3,700 km" ], "reveal": "Almost a marathon's distance.", "big": "About 37 km", "big_sub": "", "why": "It also dug up boulders of buried ice, and NASA's InSight lander felt the ground shake.", "cite": "05-20 F-97", "bank": "QZ-091" }, { "id": "b141", "level": 1, "picture": "santa-cruz", "q": "Sojourner, the first rover to drive on Mars, was planned to last a week. How long did it keep going?", "options": [ "About 12 weeks", "One day", "Exactly a week", "About 12 years" ], "reveal": "83 Martian days in 1997, nearly twelve times its plan.", "big": "", "big_sub": "", "why": "And it weighed about 11 kg, less than a checked suitcase.", "cite": "05-20 F-98", "bank": "QZ-141" }, { "id": "b142", "level": 1, "picture": "husband-hill", "q": "How did Mars Pathfinder, carrying Sojourner, land in 1997?", "options": [ "It bounced across the ground inside giant airbags", "It was lowered on a rope", "It splashed into a lake", "It landed on legs like a table" ], "reveal": "It hit the ground wrapped in airbags and bounced along like a beach ball before rolling to a stop.", "big": "", "big_sub": "", "why": "Spirit and Opportunity landed the same way.", "cite": "05-20 F-99", "bank": "QZ-142" }, { "id": "b143", "level": 2, "picture": "first-drill", "q": "How many cameras did NASA's Perseverance mission carry to Mars?", "options": [ "23", "2", "7", "100" ], "reveal": "Cameras for driving, for science and to film its own landing.", "big": "23", "big_sub": "", "why": "More cameras than most people have in their whole house.", "cite": "05-20 F-100", "bank": "QZ-143" }, { "id": "b144", "level": 1, "picture": "tracks-west", "q": "How many NASA rovers are driving on Mars right now?", "options": [ "2", "0", "1", "7" ], "reveal": "Curiosity and Perseverance.", "big": "2", "big_sub": "", "why": "Mars is the only planet we know of that is lived on entirely by robots.", "cite": "05-20 F-101", "bank": "QZ-144" }, { "id": "b145", "level": 2, "picture": "santa-cruz", "q": "NASA's InSight lander and an orbiter both caught a 2021 space rock strike on Mars. What did each record?", "options": [ "The orbiter photographed the crater; the lander felt the ground shake", "Both filmed it falling", "Astronauts reported it", "Neither: it was found by a telescope on Earth" ], "reveal": "The first time anyone matched a crater on Mars to the shaking it made.", "big": "", "big_sub": "", "why": "The impact was on Christmas Eve.", "cite": "05-20 F-102", "bank": "QZ-145" }, { "id": "b159", "level": 2, "picture": "gale-vista", "q": "Scientists grew food in fake Mars soil made on Earth. How many crops did they harvest in 2016?", "options": [ "Ten", "None", "One", "Fifty" ], "reveal": "Including tomatoes, peas, radish and rocket.", "big": "Ten", "big_sub": "", "why": "They used Earth air and added compost, so this is a first step, not a Martian allotment.", "cite": "05-20 F-103", "bank": "QZ-159" }, { "id": "b160", "level": 3, "picture": "gale-vista", "q": "In a 2024 test in fake Mars soil, what happened when tomatoes were grown alongside peas and carrots?", "options": [ "The tomatoes roughly doubled their harvest", "They all died", "The tomatoes turned blue", "Nothing changed" ], "reveal": "Growing crops together, as gardeners do on Earth, may help the first Mars farms.", "big": "", "big_sub": "", "why": "The test ran in a greenhouse on Earth.", "cite": "05-20 F-104", "bank": "QZ-160" }, { "id": "b202", "level": 1, "picture": "gale-vista", "q": "Many small craters on Mars are named after what?", "options": [ "Small towns and villages on Earth", "Superheroes", "Football clubs", "Dog breeds" ], "reveal": "The official rule: villages with fewer than 100,000 people.", "big": "", "big_sub": "", "why": "Bigger craters honour people who studied or wrote about Mars.", "cite": "05-20 F-105", "bank": "QZ-202" }, { "id": "b203", "level": 2, "picture": "gale-vista", "q": "Big valleys on Mars are named using what?", "options": [ "The word for Mars in different languages", "Names of astronauts", "Colours", "Famous ships" ], "reveal": "Small valleys are named after rivers on Earth.", "big": "", "big_sub": "", "why": "Mars's map is written in languages from all over our planet.", "cite": "05-20 F-106", "bank": "QZ-203" }, { "id": "b206", "level": 1, "picture": "gale-vista", "q": "In Holst's suite The Planets, what is the music for Mars called?", "options": [ "The Bringer of War", "The Red Wanderer", "The Bringer of Peace", "The Fire Star" ], "reveal": "Written in 1914 in a pounding 5/4 rhythm, and finished before the First World War began.", "big": "", "big_sub": "", "why": "", "cite": "05-20 F-107", "bank": "QZ-206" }, { "id": "b207", "level": 2, "picture": "gale-vista", "q": "In 2025 the biggest piece of Mars ever found on Earth sold at auction. For how much?", "options": [ "About $5.3 million", "About $5,300", "About $53,000", "About $530 million" ], "reveal": "A 24.7 kg meteorite found in the Sahara, sold by Sotheby's in New York.", "big": "", "big_sub": "", "why": "It is about 70% bigger than the next-largest piece of Mars we have.", "cite": "05-20 F-108", "bank": "QZ-207" }, { "id": "b208", "level": 3, "picture": "gale-vista", "q": "Without anyone going to fetch them, how many meteorites from Mars have been found on Earth?", "options": [ "About 400", "None", "About 4", "About 40,000" ], "reveal": "The Meteoritical Society counts 401, the first one recorded in 1815.", "big": "About 400", "big_sub": "", "why": "Each was blasted off Mars by an impact and drifted here through space.", "cite": "05-20 F-109", "bank": "QZ-208" }, { "id": "b209", "level": 2, "picture": "gale-vista", "q": "In 2026, what share of Britons thought humans would land on Mars in their lifetime?", "options": [ "About 4 in 10", "Almost nobody", "About 1 in 10", "Almost everyone" ], "reveal": "37% in a YouGov poll.", "big": "", "big_sub": "", "why": "Young people were far more hopeful: 60% of 18 to 24-year-olds, against 22% of over-65s.", "cite": "05-20 F-110", "bank": "QZ-209" } ], "picture_questions": [ { "kind": "find-mars", "level": 2, "q": "Only one of these photos was taken on Mars. Which?", "reveal": "This one: {plain}.", "why": "Taken by the {by}. {fact}" }, { "kind": "find-earth", "level": 2, "q": "Only one of these photos was taken on Earth. Which?", "reveal": "This one: {plain}.", "why": "Taken in {where}. {fact}" } ] } }, "assumptions": [ { "id": "MG-01", "section": "1.1", "confidence": "High", "text": "Three games, decided by the owner on 9 October 2026: Mars or Earth? (look at a photo, tap Mars or Earth), Fact or Fiction? (swipe a statement) and The Mars Quiz (four answers to choose from). Mars or Earth? is built first, then the quiz, then Fact or Fiction.", "why": "Owner, 9 October 2026. Picture games ask almost no effort of a visitor and suit the site's cinematic look; the plan and the research behind it are in thinking/active/mars-quiz/what-makes-it-great.md." }, { "id": "MG-02", "section": "1.2", "confidence": "High", "text": "The home page's games section sits just above Living on Mars and stays slim: a headline and three picture cards over its own backdrop (the Martian plain at blue hour, Earth as the evening star), framed by fine lines of light at the top and bottom so it reads as its own band, side by side on a wide screen, swiped one at a time on a tablet, and one above the other on a phone (owner, 10 October 2026). Each card shows its game moving: the Mars or Earth photo wipes between the two planets (on a computer the line follows the pointer), the Fact or Fiction card rocks between its two stamps, and the quiz's four answers light up in turn.", "why": "Owner, 10 October 2026: a headline and three cards, as visually stunning as possible, to persuade people to play. Showing each game in motion tells a visitor how easy it is before they tap." }, { "id": "MG-03", "section": "1.2", "confidence": "High", "text": "Until a game is built its card has no href: tapping it turns the card over to say the game is opening soon and how it works. When a game is ready, give its card an href and the same tap opens it.", "why": "No tap should lead nowhere, and the change when a game opens is one line in this file." }, { "id": "MG-04", "section": "1.2", "confidence": "High", "text": "The card pictures are Art, made with AI on Higgsfield (90-01 games-cards). The Mars or Earth pair is one made-up desert drawn twice, once with a Martian sky and once as Chile's Atacama, so the two line up exactly; the game itself will use real photographs. The words on the cards ask questions and never give the answers, so they claim nothing the library has to own.", "why": "00 L-19: beauty first; the art shows each game's idea, and the facts live in the games' own questions when they are built." }, { "id": "MG-05", "section": "1.3", "confidence": "High", "text": "Mars or Earth? shows real photos only: the Mars ones taken by NASA's Curiosity, Perseverance and Spirit rovers, the Earth ones from NASA, ESO, the Bureau of Land Management, the National Park Service and photographers on Wikimedia Commons. Each is cropped so no rover part, person, vehicle or road gives the answer away. Photos whose colours were stretched for science (false colour, or enhanced colour that turns the sky blue) are left out, so every answer is fair. Mars photos colour-balanced to Earth's daylight stay in, because that is how NASA shows them, and one fact (F-15) explains it.", "why": "Owner, 10 October 2026: build the games out in full, starting with Mars or Earth?. The game is only worth playing if the photos are real and the answers are fair." }, { "id": "MG-06", "section": "1.3", "confidence": "High", "text": "Every photo is public domain or CC BY (credited in small print under each reveal). No share-alike, non-commercial or no-derivatives photos until the legal advice on share-alike is in (90-01). The photos are fetched and cropped by 00 Engine room/make-game-photos.py, which runs on GitHub (the Fetch game photos workflow) because the build machine cannot reach NASA or Commons, and which stops if a Commons licence is not the one listed here.", "why": "The same rule the field guide and the people photos follow; the script keeps the list and the files in step." }, { "id": "MG-07", "section": "1.3", "confidence": "Medium", "text": "The game deals easier photos first and harder ones as the run grows: each photo has a level (1 easy to 3 hard), and the order sorts by level plus a random nudge, so no two runs match. One wrong answer ends the run. The best run and the photos seen are kept on the visitor's device only. A share card shows the score and the photo that ended the run; a challenge link (?beat=n) shows the friend's score to beat.", "why": "From the game research in thinking/active/mars-quiz/what-makes-it-great.md: an endless streak with a share card that shows the score is the best fit for a low-effort photo game. The levels are our judgement and can be tuned once real answer rates are known." }, { "id": "MG-08", "section": "1.4", "confidence": "High", "text": "Fact or Fiction? deals one statement at a time over a real Mars photo from Mars or Earth?'s set. The visitor drags the card right for fact or left for fiction (or taps a button, or uses the arrow keys); the card flips to say which it is, why, with a number compared to something people know. About half are facts and half fiction, mixing surprising truths with popular myths. Easier cards come first, three wrong calls end the run (three lives, MG-12), and the end, ranks, share picture and challenge link work as in Mars or Earth?. Every statement names the fact it rests on (cite): a library fact where one exists, with its numbers read live through worked_out, or one of this file's own facts (F-44 to F-56) with its source.", "why": "Owner, 10 October 2026: build Fact or Fiction? next, to the same standard. Built from the true or false questions in thinking/active/mars-quiz/question-bank.json, re-checked against the library." }, { "id": "MG-09", "section": "1.5", "confidence": "High", "text": "The Mars Quiz is a round of seven questions with four answers each: two easy, three medium and two hard, easiest first. Today's quiz is the same seven for everyone on the same day (picked from the date, numbered from the day the quiz opened), so friends can compare; a random round can be played any time. After each answer the card shows the answer, a big number and, where it helps, the real thing drawn to scale (heights, lengths, depths or sizes, read from the library or from the gazetteer's own comparison). The score shares as a row of squares that hides the answers, like the word games people already share. Every question names the fact it rests on, and its numbers, including the right answer where it is a number, are read from the owner through worked_out.", "why": "Owner, 10 October 2026: build the Mars Quiz to the same standard. The research in thinking/active/mars-quiz suggested a daily round of seven and a spoiler-free share card." }, { "id": "MG-10", "section": "1.2", "confidence": "High", "text": "Polish across the three games (owner, 10 October 2026, asked for no jargon and more wow): every Mars photo in Mars or Earth? has a plain headline (plain) above its real place name; difficulty shows as the words Easy, Medium and Hard instead of dots; a run that ends on its first photo or card says so kindly; reaching a new rank mid-run flashes a banner; a quiet wind plays under every game while sound is on; Fact or Fiction?'s first card nudges itself left and right to show it can be dragged; the Mars Quiz counts down to the next daily quiz; and once someone has played, each game's card on the home page shows their best score, read from their own device only.", "why": "Owner, 10 October 2026: fix every issue first, then make the games simpler, more visual and more immersive." }, { "id": "MG-11", "section": "1.5", "confidence": "High", "text": "The Mars Quiz's daily round works through each level's questions in one fixed shuffled order, so no question comes back until the whole level has been used; one question in every round is a picture question made from Mars or Earth?'s real photos (find the one from Mars, or the one from Earth); and the days a visitor has played in a row are counted on their device and shown on the ticket and the end screen. The question bank's 90 unused questions joined the quiz (135 in all): numbers the library owns are read from it through worked_out, and the rest rest on this file's facts F-59 onward, each with the bank's source and the file that should own it later (owner_to_be).", "why": "Owner, 10 October 2026: approved the daily fix, the streak, more questions and picture questions, so daily players do not see repeats and come back each day." }, { "id": "MG-12", "section": "1.4", "confidence": "High", "text": "Fact or Fiction? gives three lives: a wrong call costs one, and the run ends when all three are gone, so the score is the number of cards called right. Where a real picture shows the answer, the card's back opens on it (proof), with a caption and credit: NASA pictures listed in numbers.fact_or_fiction.proofs and fetched with Mars or Earth?'s photos by make-game-photos.py. The deck grew to 111 cards, then to 141 with a batch of 29 sourced myths so fiction is not the rare answer, each resting on a fact the library or this file owns and sources (cite).", "why": "Owner, 10 October 2026: a real picture that proves each answer, three lives instead of one slip, and more cards." }, { "id": "MG-13", "section": "1.3", "confidence": "High", "text": "In Mars or Earth?, every answer card links into the rest of the website (numbers.mars_or_earth.links, by the photo's gazetteer place, or earth for an Earth photo): a Mars photo opens the atlas at its place (atlas/# opens Mars Today with that place's card), a Jezero photo opens Stand in Jezero, and an Earth photo opens the real Mars on the globe. The link opens in a new tab so the run keeps going.", "why": "Owner, 10 October 2026: make each answer a door into the rest of the site." }, { "id": "MG-14", "section": "1.2", "confidence": "High", "text": "Each game has its own share picture, the one a link to it shows in a message or post: its opening screen alone, title and line over its art, with the words in numbers.home.share_tag. The game page draws it when opened with ?share, and make-stills.js takes the still (games//share.webp), so it always matches the page. The end-of-run share picture, with the visitor's score, stays as it is.", "why": "Owner, 10 October 2026: a share preview for each game. Both kinds help: the score picture for someone sharing their result, and the link picture for whoever receives the link." } ], "links": { "leans_on": [ { "ref": "02-04", "why": "The gazetteer's name for Olympus Mons, for the quiz card's sample question (read live)" }, { "ref": "02-01", "why": "Gravity, air, sound, Sun, moons, places and doses for Fact or Fiction? and the Mars Quiz (worked_out)" }, { "ref": "02-02", "why": "Dust devils, snow, storms and the air that freezes, for Fact or Fiction? and the Mars Quiz (worked_out)" }, { "ref": "02-07", "why": "Phobos and the Martian sky, for Fact or Fiction? (worked_out)" }, { "ref": "01-01", "why": "Starship's height, the launch window and the trip time, for the Mars Quiz (worked_out)" }, { "ref": "01-05", "why": "Mariner 4's photo time and Perseverance's signal delay, for the Mars Quiz (worked_out)" }, { "ref": "03-06", "why": "How much soil covers a home, for the Mars Quiz's radiation answer (worked_out)" }, { "ref": "01-02", "why": "Perseverance's landing, the body in space and Polyakov's record, for Mars Quiz questions (worked_out)" }, { "ref": "01-03", "why": "Astronaut selection and the Mars-500 experiment, for Mars Quiz questions (worked_out)" }, { "ref": "02-03", "why": "Lava tubes, buried ice, the 2021 impact and MOXIE, for Mars Quiz questions (worked_out)" }, { "ref": "02-06", "why": "Moon dust, bone loss and living on Mars time, for Mars Quiz questions (worked_out)" }, { "ref": "02-09", "why": "The Eridania sea, for Mars Quiz questions (worked_out)" }, { "ref": "03-05", "why": "Opportunity's marathon, for Mars Quiz questions (worked_out)" } ], "used_by": [] }, "open_questions": [], "sources": { "higgsfield": { "name": "Higgsfield, GPT Image 2.5 (the tool the card pictures were made with), 2026", "url": "https://higgsfield.ai/" }, "nasa_pia22209": { "name": "NASA/JPL Photojournal, PIA22209 (the photo and its caption), 2018", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA22209" }, "nasa_pia20843": { "name": "NASA/JPL Photojournal, PIA20843 (the photo and its caption), 2016", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA20843" }, "nasa_pia21043": { "name": "NASA/JPL Photojournal, PIA21043 (the photo and its caption), 2016", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA21043" }, "nasa_pia21041": { "name": "NASA/JPL Photojournal, PIA21041 (the photo and its caption), 2016", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA21041" }, "nasa_pia21042": { "name": "NASA/JPL Photojournal, PIA21042 (the photo and its caption), 2016", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA21042" }, "nasa_pia25733": { "name": "NASA/JPL Photojournal, PIA25733 (the photo and its caption), 2023", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA25733" }, "nasa_pia26367": { "name": "NASA/JPL Photojournal, PIA26367 (the photo and its caption), 2024", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA26367" }, "nasa_pia24622": { "name": "NASA/JPL Photojournal, PIA24622 (the photo and its caption), 2021", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA24622" }, "nasa_pia19400": { "name": "NASA/JPL Photojournal, PIA19400 (the photo and its caption), 2015", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA19400" }, "nasa_pia24266": { "name": "NASA/JPL Photojournal, PIA24266 (the photo and its caption), 2021", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA24266" }, "nasa_pia25414": { "name": "NASA/JPL Photojournal, PIA25414 (the photo and its caption), 2022", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA25414" }, "nasa_pia24765": { "name": "NASA/JPL Photojournal, PIA24765 (the photo and its caption), 2021", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA24765" }, "nasa_pia25172": { "name": "NASA/JPL Photojournal, PIA25172 (the photo and its caption), 2022", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA25172" }, "nasa_pia26471": { "name": "NASA/JPL Photojournal, PIA26471 (the photo and its caption), 2024", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA26471" }, "nasa_pia19803": { "name": "NASA/JPL Photojournal, PIA19803 (the photo and its caption), 2015", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA19803" }, "nasa_pia16191": { "name": "NASA/JPL Photojournal, PIA16191 (the photo and its caption), 2012", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA16191" }, "nasa_dunes_2015": { "name": "NASA JPL, Curiosity Mars rover's first up-close study of active sand dunes, 2015", "url": "https://www.jpl.nasa.gov/news/nasa-mars-rover-curiosity-begins-dune-investigation/" }, "nasa_ripples_2017": { "name": "NASA JPL, Mars rover Curiosity finds a second scale of sand ripples, not seen on Earth, 2017", "url": "https://www.jpl.nasa.gov/news/sand-ripples-on-mars-preserve-a-record-of-a-thinner-atmosphere/" }, "nasa_msl": { "name": "NASA, Mars Science Laboratory: Curiosity rover mission overview, 2015", "url": "https://science.nasa.gov/mission/msl-curiosity/" }, "nasa_spirit": { "name": "NASA, Spirit rover mission page (planned for 90 days, worked from 2004 to 2010), 2026", "url": "https://science.nasa.gov/mission/mars-exploration-rovers-spirit-and-opportunity/" }, "eso_atacama": { "name": "ESO, Desert landscape (malin 2709): 'The Atacama Desert covers a 1000km strip of land', 2015", "url": "https://commons.wikimedia.org/wiki/File:Desert_landscape_(malin_2709).jpg" }, "eso_atacama_iced": { "name": "ESO, Atacama Desert Landscape: the dry air is why La Silla and Paranal observatories stand here, 2019", "url": "https://commons.wikimedia.org/wiki/File:Atacama_Desert_Landscape_(iced_moment_870-CC).jpg" }, "nasa_arads": { "name": "NASA Ames, Atacama Rover Astrobiology Drilling Studies (ARADS), 2019", "url": "https://www.nasa.gov/ames/arads/" }, "wiki_hamada": { "name": "Wikipedia, Hamada (a desert of bare rock and stones), 2026", "url": "https://en.wikipedia.org/wiki/Hamada" }, "wiki_western_desert": { "name": "Wikipedia, Western Desert (Egypt): about two thirds of Egypt's land, 2026", "url": "https://en.wikipedia.org/wiki/Western_Desert_(Egypt)" }, "wiki_sahara": { "name": "Wikipedia, Sahara: about 9.2 million square km, comparable to China or the United States, 2026", "url": "https://en.wikipedia.org/wiki/Sahara" }, "nasa_lut": { "name": "NASA Earth Observatory, Where is the hottest place on Earth? (Lut Desert, 70.7 °C ground in 2005), 2012", "url": "https://earthobservatory.nasa.gov/images/76627/where-is-the-hottest-place-on-earth" }, "wiki_yardang": { "name": "Wikipedia, Yardang (wind-carved ridges, found on Earth and on Mars), 2026", "url": "https://en.wikipedia.org/wiki/Yardang" }, "unesco_lut": { "name": "UNESCO World Heritage Centre, Lut Desert (listed 2016), 2016", "url": "https://whc.unesco.org/en/list/1505/" }, "unesco_wadi_rum": { "name": "UNESCO World Heritage Centre, Wadi Rum Protected Area (listed 2011), 2011", "url": "https://whc.unesco.org/en/list/1377/" }, "wiki_wadi_rum": { "name": "Wikipedia, Wadi Rum (sandstone and granite; filming location of The Martian; Seven Pillars of Wisdom), 2026", "url": "https://en.wikipedia.org/wiki/Wadi_Rum" }, "wiki_mdrs": { "name": "Wikipedia, Mars Desert Research Station (near Hanksville, Utah), 2026", "url": "https://en.wikipedia.org/wiki/Mars_Desert_Research_Station" }, "blm_bisti": { "name": "Bureau of Land Management, Bisti/De-Na-Zin Wilderness (41,170 acres), 2012; 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Name of Mars, 2026", "url": "https://en.wikipedia.org/wiki/Mars_in_culture" }, "bank_qz191": { "name": "Wikipedia, Name of Mars, 2026", "url": "https://en.wikipedia.org/wiki/Name_of_Mars" }, "bank_qz192": { "name": "Wikipedia, Mars in culture, 2026", "url": "https://en.wikipedia.org/wiki/Mars_in_culture" }, "bank_qz193": { "name": "Cosmos Magazine, Johannes Kepler's obsession with Mars, 2026", "url": "https://cosmosmagazine.com/space/johannes-keplers-obsession-with-mars" }, "bank_qz194": { "name": "Wikipedia, Moons of Mars, 2026", "url": "https://en.wikipedia.org/wiki/Moons_of_Mars" }, "bank_qz195": { "name": "Astronomy.com, Aug 17 1877: Asaph Hall discovers Phobos, 2026", "url": "https://www.astronomy.com/today-in-the-history-of-astronomy/aug-17-1877-asaph-hall-discovers-phobos/" }, "bank_qz196": { "name": "NASA Science, Venetia Burney Phair, 2026", "url": "https://science.nasa.gov/people/venetia-burney-phair/" }, "bank_qz198": { "name": "Wikipedia, Lowell Observatory, 2026", "url": "https://en.wikipedia.org/wiki/Lowell_Observatory" }, "bank_qz199": { "name": "Wikipedia, History of Mars observation, 2026", "url": "https://en.wikipedia.org/wiki/History_of_Mars_observation" }, "bank_qz200": { "name": "Wikipedia, Galle (Martian crater), 2026", "url": "https://en.wikipedia.org/wiki/Galle_(Martian_crater)" }, "bank_qz201": { "name": "Wikipedia, Mars (chocolate bar), 2026", "url": "https://en.wikipedia.org/wiki/Mars_(chocolate_bar)" }, "bank_qz014": { "name": "NASA Science, Mars: Facts, 2026", "url": "https://science.nasa.gov/mars/facts/" }, "bank_qz015": { "name": "NASA Science, Mars: Facts, 2026", "url": "https://science.nasa.gov/mars/facts/" }, "bank_qz017": { "name": "NASA Science, Mars: Facts, 2026", "url": "https://science.nasa.gov/mars/facts/" }, "bank_qz052": { "name": "NASA Science, Phobos, 2026", "url": "https://science.nasa.gov/mars/moons/phobos/" }, "bank_qz070": { "name": "NASA Science, The heights of Mount Sharp; Mount Sharp inside Gale crater, 2012", "url": "https://science.nasa.gov/resource/the-heights-of-mount-sharp/" }, "bank_qz089": { "name": "ESA, Flight over Korolev crater on Mars, 2020", "url": "https://www.esa.int/ESA_Multimedia/Videos/2020/07/Flight_over_Korolev_Crater_on_Mars/(lang)" }, "bank_qz091": { "name": "NASA, NASA's InSight lander detects stunning meteoroid impact on Mars, 2022", "url": "https://www.nasa.gov/missions/insight/nasas-insight-lander-detects-stunning-meteoroid-impact-on-mars/" }, "bank_qz141": { "name": "NASA JPL, Mars Pathfinder; Wikipedia, Sojourner (rover), 2026", "url": "https://www.jpl.nasa.gov/missions/mars-pathfinder-sojourner-rover/" }, "bank_qz142": { "name": "NASA Space Place, The Mars rovers: Sojourner, 2026", "url": "https://spaceplace.nasa.gov/mars-sojourner/" }, "bank_qz143": { "name": "NASA Science, Perseverance rover components, 2021", "url": "https://science.nasa.gov/mission/mars-2020-perseverance/rover-components/" }, "bank_qz144": { "name": "NASA Science, Mars, 2026", "url": "https://science.nasa.gov/mars/" }, "bank_qz145": { "name": "NASA, NASA's InSight lander detects stunning meteoroid impact on Mars, 2022", "url": "https://www.nasa.gov/missions/insight/nasas-insight-lander-detects-stunning-meteoroid-impact-on-mars/" }, "bank_qz159": { "name": "Wired, reporting Wageningen University research, 2016", "url": "https://www.wired.com/story/vegetables-grown-in-mars-soil" }, "bank_qz160": { "name": "Reuters, Scientists explore how to improve crop yields on Mars, 2024", "url": "https://www.reuters.com/technology/space/scientists-explore-how-improve-crop-yields-mars-2024-05-01/" }, "bank_qz202": { "name": "USGS Gazetteer of Planetary Nomenclature, IAU rules and conventions, 2026", "url": "https://planetarynames.wr.usgs.gov/Page/rules" }, "bank_qz203": { "name": "USGS Gazetteer of Planetary Nomenclature, IAU rules and conventions, 2026", "url": "https://planetarynames.wr.usgs.gov/Page/rules" }, "bank_qz206": { "name": "Wikipedia, The Planets, 2026", "url": "https://en.wikipedia.org/wiki/The_Planets" }, "bank_qz207": { "name": "Scripps News, The largest known Martian meteorite just sold for more than $5 million, 2025", "url": "https://www.scrippsnews.com/science-and-tech/space/the-largest-known-martian-meteorite-just-sold-for-more-than-5-million" }, "bank_qz208": { "name": "Scripps News, quoting the Meteoritical Society, 2025", "url": "https://www.scrippsnews.com/science-and-tech/space/the-largest-known-martian-meteorite-just-sold-for-more-than-5-million" }, "bank_qz209": { "name": "YouGov, How do Britons feel about going to the Moon?, 2026", "url": "https://yougov.com/en-gb/articles/54460-how-do-britons-feel-about-going-to-the-moon" } }, "sources_checked": "10 October 2026", "changes": [ "10 October 2026 (v1.0): Written for the owner's new home page section above Living on Mars: a headline and three game cards, each with a moving preview and a picture made on Higgsfield, and a card back saying the game is opening soon until it has an href (MG-01 to MG-04).", "10 October 2026 (v1.1): The owner took off the section's eyebrow (Three quick games) and its line (Pick one. No sign-up, no rules to read.), cut the space above the headline, and asked for the section to stand apart from Living on Mars below it and not sit on plain black: it now has its own backdrop of the Arcadia plain at blue hour with Earth as the evening star (Art, 90-01 games-cards), framed by fine lines of light at its top and bottom edges (MG-02).", "10 October 2026 (v1.2): The owner asked for the three cards to stand one above the other on a phone instead of a sideways swipe row; tablets still swipe them with dots, and on a phone each card is square so the band stays slim (MG-02).", "10 October 2026 (v1.3): Mars or Earth? is built (games/mars-or-earth/), with 43 real photos (21 from Mars, 22 from Earth), each with where it was taken, who took it and a Did you know? fact (F-01 to F-43, section 1.3). Its words, ranks and photo list are in numbers.mars_or_earth (MG-05 to MG-07). The home page card now opens it.", "10 October 2026 (v1.3): Answered the open question: Mars or Earth? opens as its own page, games/mars-or-earth/, so a run can be shared by link and the home page stays light.", "10 October 2026 (v1.4): Fact or Fiction? is built (games/fact-or-fiction/): 55 statements (31 facts, 24 fictions) in numbers.fact_or_fiction, each resting on a library fact or on this file's own facts F-44 to F-56 (section 1.4), with their numbers read from 02-01, 02-02 and 02-07 through worked_out (MG-08). The home page card now opens it.", "10 October 2026 (v1.5): The Mars Quiz is built (games/mars-quiz/): 45 questions in numbers.mars_quiz, each with its picture, reveal, big number and, for many, a to-scale comparison, resting on library facts or this file's own facts (F-57, F-58 added, section 1.5), with numbers read through worked_out (MG-09). Today's quiz gives everyone the same seven each day. The home page card now opens it.", "10 October 2026 (v1.6): Polish round after a full check at five screen sizes: plain headlines for every Mars photo, Easy, Medium and Hard in words, kinder first-slip endings, rank-up banners, a quiet wind bed, a drag hint on Fact or Fiction?'s first card a countdown to the next daily quiz, and each home page card showing the visitor's own best score, kept on their device (cards' store and best) (MG-10). Layout fixes for short screens and phones on their side.", "10 October 2026 (v1.6): Plainer words where a visitor could trip: rock towers for buttes, metres a second for m/s, corrected colours for calibrated, crater for basin, and no delta or enzyme. The quiz card on the home page now says it is new every day.", "10 October 2026 (v1.7): The Mars Quiz grows to 135 questions (the question bank's 90 unused ones, numbers linked to their owners through worked_out, new facts F-59 onward with sources), works through each level in a fixed order so a daily player meets no repeats, adds a picture question to every round and counts the days played in a row (MG-11).", "10 October 2026 (v1.8): Fact or Fiction? gives three lives, shows a real NASA picture that proves the answer where one exists (proofs, 23 pictures) and grows to 111 cards (MG-12). Mars or Earth?'s answer cards link to the photo's place on the atlas, to Stand in Jezero or to the globe (links, MG-13). Each game has its own share picture for links (MG-14). Proof pictures checked once fetched: Phobos shown whole, and a clearer icy crater (PIA26321) for There is no water on Mars.", "10 October 2026 (v1.9): Fact or Fiction? gains 29 popular myths and one fact (141 cards: 79 facts, 62 fictions), each resting on a library fact, so a player can no longer win by guessing fact; ten reuse a proof picture (MG-12). The Mars Quiz draws more answers to scale (MG-09)." ], "worked_out": { "grav_pct": { "ratio": [ "02-01:numbers.gravity.mean_ms2", "02-01:numbers.earth.g_mean_ms2" ], "times": 100, "dp": 0 }, "sol_hm": { "of": "02-01:numbers.time.sol_h", "hm": true }, "drift_min": { "minus": [ "02-01:numbers.time.sol_h", 24 ], "times": 60, "dp": 0 }, "mars_year": { "of": "02-01:numbers.time.year_days", "dp": 0 }, "year_months": { "ratio": [ "02-01:numbers.time.year_days", "02-01:numbers.earth.year_days" ], "times": 12, "dp": 0 }, "mars_tilt": { "of": "02-01:numbers.time.tilt_deg", "dp": 0 }, "earth_tilt": { "of": "02-01:numbers.earth.tilt_deg", "dp": 0 }, "air_pct": { "ratio": [ "02-01:numbers.atmosphere.pressure_pa", "02-01:numbers.earth.pressure_pa" ], "times": 100, "dp": 1 }, "phoenix_snow": "02-02:numbers.phoenix_snow_km", "phobos_km": "02-01:numbers.moons.phobos_dims_km.0", "deimos_km": "02-01:numbers.moons.deimos_d_km", "phobos_fall": "02-07:numbers.phobos.fall_m_century", "break_lo": "02-07:numbers.phobos.breakup_myr.0", "break_hi": "02-07:numbers.phobos.breakup_myr.1", "sun_pct": { "ratio": [ "02-01:numbers.sun.irr_wm2", "02-01:numbers.earth.irr_wm2" ], "times": 100, "dp": 0 }, "earth_photo": "02-01:numbers.moons.earth_photo_dist_mkm", "oly_ev": { "ratio": [ "02-01:olympus.height_km", "02-01:comparisons.everest_km.value" ], "dp": 1 }, "oly_scarp": "02-01:olympus.scarp_km", "valles_km": "02-01:numbers.geography.valles_l_km", "carry_m": "02-01:numbers.atmosphere.carry_m", "carry_e": "02-01:numbers.atmosphere.carry_earth_m", "snd_hi": "02-01:numbers.atmosphere.sound_high_ms", "snd_lo": "02-01:numbers.atmosphere.sound_low_ms", "snd_e": "02-01:numbers.atmosphere.sound_earth_ms", "conscious": "02-01:numbers.atmosphere.conscious_s", "co2": "02-01:numbers.atmosphere.co2_pct", "o2": "02-01:numbers.atmosphere.o2_pct", "dd_km": "02-02:numbers.dd_record.height_km", "dd_w": "02-02:numbers.dd_record.width_m", "dd_ev": { "ratio": [ "02-02:numbers.dd_record.height_km", "02-01:comparisons.everest_km.value" ], "dp": 1 }, "sparks": "02-02:numbers.sparks.0", "dry_ice": "02-02:numbers.dry_ice_c", "atm_swing": "02-02:numbers.atm_swing_pct", "feet_c": "02-01:numbers.temperature.feet_c", "head_c": "02-01:numbers.temperature.head_c", "lt_min": { "ratio": [ "02-01:numbers.comms.dist_mkm.0", "02-01:numbers.comms.light_kms" ], "times": 16666.666666666668, "dp": 0 }, "lt_max": { "ratio": [ "02-01:numbers.comms.dist_mkm.1", "02-01:numbers.comms.light_kms" ], "times": 16666.666666666668, "dp": 0 }, "mean_c": "02-01:numbers.temperature.mean_c", "mars_80kg": { "ratio": [ "02-01:numbers.gravity.mean_ms2", "02-01:numbers.earth.g_mean_ms2" ], "times": 80, "dp": 0 }, "sol_h": { "of": "02-01:numbers.time.sol_h", "dp": 2 }, "mars_bdays": { "ratio": [ "02-01:numbers.earth.year_days", "02-01:numbers.time.year_days" ], "times": 40, "dp": 0 }, "earth_year": { "of": "02-01:numbers.earth.year_days", "dp": 0 }, "earth_pa": "02-01:numbers.earth.pressure_pa", "mars_pa": "02-01:numbers.atmosphere.pressure_pa", "earth_o2": "02-01:numbers.earth.o2_pct", "everest_km": "02-01:comparisons.everest_km.value", "moon_km": "02-01:numbers.moons.moon_d_km", "moon_phobos": { "ratio": [ "02-01:numbers.moons.moon_d_km", "02-01:numbers.moons.phobos_dims_km.0" ], "dp": 0 }, "sun_w": { "ratio": [ "02-01:numbers.earth.a_mkm", "02-01:numbers.sun.a_mkm" ], "times": 100, "dp": 0 }, "oly_km": "02-01:olympus.height_km", "ldn_ny": { "earth_km": [ "London", "New York" ], "round": 10 }, "hellas_km": { "of": "02-01:numbers.geography.hellas_depth_km", "dp": 1 }, "earth_water": "02-01:numbers.earth.water_pct", "xrays": { "ratio": [ "02-01:numbers.radiation.surface_msv_day", "02-01:numbers.doses.xray_msv" ], "dp": 0 }, "global_every": "02-02:numbers.global_every_my", "ss_h": "01-01:rockets#starship.height_m", "window_mo": "01-01:calendar.window_months", "trip_mo": { "ratio": [ "01-01:calendar.cruise_days", { "ratio": [ "02-01:numbers.earth.year_days", 12 ] } ], "dp": 0 }, "m4_h": "01-05:numbers.m4_hours_per_photo", "perse_min": { "ratio": [ "01-05:numbers.perse_delay_s", 60 ], "dp": 0 }, "opp_x": "02-02:numbers.opp_life_x", "cover_m": "03-06:numbers.cover_m", "q_0202_sparks_0": "02-02:numbers.sparks.0", "q_0207_phobos_eclipse_s": "02-07:numbers.phobos.eclipse_s", "q_0203_earth_tube_m_1": "02-03:numbers.earth_tube_m.1", "q_0203_mars_tube_m_1": "02-03:numbers.mars_tube_m.1", "q_0204_canyon_noctis_km": "02-04:numbers.canyon.noctis_km", "q_0204_canyon_ophir_km": "02-04:numbers.canyon.ophir_km", "q_0203_numbers_ce_width_m": "02-03:numbers.ce_width_m", "q_0209_eridania_area_million_km2": "02-09:numbers.eridania.area_million_km2", "q_0209_eridania_age_bn": "02-09:numbers.eridania.age_bn", "q_0305_opportunity_km": "03-05:numbers.opportunity.km", "q_0102_perse_entry_kmh": "01-02:numbers.perse.entry_kmh", "q_0102_perse_peak_c": "01-02:numbers.perse.peak_c", "q_0102_perse_rover_kg": "01-02:numbers.perse.rover_kg", "q_0103_y2017_selected": "01-03:numbers.nasa.y2017.selected", "q_0103_days_mars500": "01-03:numbers.days.mars500", "q_0103_mars500_control_conflicts": "01-03:numbers.mars500.control_conflicts", "q_0102_body_taller_m": "01-02:numbers.body.taller_m", "q_0206_numbers_esa_hip_pct_month": "02-06:numbers.esa_hip_pct_month", "q_0206_numbers_moonwalkers": "02-06:numbers.moonwalkers", "q_0102_mind_flash_min": "01-02:numbers.mind.flash_min", "q_0203_numbers_moxie_g": "02-03:numbers.moxie_g", "q_0203_numbers_moxie_runs": "02-03:numbers.moxie_runs", "q_0102_mind_polyakov_days": "01-02:numbers.mind.polyakov_days", "q_0207_clouds_amec_km": "02-07:numbers.clouds.amec_km", "q_0207_clouds_amec_kmh": "02-07:numbers.clouds.amec_kmh", "q_0203_earth_tube_m_0": "02-03:numbers.earth_tube_m.0", "q_0203_npld_global_m": "02-03:numbers.npld_global_m", "q_0305_opportunity_years": "03-05:numbers.opportunity.years", "q_0206_phoenix_weeks": "02-06:numbers.phoenix_weeks", "ff_taller_cm": "01-02:numbers.body.taller_cm", "ff_twilight_h": "02-07:numbers.twilight_h", "ff_jump_x": { "ratio": [ "02-01:numbers.earth.g_mean_ms2", "02-01:numbers.gravity.mean_ms2" ], "dp": 1 }, "ff_cloud_km": "02-07:numbers.clouds.water_max_km", "ff_dich_lo": "02-04:numbers.dich_km.0", "ff_dich_hi": "02-04:numbers.dich_km.1", "qz_tower_m": "01-01:comparisons.tower_m" } }, "quoted": { "02-04": { "file": "02-04", "title": "Interactive map", "folder": "02", "facts_file": "02-04-mars-map.json", "version": "3.24", "status": "Active", "last_updated": "10 October 2026", "about": "Facts file for 02-04 Interactive map. The page is built from this file, the library catalogue and the page template. Change a fact here, then run build.py. Words in curly brackets, like {km_px}, are filled in from the numbers in this file when the page is built, so each number is typed once. Positions use latitude north-positive and longitude east-positive from -180 to 180, the same as 02-03. The site list and map regions are read from 02-03 when the page is built, and Mars's size, air, Olympus Mons, Valles Marineris, Hellas and the Everest and Grand Canyon yardsticks are read from 02-01. The small block 'from_02_03' holds short restatements of 02-03 facts; 02-03 is right if they differ.", "one_line": "One flat map of the real Mars with four views: true colour, height, ice and where a ship can land. Tap any pin for what it is and how far it is from our city.", "shelf_life": "Place names, heights and lander positions are stable. The ice regions, the candidate sites and the lead site come from 02-03 and change when new radar or SpaceX plans appear. Re-check them with 02-03 by March 2027.", "header": { "purpose": "Put the ground, the ice and the candidate sites on one real map, so the choice of where to build can be seen, not argued from tables.", "why": "People reason about places visually. A list of latitudes does not show that the ice sits in a northern band while the caves sit on the volcanoes. The map does, at a glance.", "when": "Choosing or defending the city site, placing anything on Mars, building a map screen for the world or the website, or checking where something is.", "change": "Edit this facts file, then run build.py. Site pins, ice and cave regions belong to 02-03: change them in 02-03 and rebuild. Map images live in the assets folder.", "writing": "Every number is compared to something people know. Pictures first, short sentences, no walls of text." }, "comparisons": { "storey_m": 3.2, "walk_kmh": 5, "pitch_length_m": [ 100, 110 ], "cities": { "London": [ 51.50722, -0.1275 ], "Edinburgh": [ 55.95333, -3.18917 ], "Rome": [ 41.89333, 12.48278 ], "Cairo": [ 30.04444, 31.23583 ], "New York": [ 40.7128, -74.0061 ], "Paris": [ 48.85667, 2.35222 ], "Berlin": [ 52.52, 13.405 ], "Madrid": [ 40.41667, -3.70333 ] }, "trips": [ [ "London", "Edinburgh" ], [ "London", "Rome" ], [ "London", "Cairo" ], [ "London", "New York" ] ], "sources": [ "city_coords", "ifab_pitch" ] }, "numbers": { "tex_w": 1000, "tex_h": 500, "mola_million": 600, "mola_years": [ 1999, 2001 ], "mola_err_m": 3, "viking_images": 1000, "viking_m_px": 925, "viking_years": [ 1976, 1980 ], "dich_km": [ 1, 3 ], "tharsis_km": 5000, "tharsis_high_km": 7, "ncap_km": 1000, "ncap_million_km3": 1.6, "scap_km": 350, "scap_thick_km": 3, "scap_co2_m": 8, "insight_ellipse_m": -2650, "zhurong_m": -4099, "shoreline": { "level_m": -3760, "spread_m": 560, "age_bn": 3.6, "area_pct": 18, "mean_depth_m": 580, "volume_million_km3": 15, "head_1999_million_km3": 14 }, "hellas_lake": { "level_m": -5800 }, "drying": { "dry_by_bn": 3.2, "ocean_drop_m": 1850, "hellas_drop_m": 2500, "about": "Our estimate of how the water went (M-05): the ocean falls by ocean_drop_m and the Hellas lake by hellas_drop_m before both are gone, by about dry_by_bn billion years ago." }, "canyon": { "about": "The parts of Valles Marineris the race flies through, west to east (F-19 to F-24).", "noctis_km": 1263, "ius_km": 938, "melas_km": 547, "candor_km": 773, "ophir_km": 317, "slide_run_km": 120, "slide_ms": 100 }, "stories": { "about": "Numbers behind the place stories on the atlas cards (F-25 to F-35).", "hellas_rock_km": 370, "hellas_age_bn": 4, "utopia_km": 3300, "argyre_rock_km": 200, "argyre_age_bn": 3.9, "argyre_km": 1800, "olympus_horizon_km": 3, "stripe_km": 1930 } }, "sections": [ { "id": "4.1", "title": "The map and its data" }, { "id": "4.2", "title": "The shape of Mars" }, { "id": "4.3", "title": "Ice and caves" }, { "id": "4.4", "title": "Where a ship can land" }, { "id": "4.5", "title": "Sites and landers" }, { "id": "4.6", "title": "Every named place" }, { "id": "4.7", "title": "Old shorelines" } ], "facts": [ { "id": "F-01", "section": "4.1", "text": "Heights come from MOLA, a laser on NASA's Mars Global Surveyor. It took more than {mola_million} million measurements from {mola_y0} to {mola_y1}. Heights are measured from the areoid, Mars's version of sea level; the whole-planet reference is uncertain by at least {mola_err_m} m.", "compare": "{mola_err_m} m is about one storey.", "sources": [ "usgs_mola" ] }, { "id": "F-02", "section": "4.1", "text": "The standard colour map of Mars is the USGS Viking mosaic: about {viking_images} red- and violet-filter images from the two Viking orbiters ({viking_y0} to {viking_y1}), at {viking_m_px} m per pixel.", "compare": "One Viking pixel is about {viking_pitch} football pitches long.", "sources": [ "usgs_viking" ] }, { "id": "F-03", "section": "4.1", "text": "Our base images are the free 1k Mars maps by James Hastings-Trew (Planet Pixel Emporium), as copied into the threex.planets project on GitHub: {tex_w} by {tex_h} pixels. He made the height map from MOLA gridded data. He made the colour map by combining colour-channel images and removing a blue-green cast; he does not name their source.", "compare": "One pixel is about {km_px} km wide at the equator: {walk_px} hours on foot.", "sources": [ "pixel_emporium", "threex" ] }, { "id": "F-04", "section": "4.1", "text": "Place names and their centre points come from the official IAU list kept by the US Geological Survey (Gazetteer of Planetary Nomenclature). It gives longitudes from 0 to 360° east; this file converts them to -180 to 180 to match 02-03.", "compare": "The same switch Earth maps make: places are given as up to 180° east or west of Greenwich, not 0 to 360° east.", "sources": [ "usgs_mons", "usgs_planitia", "usgs_planum", "usgs_vm" ] }, { "id": "F-05", "section": "4.1", "text": "Lander and rover positions come from NASA's Mars24 table and NASA's spacecraft catalogue; Pathfinder's comes from Wikipedia, because NASA's own tables disagree. China's space agency fixed Zhurong's spot from orbital photos at 25.066°N, 109.925°E, {zhurong_m} m below the Martian average level.", "compare": "{n_landers} landers sent data from the surface in {lander_span} years: about one every {lander_every} years.", "sources": [ "giss_landers", "zhurong_site_2021", "nssdc_landers", "pathfinder_wiki" ] }, { "id": "F-06", "section": "4.2", "text": "Mars is split in two. The northern lowlands cover about a third of the surface and sit {dich_lo} to {dich_hi} km lower than the southern highlands.", "compare": "The step is up to about {dich_pct} percent of Everest's height, running right round the planet.", "sources": [ "dichotomy_wiki" ] }, { "id": "F-07", "section": "4.2", "text": "Tharsis is a volcanic rise about {tharsis_km} km across and up to {tharsis_high_km} km high, not counting the volcanoes on top.", "compare": "About as wide as London to New York ({ny_km} km).", "sources": [ "tharsis_wiki" ] }, { "id": "F-08", "section": "4.2", "text": "Olympus Mons, on the edge of Tharsis, rises {oly_km} km above the Martian average level and is about {oly_wide_km} km wide (02-01 F-48). Its base is about the size of Italy.", "compare": "About {oly_ev} times the height of Everest ({ev_m} m).", "sources": [ "olympus_wiki" ] }, { "id": "F-09", "section": "4.2", "text": "Valles Marineris is about {vm_len} km long, up to {vm_wide} km wide and up to {vm_deep} km deep (02-01 F-51, NASA figures).", "compare": "About {vm_gc_len} times the Grand Canyon's length ({gc_km} km) and {vm_gc_dep} times its depth ({gc_depth} km).", "sources": [ "vm_nasa" ] }, { "id": "F-10", "section": "4.2", "text": "Hellas is an impact basin about {hellas_km} km across. Its floor lies about {hellas_floor} km below the Martian average level, the lowest ground on Mars (02-01 F-50).", "compare": "Across, {hellas_trip}. The floor is {hellas_ev_pct} percent of an Everest down.", "sources": [ "hellas_wiki", "usgs_planitia" ] }, { "id": "F-11", "section": "4.2", "text": "The north polar cap is about {ncap_km} km across in summer, mostly water ice, about {ncap_vol} million km³. The south cap is about {scap_km} km across and {scap_thick_km} km thick, water ice under a permanent {scap_co2_m} m layer of frozen carbon dioxide.", "compare": "The north cap is {ncap_trip} across.", "sources": [ "polar_wiki" ] }, { "id": "F-12", "section": "4.4", "text": "Landers need low ground. NASA's InSight team wrote that a site must be low enough to have enough air above it to slow the craft on its parachute. InSight's landing zone averaged {insight_m} m below the average level.", "compare": "Lower ground means more air overhead to brake in, like a longer runway.", "sources": [ "insight_kit" ] }, { "id": "F-13", "section": "4.7", "text": "The younger of the two proposed ocean shorelines, called Contact 2, sits on average {ocean_m} m below datum, give or take {shore_spread} m. It is Late Hesperian in age.", "compare": "Deeper below Mars's datum than Earth's oceans are deep on average ({earth_ocean_km} km).", "sources": [ "scirep_2019", "parker_1993" ] }, { "id": "F-14", "section": "4.7", "text": "The plains inside that shoreline, the Vastitas Borealis Formation, date to about {ocean_age} billion years ago.", "compare": "About the same age as Jezero's lake, {jz_age} billion years ago (02-08 F-03).", "sources": [ "arxiv_2022" ] }, { "id": "F-15", "section": "4.7", "text": "Landforms around the Hellas basin line up along the contour {hellas_km} km below datum, which Moore and Wilhelms read as the shore of old, probably ice-covered lakes.", "compare": "Hellas is the lowest ground on Mars (02-01 F-50), so it would hold water longest.", "sources": [ "moore_2001", "ntrs_2001" ] }, { "id": "F-16", "section": "4.7", "text": "Filling our MOLA heights up to that shoreline, in the connected northern basin only, covers about {area_pct}% of Mars, about {depth_m} m deep on average: about {vol_mkm3} million km³ of water.", "compare": "Head and others (1999) put the basin below this shoreline at about {head_vol} million km³, close to our figure.", "sources": [ "our_ocean", "head_1999" ] }, { "id": "F-17", "section": "4.7", "text": "Mapped shorelines rise and fall by hundreds of metres, sometimes with large scatter over short distances, where a real shore should be level. Studies that model later warping of the crust can explain much of it; others take it as a reason to doubt the shore.", "compare": "Like finding a beach line that climbs a hill: either the ground moved, or it was never a beach.", "sources": [ "arxiv_2022" ] }, { "id": "F-18", "section": "4.7", "text": "Viking 1 touched down on Chryse Planitia on 20 July 1976, seven years to the day after Apollo 11 landed on the Moon on 20 July 1969.", "compare": "The first long-lived lander on Mars arrived on the Moon landing's anniversary.", "sources": [ "nasa_viking1", "nasa_apollo11" ] }, { "id": "F-19", "section": "4.2", "text": "Noctis Labyrinthus, Latin for 'labyrinth of the night', is a maze of steep-walled canyons about {noc_km} km across at the western head of Valles Marineris. It formed when the ground cracked and sank as magma drained from beneath the Tharsis volcanoes.", "compare": "About the distance from London to Madrid ({ldn_mad} km).", "sources": [ "wiki_noctis" ] }, { "id": "F-20", "section": "4.2", "text": "Ius Chasma is about {ius_km} km long. A ridge of the planet's old bedrock, Geryon Montes, runs down its middle, and side canyons cut into its walls where groundwater once seeped out at their feet (sapping).", "compare": "About the distance from London to Berlin ({ldn_ber} km).", "sources": [ "wiki_ius", "vm_wiki" ] }, { "id": "F-21", "section": "4.2", "text": "Melas Chasma, about {melas_km} km long, is the widest part of Valles Marineris. Huge landslide deposits lie where it meets the canyons on either side.", "compare": "About the distance from London to Edinburgh ({ldn_edi} km).", "sources": [ "wiki_melas" ] }, { "id": "F-22", "section": "4.2", "text": "Landslides in Valles Marineris often moved faster than {slide_ms} m/s; one in Melas Chasma ran about {slide_run_km} km from the broken wall.", "compare": "That is {slide_kmh} km/h.", "sources": [ "mazzanti_2016" ] }, { "id": "F-23", "section": "4.2", "text": "Candor Chasma, about {candor_km} km long, holds mountains of layered rock. Orbiters have found sulfates and iron oxides in it, minerals that form with water.", "sources": [ "wiki_candor" ] }, { "id": "F-24", "section": "4.2", "text": "Ophir Chasma, about {ophir_km} km long, is named after Ophir, the land of King Solomon's gold.", "compare": "A little shorter than London to Paris ({ldn_par} km).", "sources": [ "wiki_ophir" ] }, { "id": "F-25", "section": "4.2", "text": "Hellas was blasted out about {st_hel_age} billion years ago by a single impactor estimated at about {st_hel_rock} km across.", "compare": "The rock alone was {st_hel_par_x} times the distance from London to Paris.", "sources": [ "hellas_wiki" ] }, { "id": "F-26", "section": "4.2", "text": "Utopia Planitia sits inside the largest recognised impact basin on Mars, about {st_uto} km across, since filled in and buried.", "compare": "{st_uto_x} times as wide as Hellas, the deepest crater.", "sources": [ "wiki_utopia" ] }, { "id": "F-27", "section": "4.2", "text": "Argyre, a basin about {st_arg_w} km across, was made about {st_arg_age} billion years ago by an impactor about {st_arg_rock} km across. Water later collected in the basin and drained north through Uzboi Vallis towards Chryse.", "sources": [ "wiki_argyre" ] }, { "id": "F-28", "section": "4.2", "text": "Olympus Mons is so broad and gently sloped that from its summit the slopes run on past a horizon only about {st_oly_hz} km away; an observer would not see they stand on a mountain. Summit air is about {st_oly_air} percent of Mars's average surface pressure (02-01).", "sources": [ "olympus_wiki" ] }, { "id": "F-29", "section": "4.2", "text": "The weight of Tharsis shifted Mars's outer layers relative to its spin axis (true polar wander), moving the poles across the surface (Bouley and others, Nature, 2016).", "compare": "Lead author Sylvain Bouley: on Earth a shift like it would put Paris in the polar circle.", "sources": [ "bouley_2016" ] }, { "id": "F-30", "section": "4.2", "text": "Valles Marineris is mainly a rift: the crust pulled apart as Tharsis grew, and erosion and collapse widened it later.", "compare": "Like Africa's Great Rift Valley.", "sources": [ "vm_wiki" ] }, { "id": "F-31", "section": "4.2", "text": "NASA's InSight lander located its first well-placed marsquakes in Cerberus Fossae, young volcanic cracks in the Elysium region about 1,700 km east of the lander.", "sources": [ "dlr_cerberus_2020" ] }, { "id": "F-32", "section": "4.2", "text": "Chryse Planitia is where many of Mars's great outflow channels end, from the southern highlands, Valles Marineris and the flanks of Tharsis, including Kasei and Ares Valles.", "sources": [ "wiki_chryse" ] }, { "id": "F-33", "section": "4.2", "text": "The southern highlands keep stripes of magnetised rock from when Mars had a global magnetic field, mapped by Mars Global Surveyor; the longest run more than {st_stripe} km. The northern lowlands are largely free of them.", "compare": "{st_stripe_x} times the distance from London to Rome.", "sources": [ "jpl_stripes_1999" ] }, { "id": "F-34", "section": "4.3", "text": "Winds blowing off the north pole, turned by Mars's spin, carve the north cap's troughs into a spiral. The cap's layers of ice and dust record Mars's climate over millions of years.", "sources": [ "wiki_boreum" ] }, { "id": "F-35", "section": "4.3", "text": "Each spring, carbon dioxide ice on the south cap turns to gas underneath, bursts out in geysers carrying dark sand, and carves spider-shaped channels into the ice. The air across Mars grows and shrinks by about {st_air_swing} percent a year as it freezes onto and leaves the poles (02-02 F-04).", "sources": [ "wiki_australe" ] } ], "from_02_03": { "owner": "02-03", "about": "Short restatements of 02-03 and 02-01 facts, with the owner's ID. The numbers in them, and the sun limits, are read live from the owner when the page is built. The owner is right if they differ.", "quotes": [ { "id": "F-04", "text": "Arcadia Planitia has a widespread layer of 'excess' ice tens of metres thick, about {arcadia_km3} km³ in all.", "sources": [ "bramson_2015" ], "owner": "02-03" }, { "id": "F-05", "text": "Utopia Planitia has a buried deposit {ut_lo} to {ut_hi} m thick under {utc_lo} to {utc_hi} m of soil, between {utl_lo} and {utl_hi}°N, holding about as much water as Lake Superior.", "sources": [ "stuurman_2016" ], "owner": "02-03" }, { "id": "F-07", "text": "A crater {ce_width_m} m wide punched in Amazonis Planitia on 24 December 2021 threw out ice at about {ce_lat}°N, the lowest-latitude ice seen from an impact.", "sources": [ "jpl_ce_2022", "dundas_2023" ], "owner": "02-03" }, { "id": "F-08", "text": "Zhurong's radar looked {zhurong_depth_m} m down at about 25°N and found layered sediment, no sign of liquid water, and could not rule out salty ice.", "sources": [ "zhurong_2022" ], "owner": "02-03" }, { "id": "F-29", "text": "Arsia Mons has {sisters} possible cave skylights, {sis_lo} to {sis_hi} m across, high on the volcano.", "sources": [ "cushing_2007" ], "owner": "02-03" }, { "id": "F-31", "text": "Alba Mons has a lava-tube field at about {alba_lat}°N with more than {alba_segments} mapped segments, about {alba_km_f} km in all.", "sources": [ "crown_2022" ], "owner": "02-03" }, { "id": "F-33", "text": "SpaceX's site study with NASA scientists required latitude below {sun_hi}°, elevation below {sx_elev_km} km, slopes under {sx_slope_deg}° and ice nearby.", "sources": [ "golombek_2021" ], "owner": "02-03" }, { "owner": "02-01", "id": "F-05", "text": "On the Hellas floor the winter air reaches about {hellas_pa} Pa, about twice the Martian average of {mars_pa} Pa.", "sources": [] }, { "owner": "02-01", "id": "F-46", "text": "Mars has {mars_area} million km² of surface, all of it land: about as much ground as all Earth's continents ({earth_land} million km²), with no oceans between.", "sources": [] } ] }, "places": { "about": "Landmarks and landers this file owns. Hellas, Arsia Mons, Alba Mons, Utopia and Elysium Planitia are also 02-03 sites, so they appear once, as site pins, not twice. Width figures are the USGS Gazetteer diameters. Types: peak, canyon, basin, polar cap, rover or lander.", "list": [ { "id": "olympus", "name": "Olympus Mons", "type": "peak", "lat": 18.65, "lon": -133.8, "description": "The tallest volcano in the Solar System, on the north-west edge of Tharsis.", "facts": [ "F-08" ], "sources": [ "usgs_mons", "olympus_wiki" ] }, { "id": "ascraeus", "name": "Ascraeus Mons", "type": "peak", "lat": 11.92, "lon": -104.08, "description": "The northern of the three Tharsis Montes volcanoes.", "facts": [ "F-07" ], "sources": [ "usgs_mons" ], "width_km": 456 }, { "id": "pavonis", "name": "Pavonis Mons", "type": "peak", "lat": 1.48, "lon": -112.96, "description": "The middle Tharsis volcano, almost on the equator.", "facts": [ "F-07" ], "sources": [ "usgs_mons" ], "width_km": 367 }, { "id": "elysium_mons", "name": "Elysium Mons", "type": "peak", "lat": 25.02, "lon": 147.21, "description": "The main volcano of Elysium, Mars's second volcanic rise.", "facts": [], "sources": [ "usgs_mons" ], "width_km": 401 }, { "id": "valles", "name": "Valles Marineris", "type": "canyon", "lat": -13.74, "lon": -59.2, "description": "The biggest canyon system in the Solar System, running east from Tharsis. Named after the Mariner 9 team.", "facts": [ "F-09" ], "sources": [ "usgs_vm", "vm_nasa" ] }, { "id": "argyre", "name": "Argyre Planitia", "type": "basin", "lat": -49.84, "lon": -43.31, "description": "The floor of the Argyre impact basin in the southern highlands.", "facts": [], "sources": [ "usgs_planitia" ], "width_km": 893 }, { "id": "isidis", "name": "Isidis Planitia", "type": "basin", "lat": 13.94, "lon": 88.38, "description": "An impact basin floor. Perseverance landed in Jezero Crater on its western edge.", "facts": [], "sources": [ "usgs_planitia", "nssdc_landers" ], "width_km": 1225 }, { "id": "boreum", "name": "Planum Boreum (north polar cap)", "type": "polar cap", "lat": 87.32, "lon": 54.96, "description": "The north polar plateau and ice cap, mostly water ice.", "facts": [ "F-11" ], "sources": [ "usgs_planum", "polar_wiki" ] }, { "id": "australe", "name": "Planum Australe (south polar cap)", "type": "polar cap", "lat": -83.35, "lon": 157.7, "description": "The south polar plateau. Its cap is water ice under a thin permanent layer of frozen carbon dioxide.", "facts": [ "F-11" ], "sources": [ "usgs_planum", "polar_wiki" ] }, { "id": "mars3", "name": "Mars 3", "type": "rover or lander", "year": 1971, "lat": -45, "lon": -158, "description": "Soviet lander, landed 2 December 1971 in the southern highlands. It transmitted for about 20 seconds, then fell silent. The first craft to send data from the surface; position approximate.", "facts": [ "F-05" ], "sources": [ "nssdc_mars3" ] }, { "id": "viking1", "name": "Viking 1", "type": "rover or lander", "year": 1976, "lat": 22.27, "lon": -47.95, "description": "NASA lander, landed 20 July 1976 in western Chryse Planitia.", "facts": [ "F-05" ], "sources": [ "giss_landers", "nssdc_landers" ] }, { "id": "viking2", "name": "Viking 2", "type": "rover or lander", "year": 1976, "lat": 48.27, "lon": 134.28, "description": "NASA lander, landed 3 September 1976 in Utopia Planitia, about 200 km west of Mie crater.", "facts": [ "F-05" ], "sources": [ "giss_landers", "nssdc_landers" ] }, { "id": "pathfinder", "name": "Mars Pathfinder", "type": "rover or lander", "year": 1997, "lat": 19.1, "lon": -33.25, "description": "NASA lander with the small Sojourner rover, landed 4 July 1997 in Ares Vallis. Position from Wikipedia (19.10°N, 33.25°W); older NASA tables give 19.33 to 19.47°N.", "facts": [ "F-05" ], "sources": [ "pathfinder_wiki", "nssdc_landers" ] }, { "id": "spirit", "name": "Spirit", "type": "rover or lander", "year": 2004, "lat": -14.57, "lon": 175.48, "description": "NASA rover, landed 4 January 2004 in Gusev Crater.", "facts": [ "F-05" ], "sources": [ "giss_landers", "nssdc_landers" ] }, { "id": "opportunity", "name": "Opportunity", "type": "rover or lander", "year": 2004, "lat": -1.95, "lon": -5.53, "description": "NASA rover, landed 25 January 2004 in a 20 m crater on Terra Meridiani, the 'Hematite Site'.", "facts": [ "F-05" ], "sources": [ "giss_landers", "nssdc_landers" ] }, { "id": "phoenix", "name": "Phoenix", "type": "rover or lander", "year": 2008, "lat": 68.22, "lon": -125.75, "description": "NASA lander, landed 25 May 2008 on the far northern plains.", "facts": [ "F-05" ], "sources": [ "giss_landers", "nssdc_landers" ] }, { "id": "curiosity", "name": "Curiosity", "type": "rover or lander", "year": 2012, "lat": -4.59, "lon": 137.44, "description": "NASA rover, landed 6 August 2012 in Gale Crater.", "facts": [ "F-05" ], "sources": [ "giss_landers", "nssdc_landers" ] }, { "id": "insight", "name": "InSight", "type": "rover or lander", "year": 2018, "lat": 4.5, "lon": 135.62, "description": "NASA lander, landed 26 November 2018 in western Elysium Planitia. Shares a spot with 02-03's Elysium Planitia site.", "facts": [ "F-05", "F-12" ], "sources": [ "giss_landers", "nssdc_landers" ] }, { "id": "perseverance", "name": "Perseverance", "type": "rover or lander", "year": 2021, "lat": 18.44, "lon": 77.45, "description": "NASA rover, landed 18 February 2021 in Jezero Crater, on the western edge of the Isidis basin.", "facts": [ "F-05" ], "sources": [ "giss_landers", "nssdc_landers" ] }, { "id": "zhurong", "name": "Zhurong", "type": "rover or lander", "year": 2021, "lat": 25.07, "lon": 109.93, "description": "China's first Mars rover, landed 15 May 2021 in southern Utopia Planitia.", "facts": [ "F-05" ], "sources": [ "giss_landers", "zhurong_site_2021" ] }, { "id": "noctis", "name": "Noctis Labyrinthus", "type": "canyon", "lat": -7, "lon": -102.2, "description": "A maze of canyons at the western head of Valles Marineris.", "facts": [ "F-19" ], "sources": [ "wiki_noctis" ] }, { "id": "ius", "name": "Ius Chasma", "type": "canyon", "lat": -7, "lon": -85.8, "description": "The long western canyon of Valles Marineris.", "facts": [ "F-20" ], "sources": [ "wiki_ius" ] }, { "id": "geryon", "name": "Geryon Montes", "type": "canyon", "lat": -8.15, "lon": -80, "description": "The ridge down the middle of Ius Chasma. Pin read from the globe's MOLA heights (its crest).", "facts": [ "F-20" ], "sources": [ "vm_wiki", "usgs_mola" ] }, { "id": "labes", "name": "Ius Labes", "type": "canyon", "lat": -8.6, "lon": -77.6, "description": "Landslides where Ius Chasma opens into Melas Chasma. Pin read from the globe's MOLA heights.", "facts": [ "F-20", "F-22" ], "sources": [ "wiki_ius", "mazzanti_2016" ] }, { "id": "melas", "name": "Melas Chasma", "type": "canyon", "lat": -10.4, "lon": -72.7, "description": "The widest part of Valles Marineris.", "facts": [ "F-21" ], "sources": [ "wiki_melas" ] }, { "id": "candor", "name": "Candor Chasma", "type": "canyon", "lat": -6.6, "lon": -70.9, "description": "A canyon of layered mountains north of Melas Chasma.", "facts": [ "F-23" ], "sources": [ "wiki_candor" ] }, { "id": "ophir", "name": "Ophir Chasma", "type": "canyon", "lat": -4, "lon": -72.5, "description": "The northern canyon of central Valles Marineris.", "facts": [ "F-24" ], "sources": [ "wiki_ophir" ] } ] }, "labels": { "about": "Region names shown by the Names switch. Centre points from the USGS Gazetteer (Tharsis from Wikipedia). Not pins.", "list": [ { "name": "Tharsis", "lat": 0, "lon": -100, "source": "tharsis_wiki" }, { "name": "Amazonis Planitia", "lat": 25.75, "lon": -162.91, "source": "usgs_planitia" }, { "name": "Arcadia Planitia", "lat": 49.02, "lon": -171.85, "source": "usgs_planitia" }, { "name": "Chryse Planitia", "lat": 28.43, "lon": -40.31, "source": "usgs_planitia" }, { "name": "Syrtis Major", "lat": 9.2, "lon": 67.1, "source": "usgs_planum" }, { "name": "Meridiani Planum", "lat": -0.04, "lon": -3.14, "source": "usgs_planum" }, { "name": "Hesperia Planum", "lat": -21.42, "lon": 109.89, "source": "usgs_planum" }, { "name": "Lunae Planum", "lat": 10.79, "lon": -65.51, "source": "usgs_planum" }, { "name": "Daedalia Planum", "lat": -18.35, "lon": -125.95, "source": "usgs_planum" }, { "name": "Malea Planum", "lat": -65.82, "lon": 62.94, "source": "usgs_planum" } ] }, "imagery": { "about": "The page shows three images from the assets folder. They were made in Python from the two 1k textures (F-03): hill shading from the height map (light from the north-west), colour ramps from 'height_ramp', and heights read from the grey levels with a straight line fitted through the 'height_anchors' (assumption M-03). An anchor with a 'site' takes its position and height from that 02-03 site when the page is built; 'grey' is our own reading of the texture there. The ice and landing views draw their shapes live from 02-03.", "texture_files": { "colour": "https://raw.githubusercontent.com/jeromeetienne/threex.planets/master/images/marsmap1k.jpg", "height": "https://raw.githubusercontent.com/jeromeetienne/threex.planets/master/images/marsbump1k.jpg" }, "assets": { "colour": "assets/mars-colour.jpg", "height": "assets/mars-height.jpg", "lowground": "assets/mars-lowground.png" }, "left_edge_lon": 0, "height_anchors": [ { "name": "Hellas floor, typical depth", "lat": -34.4, "lon": 59.6, "km": -7.152, "grey": 10.4, "source": "hellas_wiki" }, { "name": "Zhurong", "lat": 25.066, "lon": 109.925, "km": -4.099, "grey": 34.7, "source": "zhurong_site_2021" }, { "name": "SpaceX AP-1", "site": "arcadia", "grey": 36.2, "source": "golombek_2021", "note": "Reads the lead site from 02-03. If the pin ever moves off AP-1, give this anchor its own entry (like AP-9's numbers.ap9) so the height fit does not move with it." }, { "name": "SpaceX AP-9", "from_02_03": "ap9", "grey": 36.2, "source": "golombek_2021" }, { "name": "SpaceX EM-16", "site": "erebus", "grey": 36.3, "source": "golombek_2021" }, { "name": "SpaceX PM-1", "site": "phlegra", "grey": 48.4, "source": "golombek_2021" }, { "name": "InSight zone", "lat": 4.5, "lon": 135.62, "km": -2.65, "grey": 46.6, "source": "insight_kit" }, { "name": "Olympus Mons summit", "lat": 18.65, "lon": -133.8, "km": 21.287, "grey": 234.8, "source": "olympus_wiki" } ], "height_ramp": [ [ -8, "#1B3A63" ], [ -5.5, "#2F6690" ], [ -4, "#4F8FA6" ], [ -2.5, "#86B3A4" ], [ -1, "#C5C08C" ], [ 0.5, "#D8B77E" ], [ 2.5, "#CF9258" ], [ 5, "#B06A40" ], [ 9, "#8A5238" ], [ 14, "#A58A7C" ], [ 18, "#DCD2CA" ], [ 22, "#FFFFFF" ] ] }, "assumptions": [ { "id": "M-01", "confidence": "Medium", "text": "02-03 holds the lead candidate site, Arcadia Planitia, pinned on SpaceX's AP-1 site at {arc_lat}°N (02-03 R-02); 04-01-01 lays the town out round it (FC-01). This map measures every distance from that pin and calls it 'the city'.", "why": "Points to 02-03 R-02 as a map decision. Erebus Montes is only {d_erebus} km away. Utopia ({d_utopia} km) is the next icy site; Acidalia is the fallback if Arcadia has no safe natural pad (02-03 R-09)." }, { "id": "M-02", "confidence": "Low", "text": "The later lava-tube outpost goes on Arsia Mons, whose caves lie about {d_arsia} km from the city (measured to 02-03's Arsia survey point), at the skylight Jeanne on the volcano's north-east flank (04-01-02 LT-01 gives its own distance). Alba Mons, {d_alba} km away, reaches the ice latitudes and stays the fallback.", "why": "Both distances are worked out from the 02-03 pins along the surface. {d_arsia} km is about London to Cairo ({cairo_km} km). People and supplies go by Starship hop, not a rover trip of weeks (04-01-02 LT-06)." }, { "id": "M-03", "confidence": "Medium", "text": "The landing view shades ground that meets two of 02-03's rules: below {sx_elev_km} km and within {sun_hi}° of the equator. Heights are read from the grey height texture with a straight line fitted through {n_anchor} known heights; the fit misses them by up to {fit_err} km.", "why": "The texture's grey levels have no published scale, so we calibrated them ourselves (F-01, F-03). Slopes, rocks and dust, the other rules, are too small to see at {km_px} km per pixel, so a shaded area is 'worth a closer look', not 'safe'." }, { "id": "M-04", "confidence": "Low", "text": "The ice view draws 02-03's rough ice and cave boxes as they are. Edges are good to several degrees, not to a landing ellipse.", "why": "02-03 calls them sketches of where the cited facts point, not survey data. Replace them with traced SWIM contours when a higher-detail map is needed." }, { "id": "M-05", "confidence": "Low", "text": "How the ancient water went: the ocean shrinks into the deepest basins, the last seas freeze over, and the ice is gone by about {dry_by} billion years ago. Hellas drains last.", "why": "The rocks date the shoreline (F-14) but not how fast the water went. This order follows the lowest ground and a cooling, thinning air; the dates in between are our estimate. Moved here from 05-11 TT-01 on 30 September 2026, so every page that shows the drying tells the same story.", "moves_to": "" } ], "links": { "leans_on": [ { "ref": "02-03", "why": "Read live: the site list with pins and heights, ice and cave regions, sun limits, landing rules (F-33) and the lead site (R-02)" }, { "ref": "02-03 R-03", "why": "Where the later lava-tube outpost might go, for the M-02 distances" }, { "ref": "02-01", "why": "Read live: Mars's size and land area, air, Olympus Mons, Valles Marineris, Hellas, and the Everest and Grand Canyon yardsticks" }, { "ref": "02-07 SK-01", "why": "The sky colours, for the opening picture's sky (read live); Phobos's and Deimos's orbits, for the gazetteer (read live)" }, { "ref": "02-08", "why": "Jezero's position, lake and landing date, for its gazetteer entry (read live)" }, { "ref": "02-09", "why": "Positions of Home Plate, Eridania and Nili Fossae for their gazetteer entries (read live)" }, { "ref": "02-02", "why": "The yearly swing in air pressure (02-02 F-04), for the south ice cap's story (read live)" } ], "used_by": [ { "ref": "05-13 Mars Atlas", "why": "The gazetteer's places and robots, the ancient shorelines and the Earth cities for comparisons, on the atlas (read live)" }, { "ref": "04-01-03", "why": "City positions on Earth, for the London to New York comparison (read live)" }, { "ref": "04-01-02 The lava-tube outpost", "why": "Reads M-02: the outpost candidates and the football-pitch length (read live)" }, { "ref": "05-01", "why": "The website's globe reads the same pins" }, { "ref": "00-02 The engine", "why": "Place names and positions for the world map" }, { "ref": "02-05 The site up close", "why": "Reads places and region centres (Viking 2, Phoenix, Olympus Mons, Amazonis, Arcadia) and the city positions, for comparisons (read live)" }, { "ref": "05-02 The Olympus race", "why": "Reads the Olympus Mons pin, where the climb finishes; the canyon run's landmark pins and gazetteer entries, one gate at each (F-19 to F-24); and the London and Edinburgh coordinates, for comparisons (read live)" }, { "ref": "05-03 Guided tours", "why": "The Olympus Mons summit pin, for the hop over the mountain (read live)" }, { "ref": "05-06 Free roam", "why": "The places a visitor can fly to on the planet (read live)" }, { "ref": "05-08 The journey experience", "why": "The Olympus Mons pin, for the sunlit summit on approach (read live)" }, { "ref": "00-05 Writing and visual standard", "why": "The map's height colours, as an example of a sourced scale (read live)" }, { "ref": "05-11", "why": "The gazetteer: every place's plain name, hook, card and position, for the globe (read live)" }, { "ref": "05-12", "why": "City experience reads this source live through the generated library bundle." }, { "ref": "02-09", "why": "The places each ancient lifeform is shown at, and how long the surface stayed wet (M-05)" }, { "ref": "04-01-04 The cities of Mars", "why": "The gazetteer's plain names and the Earth cities, for the later towns and their distances (read live)" }, { "ref": "05-18 Mars Atmosphere", "why": "Reads existing place names and links from the gazetteer." }, { "ref": "05-20", "why": "Mars games: the gazetteer's places for the quiz card, the Mars photos and the to-scale drawings, and canyon lengths for Mars Quiz questions (read live and worked_out)" } ] }, "open_questions": [ "05-01 website: its Hellas pin sits at 39°S, 82°E and its other pins presumably still use the old 02-04 positions (Arcadia 38°N, 165°W). 02-03 now owns the pins (Hellas 42.4°S, 70.5°E; Arcadia on SpaceX's AP-1 at {arc_lat}°N). The website should read 02-03's site list.", "02-03: its Utopia pin sits at the basin centre (46.7°N). The radar ice deposit is in south-western Utopia, 39 to 49°N (Planetary Society, Stuurman 2016). Consider moving the pin into the deposit once its longitude is sourced; its ice box already spans 85 to 130°E.", "02-03: its Elysium Planitia pin is exactly on InSight's landing spot. The map draws the two pins side by side with a leader line. Fine if intended.", "Higher-detail base maps (MOLA at 463 m per pixel, the USGS Viking mosaic) would sharpen zoomed views: for 02-04 and 00-02 The engine, when the world's globe is built.", "Local terrain inside the chosen plain (craters and troughs under each vault row and pad): the first robot drill and ground radar, as 04-01-01 notes. The well field and the port are now placed (04-01-01 FC-02, FC-04).", "Gazetteer: Syrtis Major, Hesperia Planum, Lunae Planum, Daedalia Planum and Malea Planum have no sourced hook yet ('to_find'). Each needs one relatable, sourced fact before it gets a card." ], "changes": [ "25 September 2026 (before v3.2): Rebuilt as twin files (this facts file plus the page). Version 2.1 was 16 September 2026. The page is still a flat map; the 3D globe stays on the website.", "25 September 2026 (before v3.2): Updated the pins to 02-03's shared site list: ten sites instead of six. Added Phlegra Montes, Acidalia Planitia, Alba Mons and Elysium Planitia. Arcadia moved from 38°N, 165°W to SpaceX's AP-9 site at 40.0°N, 156.7°W; Deuteronilus from 42°N to 43.9°N.", "25 September 2026 (before v3.2): Corrected: the Arcadia ice is tens of metres thick, not 170 m; 170 m is Utopia's maximum (02-03 F-04, F-05). Utopia holds about one Lake Superior, not 1.2.", "25 September 2026 (before v3.2): Corrected: the 35°N ice-exposing crater is in Amazonis Planitia, not Arcadia (02-03 F-07). Zhurong found no liquid water to 80 m; it did not rule out ice (02-03 F-08).", "25 September 2026 (before v3.2): Corrected: the ice and the lava tubes are not on opposite sides of the planet. They sit in different latitude bands; Arsia is about 3,500 km from the city and Alba Mons has tubes at 40°N.", "25 September 2026 (before v3.2): Corrected: Olympus Mons is about 22 km high (quoted from 02-01), about 2.5 Everests, and covers about the area of Italy, not France. (Superseded in v3.1: 21.3 km and 2.4 Everests, read live from 02-01.)", "25 September 2026 (before v3.2): Corrected: the air on the Hellas floor is about 1/80 of Earth's, not 'under a hundredth'. It is about double the Martian average, not 'nearly twice'.", "25 September 2026 (before v3.2): Corrected: the Arsia skylights are possible cave openings 100 to 250 m across; the 2007 NASA report does not call them lava tubes.", "25 September 2026 (before v3.2): Corrected: the colour base is not certainly Viking data. Its maker combined colour-channel images he does not name. The height base is MOLA, as he states.", "25 September 2026 (before v3.2): Corrected: Argyre is not east of Hellas on this map; it is far to the right, near 43°W. The map text no longer gives directions that depend on the image.", "25 September 2026 (before v3.2): Removed unsourced claims: the dichotomy boundary at '20 to 40°N', Tharsis 'the size of Europe', Hellas 'the width of the Mediterranean', and ice 'under almost everything above 60°'.", "25 September 2026 (before v3.2): Removed the hand-drawn Tharsis and pole 'no' zones of the landing view. The view now shades ground that meets 02-03's height and latitude rules, from calibrated heights.", "25 September 2026 (before v3.2): Updated lander positions to NASA's Mars24 table and China's published Zhurong fix. All ten were already right to within about a degree.", "25 September 2026 (before v3.2): Added clickable pins for peaks, the canyon, basins, polar caps and landers, each with a card, a type icon and its fact IDs. Added a zoom, a scale bar with familiar trips, and distances from the city.", "25 September 2026 (before v3.2): Added M-03 (how the landing view is made) and M-04 (the ice view is a sketch). Updated M-01 to 40°N and M-02 to a worked-out distance.", "25 September 2026 (before v3.2): 25 September 2026, version 3.1: the site list and map regions are now read from 02-03 when the page is built, not copied. Short quotes stay, labelled with 02-03's IDs.", "25 September 2026 (before v3.2): Updated: Olympus Mons, Valles Marineris, Hellas, Mars's size and air, Everest (8,849 m), the Grand Canyon and Earth's air (1,013 mb) are now read from 02-01. Valles Marineris uses NASA's 3,870 km long, 600 km wide, 9.3 km deep: about 9 times the Grand Canyon's length and 5 times its depth.", "25 September 2026 (before v3.2): Corrected: the Hellas height anchor now sits at the basin's deepest point (34.4°S, 59.6°E), not its centre. The height fit, the height map, the landing view and the height ladder were redone.", "25 September 2026 (before v3.2): Added: Mars's land area against Earth's continents (02-01 F-46), and Mars 3 (1971), the first lander to send data. Lander count is now 11.", "25 September 2026 (before v3.2): Updated: F-01 now says the planet-wide height reference is uncertain by at least 3 m; M-01 says 02-03 holds the lead candidate site and 04.01 Cities fixes the exact spot.", "25 September 2026 (before v3.2): Removed: the rim height of Hellas and open questions made stale by reading 02-01 and 02-03 live.", "25 September 2026 (v3.2): Updated M-01: points to 02-03 R-02 and R-09 (Utopia is the next icy site; Acidalia is the fallback landing ground) instead of calling Utopia 'the strong alternative'. M-02: the tube outpost's place is undecided (02-03 R-03).", "25 September 2026 (v3.2): Removed from_02_03.sun_bands_deg (30 and 41): the sun scores now read 02-03's sun_limits_deg (30 and 40). The 'Where to land' view now labels the north 'outside SpaceX's solar limit', not 'too little sun'.", "25 September 2026 (v3.2): Corrected: the Hellas height anchor is renamed 'Hellas floor, typical depth'. Wikipedia gives the basin's depth (about 7,152 m), not its deepest point, and the lowest point on Mars is elsewhere (Badwater crater). Removed F-10's 'deepest point at about 34°S, 60°E'. The anchor's position and grey reading are unchanged, so the images are unchanged.", "25 September 2026 (v3.2): Corrected: Mars Pathfinder moved from 19.47°N to 19.10°N, 33.25°W (Wikipedia). Checked: the Arcadia Planitia label (49.02°N, 188.15°E) matches the USGS Gazetteer's current centre; Wikipedia's 47.2°N is an older value.", "25 September 2026 (v3.2): Updated: the AP-9, EM-16 and PM-1 height anchors now read their position and height from 02-03's site list, so the lead pin is exactly 40.02°N, 156.65°W. Positions on cards show up to two decimals.", "25 September 2026 (v3.2): Corrected links: 03-02 reads 02-03 F-35, not this file, so it is no longer listed as a user. The base-map question now points to 00-02 and 02-04, not 90 Making-of. Page title now 'Interactive map', matching the catalogue.", "25 September 2026 (v3.2): marked the old 22 km Olympus change line as superseded; Hellas air wording matches 02-03 (about twice the average).", "25 September 2026 (v3.3): the city pin moved to SpaceX's AP-1 (02-03 R-02). The AP-1 height anchor now reads the lead site from 02-03, and the AP-9 anchor reads 02-03 numbers.ap9. Both heights are unchanged (-3.9 km), so the height map needed no refit. M-01 and the website note say AP-1.", "26 September 2026 (v3.4): used_by lists 02-05 The site up close, which reads its places and the city positions.", "26 September 2026 (v3.5): M-02 now says the outpost goes on Arsia Mons at Jeanne (04-01-02 LT-01), reached by Starship hop (LT-06), with Alba Mons the fallback. M-01 points to 04-01-01. The local-terrain question now says the well field and port are placed (04-01-01 FC-02, FC-04). used_by: the old 04.01 Cities line becomes 04-01-02; adds 05-02.", "26 September 2026 (v3.6): used_by: back-links for 05-03, 05-06, 05-08 (wave 6 pages, from their leans_on as written today).", "26 September 2026 (v3.7): F-04 has a comparison line; the shelf life names a re-check date (March 2027), as the Research log (90-04) audit asked. Back-link for 00-05, which reads the map's height colours live.", "26 September 2026 (v3.8): Beauty pass: a new opening picture, Mars from space with the AP-1 pin, labelled as art; heights and depths in 4.2 are now drawn as hill and trench profiles (true heights, widths not to scale) over a sky and ground wash instead of plain bars; the height ladder's long labels fit on a phone.", "26 September 2026 (v3.9): Final fix round: The opening picture's sky colours are now read live from 02-07 SK-01 instead of typed; leans_on and quotes add 02-07. M-02: the distance to Arsia is to 02-03's Arsia caves survey point, not to the skylight Jeanne; Jeanne's own distance is 04-01-02's", "28 September 2026 (v3.10): Used by the Jezero science town (04-01-03).", "29 September 2026 (v3.11): New gazetteer (rule L-22): the one list of every named place in the library, with a plain name, category, label, relatable hook and, for the main places, a card with a to-scale comparison. Numbers are worked out by build.py from the files that own them. Now reads 02-08 for Jezero. Used by the Mars Through Time globe (05-11).", "30 September 2026 (v3.12): New section 4.7 Old shorelines: the ocean shoreline, its age, the Hellas lake, the ocean's size and the debate moved here from 05-11 (F-13 to F-17), with the drying story as M-05, so the planet's ancient water lives with the planet (00 L-24). Gazetteer entries can now carry their Ancient Mars names (the northern ocean, the Hellas lake, AP-1 as sea floor, Jezero's lake), moved here from 05-11's era labels.", "30 September 2026 (v3.13): Added the city experience to the files that read this source.", "1 October 2026 (v3.14): The city site's plain name is now 'Arcadia City site', after the owner named the city (04-01-01 FC-19).", "1 October 2026 (v3.15): Used by the Mars Atlas (05-13).", "1 October 2026 (v3.16): Hooks a visitor can relate to, asked by the owner: Arcadia's plain name is now Arcadia City, with the hook 'Where the first city on Mars will stand'; the northern lowlands' hook says an ocean may once have been there (the height step stays on its card); Phobos is 'a moon the size of a city' and says a Mars day, not a sol.", "2 October 2026 (v3.17): Asked by the owner (00-05 ST-18): the place cards a visitor reads now paint the scene instead of hedging. The ancient ocean, the Hellas lake and Arcadia's sea floor are told as true of their time ('An ocean across the north', 'A frozen lake in the deepest crater'), with no 'datum', 'may have been' or 'scientists still argue'; the debate stays in F-17 and under the website's 'What's real here?'. Today's lowlands card says only what is real and invites the visitor back in time. Phobos's card no longer shows a file number or the word sol, and Arcadia's no longer says AP-1.", "3 October 2026 (v3.18): Three new gazetteer places for the First Martians story (05-14): Home Plate, the Eridania basin and Nili Fossae. Their positions are owned by 02-09 and read live.", "3 October 2026 (v3.19): Now also used by 04-01-04 The cities of Mars, which places the towns of Many Cities and Self-sustaining Mars.", "3 October 2026 (v3.20): The gazetteer gains an 'earth' line for each place named on the atlas: one fact tied to something on Earth, every number worked out (th_pct, hel_gc_x, arg_ed_x, ely_ed_pct, scap_storeys and others). Argyre, Elysium Mons, Chryse and the southern highlands get a headline and a big number. New F-18: Viking 1 landed seven years to the day after Apollo 11. Asked for by the owner.", "4 October 2026 (v3.21): The parts of Valles Marineris the race's canyon run flies through (05-02 OR-18): new pins and gazetteer entries for the Labyrinth of Night (Noctis Labyrinthus), the Long Canyon (Ius Chasma), the Ridge Down the Middle (Geryon Montes), the Giant Landslides (Ius Labes), the Widest Stretch (Melas Chasma), the Layered Mountains (Candor Chasma) and the Canyon of Gold (Ophir Chasma), with facts F-19 to F-24 and numbers.canyon. Paris, Berlin and Madrid join the Earth cities, so each canyon's length is worked out against a familiar trip. Asked for by the owner.", "5 October 2026 (v3.22): Mars Atmosphere reads the canonical planet or gazetteer data.", "10 October 2026 (v3.23): 05-20 Mars games reads the gazetteer's name for Olympus Mons for its quiz card (link added both ways).", "10 October 2026 (v3.24): Added F-25 to F-35 and a 'story' line for the 11 places named on the home atlas (Hellas, Utopia, Argyre, Olympus Mons, Tharsis, Valles Marineris, Elysium Mons, Chryse, the southern highlands and both ice caps): how each came to be or its most striking fact, at the owner's request. Numbers in numbers.stories; reads 02-02 F-04 for the air swing." ], "sources_checked": "10 October 2026", "sources": { "usgs_mola": { "name": "USGS Astrogeology, Mars MGS MOLA DEM 463m (Smith and others, 2001; released 2003)", "url": "https://astrogeology.usgs.gov/search/map/mars_mgs_mola_dem_463m" }, "usgs_viking": { "name": "USGS Astrogeology, Mars Viking Global Color Mosaic 925m (PDS release 2001)", "url": "https://astrogeology.usgs.gov/search/map/mars_viking_global_color_mosaic_925m" }, "pixel_emporium": { "name": "James Hastings-Trew, Planet Pixel Emporium, Mars texture maps (site 2006, accessed September 2026)", "url": "https://planetpixelemporium.com/mars.html" }, "threex": { "name": "Jerome Etienne, threex.planets (GitHub), README and images folder (accessed September 2026)", "url": "https://github.com/jeromeetienne/threex.planets" }, "usgs_mons": { "name": "USGS Gazetteer of Planetary Nomenclature, Mars: Mons, montes (2026)", "url": "https://planetarynames.wr.usgs.gov/SearchResults?Target=20_Mars&Feature+Type=27_Mons,+montes" }, "usgs_planitia": { "name": "USGS Gazetteer of Planetary Nomenclature, Mars: Planitia (2026)", "url": "https://planetarynames.wr.usgs.gov/SearchResults?Target=20_Mars&Feature+Type=31_Planitia%2C+planitiae" }, "usgs_planum": { "name": "USGS Gazetteer of Planetary Nomenclature, Mars: Planum (2026)", "url": "https://planetarynames.wr.usgs.gov/SearchResults?Target=20_Mars&Feature+Type=32_Planum,+plana" }, "usgs_vm": { "name": "USGS Gazetteer of Planetary Nomenclature, Valles Marineris (2026)", "url": "https://planetarynames.wr.usgs.gov/Feature/6288" }, "giss_landers": { "name": "NASA GISS, Mars24 Sunclock: Mars lander missions, coordinates table (accessed September 2026)", "url": "https://www.giss.nasa.gov/tools/mars24/help/landers.html" }, "nssdc_landers": { "name": "NASA NSSDC Master Catalog, lander and rover pages (Viking 1 and 2, Pathfinder, Spirit, Opportunity, Phoenix, MSL, InSight, Mars 2020) (accessed September 2026)", "url": "https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1975-075C" }, "zhurong_site_2021": { "name": "Liu and others, Geomorphic contexts and science focus of the Zhurong landing site on Mars, Nature Astronomy, 2021 (CNSA landing fix)", "url": "https://www.nature.com/articles/s41550-021-01519-5" }, "dichotomy_wiki": { "name": "Wikipedia, Martian dichotomy, 2026", "url": "https://en.wikipedia.org/wiki/Martian_dichotomy" }, "tharsis_wiki": { "name": "Wikipedia, Tharsis, 2026", "url": "https://en.wikipedia.org/wiki/Tharsis" }, "olympus_wiki": { "name": "Wikipedia, Olympus Mons, 2026", "url": "https://en.wikipedia.org/wiki/Olympus_Mons" }, "vm_nasa": { "name": "NASA Science, Valles Marineris: the Grand Canyon of Mars (accessed September 2026)", "url": "https://science.nasa.gov/resource/valles-marineris-the-grand-canyon-of-mars/" }, "polar_wiki": { "name": "Wikipedia, Martian polar ice caps, 2026", "url": "https://en.wikipedia.org/wiki/Martian_polar_ice_caps" }, "insight_kit": { "name": "NASA JPL, InSight landing press kit: landing site, 2018", "url": "https://www.jpl.nasa.gov/news/press_kits/insight/landing/mission/landing-site" }, "city_coords": { "name": "Wikipedia city articles (London, Edinburgh, Rome, Cairo, New York City, Paris, Berlin, Madrid): coordinates, 2026", "url": "https://en.wikipedia.org/wiki/London" }, "hellas_wiki": { "name": "Wikipedia, Hellas Planitia, 2026", "url": "https://en.wikipedia.org/wiki/Hellas_Planitia" }, "ifab_pitch": { "name": "IFAB, Laws of the Game, Law 1: The field of play (accessed September 2026)", "url": "https://www.theifab.com/laws/latest/the-field-of-play/" }, "bramson_2015": { "name": "Bramson and others, Widespread excess ice in Arcadia Planitia, Mars, Geophysical Research Letters, 2015 (arXiv 1509.03210)", "url": "https://arxiv.org/abs/1509.03210" }, "crown_2022": { "name": "Planetary Science Institute, Large concentration of lava tubes on Alba Mons (Crown, Scheidt and Berman, JGR Planets), 2022", "url": "https://www.psi.edu/blog/psi-scientists-analyze-large-concentration-of-lava-tubes-on-martian-volcano-alba-mons/" }, "cushing_2007": { "name": "NASA JPL, NASA orbiter finds possible cave skylights on Mars (Cushing and others), 2007", "url": "https://www.jpl.nasa.gov/news/nasa-orbiter-finds-possible-cave-skylights-on-mars/" }, "dundas_2023": { "name": "Dundas and others, A large new crater exposes the limits of water ice on Mars, Geophysical Research Letters, 2023", "url": "https://doaj.org/article/a8658c3c93fd400a89d163a2d12500d7" }, "golombek_2021": { "name": "Golombek, Wooster and others, SpaceX Starship landing sites on Mars, LPSC 2021", "url": "https://www.hou.usra.edu/meetings/lpsc2021/pdf/2420.pdf" }, "jpl_ce_2022": { "name": "NASA JPL, InSight lander detects stunning meteoroid impact on Mars, 2022", "url": "https://www.jpl.nasa.gov/news/nasas-insight-lander-detects-stunning-meteoroid-impact-on-mars/" }, "stuurman_2016": { "name": "NASA JPL, Mars ice deposit holds as much water as Lake Superior (Stuurman and others), 2016", "url": "https://www.jpl.nasa.gov/news/mars-ice-deposit-holds-as-much-water-as-lake-superior/" }, "zhurong_2022": { "name": "Li and others, Layered subsurface in Utopia Basin of Mars revealed by Zhurong rover radar, Nature, 2022", "url": "https://www.nature.com/articles/s41586-022-05147-5" }, "nssdc_mars3": { "name": "NASA NSSDC Master Catalog, Mars 3 lander (accessed September 2026)", "url": "https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1971-049F" }, "pathfinder_wiki": { "name": "Wikipedia, Mars Pathfinder: landing site 19.10°N, 33.25°W (accessed September 2026)", "url": "https://en.wikipedia.org/wiki/Mars_Pathfinder" }, "scirep_2019": { "name": "Scientific Reports (2019), The 1997 Mars Pathfinder spacecraft landing site: spillover deposits from an early Mars inland sea (Contact 2 at -3,760 m, give or take 560 m)", "url": "https://www.nature.com/articles/s41598-019-39632-1" }, "parker_1993": { "name": "Parker, Gorsline, Saunders, Pieri and Schneeberger (1993), Coastal geomorphology of the Martian northern plains, Journal of Geophysical Research 98", "url": "https://doi.org/10.1029/93JE00225" }, "arxiv_2022": { "name": "Impact Craters and the Observability of Ancient Martian Shorelines (arXiv 2206.09816, 2022), citing Ivanov et al. (2017) for the 3.6 billion year age and Citron et al. (2018) for crustal warping", "url": "https://arxiv.org/abs/2206.09816" }, "moore_2001": { "name": "Moore and Wilhelms (2001), Hellas as a possible site of ancient ice-covered lakes on Mars, Icarus 154 (USGS)", "url": "https://pubs.usgs.gov/publication/70023375" }, "ntrs_2001": { "name": "NASA Technical Reports Server, abstract of Moore and Wilhelms (2001), naming the -5.8 km contour", "url": "https://ntrs.nasa.gov/citations/20010044409" }, "head_1999": { "name": "Head and others (1999), Possible ancient oceans on Mars: evidence from Mars Orbiter Laser Altimeter data (abstract; basin volume about 1.4 x 10^7 km³)", "url": "https://corpora.tika.apache.org/base/docs/govdocs1/407/407748.pdf" }, "our_ocean": { "name": "Our measurement, September 2026: mars-through-time/make-textures.py fills the MOLA heights to the shoreline and adds up area and depth, weighting each map row by latitude", "url": "https://github.com/arjunbrara123/wake-up-on-mars" }, "nasa_viking1": { "name": "NASA Science, Viking 1 (mission page, accessed October 2026)", "url": "https://science.nasa.gov/mission/viking/" }, "nasa_apollo11": { "name": "NASA, Apollo 11 mission overview (accessed October 2026)", "url": "https://www.nasa.gov/mission/apollo-11/" }, "wiki_noctis": { "name": "Wikipedia, Noctis Labyrinthus (accessed October 2026)", "url": "https://en.wikipedia.org/wiki/Noctis_Labyrinthus" }, "wiki_ius": { "name": "Wikipedia, Ius Chasma (accessed October 2026)", "url": "https://en.wikipedia.org/wiki/Ius_Chasma" }, "vm_wiki": { "name": "Wikipedia, Valles Marineris (accessed October 2026)", "url": "https://en.wikipedia.org/wiki/Valles_Marineris" }, "wiki_melas": { "name": "Wikipedia, Melas Chasma (accessed October 2026)", "url": "https://en.wikipedia.org/wiki/Melas_Chasma" }, "mazzanti_2016": { "name": "Mazzanti and others, Inferring the high velocity of landslides in Valles Marineris on Mars from morphological analysis, Earth, Planets and Space 68 (2016)", "url": "https://link.springer.com/article/10.1186/s40623-015-0369-x" }, "wiki_candor": { "name": "Wikipedia, Candor Chasma (accessed October 2026)", "url": "https://en.wikipedia.org/wiki/Candor_Chasma" }, "wiki_ophir": { "name": "Wikipedia, Ophir Chasma (accessed October 2026)", "url": "https://en.wikipedia.org/wiki/Ophir_Chasma" }, "wiki_utopia": { "name": "Wikipedia, Utopia Planitia (accessed October 2026)", "url": "https://en.wikipedia.org/wiki/Utopia_Planitia" }, "wiki_argyre": { "name": "Wikipedia, Argyre Planitia (accessed October 2026)", "url": "https://en.wikipedia.org/wiki/Argyre_Planitia" }, "bouley_2016": { "name": "Bouley and others, Late Tharsis formation and implications for early Mars, Nature, 2016 (reported by Smithsonian Magazine, 2016)", "url": "https://www.smithsonianmag.com/smart-news/martian-volcanoes-spewed-so-much-lava-planets-surface-shifted-180958277/" }, "dlr_cerberus_2020": { "name": "DLR, InSight locates marsquakes in the Cerberus Fossae region, 2020", "url": "https://www.dlr.de/en/images/2020/1/insight-locates-marsquakes-in-the-cerberus-fossae-region" }, "wiki_chryse": { "name": "Wikipedia, Chryse Planitia (accessed October 2026)", "url": "https://en.wikipedia.org/wiki/Chryse_Planitia" }, "jpl_stripes_1999": { "name": "NASA JPL, Magnetic stripes preserve record of ancient Mars, 1999", "url": "https://www.jpl.nasa.gov/news/magnetic-stripes-preserve-record-of-ancient-mars" }, "wiki_boreum": { "name": "Wikipedia, Planum Boreum (accessed October 2026)", "url": "https://en.wikipedia.org/wiki/Planum_Boreum" }, "wiki_australe": { "name": "Wikipedia, Planum Australe (accessed October 2026)", "url": "https://en.wikipedia.org/wiki/Planum_Australe" } }, "gazetteer": { "about": "The one list of every named place in the library (rule L-22), and the only place their plain names and hooks are written. Each entry points to where its position is owned ('where', written file:path#id), gives a plain name a visitor would recognise, a category, a label and a hook: one relatable line. Places with a card also have a headline, a big number, a short paragraph, an 'earth' line (one fact tied to something on Earth, shown on the atlas's place cards) and a to-scale comparison. Every number is a 'worked_out' rule read from the file that owns it; build.py checks and works them out once and gives the results to every page and to the website. A place with no sourced hook yet carries 'to_find' instead. 'label_at' positions are chosen for legibility where a region has no official centre: that choice is art. An entry may also give 'eras': how the place is named and described in another era (for now, Ancient Mars), filled the same way. An entry may also give a 'story': one surprising line on how the place came to be (or the most striking thing about it), shown on the atlas's and the globe's place cards.", "categories": { "mountain": "Mountain", "canyon": "Canyon", "crater": "Crater or basin", "plain": "Plain", "region": "Region", "ice": "Ice", "cave": "Caves", "site": "Landing site", "robot": "Robot", "moon": "Moon" }, "worked_out": { "oly_km": { "of": "02-01:olympus.height_km", "dp": 1 }, "oly_w": "02-01:olympus.width_km", "oly_ev": { "ratio": [ "02-01:olympus.height_km", "02-01:comparisons.everest_km.value" ], "dp": 1 }, "pav_pit": "02-01:numbers.geography.pavonis_pit_m", "vm_l": "02-01:numbers.geography.valles_l_km", "vm_w": "02-01:numbers.geography.valles_w_km", "vm_d": { "of": "02-01:numbers.geography.valles_d_km", "dp": 1 }, "vm_gc_l": { "ratio": [ "02-01:numbers.geography.valles_l_km", "02-01:comparisons.grand_canyon_km.value" ], "dp": 0 }, "vm_gc_d": { "ratio": [ "02-01:numbers.geography.valles_d_km", "02-01:comparisons.grand_canyon_depth_km.value" ], "dp": 0 }, "vm_room_m": { "minus": [ "02-01:numbers.geography.valles_d_km", "02-01:comparisons.everest_km.value" ], "times": 1000, "round": 10 }, "hel_w": "02-01:numbers.geography.hellas_w_km", "hel_d": { "of": "02-01:numbers.geography.hellas_depth_km", "dp": 1 }, "hel_ocean_x": { "ratio": [ "02-01:numbers.geography.hellas_depth_km", "02-01:comparisons.ocean_depth_km.value" ], "dp": 1 }, "hel_air_x": { "ratio": [ "02-01:numbers.atmosphere.hellas_pa", "02-01:numbers.atmosphere.pressure_pa" ], "dp": 1 }, "hel_rome_x": { "ratio": [ "02-01:numbers.geography.hellas_w_km", { "earth_km": [ "London", "Rome" ] } ], "dp": 1 }, "th_km": "02-04:numbers.tharsis_km", "th_h": "02-04:numbers.tharsis_high_km", "ny_km": { "earth_km": [ "London", "New York" ], "round": 10 }, "dich_lo": "02-04:numbers.dich_km.0", "dich_hi": "02-04:numbers.dich_km.1", "dich_pct": { "ratio": [ "02-04:numbers.dich_km.1", "02-01:comparisons.everest_km.value" ], "times": 100, "dp": 0 }, "ncap_km": "02-04:numbers.ncap_km", "ncap_vol": "02-04:numbers.ncap_million_km3", "ncap_ed_x": { "ratio": [ "02-04:numbers.ncap_km", { "earth_km": [ "London", "Edinburgh" ] } ], "dp": 1 }, "scap_km": "02-04:numbers.scap_km", "scap_thick": "02-04:numbers.scap_thick_km", "scap_co2": "02-04:numbers.scap_co2_m", "arc_km3": "02-03:numbers.arcadia_km3", "ap1_km": { "of": "02-03:sites.list#arcadia.elev_km", "times": -1, "dp": 1 }, "ut_lo": "02-03:numbers.utopia_thick_m.0", "ut_hi": "02-03:numbers.utopia_thick_m.1", "utc_lo": "02-03:numbers.utopia_cover_m.0", "utc_hi": "02-03:numbers.utopia_cover_m.1", "uti_lo": "02-03:numbers.utopia_ice_pct.0", "uti_hi": "02-03:numbers.utopia_ice_pct.1", "zh_year": "02-04:places.list#zhurong.year", "opp_year": "02-04:places.list#opportunity.year", "alba_segments": "02-03:numbers.alba_segments", "sisters": "02-03:numbers.sisters", "sis_lo": "02-03:numbers.sister_m.0", "sis_hi": "02-03:numbers.sister_m.1", "ce_w": "02-03:numbers.ce_width_m", "ce_lat": "02-03:numbers.ce_lat", "jz_age": "02-08:numbers.lake.age_bn", "jz_w": "02-08:numbers.jezero.width_km", "jz_lake_w": "02-08:numbers.lake.width_km", "jz_lake_m": "02-08:numbers.lake.depth_m", "jz_wm_x": { "ratio": [ "02-08:numbers.lake.width_km", "02-08:numbers.everyday.windermere_km" ], "dp": 1 }, "jz_landed": "02-08:numbers.landing.date", "ph_long": "02-01:numbers.moons.phobos_dims_km.0", "ph_man_x": { "ratio": [ "02-01:numbers.moons.phobos_dims_km.0", "02-01:comparisons.manhattan_km.value" ], "dp": 1 }, "ph_up": "02-07:numbers.phobos.above_km", "ph_laps": { "ratio": [ "02-01:numbers.time.sol_h", { "of": "02-07:numbers.phobos.period_days", "times": 24 } ], "dp": 1 }, "de_d": "02-01:numbers.moons.deimos_d_km", "de_orbit": "02-07:numbers.deimos.a_km", "de_period": { "of": "02-07:numbers.deimos.period_days", "times": 24, "hm": true }, "th_pct": { "ratio": [ "02-04:numbers.tharsis_km", "02-01:numbers.geography.radius_km" ], "times": 15.9155, "dp": 0 }, "hel_gc_x": { "ratio": [ "02-01:numbers.geography.hellas_depth_km", "02-01:comparisons.grand_canyon_depth_km.value" ], "dp": 0 }, "arg_w": "02-04:places.list#argyre.width_km", "arg_ed_x": { "ratio": [ "02-04:places.list#argyre.width_km", { "earth_km": [ "London", "Edinburgh" ] } ], "dp": 1 }, "ely_w": "02-04:places.list#elysium_mons.width_km", "ely_ed_pct": { "ratio": [ "02-04:places.list#elysium_mons.width_km", { "earth_km": [ "London", "Edinburgh" ] } ], "times": 100, "dp": 0 }, "v1_year": "02-04:places.list#viking1.year", "pf_year": "02-04:places.list#pathfinder.year", "scap_storeys": { "ratio": [ "02-04:numbers.scap_co2_m", "02-04:comparisons.storey_m" ], "dp": 1 }, "ed_km": { "earth_km": [ "London", "Edinburgh" ], "round": 10 } }, "list": [ { "id": "olympus", "where": "02-04:places.list#olympus", "plain_name": "Tallest mountain", "category": "mountain", "label": "real", "hook": "{oly_ev} times the height of Everest", "headline": "The tallest volcano in the Solar System", "big": "{oly_ev}×", "big_sub": "the height of Everest", "detail": "It rises {oly_km} km above Mars's average ground level and is about {oly_w} km wide, with a base about the size of Italy. The slopes are so gentle that a walker would barely notice the climb.", "compare": { "kind": "heights", "items": [ [ "Everest", "02-01:comparisons.everest_km.value", "earth" ], [ "Olympus Mons", "02-01:olympus.height_km", "mars" ] ] }, "facts": [ "02-01 F-48", "02-04 F-08", "02-04 F-28" ], "earth": "Its base would cover Italy, yet its slopes are so gentle that a walker would barely notice the climb.", "story": "Stand on the summit and you can't tell you're on a mountain: the slopes roll on past a horizon just {st_oly_hz} km away, and the air is only {st_oly_air}% as thick as at Mars's average ground." }, { "id": "tharsis", "where": "02-04:labels.list#Tharsis", "plain_name": "Volcano country", "category": "region", "label": "real", "hook": "About as wide as London to New York", "headline": "A bulge of giant volcanoes", "big": "{th_km} km", "big_sub": "across, and up to {th_h} km high", "detail": "A huge volcanic rise topped by three giant volcanoes in a row, with Olympus Mons on its edge. It is about as wide as London to New York ({ny_km} km).", "compare": { "kind": "lengths", "items": [ [ "London to New York", { "earth_km": [ "London", "New York" ] }, "earth" ], [ "Tharsis", "02-04:numbers.tharsis_km", "mars" ] ] }, "facts": [ "02-04 F-07", "02-04 F-29" ], "earth": "It stretches {th_pct}% of the way round Mars: on Earth, about as far as London to New York ({ny_km} km).", "story": "So heavy it tipped the planet: its weight slid the whole surface of Mars round and moved the poles. On Earth, the same shift would put Paris inside the Arctic Circle." }, { "id": "ascraeus", "where": "02-04:places.list#ascraeus", "plain_name": "Tharsis volcano, north", "category": "mountain", "label": "real", "hook": "One of three giant volcanoes in a row, {@width_km} km wide", "facts": [ "02-04 F-07" ] }, { "id": "pavonis", "where": "02-04:places.list#pavonis", "plain_name": "Tharsis volcano, middle", "category": "mountain", "label": "real", "hook": "A pit about {pav_pit} m deep may be a cave skylight", "facts": [ "02-01 F-52" ] }, { "id": "arsia", "where": "02-03:sites.list#arsia", "plain_name": "Volcano with cave skylights", "category": "cave", "label": "real", "hook": "{sisters} possible skylights, {sis_lo} to {sis_hi} m across", "facts": [ "02-03 F-29" ] }, { "id": "alba", "where": "02-03:sites.list#alba", "plain_name": "Lava-tube volcano", "category": "cave", "label": "real", "hook": "More than {alba_segments} mapped lava-tube segments", "facts": [ "02-03 F-31" ] }, { "id": "elysium_mons", "where": "02-04:places.list#elysium_mons", "plain_name": "Elysium's big volcano", "category": "mountain", "label": "real", "hook": "Peak of Mars's second volcano region, {@width_km} km wide", "facts": [ "02-04 F-04", "02-04 F-31" ], "headline": "The peak of Mars's second volcano region", "big": "{ely_w} km", "big_sub": "wide at its base", "earth": "Its base alone is about {ely_ed_pct}% of the way from London to Edinburgh.", "story": "Mars still shakes here. The long cracks beside this volcano are where NASA's InSight lander traced its first big marsquakes." }, { "id": "valles", "where": "02-04:places.list#valles", "plain_name": "Grand Canyon of Mars", "category": "canyon", "label": "real", "hook": "Everest would fit inside, with {vm_room_m} m to spare", "headline": "The biggest canyon in the Solar System", "big": "{vm_gc_d}×", "big_sub": "as deep as the Grand Canyon", "detail": "About {vm_l} km long, up to {vm_w} km wide and up to {vm_d} km deep. Laid across the USA it would stretch from California to New York, about {vm_gc_l} times the Grand Canyon's length.", "compare": { "kind": "canyon", "items": [ [ "Valles Marineris", "02-01:numbers.geography.valles_d_km", "mars" ], [ "Grand Canyon", "02-01:comparisons.grand_canyon_depth_km.value", "earth" ], [ "Everest", "02-01:comparisons.everest_km.value", "earth" ] ] }, "facts": [ "02-01 F-51", "02-04 F-09", "02-04 F-30" ], "earth": "Laid across the USA it would reach from California to New York, {vm_gc_l} times the Grand Canyon's length.", "story": "No river carved it. The ground tore apart as the giant volcanoes next door swelled, the way Africa's Great Rift Valley is opening on Earth." }, { "id": "hellas", "where": "02-03:sites.list#hellas", "name": "Hellas Planitia", "plain_name": "Deepest crater", "category": "crater", "label": "real", "hook": "{hel_d} km deep, the lowest ground on Mars", "headline": "The deepest basin on Mars", "big": "{hel_d} km", "big_sub": "below average ground level", "detail": "A crater {hel_w} km across, blasted out by a giant impact: {hel_rome_x} times the distance from London to Rome. Its floor is {hel_ocean_x} times as deep as Earth's oceans are on average, and the air down there is about {hel_air_x} times as thick as the Mars average.", "compare": { "kind": "depths", "items": [ [ "Earth's oceans, average", "02-01:comparisons.ocean_depth_km.value", "earth" ], [ "Hellas floor", "02-01:numbers.geography.hellas_depth_km", "mars" ] ] }, "facts": [ "02-01 F-50", "02-03 F-36", "02-04 F-10", "02-04 F-25" ], "eras": { "ancient": { "plain_name": "Hellas lake", "label": "world", "hook": "An ice-capped lake, {hellas_km} km down", "headline": "A frozen lake in the deepest crater", "big": "{hellas_km} km", "big_sub": "below Mars's average ground level, at the water's edge", "detail": "A sheet of ice caps a lake at the bottom of the planet's deepest crater. Its shoreline is still written in the landforms around the basin today.", "facts": [ "02-04 F-15" ] } }, "earth": "About {hel_gc_x} times as deep as the Grand Canyon, and {hel_rome_x} times as wide as London to Rome.", "story": "A single rock {st_hel_rock} km wide punched this hole {st_hel_age} billion years ago. The rock alone was wider than London to Paris." }, { "id": "argyre", "where": "02-04:places.list#argyre", "plain_name": "Giant impact crater", "category": "crater", "label": "real", "hook": "Its floor alone is {@width_km} km across", "facts": [ "02-04 F-04", "02-04 F-27" ], "headline": "One of the great impact basins of the south", "big": "{arg_w} km", "big_sub": "across its floor", "earth": "Its floor alone is {arg_ed_x} times as wide as London to Edinburgh ({ed_km} km).", "story": "A rock {st_arg_rock} km wide carved this basin {st_arg_age} billion years ago. Later it filled with water, which spilled out north through a long channel." }, { "id": "isidis", "where": "02-04:places.list#isidis", "plain_name": "Impact basin by Jezero", "category": "crater", "label": "real", "hook": "Perseverance landed on its western edge", "facts": [ "02-04 F-05" ] }, { "id": "jezero", "where": "02-08:numbers.jezero", "name": "Jezero Crater", "plain_name": "Old lake bed", "category": "crater", "label": "real", "hook": "A lake filled it {jz_age} billion years ago", "headline": "An old lake bed, explored by a rover", "big": "{jz_age} billion", "big_sub": "years since a lake filled it", "detail": "A river once filled this {jz_w} km crater with a lake {jz_lake_w} km across, {jz_wm_x} times the length of Windermere, and up to {jz_lake_m} m deep. NASA's Perseverance rover landed here on {jz_landed} to search its old river delta.", "compare": { "kind": "lengths", "items": [ [ "Windermere", "02-08:numbers.everyday.windermere_km", "earth" ], [ "Jezero's lake", "02-08:numbers.lake.width_km", "sea" ] ] }, "facts": [ "02-08 F-01", "02-08 F-02", "02-08 F-03", "02-08 F-04" ], "eras": { "ancient": { "plain_name": "Jezero lake", "hook": "A river-fed lake, {jz_age} billion years ago", "headline": "A lake with a river delta", "big": "{jz_lake_w} km", "big_sub": "across, and up to {jz_lake_m} m deep", "detail": "A river poured through a gap in the crater's western rim and built a delta into a lake {jz_lake_w} km across. The rocks Perseverance is exploring today were laid down here." } } }, { "id": "christmas_eve", "where": "02-03:sites.markers#christmas_eve", "name": "2021 impact crater", "plain_name": "Crater that dug up ice", "category": "crater", "label": "real", "hook": "A fresh {ce_w} m crater threw out ice at about {ce_lat}°N", "facts": [ "02-03 F-07" ] }, { "id": "lowlands", "where": "02-04:facts#F-06", "name": "The northern plains", "label_at": [ 58, 150 ], "plain_name": "Northern lowlands", "category": "region", "label": "real", "hook": "A third of Mars, sunk up to {dich_hi} km below the rest", "headline": "Mars is split in two", "big": "{dich_lo} to {dich_hi} km", "big_sub": "lower than the southern highlands", "detail": "The northern lowlands cover about a third of the planet. The step down from the south runs right round Mars and is up to {dich_pct}% of Everest's height. Go back in time and this low ground fills with an ocean.", "compare": { "kind": "heights", "items": [ [ "Everest", "02-01:comparisons.everest_km.value", "earth" ], [ "The great step", "02-04:numbers.dich_km.1", "mars" ] ] }, "facts": [ "02-04 F-06" ], "eras": { "ancient": { "plain_name": "Northern ocean", "label": "world", "hook": "{area_pct}% of Mars under water", "headline": "An ocean across the north", "big": "{area_pct}%", "big_sub": "of Mars under water", "detail": "An ocean covers the northern plains, about {depth_m} m deep on average, its shore wrapping right round the planet. Billions of years from now, the first city will stand on its floor.", "compare": { "kind": "depths", "items": [ [ "Earth's oceans, average", "02-01:comparisons.ocean_depth_km.value", "earth" ], [ "This ocean, average", { "of": "02-04:numbers.shoreline.mean_depth_m", "times": 0.001 }, "sea" ] ] }, "facts": [ "02-04 F-13", "02-04 F-14", "02-04 F-16" ] } } }, { "id": "highlands", "where": "02-04:facts#F-06", "name": "The southern highlands", "label_at": [ -30, -10 ], "plain_name": "Southern highlands", "category": "region", "label": "real", "hook": "{dich_lo} to {dich_hi} km higher than the north", "facts": [ "02-04 F-06", "02-04 F-33" ], "headline": "The old, cratered south", "big": "{dich_lo} to {dich_hi} km", "big_sub": "higher than the northern plains", "earth": "The step up from north to south is up to {dich_pct}% of the height of Everest.", "story": "The rock here still holds a lost magnetic field, frozen in stripes up to {st_stripe} km long, {st_stripe_x} times London to Rome. The north has almost none." }, { "id": "boreum", "where": "02-04:places.list#boreum", "name": "Planum Boreum", "plain_name": "North ice cap", "category": "ice", "label": "real", "hook": "{ncap_ed_x} times London to Edinburgh across", "headline": "The north ice cap", "big": "{ncap_vol} million km³", "big_sub": "of ice, mostly water", "detail": "About {ncap_km} km across in summer: {ncap_ed_x} times the distance from London to Edinburgh.", "compare": { "kind": "lengths", "items": [ [ "London to Edinburgh", { "earth_km": [ "London", "Edinburgh" ] }, "earth" ], [ "North ice cap", "02-04:numbers.ncap_km", "mars" ] ] }, "facts": [ "02-04 F-11", "02-04 F-34" ], "earth": "About {ncap_ed_x} times as wide as London to Edinburgh.", "story": "Wind spinning off the pole carves the ice into a giant swirl, and its layers stack up like tree rings: a diary of Mars's weather over millions of years." }, { "id": "australe", "where": "02-04:places.list#australe", "name": "Planum Australe", "plain_name": "South ice cap", "category": "ice", "label": "real", "hook": "Water ice under {scap_co2} m of dry ice", "headline": "The south ice cap", "big": "{scap_co2} m", "big_sub": "of dry ice on top", "detail": "Water ice about {scap_km} km across and {scap_thick} km thick, under a permanent layer of frozen carbon dioxide: the same stuff as the dry ice used for stage smoke.", "facts": [ "02-04 F-11", "02-04 F-35" ], "earth": "Its top layer of dry ice alone is about {scap_storeys} storeys of a building deep.", "story": "Each winter so much air freezes onto the poles that the whole sky of Mars thins by about {st_air_swing}%. In spring it bursts out of this ice in geysers that scratch spiders into it." }, { "id": "deuteronilus", "where": "02-03:sites.list#deuteronilus", "plain_name": "Glacier country", "category": "ice", "label": "real", "hook": "Glaciers hidden under rock, confirmed by radar", "facts": [ "02-03 F-03" ] }, { "id": "utopia", "where": "02-03:sites.list#utopia", "name": "Utopia Planitia", "plain_name": "Buried ice sheet", "category": "plain", "label": "real", "hook": "About a Lake Superior of water, under the soil", "headline": "A hidden ice sheet", "big": "{ut_lo} to {ut_hi} m", "big_sub": "thick, under {utc_lo} to {utc_hi} m of soil", "detail": "Radar found a buried layer that is {uti_lo} to {uti_hi}% water ice and covers more ground than New Mexico. It holds about as much water as Lake Superior. China's Zhurong rover landed nearby in {zh_year}.", "facts": [ "02-03 F-05", "02-04 F-26" ], "earth": "It holds about as much water as Lake Superior, and covers more ground than New Mexico.", "story": "The biggest impact crater on Mars hides under this plain: {st_uto} km across, {st_uto_x} times as wide as Hellas, filled in and smoothed flat." }, { "id": "arcadia", "where": "02-03:sites.list#arcadia", "also": [ "02-04:labels.list#Arcadia Planitia" ], "name": "AP-1, Arcadia Planitia", "plain_name": "Arcadia City", "category": "site", "label": "world", "hook": "Where the first city on Mars will rise", "headline": "Where Arcadia City will stand", "big": "{arc_km3} km³", "big_sub": "of buried ice across Arcadia", "detail": "Low, flat ground that SpaceX has scouted for its first landings, {ap1_km} km below Mars's average ground level. Under it lies a sheet of ice tens of metres thick: water for drinking, breathing and rocket fuel, right under the city's feet. Across Arcadia it adds up to roughly a Lake Superior.", "facts": [ "02-03 R-02", "02-03 F-04" ], "eras": { "ancient": { "hook": "Sea floor, {ap1_sea_m} m under the waves", "detail": "The ground where Arcadia City will one day stand lies here on the sea floor, about {ap1_sea_m} m under the waves.", "facts": [ "02-04 F-13", "02-03 R-02" ] } } }, { "id": "erebus", "where": "02-03:sites.list#erebus", "plain_name": "SpaceX candidate site EM-16", "category": "site", "label": "real", "hook": "The strongest shallow-ice radar signal of SpaceX's sites", "facts": [ "02-03 F-33" ] }, { "id": "phlegra", "where": "02-03:sites.list#phlegra", "plain_name": "SpaceX candidate site PM-1", "category": "site", "label": "real", "hook": "The sunniest of the icy candidates", "facts": [ "02-03 F-33" ] }, { "id": "acidalia", "where": "02-03:sites.list#acidalia", "plain_name": "Northern landing plain", "category": "plain", "label": "real", "hook": "Smooth ground that suits a natural landing", "facts": [ "02-03 F-35" ] }, { "id": "elysium", "where": "02-03:sites.list#elysium", "plain_name": "InSight's plain", "category": "plain", "label": "real", "hook": "Flat, dry and warm by Mars standards", "facts": [ "02-03 F-27" ] }, { "id": "amazonis", "where": "02-04:labels.list#Amazonis Planitia", "plain_name": "Smooth northern plain", "category": "plain", "label": "real", "hook": "A 2021 impact here threw out buried ice", "facts": [ "02-03 F-07" ] }, { "id": "chryse", "where": "02-04:labels.list#Chryse Planitia", "plain_name": "The first landing plain", "category": "plain", "label": "real", "hook": "Viking 1 and Pathfinder both landed here", "facts": [ "02-04 F-05", "02-04 F-18", "02-04 F-32" ], "headline": "Where the first robots set down", "big": "{v1_year}", "big_sub": "Viking 1 lands here", "earth": "Viking 1 touched down here seven years to the day after Apollo 11 landed on the Moon. Pathfinder followed in {pf_year}.", "story": "The great flood channels of Mars all end here. Water from the southern highlands and the Grand Canyon of Mars poured down into this low plain." }, { "id": "meridiani", "where": "02-04:labels.list#Meridiani Planum", "plain_name": "Opportunity's plain", "category": "plain", "label": "real", "hook": "Opportunity landed here in {opp_year}", "facts": [ "02-04 F-05" ] }, { "id": "syrtis", "where": "02-04:labels.list#Syrtis Major", "plain_name": "Syrtis Major", "category": "region", "label": "real", "to_find": "A sourced, relatable fact about Syrtis Major.", "facts": [ "02-04 F-04" ] }, { "id": "hesperia", "where": "02-04:labels.list#Hesperia Planum", "plain_name": "Hesperia Planum", "category": "plain", "label": "real", "to_find": "A sourced, relatable fact about Hesperia Planum.", "facts": [ "02-04 F-04" ] }, { "id": "lunae", "where": "02-04:labels.list#Lunae Planum", "plain_name": "Lunae Planum", "category": "plain", "label": "real", "to_find": "A sourced, relatable fact about Lunae Planum.", "facts": [ "02-04 F-04" ] }, { "id": "daedalia", "where": "02-04:labels.list#Daedalia Planum", "plain_name": "Daedalia Planum", "category": "plain", "label": "real", "to_find": "A sourced, relatable fact about Daedalia Planum.", "facts": [ "02-04 F-04" ] }, { "id": "malea", "where": "02-04:labels.list#Malea Planum", "plain_name": "Malea Planum", "category": "plain", "label": "real", "to_find": "A sourced, relatable fact about Malea Planum.", "facts": [ "02-04 F-04" ] }, { "id": "mars3", "where": "02-04:places.list#mars3", "plain_name": "Mars 3 lander", "category": "robot", "label": "real", "hook": "Landed {@year}: the first to send data from the surface", "facts": [ "02-04 F-05" ] }, { "id": "viking1", "where": "02-04:places.list#viking1", "plain_name": "Viking 1 lander", "category": "robot", "label": "real", "hook": "Landed {@year} on Chryse Planitia", "facts": [ "02-04 F-05" ] }, { "id": "viking2", "where": "02-04:places.list#viking2", "plain_name": "Viking 2 lander", "category": "robot", "label": "real", "hook": "Landed {@year} on Utopia Planitia", "facts": [ "02-04 F-05" ] }, { "id": "pathfinder", "where": "02-04:places.list#pathfinder", "plain_name": "Pathfinder and Sojourner", "category": "robot", "label": "real", "hook": "Landed {@year} with the small Sojourner rover", "facts": [ "02-04 F-05" ] }, { "id": "spirit", "where": "02-04:places.list#spirit", "plain_name": "Spirit rover", "category": "robot", "label": "real", "hook": "Landed {@year} in Gusev Crater", "facts": [ "02-04 F-05" ] }, { "id": "opportunity", "where": "02-04:places.list#opportunity", "plain_name": "Opportunity rover", "category": "robot", "label": "real", "hook": "Landed {@year} on Meridiani Planum", "facts": [ "02-04 F-05" ] }, { "id": "phoenix", "where": "02-04:places.list#phoenix", "plain_name": "Phoenix lander", "category": "robot", "label": "real", "hook": "Landed {@year} on the far northern plains", "facts": [ "02-04 F-05" ] }, { "id": "curiosity", "where": "02-04:places.list#curiosity", "plain_name": "Curiosity rover", "category": "robot", "label": "real", "hook": "Here since {@year}, in Gale Crater", "facts": [ "02-04 F-05", "02-01 F-16" ], "name": "Gale Crater", "headline": "Curiosity's home", "big": "{@year}", "big_sub": "the year Curiosity landed", "detail": "NASA's Curiosity rover landed in Gale Crater in {@year}. In April 2015 it photographed a Martian sunset, when the sky round the Sun turns blue: the reverse of Earth." }, { "id": "insight", "where": "02-04:places.list#insight", "plain_name": "InSight lander", "category": "robot", "label": "real", "hook": "Landed {@year} on Elysium Planitia", "facts": [ "02-04 F-05" ] }, { "id": "perseverance", "where": "02-04:places.list#perseverance", "plain_name": "Perseverance rover", "category": "robot", "label": "real", "hook": "Landed {@year} in Jezero Crater", "facts": [ "02-04 F-05" ] }, { "id": "zhurong", "where": "02-04:places.list#zhurong", "plain_name": "Zhurong rover", "category": "robot", "label": "real", "hook": "China's first Mars rover, landed {@year}", "facts": [ "02-04 F-05" ], "also": [ "02-03:sites.markers#zhurong" ] }, { "id": "phobos", "where": "02-01:numbers.moons", "name": "Phobos", "plain_name": "Phobos", "category": "moon", "label": "real", "hook": "A moon the size of a city, circling {ph_laps} times a Mars day", "headline": "A moon the size of a city", "big": "{ph_long} km", "big_sub": "long, {ph_man_x} times the length of Manhattan", "detail": "A lumpy rock that skims only {ph_up} km above the ground, racing round {ph_laps} times a Mars day. Because it outruns the planet's spin, it rises in the west and sets in the east, crossing the sky about twice a day.", "compare": { "kind": "lengths", "items": [ [ "Manhattan", "02-01:comparisons.manhattan_km.value", "earth" ], [ "Phobos", "02-01:numbers.moons.phobos_dims_km.0", "mars" ] ] }, "facts": [ "02-01 F-42", "02-07 F-07" ] }, { "id": "deimos", "where": "02-01:numbers.moons", "name": "Deimos", "plain_name": "Deimos", "category": "moon", "label": "real", "hook": "From the ground it looks like a bright star", "headline": "The small, far moon", "big": "{de_d} km", "big_sub": "across", "detail": "Mars's outer moon circles {de_orbit} km from the planet's centre, once every {de_period}. From the surface it shines like a star, as bright as Venus seen from Earth.", "facts": [ "02-01 F-44", "02-07 F-13" ] }, { "id": "home_plate", "where": "02-09:numbers.home_plate", "name": "Home Plate", "plain_name": "Hot-spring stone", "category": "region", "label": "real", "hook": "Silica like a hot spring's, {@width_m} m across", "facts": [ "02-09 F-12" ] }, { "id": "eridania", "where": "02-09:numbers.eridania", "name": "Eridania basin", "plain_name": "Lost southern sea", "category": "region", "label": "real", "hook": "Once held more water than all Mars's other lakes", "facts": [ "02-09 F-13" ] }, { "id": "nili_fossae", "where": "02-09:numbers.nili", "name": "Nili Fossae", "plain_name": "Hydrogen troughs", "category": "region", "label": "real", "hook": "Troughs {@length_km} km long, where rock makes hydrogen", "facts": [ "02-09 F-19" ] }, { "id": "noctis", "where": "02-04:places.list#noctis", "plain_name": "Labyrinth of Night", "category": "canyon", "label": "real", "hook": "A maze of canyons {noc_km} km across, about London to Madrid", "headline": "Where the Grand Canyon of Mars begins", "detail": "The ground here cracked and sank as magma drained away beneath the great volcanoes, leaving a maze of steep-walled canyons and tall mesas.", "facts": [ "02-04 F-19" ] }, { "id": "ius", "where": "02-04:places.list#ius", "plain_name": "The Long Canyon", "category": "canyon", "label": "real", "hook": "{ius_km} km of canyon, about London to Berlin", "headline": "The first great trench of the Grand Canyon of Mars", "detail": "A single canyon about {ius_km} km long, with side canyons carved where water seeped out at the foot of the walls.", "facts": [ "02-04 F-20" ] }, { "id": "geryon", "where": "02-04:places.list#geryon", "plain_name": "The Ridge Down the Middle", "category": "canyon", "label": "real", "hook": "A mountain ridge of ancient bedrock splits the canyon in two", "headline": "Two canyons for the price of one", "detail": "The ridge is the planet's old bedrock, left standing as the ground on either side dropped away.", "facts": [ "02-04 F-20" ] }, { "id": "labes", "where": "02-04:places.list#labes", "plain_name": "The Giant Landslides", "category": "canyon", "label": "real", "hook": "Whole canyon walls collapsed here, racing across the floor at over {slide_kmh} km/h", "headline": "Walls that fell", "detail": "Landslides in this canyon ran up to {slide_run_km} km across the floor.", "facts": [ "02-04 F-20", "02-04 F-22" ] }, { "id": "melas", "where": "02-04:places.list#melas", "plain_name": "The Widest Stretch", "category": "canyon", "label": "real", "hook": "The canyon's widest part, {melas_km} km long: about London to Edinburgh", "headline": "The heart of the Grand Canyon of Mars", "detail": "The widest part of the whole canyon system, with landslides piled up where it meets the canyons on either side.", "facts": [ "02-04 F-21" ] }, { "id": "candor", "where": "02-04:places.list#candor", "plain_name": "The Layered Mountains", "category": "canyon", "label": "real", "hook": "Mountains of rock laid down layer on layer, holding minerals that form in water", "headline": "A canyon full of mountains", "detail": "Its walls and mesas are stacked like the pages of a book, each layer a chapter of Mars's past.", "facts": [ "02-04 F-23" ] }, { "id": "ophir", "where": "02-04:places.list#ophir", "plain_name": "The Canyon of Gold", "category": "canyon", "label": "real", "hook": "Named after King Solomon's land of gold, and {ophir_km} km long", "headline": "The end of the run", "detail": "Ophir's walls show bands of dark volcanic rock and pale, layered deposits.", "facts": [ "02-04 F-24" ] } ] }, "worked_out": { "ocean_m": { "of": "02-04:numbers.shoreline.level_m", "times": -1 }, "shore_spread": "02-04:numbers.shoreline.spread_m", "ocean_age": "02-04:numbers.shoreline.age_bn", "area_pct": "02-04:numbers.shoreline.area_pct", "depth_m": "02-04:numbers.shoreline.mean_depth_m", "vol_mkm3": "02-04:numbers.shoreline.volume_million_km3", "head_vol": "02-04:numbers.shoreline.head_1999_million_km3", "earth_ocean_km": { "of": "02-01:comparisons.ocean_depth_km.value", "dp": 2 }, "ocean_depth_km": { "of": "02-04:numbers.shoreline.mean_depth_m", "times": 0.001, "dp": 2 }, "hellas_km": { "of": "02-04:numbers.hellas_lake.level_m", "times": -0.001, "dp": 1 }, "ap1_sea_m": { "minus": [ "02-04:numbers.shoreline.level_m", { "of": "02-03:sites.list#arcadia.elev_km", "times": 1000 } ] }, "dry_by": "02-04:numbers.drying.dry_by_bn", "jz_age": "02-08:numbers.lake.age_bn", "noc_km": "02-04:numbers.canyon.noctis_km", "ius_km": "02-04:numbers.canyon.ius_km", "melas_km": "02-04:numbers.canyon.melas_km", "candor_km": "02-04:numbers.canyon.candor_km", "ophir_km": "02-04:numbers.canyon.ophir_km", "slide_ms": "02-04:numbers.canyon.slide_ms", "slide_run_km": "02-04:numbers.canyon.slide_run_km", "slide_kmh": { "of": "02-04:numbers.canyon.slide_ms", "times": 3.6, "round": 10 }, "ldn_mad": { "earth_km": [ "London", "Madrid" ], "round": 10 }, "ldn_ber": { "earth_km": [ "London", "Berlin" ], "round": 10 }, "ldn_edi": { "earth_km": [ "London", "Edinburgh" ], "round": 10 }, "ldn_par": { "earth_km": [ "London", "Paris" ], "round": 10 }, "st_hel_rock": "02-04:numbers.stories.hellas_rock_km", "st_hel_age": "02-04:numbers.stories.hellas_age_bn", "st_hel_par_x": { "ratio": [ "02-04:numbers.stories.hellas_rock_km", { "earth_km": [ "London", "Paris" ] } ], "dp": 1 }, "st_uto": "02-04:numbers.stories.utopia_km", "st_uto_x": { "ratio": [ "02-04:numbers.stories.utopia_km", "02-01:numbers.geography.hellas_w_km" ], "dp": 1 }, "st_arg_rock": "02-04:numbers.stories.argyre_rock_km", "st_arg_age": "02-04:numbers.stories.argyre_age_bn", "st_arg_w": "02-04:numbers.stories.argyre_km", "st_oly_hz": "02-04:numbers.stories.olympus_horizon_km", "st_oly_air": { "ratio": [ "02-01:numbers.atmosphere.olympus_pa", "02-01:numbers.atmosphere.pressure_pa" ], "times": 100, "dp": 0 }, "st_stripe": { "of": "02-04:numbers.stories.stripe_km", "round": 10 }, "st_stripe_x": { "ratio": [ "02-04:numbers.stories.stripe_km", { "earth_km": [ "London", "Rome" ] } ], "dp": 1 }, "st_air_swing": "02-02:numbers.atm_swing_pct" } }, "02-01": { "file": "02-01", "title": "Physical constraints", "folder": "02", "facts_file": "02-01-physical-constraints.json", "version": "2.27", "status": "Active", "last_updated": "10 October 2026", "about": "Facts file for 02-01 Physical constraints, the physics of Mars that every other file builds on. The page is built from this file, the library catalogue and the page template. Change a fact here, then run build.py. Words in curly brackets, like {g}, are filled in from the numbers in this file when the page is built, so each number is typed once.", "one_line": "The physical rules of Mars: gravity, air, light, time, cold, radiation, dust, water, distance and scale. Every other file obeys this one.", "shelf_life": "The physics does not change, but the published figures do. NASA revised its Mars Fact Sheet in May 2025 (gravity now 3.73 mean), radiation doses rise and fall with the 11-year solar cycle, and the US perchlorate limit is still a 2026 proposal. Re-check these by September 2027, or before relying on them.", "header": { "purpose": "Pin down the real physics of Mars once: what is measured (Part One) and what we assume where nobody knows yet (Part Two).", "why": "Without one agreed Mars, every file and session quietly invents a slightly different planet and the world stops being believable.", "when": "Designing anything physical, writing any scene or tour, building game physics, lighting the sky, timing anything, or checking another file for realism.", "change": "Part One changes only with a cited source. Part Two assumptions can be challenged one at a time by ID. Edit this facts file, then run build.py.", "writing": "Every number is compared to something people know. Pictures first, short sentences, no walls of text." }, "comparisons": { "about": "Familiar yardsticks used only to compare. Each one either has a source below or is marked as our own round figure.", "person_kg": 80, "person_m": 1.8, "eye_m": 1.7, "drop_m": 2, "earth_jump_m": 0.5, "earth_jump_note": "a comfortable standing jump, not a measured figure (same figure as 00-02)", "window_fall_m": 3, "crate_kg": 100, "walk_kmh": 5, "storey_m": 3.2, "drink_l_day": 2, "room_m3": 50, "south_pole_july_c": { "value": -60.2, "source": "wiki_southpole" }, "vostok_c": { "value": -89.2, "source": "wmo_vostok" }, "everest_km": { "value": 8.849, "source": "britannica_everest" }, "manhattan_km": { "value": 21.6, "source": "wiki_manhattan" }, "ocean_depth_km": { "value": 3.682, "source": "noaa_ocean" }, "grand_canyon_km": { "value": 446, "source": "nps_grca", "note": "277 miles" }, "grand_canyon_depth_km": { "value": 1.83, "source": "nps_grca", "note": "6,000 feet at its deepest" }, "hair_um": { "value": 70, "source": "epa_pm" }, "pm25_um": { "value": 2.5, "source": "epa_pm" }, "beaufort": { "source": "metoffice_beaufort", "light_breeze_ms": 3, "storm_ms": 27 }, "std_atmosphere": { "source": "us_std_atm", "about": "U.S. Standard Atmosphere 1976 layers: base height (km), lapse rate (K per m), base temperature (K), base pressure (Pa). Used to find the height on Earth where the air is as thin as a given pressure.", "layers": [ [ 0, -0.0065, 288.15, 101325 ], [ 11, 0, 216.65, 22632.1 ], [ 20, 0.001, 216.65, 5474.89 ], [ 32, 0.0028, 228.65, 868.019 ], [ 47, 0, 270.65, 110.906 ] ], "R": 8.3144598, "g0": 9.80665, "M": 0.0289644 } }, "numbers": { "gravity": { "mean_ms2": 3.73, "eq_ms2": 3.69, "pole_ms2": 3.73, "escape_kms": 5.03 }, "earth": { "g_mean_ms2": 9.82, "escape_kms": 11.19, "pressure_pa": 101325, "o2_pct": 20.95, "n2_pct": 78.08, "density_kgm3": 1.217, "scale_height_km": 8.5, "a_mkm": 149.598, "peri_mkm": 147.095, "aph_mkm": 152.1, "irr_wm2": 1361, "tilt_deg": 23.44, "year_days": 365.256, "radius_km": 6371, "land_mkm2": 148.94, "water_pct": 70.8, "mean_c": 15, "eccentricity": 0.0167 }, "atmosphere": { "pressure_pa": 636, "pressure_range_pa": [ 400, 870 ], "olympus_pa": 72, "hellas_pa": 1240, "co2_pct": 95.1, "n2_pct": 2.59, "ar_pct": 1.94, "o2_pct": 0.16, "co_pct": 0.06, "h2o_ppm": 210, "density_kgm3": 0.016, "molecular_weight": 43.49, "scale_height_km": 11, "armstrong_pa": 6250, "conscious_s": 14, "sound_low_ms": 240, "sound_high_ms": 250, "sound_split_hz": 240, "sound_earth_ms": 343, "carry_m": 8, "carry_earth_m": 65, "talk_m": 5 }, "sun": { "a_mkm": 227.956, "peri_mkm": 206.65, "aph_mkm": 249.261, "irr_wm2": 586.2, "eccentricity": 0.0935 }, "time": { "sol_h": 24.6597, "year_days": 686.98, "tilt_deg": 25.19, "synodic_days": 779.94 }, "temperature": { "mean_c": -59, "high_c": 20, "low_c": -153, "feet_c": 24, "head_c": 0, "viking_c": [ -89, -31 ] }, "radiation": { "surface_msv_day": 0.64, "cycle_msv_day": [ 0.64, 1 ], "peak_depth_m": 0.3, "shield_m": [ 1, 1.6 ], "shield_target_msv": 100, "surface_msv_day_pm": 0.12, "cycle_mgy_day": [ 0.2, 0.32 ], "cycle_note": "0.64 mSv is RAD's measured dose equivalent near solar maximum (Hassler 2014). 1.0 is our scaling: the solar-minimum absorbed dose (0.32 mGy) times the same ratio. Guo et al. 2021 give the absorbed doses." }, "doses": { "flight_msv": 0.035, "xray_msv": 0.1, "background_msv": 3, "ct_chest_msv": 6.1, "uk_limit_msv": 20 }, "dust": { "radius_um": 1.5, "perchlorate_phoenix_pct": [ 0.4, 0.6 ], "perchlorate_curiosity_max_pct": 1.05, "perchlorate_ref_pct": 0.5, "epa_ugl": 20, "epa_options_ugl": [ 20, 40, 80 ], "opp_2014_wh": [ 375, 620 ] }, "water": {}, "comms": { "dist_mkm": [ 54.6, 401.4 ], "light_kms": 299792.458 }, "moons": { "phobos_dims_km": [ 26, 23, 18 ], "phobos_d_km": 22, "phobos_cross": "4 h 15 min", "phobos_every": "11 h 6 min", "phobos_max_lat": 70.4, "deimos_dims_km": [ 16.1, 11.8, 10.2 ], "deimos_d_km": 12.5, "deimos_up_days": 2.48, "moon_d_km": 3474.8, "earth_photo": "31 January 2014", "earth_photo_dist_mkm": 160 }, "geography": { "radius_km": 3389.5, "hellas_depth_km": 7.152, "hellas_w_km": 2300, "valles_l_km": 3870, "valles_w_km": 600, "valles_d_km": 9.3, "pavonis_pit_m": 90 }, "copies_of_03_06": { "about": "Sanctioned copy (00 L-17) of the town's burial depth, which 03-06 HA-01 owns (03-06 numbers.cover_m). The shielding drawing and F-28 need it, and 02 may not quote 03. build.py stops if the two differ.", "cover_m": 3 }, "orbits": { "epoch_jd": 2451545, "valid_years": [ 1800, 2050 ], "obliquity_deg": 23.43928, "au_km": 149597870.7, "earth_accuracy_arcsec": 20, "earth": { "a_au": [ 1.00000261, 5.62e-06 ], "e": [ 0.01671123, -4.392e-05 ], "i_deg": [ -1.531e-05, -0.01294668 ], "l_deg": [ 100.46457166, 35999.37244981 ], "peri_deg": [ 102.93768193, 0.32327364 ], "node_deg": [ 0, 0 ] }, "mars": { "a_au": [ 1.52371034, 1.847e-05 ], "e": [ 0.0933941, 7.882e-05 ], "i_deg": [ 1.84969142, -0.00813131 ], "l_deg": [ -4.55343205, 19140.30268499 ], "peri_deg": [ -23.94362959, 0.44441088 ], "node_deg": [ 49.55953891, -0.29257343 ] }, "about": "JPL's approximate elements (Table 1): each is [value at noon on 1 January 2000, change per century]. 'earth' is the Earth and Moon's shared centre." }, "clock": { "w0_deg": 176.63, "w_deg_per_day": 350.89198226, "tt_minus_utc_s": 69.184, "leap_seconds": 37, "tt_minus_tai_s": 32.184, "last_leap": "31 December 2016", "about": "How Mars's turn and astronomers' time are counted. w0_deg and w_deg_per_day: the IAU spin model. tt_minus_utc_s: how far Terrestrial Time runs ahead of ordinary clock time (this file owns it; 03-13's Mars Sol Date reads it)." }, "interior": { "about": "Inside Mars, from NASA's InSight lander and studies of Martian rock (F-56, F-57). The 2023 core radius replaces the 2021 one, kept for the record.", "core_radius_km": 1650, "core_radius_2021_km": 1830, "crust_km": [ 24, 72 ], "mantle_feo_pct": 14.7, "earth_mantle_feo_pct": 8.05 }, "look": { "from": "S-31", "about": "How the four dangers (thin air, cold, radiation and dust) and the city's answers to them look, so every picture, film and 3D scene of them matches (00-05 ST-20). The places are owned elsewhere and named beside each part: the plain by 02-05's look, the rows by 03-06's, the airlocks by 03-07 and the suits by 03-08. Shown in The First Martian City unless a part says otherwise.", "words": { "cover": "03-06:numbers.cover_m" }, "places": { "way_in": { "name": "The way in", "outside": "The end of a buried row: the long soil mound {cover} m thick over its steel vault (03-06 HA-01), and at its end the entrance porch, a printed airlock with a lamp, a small window, a grille to stamp the dust off, brushes, dust-shield panels and a blow-off nozzle under a canopy (03-07 AD-04). Radiator panels stand on the mound's flank (S-17). A pair of suited people coming home, red dust on their boots and knees.", "inside": "Cut away: the porch, then the lock with a vacuum and magnet wand, then the clean change room and a warm, bright room beyond, where people are in everyday clothes (03-07 AD-04, AD-05)." }, "plain": { "name": "Out on the plain", "outside": "02-05's plain: fine red soil, polygons, a flat skyline, butterscotch sky. Fine dust clings to everything that goes out (S-13)." } }, "palette": { "suit_white": "#F4F2EE", "suit_graphite": "#2E2C31", "suit_coral": "#E0825E", "visor": "#B88A3A", "soil": "#B4643C", "lamp": "#FFD9A8" }, "light": "Golden hour or dusk, so the porch lamp and the warm room inside glow against the cold plain; the blue glow round the setting Sun (02-07 F-02).", "people": "Outside always in suits and in pairs (03-08 SS-05), dusty from the plain; inside in everyday clothes. Small and natural, never posed.", "eras": { "city": "Classic airlocks and suitport locks at the rows' ends; heavy white suits (03-07 AD-06, 03-08 SS-13).", "far": "Slim second-skin suits for the plain, and people in everyday clothes under the domes' water roofs (03-06 HA-14)." }, "never": [ "Helmets off or skin bare outside", "Soil heaped straight on a home with no steel shell under it (03-06 HA-02)", "Dust inside the clean rooms", "Frozen or burst bodies, or anything gory", "A blue daytime sky, snow, rain, puddles or anything green growing outside", "Anyone outside without a suit, or working outside alone (03-08 SS-05)", "People posed for the camera or staring at it", "Brass, copper or old-fashioned gauges and lamps" ], "shots": [ { "id": "way_in_cut", "name": "The way in, cut open", "frame": "At dusk, the end of a buried row sliced open: the steel vault under its thick band of soil, radiator panels on the mound, and the entrance porch cut away to show a suited pair being brushed and blown clean on the porch, the lock beyond, and a warm room where people sit in everyday clothes. The plain and a blue-glowing sunset behind." } ], "open": [] } }, "olympus": { "about": "Olympus Mons figures are owned by this file. 00-01 and later map and game files quote them from here.", "height_km": 21.3, "height_note": "above Mars's average level (datum): MOLA gives 21.287 km (Wikipedia). Britannica's 22 km is measured from the surrounding area.", "above_plains_km": 26, "width_km": 600, "width_note": "Wikipedia 600 km, ASU THEMIS 585 km, Britannica 700 km", "slope_deg": [ 2, 5 ], "slope": "mostly 2 to 5 degrees, so gentle you would barely notice you were climbing", "scarp_km": 8, "summit_pa": 72, "sources": [ "wiki_olympus", "asu_themis", "britannica_olympus" ], "base_like": "about the size of Italy (about 300,000 km², Wikipedia)" }, "sections": [ { "id": "1.1", "title": "Gravity", "short": "Gravity" }, { "id": "1.2", "title": "Atmosphere", "short": "Air" }, { "id": "1.3", "title": "Sunlight and sky", "short": "Sunlight" }, { "id": "1.4", "title": "Time", "short": "Time" }, { "id": "1.5", "title": "Temperature", "short": "Temperature" }, { "id": "1.6", "title": "Radiation", "short": "Radiation" }, { "id": "1.7", "title": "Dust and regolith", "short": "Dust" }, { "id": "1.8", "title": "Water", "short": "Water" }, { "id": "1.9", "title": "Communications and distance", "short": "Distance" }, { "id": "1.10", "title": "Moons and night sky", "short": "Moons" }, { "id": "1.11", "title": "Scale and geography", "short": "Scale" } ], "facts": [ { "id": "F-01", "section": "1.1", "text": "Mars's average surface gravity is {g} m/s², against Earth's {g_earth} m/s². NASA also lists {g_eq} m/s² at the equator, where the spin flings you outward a little, and {g_pole} m/s² at the poles.", "compare": "{g_pct}% of Earth's pull: an {body_kg} kg adult weighs what a {feel_kg} kg child weighs on Earth.", "sources": [ "nasa_mars", "nasa_earth" ] }, { "id": "F-02", "section": "1.1", "text": "Things fall with that weaker pull. An object dropped from {drop_m} m, about head height, takes {fall_mars} s to land, against {fall_earth} s on Earth.", "compare": "{fall_ratio} times as long: it looks a little like slow motion.", "sources": [ "nasa_mars", "nasa_earth" ] }, { "id": "F-03", "section": "1.1", "text": "Escape velocity, the speed needed to leave the planet for good, is {esc} km/s, against Earth's {esc_earth} km/s.", "compare": "{esc_pct}% of Earth's: less than half the speed, so leaving Mars takes far less fuel.", "sources": [ "nasa_mars", "nasa_earth" ] }, { "id": "F-04", "section": "1.2", "text": "Average surface pressure is {p_pa} Pa ({p_mb} millibars). At average height it varies from about {p_lo} to {p_hi} Pa with season and weather, as carbon dioxide freezes onto the poles and returns. Height matters even more (F-05).", "compare": "{p_pct}% of Earth's sea-level air. On Earth you would have to climb about {alt_same} km, nearly {alt_ev} Everests, to find air this thin.", "sources": [ "nasa_mars", "us_std_atm" ] }, { "id": "F-05", "section": "1.2", "text": "Pressure also changes with height: about {olympus_pa} Pa on the summit of Olympus Mons, and about {hellas_pa} Pa on the floor of the Hellas basin in winter.", "compare": "The bottom of Hellas has about {hellas_x} times the air of the Olympus summit.", "sources": [ "wiki_olympus", "wiki_hellas" ] }, { "id": "F-06", "section": "1.2", "text": "By volume the air is {co2}% carbon dioxide, {n2}% nitrogen, {ar}% argon, {o2}% oxygen and {co}% carbon monoxide, with {h2o} parts per million of water vapour.", "compare": "Earth's air is {o2_earth}% oxygen: {o2_x} times the share. Counting the thin air too, each breath on Mars holds about {o2pp_x} times less oxygen.", "sources": [ "nasa_mars", "nasa_earth" ] }, { "id": "F-07", "section": "1.2", "text": "Below about {arm_pa} Pa, water in the body boils at body temperature (the Armstrong limit). On Earth that pressure is reached about {arm_km} km up. Mars's surface air is about {arm_x} times thinner than that.", "compare": "The Armstrong limit is about {arm_ev} Everests up; Mars is far beyond it.", "sources": [ "wiki_armstrong", "nasa_mars" ] }, { "id": "F-08", "section": "1.2", "text": "In an accidental exposure to near-vacuum in a NASA test chamber, the subject stayed conscious for about {conscious_s} seconds. After one or two minutes of exposure, a person is dying.", "compare": "{conscious_s} seconds is about the time oxygen-starved blood takes to travel from the lungs to the brain.", "sources": [ "nasa_vacuum" ] }, { "id": "F-09", "section": "1.2", "text": "The atmosphere's scale height, the climb over which pressure falls to about a third, is {sh} km, against about {sh_earth} km on Earth.", "compare": "Mars's air is thin, but it thins out more slowly as you go up. Worked out from F-04, F-09 and 02-03's lead site, about {site_km} km below average level: the air there is about {site_pa} Pa, roughly {site_more}% more than the planet-wide average.", "sources": [ "nasa_mars", "nasa_earth" ] }, { "id": "F-10", "section": "1.2", "text": "Perseverance's microphone measured two speeds of sound: about {snd_lo} m/s for low notes and {snd_hi} m/s for notes above {snd_hz} Hz. On Earth sound travels at {snd_earth} m/s.", "compare": "About {snd_pct}% of Earth's speed, and the high notes of a sound arrive slightly before the low ones.", "sources": [ "jpl_sound_2022", "cnrs_2022" ] }, { "id": "F-11", "section": "1.2", "text": "Sound carries only a short way: it fades out after about {carry_mars} m, against about {carry_earth} m on Earth, and high notes are lost first. Two people {talk_m} m apart would struggle to hold a conversation.", "compare": "Sound carries only about 1/{carry_x} as far as on Earth.", "sources": [ "jpl_sound_2022", "cnrs_2022" ] }, { "id": "F-12", "section": "1.2", "text": "The air is too thin for liquid water to last on the surface. It freezes or turns straight to vapour.", "compare": "Earth's surface is {ocean_pct}% water. Mars has no seas, lakes, rivers or rain.", "sources": [ "nasa_facts", "wiki_earth" ] }, { "id": "F-13", "section": "1.3", "text": "Mars orbits the Sun at an average {a_mars} million km, against Earth's {a_earth} million. Its orbit is stretched (eccentricity {ecc}, Earth {ecc_earth}): it swings between {peri} and {aph} million km.", "compare": "{au} times as far out. The yearly swing is {swing} million km; Earth's is only {swing_earth} million.", "sources": [ "nasa_mars", "nasa_earth" ] }, { "id": "F-14", "section": "1.3", "text": "Sunlight at the top of the air averages {irr} W/m², against {irr_earth} W/m² at Earth. Over the Mars year it swings from about {irr_lo} to {irr_hi} W/m².", "compare": "{irr_pct}% of Earth's sunlight: a solar panel needs about {panel_x} times the area to collect the same power, before dust.", "sources": [ "nasa_mars", "nasa_earth" ] }, { "id": "F-15", "section": "1.3", "text": "From Mars the Sun looks about {sun_size} as wide as it does from Earth.", "compare": "Only {sun_area}% of the disc area: a bright coin rather than a blazing disc.", "sources": [ "nasa_mars", "nasa_earth" ] }, { "id": "F-16", "section": "1.3", "text": "Fine dust colours the sky: yellow to orange by day. At sunset the sky close to the Sun turns blue, because the dust scatters blue light forward, near the Sun's direction. Curiosity photographed this in Gale crater in April 2015.", "compare": "The reverse of Earth, which has blue days and red sunsets.", "sources": [ "jpl_sunset_2015", "nasa_facts" ] }, { "id": "F-17", "section": "1.4", "text": "A Mars day, called a sol, lasts {sol_h} h {sol_m} min {sol_s} s.", "compare": "{sol_pct}% longer than an Earth day: like a clock that gains about {extra_min} minutes every day.", "sources": [ "nasa_mars" ] }, { "id": "F-18", "section": "1.4", "text": "A Mars year lasts {year_d} Earth days, which is {year_sols} sols.", "compare": "{year_ratio} Earth years: a 40-year-old would have had only {age40} Mars birthdays.", "sources": [ "nasa_mars" ] }, { "id": "F-19", "section": "1.4", "text": "Mars is tilted {tilt}° (Earth {tilt_earth}°), so it has seasons. The stretched orbit makes them uneven: from {season_lo} sols (northern autumn) to {season_hi} sols (northern spring), as counted in 02-02 F-01. Southern summer comes when Mars is closest to the Sun, so it is short and warm; southern winter is long and cold.", "compare": "{season_lo_mo} to {season_hi_mo} Earth months each: roughly twice an Earth season.", "sources": [ "nasa_mars", "nasa_earth", "wiki_timekeeping" ] }, { "id": "F-20", "section": "1.5", "text": "The average temperature is about {t_mean}°C.", "compare": "About the same as a midwinter (July) day at the South Pole, which averages {t_sp}°C.", "sources": [ "nasa_mars", "wiki_southpole" ] }, { "id": "F-21", "section": "1.5", "text": "Temperatures range from about {t_high}°C (equator, summer noon) down to about {t_low}°C (the poles).", "compare": "The low is {t_low_below} degrees colder than the coldest temperature ever measured on Earth: {t_vostok}°C at Vostok, Antarctica, in 1983.", "sources": [ "nasa_facts", "wmo_vostok" ] }, { "id": "F-22", "section": "1.5", "text": "The thin air holds little heat. NASA says that standing on the equator at noon would feel like spring at your feet ({t_feet}°C) and winter at your head ({t_head}°C).", "compare": "A {feet_head}-degree difference over the height of one person.", "sources": [ "nasa_facts" ] }, { "id": "F-23", "section": "1.5", "text": "At the Viking 1 landing site the air swings from about {vk_lo}°C to {vk_hi}°C in a single day.", "compare": "A {vk_swing}-degree swing every sol, and the night low matches Earth's all-time record cold.", "sources": [ "nasa_mars", "wmo_vostok" ] }, { "id": "F-24", "section": "1.6", "text": "Mars has no global magnetic field today, only patches of magnetised crust in the southern hemisphere, and its air is too thin to stop much radiation.", "compare": "Earth's magnetic field and thick air block most of the cosmic rays that reach Mars's ground.", "sources": [ "nasa_facts", "swri_2013" ] }, { "id": "F-25", "section": "1.6", "text": "Curiosity's RAD instrument measured an average dose of {rad_day} ± {rad_pm} mSv per day on the surface near solar maximum (August 2012 to June 2013, Hassler et al. 2014).", "compare": "About {rad_year} mSv a year: {rad_bg_x} years of natural background on Earth, or about {rad_ct} chest CT scans.", "sources": [ "hassler_2014", "radiologyinfo" ] }, { "id": "F-26", "section": "1.6", "text": "The dose changes with the 11-year solar cycle. RAD's absorbed dose rose from about {gy_lo} mGy a day near solar maximum (2012 to 2015) to about {gy_hi} at solar minimum (2019 to 2020), roughly {rad_lo} to {rad_hi} mSv a day (Guo et al. 2021; the {rad_hi} is our scaling of their figure).", "compare": "About {rad_y_lo} to {rad_y_hi} mSv a year; even the low end is about {rad_uk_lo} times the UK yearly limit for radiation workers.", "sources": [ "guo_2021", "hassler_2014", "irr17" ] }, { "id": "F-27", "section": "1.6", "text": "Solar storms add sudden spikes. In the event of 10 September 2017 the surface dose rate doubled within hours. That one was harmless; larger ones can come with little warning.", "compare": "Double the normal rate, for hours to days.", "sources": [ "guo_2021" ] }, { "id": "F-28", "section": "1.6", "text": "Soil shields, but a thin layer makes things worse at first. A computer model of cosmic rays alone (Zhang et al. 2022) puts the dose peak about {peak_cm} cm down, where cosmic rays smash into showers of secondary particles, and finds that about {sh_lo} to {sh_hi} m of soil brings the yearly dose below {sh_target} mSv; the depth depends on altitude and solar activity.", "compare": "{sh_target} mSv is still {sh_uk_x} times the UK worker limit ({uk_lim} mSv), so reaching Earth-like doses needs more. The town uses {cover_m} m (03-06 HA-01).", "sources": [ "zhang_2022", "space_2022", "irr17" ] }, { "id": "F-29", "section": "1.6", "text": "Everyday doses for comparison: a one-way flight across the USA {flight} mSv, a chest X-ray {xray} mSv, a year of natural background about {bg} mSv, a chest CT scan {ct_chest} mSv.", "compare": "One sol on the Mars surface is about {sol_xray} chest X-rays, or {sol_flights} coast-to-coast flights.", "sources": [ "cdc_flight", "radiologyinfo" ] }, { "id": "F-30", "section": "1.7", "text": "Airborne dust grains average about {dust_r} µm in radius, so about {dust_d} µm across (Spirit and Opportunity, 2004).", "compare": "About {dust_hair} grains side by side span one human hair ({hair} µm): as fine as the PM2.5 particles in city smog.", "sources": [ "lemmon_2004", "epa_pm" ] }, { "id": "F-31", "section": "1.7", "text": "The grains are very probably electrically charged, by rubbing together and by ultraviolet light, which makes them cling to everything.", "compare": "Like dust clinging to a television screen.", "sources": [ "nasa_dust_2012" ] }, { "id": "F-32", "section": "1.7", "text": "The soil holds perchlorate salts: {pc_phx_lo} to {pc_phx_hi}% by weight at the Phoenix site, and up to about {pc_cur}% in one Curiosity sample. Perchlorate stops the thyroid gland taking up iodine.", "compare": "One gram of soil at {pc_ref}% could push {pc_l} litres of water over the strictest limit the US EPA proposed in January 2026 ({epa} µg per litre; options {epa_opts}): about {pc_days} days of one person's drinking water.", "sources": [ "rzymski_2024", "epa_2026" ] }, { "id": "F-53", "section": "1.7", "text": "The dust and soil are weathered basalt: about {sio2}% silica and about {fe_ox}% iron oxides, the rust that colours Mars red (02-03 F-16).", "compare": "Nearly half is silica, the stuff of sand and glass.", "sources": [ "nasa_facts" ] }, { "id": "F-33", "section": "1.7", "text": "Global dust storms and dust detail belong to 02-02. Its figures: big storms come in southern spring and summer (02-02 F-12); a planet-wide storm comes about once every {gds_my} Mars years (02-02 F-13); in June 2018 Opportunity saw a record opacity of {tau}, against {tau_2007} in 2007 (02-02 F-17), and the solar-powered rover fell silent.", "compare": "Every {gds_my} Mars years is about {gds_ey} Earth years. Like a solar eclipse lasting up to about {storm_mo} months (the 2001 storm, 02-02 F-16): deadly for anything relying only on solar power.", "sources": [ "nasa_storms_2015", "jpl_opportunity_2018" ] }, { "id": "F-34", "section": "1.7", "text": "The strongest storm winds reach about {wind_mph} mph ({wind_ms} m/s, 02-02 F-20), but the air is only about {dens_pct}% as dense as Earth's.", "compare": "Storm force on the Beaufort scale ({wind_ms} m/s), but it pushes like a {felt_ms} m/s light breeze. Nobody gets blown over.", "sources": [ "nasa_storms_2015", "nasa_mars", "nasa_earth", "metoffice_beaufort" ] }, { "id": "F-35", "section": "1.7", "text": "Dust devils belong to 02-02. The tallest photographed was about {dd_km} km high and {dd_w} m wide (02-02 F-25).", "compare": "{dd_ev} times the height of Everest, yet carrying little force for the same reason storms do not.", "sources": [ "jpl_devil_2012", "britannica_everest" ] }, { "id": "F-36", "section": "1.8", "text": "Buried ice belongs to 02-03. Its figures: {scarps} eroding cliffs at {sc_lat_lo} to {sc_lat_hi}° latitude expose ice sheets more than {ice_m} m thick, starting as little as {ice_top_lo} to {ice_top_hi} m below the surface (02-03 F-06, Dundas et al. 2018). Shallow ground ice lies under roughly a third of the surface (02-03 F-01).", "compare": "More than {ice_storeys} storeys of ice, under less soil than a person is tall.", "sources": [ "usgs_ice_2018" ] }, { "id": "F-37", "section": "1.8", "text": "Ordinary soil holds water too: about {soil_pct}% by weight at Gale crater, released by heating (02-03 F-11).", "compare": "About {soil_l} litre of water (Leshin's 'two pints', 02-03 F-11) from every cubic foot ({cuft_l} litres, a box {cube_cm} cm on each side) of soil.", "sources": [ "space_water_2013" ] }, { "id": "F-38", "section": "1.8", "text": "The air holds only {h2o} parts per million of water vapour.", "compare": "A {room_m3} m³ room full of Mars air holds about {room_water_g} g of water: a drop or two.", "sources": [ "nasa_mars" ] }, { "id": "F-39", "section": "1.9", "text": "Earth and Mars are between {d_min} and {d_max} million km apart, depending on where they are in their orbits.", "compare": "A radio message takes {lt_min} to {lt_max} minutes one way, so the fastest possible reply takes {rt_min} to {rt_max} minutes. No live calls.", "sources": [ "nasa_mars" ] }, { "id": "F-40", "section": "1.9", "text": "About every two years the Sun passes between Earth and Mars, and missions stop sending commands for a few weeks. 01-05 F-26 owns the dates and how long the pauses last: {conj0}; {conj1}.", "compare": "Once every {syn_mo} months, a fortnight or more of near silence.", "sources": [ "nasa_conj_2025" ] }, { "id": "F-41", "section": "1.9", "text": "Earth and Mars line up for the shortest trips once every {syn_d} days. Perseverance's trip took {persev_d} days (01-01 F-16, from {persev_launch} to {persev_land}). Rockets and journeys belong to 01-01.", "compare": "A bus that leaves every {syn_mo} months and takes about {persev_mo} months to arrive.", "sources": [ "nasa_mars", "nasa_m2020" ] }, { "id": "F-42", "section": "1.10", "text": "Phobos is a lumpy rock {phobos_dims} km across. It orbits so fast that it rises in the west and sets in the east. Seen from the equator it crosses the sky in about {phobos_cross} and comes round about twice a sol (every {phobos_every}). 02-07 F-08 works out the lower, shorter passes seen from our site.", "compare": "About as long as Manhattan ({manhattan} km). Our Moon is about {moon_x} times wider.", "sources": [ "wiki_phobos", "nasa_mars", "wiki_manhattan", "nasa_moon" ] }, { "id": "F-43", "section": "1.10", "text": "Seen overhead from near the equator, Phobos is about a third as wide as the full Moon looks from Earth. From our site it never passes overhead (02-07 F-08, F-09). Because it orbits over the equator, it cannot be seen at all from latitudes above {phobos_lat}°.", "compare": "A third of a full Moon, crossing backwards.", "sources": [ "wiki_phobos" ] }, { "id": "F-44", "section": "1.10", "text": "Deimos is about {deimos_d} km across and looks almost like a star. At its brightest it is as bright as Venus seen from Earth. Seen from the equator it stays up for about {deimos_up} days between rising and setting (02-07 F-13 works it out for our site).", "compare": "About {deimos_man}% of the length of Manhattan.", "sources": [ "wiki_deimos", "wiki_manhattan" ] }, { "id": "F-45", "section": "1.10", "text": "Earth shows up as the brightest star in the evening or morning sky, with our Moon just beside it. Curiosity photographed both on {earth_photo}, from {earth_dist} million km away.", "compare": "Earth shines brighter than any star in the Martian night sky.", "sources": [ "jpl_earth_2014" ] }, { "id": "F-46", "section": "1.11", "text": "Mars is {mars_d} km across, about half Earth's width, with {area} million km² of surface.", "compare": "{area_land_pct}% of Earth's dry land ({land} million km²): about as much ground as all Earth's continents, with no oceans between.", "sources": [ "nasa_mars", "wiki_earth", "nasa_facts" ] }, { "id": "F-47", "section": "1.11", "text": "A smaller planet curves away sooner. With eyes {eye} m above flat ground, the horizon is about {hz_mars} km away, against {hz_earth} km on Earth.", "compare": "A {hz_walk}-minute walk to the edge of the world. On an Earth beach you see about {hz_pct}% further.", "sources": [ "nasa_mars", "nasa_earth" ] }, { "id": "F-48", "section": "1.11", "text": "Olympus Mons, the largest volcano in the solar system, rises about {oly_h} km above Mars's average level, and about {oly_plains} km above the plains to its north-west. It is about {oly_w} km wide, and its flanks slope only {oly_slope_txt}.", "compare": "{oly_ev} Everests high, with a base about the size of Italy (about 300,000 km²). So gentle that a walker would barely notice the climb.", "sources": [ "wiki_olympus", "asu_themis", "britannica_everest" ] }, { "id": "F-49", "section": "1.11", "text": "Its edge is a cliff up to {oly_scarp} km tall.", "compare": "In places, almost an Everest of sheer cliff.", "sources": [ "wiki_olympus", "britannica_everest" ] }, { "id": "F-50", "section": "1.11", "text": "The Hellas basin is about {hellas_w} km across, and its floor lies about {hellas_d} km below Mars's average level.", "compare": "Nearly {hellas_ocean_x} times the average depth of Earth's oceans ({ocean} km).", "sources": [ "wiki_hellas", "noaa_ocean" ] }, { "id": "F-51", "section": "1.11", "text": "Valles Marineris is a canyon system about {vm_l} km long, up to {vm_w} km wide and up to {vm_d} km deep from rim to floor.", "compare": "Long enough to stretch from California to New York: about {vm_gc_l} times the Grand Canyon's length and {vm_gc_d} times its greatest depth.", "sources": [ "nasa_facts", "nps_grca" ] }, { "id": "F-52", "section": "1.11", "text": "Lava tubes belong to 02-03. Its figures: Earth's tubes are usually {tube_lo} to {tube_hi} m across. From orbit, Martian collapse chains are {cc_lo} to {cc_hi} m wide, and the tubes beneath are estimated at up to about {mtube_hi} m wide, on average about {tube_x} times Earth's by volume, because of the lower gravity (02-03 F-28, Sauro et al. 2020). Pits that may be skylights into tubes have been photographed, such as one about {pit_m} m deep on Pavonis Mons.", "compare": "An Earth tube is at most about {tube_storeys} storeys across; the widest Mars tubes could hold a town.", "sources": [ "sauro_2020", "phys_2020", "jpl_pavonis_2014" ] }, { "id": "F-53", "section": "1.3", "text": "Where Earth and Mars are on any date comes from JPL's published orbit elements: six numbers for each planet at the start of {orb_epoch} and how fast each drifts, fitted to JPL's full planetary ephemeris for the years {orb_from} to {orb_to}. The Earth numbers are for the shared centre of the Earth and the Moon. Earth's place comes out right to about {orb_arcsec} arcseconds.", "compare": "Worked out: {orb_arcsec} arcseconds at Earth's distance from the Sun is about {orb_err_km} km, roughly one Earth width ({earth_w} km). That moves a radio message's travel time by about {orb_err_s} of a second.", "sources": [ "jpl_approx_pos" ] }, { "id": "F-54", "section": "1.4", "text": "Mars turns {spin_rate}° a day against the stars, starting from {spin_w0}° at noon on 1 January 2000. Angles are measured from the small crater Airy-0, which marks 0° longitude. This is the IAU's standard model for Mars's spin.", "compare": "Worked out: one full turn takes {spin_h} h {spin_m} min, about {spin_short} minutes less than a sol (F-17), because Mars also moves along its orbit and has to turn a little further to face the Sun again.", "sources": [ "iau_2009", "nasa_mars" ] }, { "id": "F-55", "section": "1.4", "text": "Astronomers' clocks (Terrestrial Time) run {tt_s} seconds ahead of the clocks on our phones: {leap_n} leap seconds added since 1972, plus a fixed {tt_fixed} seconds. None has been added since {last_leap}, and none will be at the end of 2026.", "compare": "Just over a minute, which is enough for Phobos to travel about {tt_phobos_deg}° round Mars (02-07 F-07).", "sources": [ "iers_c72" ] }, { "id": "F-56", "section": "1.11", "text": "NASA's InSight lander listened to marsquakes to see inside Mars. Its crust is {crust_lo} to {crust_hi} km thick on average (Knapmeyer-Endrun and others, Science, 2021). Its metal core, mostly iron, has a radius of about {core_km} km, under a layer of molten rock at the bottom of the mantle (Samuel and others, Nature, 2023; a 2021 study had put the core at {core_2021} km).", "compare": "The core reaches about {core_pct}% of the way from the centre to the surface; the crust is a skin about {crust_pct}% as thick as Mars is wide.", "sources": [ "insight_crust_2021", "insight_core_2023" ] }, { "id": "F-57", "section": "1.7", "text": "Mars's rock is rich in iron. Its mantle is about {feo_mars}% iron oxide by weight (Yoshizaki and McDonough, 2020), against about {feo_earth}% in Earth's mantle (McDonough and Sun, 1995). Its lavas carry that iron to the surface, which is why rusting can turn the whole planet red (02-03 F-37).", "compare": "About {feo_x} times as much iron oxide as Earth's mantle.", "sources": [ "yoshizaki_2020", "mcdonough_1995" ] }, { "id": "F-58", "section": "1.7", "text": "The wind cleans as well as dirties. In March 2014 a run of wind events swept much of the dust off Opportunity's solar panels: by mid-April they made more than {opp_hi} watt-hours a day, against less than {opp_lo} in January.", "compare": "Like a car's dusty windscreen wiped clean: the same panels gave about two thirds more power.", "sources": [ "nasa_pia18079" ] } ], "assumption_groups": [ { "id": "2.1", "title": "Movement and the body", "icon": "body" }, { "id": "2.2", "title": "Light, colour and shadow", "icon": "sun" }, { "id": "2.3", "title": "Sound", "icon": "sound" }, { "id": "2.4", "title": "Dust behaviour", "icon": "dust" }, { "id": "2.5", "title": "Heat and cold", "icon": "thermo" }, { "id": "2.6", "title": "Living underground", "icon": "under" }, { "id": "2.7", "title": "Air, water, power and food", "icon": "drop" }, { "id": "2.8", "title": "Time and the rhythm of life", "icon": "clock" }, { "id": "2.9", "title": "The horizon and the view", "icon": "eye" } ], "assumptions": [ { "id": "S-01", "group": "2.1", "title": "Walking gait", "confidence": "High", "text": "In {g_pct}% gravity a normal Earth walk is inefficient. People take longer, slower strides with a slight bounce, like a milder version of the Apollo moonwalkers' lope. Indoors they move with a loose, skipping economy. Running is a series of long bounds.", "why": "Gravity is the main variable (F-01). Apollo film and parabolic-flight studies point this way." }, { "id": "S-02", "group": "2.1", "title": "Falling and jumping", "confidence": "High", "text": "A standing jump goes about {jump_x} times as high: a comfortable {jump_earth} m hop becomes about {jump_mars} m, lifting your feet to chest height. A fall from {win_m} m (a first-floor window) lands like a fall from {win_eq} m on Earth (a kitchen worktop). Dropped tools take long enough to land to feel wrong to a new arrival. Ceilings can be higher, stairs steeper, and mistakes are more forgiving.", "why": "Jump height and landing speed follow directly from gravity (F-01, F-02)." }, { "id": "S-03", "group": "2.1", "title": "Heavy objects", "confidence": "High", "text": "A {crate} kg crate lifts as if it were {crate_feel} kg, but it still has {crate} kg of inertia. Pushing it into motion is as hard as on Earth, and stopping it is just as hard. The classic Mars injury we assume: being crushed or knocked down by something you could lift but could not stop.", "why": "Weight changes with gravity; mass, and the effort to start or stop it, does not (F-01)." }, { "id": "S-04", "group": "2.1", "title": "Deconditioning", "confidence": "Medium", "text": "Residents lose bone and muscle over the years unless they train hard. We assume daily resistance exercise of about 1.5 to 2 hours, and that long-term residents may find it hard to return to Earth comfortably after about a decade.", "why": "A working figure with no direct evidence. Space station data at zero gravity is the closest comparison, and {g_pct}% gravity is probably much kinder. 04-02-03 SG-03 builds its decade decision on this; the body physics stays here.", "moves_to": "" }, { "id": "S-05", "group": "2.1", "title": "Suit movement", "confidence": "Medium", "text": "Surface suits are mechanical counter-pressure suits or low-pressure soft suits with hard torsos: far more mobile than Apollo suits, but still stiff at the joints. Bending to pick something up is awkward and kneeling is a deliberate act. People outside move with a careful deliberateness.", "why": "Unprotected exposure is fatal within minutes (F-07, F-08), so everyone outside is suited. The suit type is our engineering choice. 03-08 SS-01 chooses the hard-torso, rear-entry gas suit." }, { "id": "S-30", "group": "2.1", "title": "One gravity for the whole world", "confidence": "High", "text": "The 3D world uses {g} m/s² everywhere. Real gravity varies by about 1% between the equator ({g_eq}) and the poles ({g_pole}), and slightly with height: too little for anyone to feel.", "why": "New in version 2.0. Follows F-01 and keeps the engine simple: 00-02 reads this value as surface_gravity." }, { "id": "S-06", "group": "2.2", "title": "Daylight quality", "confidence": "High", "text": "Midday outdoors looks like a dim, hazy late afternoon on Earth with a warm tan cast: think of a dull November afternoon in London rather than a summer day. Colours are muted and shifted towards orange and brown, and white objects look cream. Shadows are softer than you would expect because dust scatters so much light, but they are still clearly there.", "why": "{irr_pct}% sunlight plus a dust-lit sky (F-14, F-16, F-30). The London comparison is a judgement, not a measurement." }, { "id": "S-07", "group": "2.2", "title": "Blue sunsets", "confidence": "High", "text": "Sunset is the signature sight of Mars. The sky near the Sun goes cool blue while the rest stays tan, and twilight lingers because dust high in the air keeps catching light. In the world, the blue sunset is a cultural touchstone: it is what people go up to the surface to see.", "why": "The blue sunset is measured (F-16). Making it a cultural touchstone is our story choice." }, { "id": "S-08", "group": "2.2", "title": "Interior lighting", "confidence": "Medium", "text": "Most people live buried and rarely see daylight. Interiors use full-spectrum, tunable lighting on a {sol_h} h {sol_m} min cycle that mimics Earth daylight rather than Mars daylight, to keep sleep and mood steady. Inside feels like Earth, outside feels alien, and the change at an airlock is jarring. Light shafts and periscopes bring real sky into a few shared spaces as a luxury.", "why": "Follows from living underground (S-18) and the sol (F-17)." }, { "id": "S-09", "group": "2.2", "title": "Night", "confidence": "High", "text": "Nights are pitch black and packed with stars when dust is low. Phobos crossing the sky backwards in a few hours is a visible, slightly unsettling thing residents notice. Earth is the brightest thing in the morning or evening sky, and people look for it.", "why": "Neither moon gives much light (F-42 to F-44); Earth is a bright evening star (F-45)." }, { "id": "S-10", "group": "2.3", "title": "Outdoor sound", "confidence": "High", "text": "Outside, sound is thin, quiet and dull. High notes die within metres, and even unsuited people {talk_m} m apart could hardly talk. In practice all outdoor talk is by radio, and the sound inside a suit is your own breathing, the pumps and the radio. A storm wind is a faint low hiss through the suit, never a roar.", "why": "Measured by Perseverance's microphone (F-10, F-11)." }, { "id": "S-11", "group": "2.3", "title": "Indoor sound", "confidence": "Medium", "text": "Habitats run at reduced pressure with extra oxygen (S-21), so sounds are a little quieter than on Earth for the same effort. Small hard-walled rooms sound dead rather than echoey. There is a permanent background of fans, pumps and air handling; true silence is alarming because it means something has stopped.", "why": "Thinner air carries sound less strongly. Version 1 said voices sound higher; that was removed, because pitch depends on the gas mix and temperature, not the pressure." }, { "id": "S-12", "group": "2.4", "title": "Dust in the air", "confidence": "Medium", "text": "Kicked-up grit and sand fly in long, slow arcs. Kicked at the same speed, a grain stays in the air about {throw_x} times as long as on Earth and lands about {throw_x} times as far away. Dropped from the same height, it takes only {fall_ratio} times as long to land. The finest dust is so light that it hangs as haze for a long time. A rover leaves a plume that drifts for tens of seconds; footsteps raise little puffs. In the game, thrown particles follow Mars gravity, and fine dust lingers.", "why": "Grit follows gravity (F-01, F-02): time in the air for something thrown at a set speed grows with Earth's gravity divided by Mars's; time to fall a set height grows only with the square root of that. Version 1 said all dust falls at about 40% of the speed visitors expect; that is true for grit, but very fine dust settles by different rules in thin air, so confidence drops to Medium. Version 2.1 used the drop figure for kicked grit; corrected in 2.2." }, { "id": "S-13", "group": "2.4", "title": "Dust on everything", "confidence": "High", "text": "Dust clings to suits, tools and vehicles and works into every seal and joint. Airlocks are the most important rooms in the settlement, with multi-stage cleaning: electrostatic wands, brushing, air blasts and vacuum. Bringing dust inside is a serious breach because of perchlorate. A suit that has been outside never enters living space.", "why": "Fine, charged, toxic dust (F-30 to F-32)." }, { "id": "S-14", "group": "2.4", "title": "Dust storms", "confidence": "Medium", "text": "See 02-02 W-04, which owns what a dust storm is like to live through. The physics stays here: a storm wind pushes like a light breeze (F-34), so nobody is blown away.", "why": "Storm experience belongs to 02-02 (weather). Moved in version 2.2 so it is written once. Wind force is F-34.", "moved_to": "02-02 W-04" }, { "id": "S-15", "group": "2.4", "title": "Static", "confidence": "Medium", "text": "See 02-02 W-07, which owns static sparks and how the settlement guards against them. The physics stays here: dust grains are charged and cling to everything (F-31).", "why": "Static sparks are recorded in 02-02 F-26 and owned by 02-02 W-07. Moved in version 2.2 so it is written once.", "moved_to": "02-02 W-07" }, { "id": "S-16", "group": "2.5", "title": "Cold does not feel like Earth cold", "confidence": "High", "text": "Standing outside at {t_mean}°C in a suit is not like standing in {t_mean}°C air on Earth, because the thin air carries away little heat. Most heat leaves through the boots (into the ground) and by radiating to the sky. Suits are insulated most heavily at the feet. Sun on one side and shade on the other feels like a strong hot-cold split.", "why": "Thin air holds and moves little heat (F-04, F-22)." }, { "id": "S-17", "group": "2.5", "title": "Everything is a heat problem", "confidence": "High", "text": "Waste heat is hard to get rid of because there is little air to carry it away, so radiators are big and visible on every habitat and vehicle. Anything left out at night freezes hard: outdoor equipment is rated to about {rate_c}°C, below the {dry_ice}°C at which dry-ice frost forms, and machines are warmed up before use.", "why": "Thin air and big daily swings (F-21, F-23). 02-02 W-06 puts dry-ice frost on parked vehicles on winter mornings, and dry ice needs about {dry_ice}°C (02-02 F-08), so the rating sits just below that. The margin is our choice; kit for the poles ({t_low}°C, F-21) needs more. Version 2.1 said -100°C, which was warmer than the frost." }, { "id": "S-18", "group": "2.6", "title": "Settlement form", "confidence": "High", "text": "The settlement is mostly underground or buried: in lava tubes where available, otherwise in cut-and-cover trenches or modules under metres of soil (how deep is 03-06 HA-01). Glass domes and see-through surface habitats are not part of this world. On the surface: landing pads, solar and reactor fields, radiators, antennas, industrial plant, heavily shielded greenhouse skylights and short-stay viewing rooms.", "why": "About 1 to 1.6 m of soil gets the dose below 100 mSv a year (F-28), so burial itself is High confidence and stays here as a world rule. The burial depth is an engineering choice: it moved to 03-06 HA-01 (Medium), which chooses {cover_m} m. The physics stays here.", "confidence_note": "High that the town is buried; the depth (Medium) is 03-06 HA-01", "moved_to": "03-06 HA-01" }, { "id": "S-19", "group": "2.6", "title": "Lava tube outposts", "confidence": "Medium", "text": "Lava tubes are used where they exist, for outposts such as Arsia Mons or Alba Mons: a natural rock roof as radiation shield over closed pressure shells set on the tube floor (04-01-02 LT-04). The main city is not in a tube, because the lead site (02-03 R-02, Arcadia) has ice but no tubes; it is buried modules, per S-18.", "why": "Martian tubes can be huge (F-52, from 02-03). Where the tubes are belongs to 02-03; 04-01-02 LT-01 places the outpost at the skylight Jeanne on Arsia Mons." }, { "id": "S-20", "group": "2.6", "title": "Living enclosed", "confidence": "Medium", "text": "Being shut in, with no horizon, is the main long-term strain on people, more than danger. Design answers: large shared caverns with projected sky, green growing spaces visible from homes, and regular surface trips as a right rather than a job.", "why": "A judgement based on long stays in polar bases and space stations. No direct evidence yet." }, { "id": "S-21", "group": "2.7", "title": "Habitat air", "confidence": "Medium", "text": "See 03-09 LS-01, which now owns the habitat air: its pressure, its oxygen share and how oxygen is made.", "why": "Moved in version 2.6 so the cabin air is written once. The physics stays here: the air outside is {co2}% carbon dioxide (F-06), with a little nitrogen and argon, which 03-09 LS-02 uses as the buffer gas.", "moved_to": "03-09 LS-01" }, { "id": "S-22", "group": "2.7", "title": "Water source", "confidence": "Medium", "confidence_note": "High that it is ice, Medium on the method", "text": "Water comes from buried ice, dug out or melted out, then cleaned of perchlorate and dust and stored in large buried tanks. Inside, water is recycled at over 95%: this week's shower water is mostly last week's, cleaned. Ice mining is a major surface job and one of the day-in-the-life missions.", "why": "Ice sheets lie close under the surface (F-36). The International Space Station now recycles {iss_pct}% of its water (01-01 F-30), so 95% is reachable. How the ice is mined belongs to 03-01.", "sources": [ "usgs_ice_2018" ], "moves_to": "" }, { "id": "S-23", "group": "2.7", "title": "Power", "confidence": "High", "text": "See 03-03 G-01, which now owns the power plan.", "why": "Moved in version 2.2 so the power plan is written once. The physics it rests on stays here: sunlight is only {irr_pct}% of Earth's (F-14), and global storms dim it for up to about {storm_mo} months (F-33).", "moved_to": "03-03 G-01" }, { "id": "S-24", "group": "2.7", "title": "Food", "confidence": "Medium", "text": "See 03-10, which now owns how the farms are built (GF-01) and the diet (GF-05): mostly plants, grown in buried farms under lamps.", "why": "Moved in version 2.6 so food is written once. The reasons stay here: living underground (S-18) and the long gap between supply ships (F-41).", "moved_to": "03-10" }, { "id": "S-25", "group": "2.8", "title": "The sol is the day", "confidence": "High", "text": "Everyone lives on the sol. Clocks show 24 hours, each stretched by {sol_pct}% to absorb the extra {extra_min} minutes, as Mars missions already do. Nobody thinks about Earth time except when scheduling messages.", "why": "The sol (F-17) and the lander-mission convention of a stretched 24-hour Mars clock.", "sources": [ "wiki_timekeeping" ] }, { "id": "S-26", "group": "2.8", "title": "Seasons are long and named", "confidence": "High", "text": "See 02-02 W-08, which keeps the calendar's basis (it runs on Ls, the season angle). The calendar itself, its year and its seasons, is 04-03-01 CF-03 and CF-04; its customs are 04-03-03's. The physics stays here: seasons last about twice as long as Earth's (F-19).", "why": "Moved in version 2.2 so the calendar is written once. Season lengths from F-19. Raised from Low to High because only the season lengths remain here.", "moved_to": "02-02 W-08" }, { "id": "S-27", "group": "2.8", "title": "Earth lag as a way of life", "confidence": "High", "text": "Nothing from Earth is live. News arrives in batches, video calls are recorded messages, and software updates, medical advice and instructions all arrive late. The settlement is self-reliant because it has to be, and this breeds a distinct local identity within a generation.", "why": "Light-time and conjunctions (F-39, F-40). The identity part is our story choice." }, { "id": "S-28", "group": "2.9", "title": "The world looks smaller", "confidence": "Medium", "text": "The close horizon, and a landscape with no trees or buildings to give scale, make distances hard to judge. Distant hills look nearer than they are. New arrivals often misjudge walking distances, perhaps by as much as double. People navigate by vehicle and route markers.", "why": "The horizon is closer (F-47). Apollo crews misjudged distances on the Moon. The 'double' figure is a guess, so confidence drops to Medium; version 1 also wrongly said there is no haze, but Mars always has some dust haze (F-33)." }, { "id": "S-29", "group": "2.9", "title": "The landscape is quiet and still", "confidence": "High", "text": "No weather in the Earth sense, no water, no life, and no movement except dust devils and the slow crawl of shadows. The feeling of the surface is stillness, so any motion (a rover, a person, a dust devil) draws the eye at once. 05 Visiting Mars should lean into this.", "why": "No liquid water (F-12), little sound (F-11), and little wind force (F-34)." }, { "id": "S-31", "group": "2.6", "title": "The four dangers' look book", "confidence": "Medium", "text": "How the four dangers and the city's answers to them look is fixed in numbers.look: the way in at the end of a buried row and the plain outside, their colours and light, each era, what must never appear and the signature shot. Every picture, film and 3D scene of them is made from it and checked against it.", "why": "00-05 ST-20 (owner, 10 October 2026). Built from F-07, F-21, F-24, F-31, F-32, S-13, S-17, 03-06 HA-01, HA-02 and 03-07 AD-04, choosing the most beautiful option they allow (00 L-19)." } ], "world_spec": { "about": "The numbers the engine (00-02) reads for world physics. The format belongs to the engine; the numbers belong to this file. Each names the fact or assumption it comes from.", "surface_gravity": { "value": 3.73, "unit": "m/s²", "earth_value": 9.82, "from": "F-01", "source": "nasa_mars", "path": "numbers.gravity.mean_ms2" }, "sol_hours": { "value": 24.6597, "unit": "h", "from": "F-17", "path": "numbers.time.sol_h" }, "year_sols": { "value": 668.6, "unit": "sols", "from": "F-18" }, "surface_pressure_pa": { "value": 636, "unit": "Pa", "from": "F-04", "path": "numbers.atmosphere.pressure_pa" }, "air_density_kgm3": { "value": 0.016, "unit": "kg/m³", "from": "F-34", "path": "numbers.atmosphere.density_kgm3" }, "sunlight_wm2": { "value": 586.2, "unit": "W/m²", "from": "F-14", "path": "numbers.sun.irr_wm2" }, "sound_speed_ms": { "value": 240, "unit": "m/s", "from": "F-10", "path": "numbers.atmosphere.sound_low_ms" }, "olympus_height_km": { "value": 21.3, "unit": "km", "from": "F-48", "path": "olympus.height_km" }, "olympus_width_km": { "value": 600, "unit": "km", "from": "F-48", "path": "olympus.width_km" }, "year_days": { "value": 686.98, "unit": "Earth days", "from": "F-18", "path": "numbers.time.year_days" }, "light_speed_kms": { "value": 299792.458, "unit": "km/s", "from": "F-39", "path": "numbers.comms.light_kms" }, "planet_orbits": { "value": { "epoch_jd": 2451545, "valid_years": [ 1800, 2050 ], "obliquity_deg": 23.43928, "au_km": 149597870.7, "earth_accuracy_arcsec": 20, "earth": { "a_au": [ 1.00000261, 5.62e-06 ], "e": [ 0.01671123, -4.392e-05 ], "i_deg": [ -1.531e-05, -0.01294668 ], "l_deg": [ 100.46457166, 35999.37244981 ], "peri_deg": [ 102.93768193, 0.32327364 ], "node_deg": [ 0, 0 ] }, "mars": { "a_au": [ 1.52371034, 1.847e-05 ], "e": [ 0.0933941, 7.882e-05 ], "i_deg": [ 1.84969142, -0.00813131 ], "l_deg": [ -4.55343205, 19140.30268499 ], "peri_deg": [ -23.94362959, 0.44441088 ], "node_deg": [ 49.55953891, -0.29257343 ] }, "about": "JPL's approximate elements (Table 1): each is [value at noon on 1 January 2000, change per century]. 'earth' is the Earth and Moon's shared centre." }, "unit": "au, degrees, and change per century from 1 January 2000", "from": "F-53", "path": "numbers.orbits" }, "mars_clock": { "value": { "w0_deg": 176.63, "w_deg_per_day": 350.89198226, "tt_minus_utc_s": 69.184, "leap_seconds": 37, "tt_minus_tai_s": 32.184, "last_leap": "31 December 2016", "about": "How Mars's turn and astronomers' time are counted. w0_deg and w_deg_per_day: the IAU spin model. tt_minus_utc_s: how far Terrestrial Time runs ahead of ordinary clock time (this file owns it; 03-13's Mars Sol Date reads it)." }, "unit": "degrees, degrees per day, Julian date, seconds", "from": "F-54, F-55", "path": "numbers.clock" } }, "links": { "leans_on": [ { "ref": "00", "why": "The rulebook: twin files, facts versus assumptions, who owns what" }, { "ref": "00-02", "why": "The engine's format for the world spec below" }, { "ref": "01-01", "why": "Quoted: Perseverance's 203-day trip (01-01 F-16, in F-41) and space station water recycling (01-01 F-30, in S-22)" }, { "ref": "02-02", "why": "Quoted: seasons (02-02 F-01), storms and opacity (F-12, F-13, F-17), storm length (F-16), storm wind (F-20), dust devils (F-25), dry-ice frost (F-08, W-06). Storm life, static and the calendar now point to 02-02 W-04, W-07 and W-08" }, { "ref": "02-03", "why": "Quoted: ice cliffs (02-03 F-06), soil water (F-11), soil make-up (F-16), lava tubes (F-28), the lead site's height (site list)." }, { "ref": "01-05 F-26", "why": "Quoted: the conjunction dates and pause lengths, in F-40 (read live)" }, { "ref": "02-07 SK-01", "why": "The sky colours, for the opening picture's sky (read live)" } ], "used_by": [ { "ref": "05-20", "why": "Mars games: gravity, air, sound, Sun, moons, places and doses for Fact or Fiction? and the Mars Quiz (worked_out)" }, { "ref": "05-19", "why": "Mars's and Earth's gravity, for walking, jumping and every throw in the playable world" }, { "ref": "05-17", "why": "Mars's gravity against Earth's, for how high people jump on the Living on Mars Weekends card" }, { "ref": "05-12 A Living City", "why": "Mars's gravity, sol length, axial tilt and the sunlight at the top of the air, for the solar-led power plan in the viewer (read live)" }, { "ref": "05-13 Mars Atlas", "why": "Mars's and Earth's radius, for the atlas's distances and shares of the way round (read live)" }, { "ref": "04-01-03", "why": "Mars's radius and gravity, for the hop from AP-1 (read live)" }, { "ref": "05-10", "why": "Gravity, sound, sunlight, radiation, the sol and the distance to Earth, for the viewer's pins (read live)" }, { "ref": "02-02", "why": "Weather builds on the air, dust and wind physics here, and cites S-08 (periscopes and viewing rooms, W-05)" }, { "ref": "02-03", "why": "Resources quote the air mix, perchlorate, surface and Hellas pressure, Hellas depth, Mars's radius and the air densities" }, { "ref": "02-04", "why": "Interactive map quotes Mars's size, air, land area, Olympus Mons, Valles Marineris, Hellas and the yardsticks from here" }, { "ref": "03-01", "why": "Water extraction reads gravity (F-01) and builds on S-22 (ice and recycling) and S-18 (buried town)" }, { "ref": "03-02", "why": "Landing pads read gravity (F-01) and cite S-03 (heavy cargo, gravity versus inertia) and S-18 (buried town)" }, { "ref": "00-02", "why": "The engine reads surface gravity and the world spec (labelled example); its sky model reads the planet orbits and the Mars clock (F-53 to F-55) to put the Sun and Earth in the right place" }, { "ref": "04-01-02 The lava-tube outpost", "why": "Reads F-04, F-28 and F-52, with gravity and radius: air pressure, the surface dose and how soil cuts it, and the Pavonis pit's depth (read live). LT-04 narrows S-19: the tube is a roof over pressure shells" }, { "ref": "03-03 Power", "why": "Reads F-14, F-17, F-25, F-11, S-18: Sunlight at the top of the air, Mars against Earth (read live); The length of a sol, and Mars's tilt, for day and night at our site (read live); Mars's own surface radiation, to compare a reactor's keep-out dose (read live); How far sound carries, for what a reactor sounds like (read live); The town is buried; reactors, radiators and solar fields are on the surface" }, { "ref": "03-04 Fuel plant", "why": "Reads F-04, F-06, F-34, F-20, F-11, S-17: Average air pressure (read live); Carbon dioxide and oxygen in the air (read live); Air density, for how much air holds a ship's carbon dioxide (read live); Average temperatures on Mars and Earth, for heat leaking into tanks (read live); How far sound carries, for what the plant sounds like (read live); Everything is a heat problem: big radiators" }, { "ref": "03-05 Vehicles and port", "why": "Reads F-01, F-39, S-13: Mars and Earth gravity, for crane loads and weights (read live); The 3 to 22 minute signal delay, for remote driving (read live); Dust clings to vehicles and works into seals; Mars radius, person height, walking pace and how far a voice carries (read live)" }, { "ref": "02-05 The site up close", "why": "Reads Mars's radius, tilt, sol, year and orbit, the horizon sum (F-47), air pressure, scale height and densities, Olympus Mons and the yardsticks (read live)" }, { "ref": "02-06 The human body on Mars", "why": "Reads F-01, F-07, F-08, F-17, F-25, F-26, F-28, F-29, F-30, F-32, F-39: gravity, pressure, consciousness in near-vacuum, the sol, surface dose, the solar cycle, soil shielding, everyday doses, dust, perchlorate and the light delay (read live); cites F-27, F-31 and S-01, S-03, S-04, S-08, S-13, S-18, S-20, S-25; S-04 moves there" }, { "ref": "02-07 The Mars sky", "why": "Reads the orbits, sunlight, the Sun's size, tilt and sol, dust size, Earth-Mars distance and the moons (F-13 to F-19, F-30, F-39 to F-45, read live); F-42 to F-44 point to its F-08, F-09 and F-13 for the moons seen from our site" }, { "ref": "03-06 Habitats", "why": "Reads F-01, F-25, F-26, F-28: gravity, the surface dose, the solar cycle and how soil cuts the dose, for the burial depth and the viewing rooms (read live). S-18's burial depth moved there (HA-01). Cites S-08, S-10, S-19, S-20" }, { "ref": "03-07 Airlocks, suitports and dust", "why": "Reads F-04, F-07, F-30, F-32: air pressure, the Armstrong limit, dust grain size and perchlorate (read live). Cites F-31 (charged dust), S-13 (multi-stage airlocks) and S-18 (every trip out is through a door)" }, { "ref": "03-08 Spacesuits", "why": "Reads F-01, F-04, F-07, F-08, F-21, F-25, F-29: gravity, pressure, the Armstrong limit, seconds of consciousness, the coldest nights and the dose of a spacewalk (read live). Cites S-01, S-02, S-05, S-10, S-13, S-16, S-20; SS-01 picks the hard-torso gas suit S-05 allows" }, { "ref": "03-09 Life support", "why": "Reads F-04 and F-06: the air pressure outside and the air's mix, for the buffer gas (read live). S-21's habitat air moved there (LS-01). Cites S-13, S-18, S-22" }, { "ref": "03-10 Greenhouses and food", "why": "Reads F-06 and F-32: the air's carbon dioxide and perchlorate in the soil (read live). How the farms are built and the diet moved there from S-24 (GF-01, GF-05). Cites F-53 (soil is weathered basalt), S-08, S-18" }, { "ref": "03-11 Construction and materials", "why": "Reads F-01, F-20, F-28: gravity, the average temperature and how soil shields, for cover, lifting and sintering (read live). Cites S-13, S-17, S-18" }, { "ref": "03-12 Manufacturing", "why": "Cites S-13 (fine machines live indoors, away from dust) and S-18 (the clean workshop, and why viewing-room glass matters)" }, { "ref": "04-01-01 The first city", "why": "Reads Mars's radius, for the horizon, the flat-map error and degrees to metres, and Phobos's size (read live)" }, { "ref": "04-02-01 How the city is run", "why": "Reads the closest and farthest Earth-Mars distance, the speed of light and the UK worker dose limit (read live). Cites S-20 (time under the sky as a right) and S-22 (recycling)" }, { "ref": "04-02-03 Staying for good", "why": "Reads F-25: the open-surface dose, for a child's year in the City (read live). SG-03 turns S-04's decade into the decade decision" }, { "ref": "03-13 Local communications", "why": "Reads F-17, F-39 and F-47: the sol, the Earth delay and the horizon (read live). Cites F-24 (no compass), F-34 (storm winds are gentle, so masts are easy), S-10 (outside, all talk is by radio) and S-25 (the stretched sol)" }, { "ref": "03-14 Medical bay", "why": "Reads F-01, F-04, F-20 and F-39: gravity for surgery, air pressure, the average temperature and the light delay (read live). Cites S-13: a suit that has been outside never enters living space" }, { "ref": "03-15 Waste and recycling", "why": "Reads F-20: the average temperature, for the frozen store (read live)" }, { "ref": "05-02 The Olympus race", "why": "Reads Olympus Mons's height, width, slopes and cliff (F-48, F-49), the air at average level and the summit (F-04, F-05, F-34), gravity (F-01), the speed of sound (F-10), the Earth air table and the Everest, Grand Canyon and walking yardsticks (read live)" }, { "ref": "04-02-02 Money and trade", "why": "Reads Mars's radius, for the distance to Jezero (read live)" }, { "ref": "04-03-01", "why": "The calendar and festivals: the sol and the Mars year (F-17, F-18), the tilt (F-19), Earth's tilt and year, and the synodic period, read live" }, { "ref": "04-03-02 Food and home life", "why": "F-01: Mars and Earth gravity, for dropping, pouring and tossing (read live); F-04: Mars air pressure, for water boiling outside (read live); F-17: the sol, for the night in real time (read live); S-08: lamps on the sol cycle; S-25: clock hours stretched to fit the sol" }, { "ref": "04-03-03 Language and culture", "why": "F-10: the speed of sound outdoors (read live); F-11: how far sound carries outdoors (read live); S-04: daily exercise, which sport counts towards (LG-10); S-11: indoor sound; LG-07 agrees voices do not sound higher; F-01: Mars and Earth gravity, for jumps and throws (read live); F-17: the sol's length, for the seven-sol week (read live); F-41: Earth's return every synodic period, for the sky culture (read live); F-06: Mars's nitrogen and argon shares, for the town's buffer gas (read live)" }, { "ref": "04-04-01 Jobs", "why": "The sol's length and the Earth-Mars distance, for watches and the question-and-answer delay (read live); S-04 exercise, S-20 surface trips" }, { "ref": "04-04-02 A day in the life", "why": "F-17: the sol's length, for the town hour and the Earth clock's slide (read live); F-25: surface dose, for a walk's dose (read live); F-39: Earth-Mars distances, for the message delay (read live); S-04: daily training, and its length; S-25: everyone lives on the sol, on stretched hours; S-10: outside sound, for the feel of home and of a walk" }, { "ref": "04-04-03 Safety and emergencies", "why": "F-04: the pressure of Mars air, for leaks and LeBlanc (read live); F-07: the Armstrong limit, where body water boils (read live)" }, { "ref": "04-05-01 Characters", "why": "S-04: staying past a decade may make a return to Earth hard; F-39: Earth to Mars distance, for the remote-operation comparison (read live)" }, { "ref": "04-05-02 Arrival day", "why": "Gravity, falls, the horizon, sound outside and the planets' synodic period (read live); S-06, S-07, S-08 for light and sunsets" }, { "ref": "05-03 Guided tours", "why": "Mars's radius, sol and year, eye height and sound (F-11, F-17, F-18), for the dawn line, horizons, launch light and the silent window (read live)" }, { "ref": "05-04 Missions", "why": "Gravity for the falling cup and the Earth-Mars distance for the delay (read live); the planet orbits (F-53) let the engine work out the distance on each mission's date" }, { "ref": "05-05 The Q&A guide", "why": "Gravity (F-01) and the jump (S-02), the Earth-Mars distances (F-39) and the speed of light, the Armstrong limit (F-07, F-08), the blue sunset (F-16) and outdoor sound (S-10) (read live)" }, { "ref": "05-06 Free roam", "why": "The horizon (F-47), eye height, the planet's radius, the sol and tilt, the light, sound and stillness (S-06, S-10, S-29) and the buried town (S-18) (read live)" }, { "ref": "05-07 First-time onboarding", "why": "Mars's size, sound (F-10, F-11), the Earth distance (F-39), the sol and orbits, and the Earth air yardsticks (read live)" }, { "ref": "05-08 The journey experience", "why": "Gravity, the speed of sound and how far sound carries (F-10, F-11) (read live)" }, { "ref": "00-04 Glossary and units", "why": "F-17: the sol, for the day and sol clock faces and the units table (read live); F-18: the Mars year, for the orbit drawing and the units table (read live); F-04: Mars and Earth air pressure and the Armstrong limit, for the pressure ladder (read live); F-25: the surface dose and everyday doses, for the dose ladder (read live); F-14: sunlight at Mars, for Mars noon in lux (read live)" }, { "ref": "00-05 Writing and visual standard", "why": "F-17: the sol's length, for a before-and-after example (read live)" }, { "ref": "02-08", "why": "Mars's radius, for the distance from Jezero to AP-1 (read live)" }, { "ref": "05-11", "why": "The moons' sizes, the sol, Olympus Mons, Valles Marineris, Hellas and the Everest, Grand Canyon, ocean and Manhattan yardsticks, for the globe; the planet orbits and the Mars clock (F-53 to F-55) for its Right now view (read live)" }, { "ref": "03-16", "why": "Distances and light speed, air density, surface dose and temperature (read live)" }, { "ref": "04-02-04", "why": "A human hair's width, to compare chip lines (read live)" }, { "ref": "04-01-04 The cities of Mars", "why": "Mars's and Earth's radius, for distances between the later towns (read live)" }, { "ref": "05-15 Engine lab", "why": "Mars's air, gravity and carbon dioxide for the lab's Mars setting; the Vostok record for its cold comparisons" }, { "ref": "05-18 Mars Atmosphere", "why": "Reads the planet radius and rotation." } ] }, "open_questions": [ "NASA's Mars facts page (updated July 2026) says Olympus Mons is 'more than 25 miles (40 km) tall from base to summit'. This does not match NASA's own THEMIS team (26 km above the plains) or Britannica (22 km). We use 21.3 km above datum (MOLA 21.287 km) and 26 km above the plains; flagged for re-checking.", "The depth of soil that brings the dose down to Earth-like levels (a few mSv a year) was not found in the sources checked; only the 100 mSv depth (1 to 1.6 m). Röstel et al. 2020 (JGR Planets) should answer it but was not reachable. Until then the town's depth (03-06 HA-01) is a margin, not a proven figure. Meanwhile 02-06 HB-02 sets a planning ceiling for the dose inside the buried town.", "For the engine (00-02): the world spec gives one planet-wide pressure ({p_pa} Pa). At the lead site, about {site_km} km below average level (02-03), the air works out at about {site_pa} Pa (shown under F-09). Should the engine read pressure by height instead? Not added as a world spec number, because it would be a typed copy of a worked-out figure." ], "changes": [ "25 September 2026 (before v2.2): Rebuilt as twin files (this facts file plus the page) with diagrams and the library bar. This file was once called CANON-01; that name is retired. Version 1.3 was 16 September 2026.", "25 September 2026 (before v2.2): Corrected surface gravity from 3.72 to 3.73 m/s², the mean value in NASA's Mars Fact Sheet (revised May 2025), and Earth from 9.81 to 9.82 to match. Still 38%.", "25 September 2026 (before v2.2): Corrected surface pressure from 610 to 636 Pa (6.36 millibars, NASA Fact Sheet), with the seasonal range 400 to 870 Pa. The Olympus summit is 72 Pa, not 30; the Hellas floor is 1,240 Pa in winter.", "25 September 2026 (before v2.2): Corrected the air mix to the Fact Sheet's Curiosity-era figures: nitrogen 2.59% (was 2.7), argon 1.94% (was 1.6), oxygen 0.16% (was 0.13), carbon monoxide 0.06% (was 0.08). Oxygen is 131 times scarcer by share, not 160.", "25 September 2026 (before v2.2): Corrected the Earth altitude with Mars-thin air to about 34 km, worked out from the standard atmosphere. Armstrong limit updated to 6,250 Pa at 19.2 km.", "25 September 2026 (before v2.2): Corrected consciousness in a near-vacuum to about 14 seconds (NASA), dying after one to two minutes.", "25 September 2026 (before v2.2): Updated sound with Perseverance's 2022 measurements: 240 and 250 m/s, and sound fading after about 8 m against 65 m on Earth.", "25 September 2026 (before v2.2): Corrected the average temperature from -63°C to about -59°C (NASA Fact Sheet) and the low from -140°C to about -153°C (NASA). Replaced the unsourced 60 to 100°C daily swing and the Sahara comparison with Viking 1's measured -89 to -31°C.", "25 September 2026 (before v2.2): Added NASA's 'spring at your feet, winter at your head' figures (24°C and 0°C) in place of the unsourced 20°C gap.", "25 September 2026 (before v2.2): Updated radiation to Hassler et al. 2014: 0.67 mSv per day (was 0.65 to 0.7), about 245 mSv a year, plus the 0.25 to 0.95 solar-cycle range. Comparisons now use sourced doses: about 40 chest CTs (was 25 CT scans), 82 years of background (was a century), 12 times the UK worker limit (was about ten).", "25 September 2026 (before v2.2): Corrected shielding: 2 to 3 m of soil giving close to Earth-normal dose was not supported. Replaced with Zhang et al. 2022: dose peaks about 30 cm down and 1 to 1.6 m gets it below 100 mSv a year. Moved the 3 m choice into S-18.", "25 September 2026 (before v2.2): Corrected dust size to about 3 µm across (1.5 µm radius, Lemmon 2004), 23 grains per hair (was 1 to 3 µm, 25 to 70 grains). Removed 'closer to cigarette smoke' (unsourced).", "25 September 2026 (before v2.2): Corrected perchlorate to 0.4 to 0.6% at Phoenix and up to about 1% at Curiosity. Removed the seawater comparison (0.5% is a seventh of seawater's saltiness, not a fifth to a third) and the teaspoon and hot-tub figures; replaced with 1 gram spoiling 250 litres at the EPA's proposed 2026 limit.", "25 September 2026 (before v2.2): Corrected storm wind force: air density is about 1.3% of Earth's; a 27 m/s storm pushes like a 3 m/s light breeze (was 7 mph). Removed 'daylight falls to a few percent' and added the measured 2018 opacity of 10.8.", "25 September 2026 (before v2.2): Corrected dust devils: one seen from orbit in 2012 was about 20 km tall, far taller than the 'hundreds of metres, taller than The Shard' in version 1.", "25 September 2026 (before v2.2): Corrected buried ice sheets to more than 100 m thick (was 'tens of metres, ten storeys'), and the soil-water yield to about 1 litre per cubic foot (was 'a wheelbarrow gives a couple of litres').", "25 September 2026 (before v2.2): Updated light-time to 3.0 to 22.3 minutes from the Fact Sheet's closest and furthest distances; conjunction blackouts are two to three weeks (was about two weeks). Launch-window and transit detail now points to 01-01, with Perseverance's 203-day trip as the sourced example.", "25 September 2026 (before v2.2): Corrected Phobos to 26 x 23 x 18 km, rising twice a sol (was 'two or three times'), and Deimos to about 2.5 days between rising and setting (was 2.7 sols). Removed 'the width of central London' (unsourced).", "25 September 2026 (before v2.2): Corrected Olympus Mons from about 21 km to about 22 km above datum (26 km above the plains), 600 km wide with 2 to 5 degree slopes, and its base from 'the size of France' to about the size of Arizona. Olympus figures are now owned here. Removed the Burj Khalifa comparison. (Height and base superseded in version 2.1: 21.3 km, about the size of Italy.)", "25 September 2026 (before v2.2): Corrected Valles Marineris to NASA's 3,870 km long and up to 9.3 km deep (was 4,000 km and 7 km), and Hellas to 7.2 km below datum (was about 7 km). Removed 'London to Baghdad' and 'Hyde Park' comparisons (unsourced).", "25 September 2026 (before v2.2): Corrected lava tubes: 'widths of 100 m and more are plausible' is now Sauro et al. 2020's 10 to 1,000 times Earth's volume, with the Pavonis Mons pit as an example skylight.", "25 September 2026 (before v2.2): Moved 'a dull November afternoon in London' from facts into S-06, and 'nights are very dark' into S-09.", "25 September 2026 (before v2.2): Changed S-02 to use a 0.5 m Earth jump (the figure 00-02 uses), giving about 1.3 m on Mars (was 40 cm to 1 m).", "25 September 2026 (before v2.2): Lowered confidence: S-12 High to Medium (fine dust does not simply fall slower), S-28 High to Medium (the 'factor of two' is a guess, and Mars does have dust haze).", "25 September 2026 (before v2.2): Changed S-11: removed 'voices sound slightly higher' (pitch does not depend on pressure). Removed S-07's unsourced 'up to two hours' of twilight. Removed S-21's La Paz comparison and worked the heights out instead.", "25 September 2026 (before v2.2): Added S-30: one gravity value for the whole 3D world, read by the engine.", "25 September 2026 (before v2.2): Added a world spec for the engine, and sources for every fact (version 1 had none).", "25 September 2026 (before v2.2): Revised S-19 from 'the main city sits inside a lava tube' to lava-tube outposts, because the lead site chosen in 02-03 (Arcadia) has no lava tubes.", "25 September 2026 (before v2.2): Updated in version 2.1 (25 September 2026) after independent review:", "25 September 2026 (before v2.2): Corrected Olympus Mons to 21.3 km above Mars's average level (MOLA 21.287 km) and its base to about the size of Italy; Britannica's 22 km is kept only as a note. 2.4 Everests. Olympus diagram tightened.", "25 September 2026 (before v2.2): Corrected F-26: the solar-cycle range is now RAD's absorbed dose, 0.20 mGy a day near solar maximum to 0.32 at solar minimum (Guo et al. 2021), about 0.64 to 1.0 mSv a day (1.0 is our scaling), 235 to 365 mSv a year. The old 0.25 to 0.95 range was not supported.", "25 September 2026 (before v2.2): Corrected F-25 to Hassler 2014's 0.64 ± 0.12 mSv a day near solar maximum (was 0.67 from the SwRI release): about 234 mSv a year, 78 years of background, about 38 chest CT scans.", "25 September 2026 (before v2.2): Changed F-28 to say it is a computer model of cosmic rays only, and that the depth depends on altitude and solar activity.", "25 September 2026 (before v2.2): Added the orbit's eccentricity, 0.0935 (NASA Fact Sheet), to F-13.", "25 September 2026 (before v2.2): Changed F-32 to name the strictest of the EPA's January 2026 proposed limits (options 20, 40 or 80 µg per litre). Renamed the perchlorate review to its real first author, Rzymski et al. 2024.", "25 September 2026 (before v2.2): Changed F-40: commanding pauses last two to four weeks (the 2025 to 2026 pause was 25 days).", "25 September 2026 (before v2.2): Changed F-04: pressure ranges 400 to 870 Pa with height and season.", "25 September 2026 (before v2.2): Changed F-19 to read season lengths live from 02-02 F-01 (143 to 193 sols), and restored that southern summer is short and warm, southern winter long and cold.", "25 September 2026 (before v2.2): Changed duplicated facts to quote their owners live, with labels: global storms and opacity (02-02 F-12, F-13, F-17) and the 20 km dust devil (02-02 F-25) in F-33 and F-35; ice cliffs and soil water (02-03 F-06, F-11) in F-36 and F-37; lava tubes (02-03 F-28, now 20 to 450 m and about 80 times Earth's volume) in F-52; Perseverance's 203-day trip (01-01 F-16) in F-41. Storm frequency is now about 5.6 Earth years.", "25 September 2026 (before v2.2): Added F-53, quoting 02-03 F-16: dust and soil are about half silica with iron oxides, the red colour. The version 1 claim that the silicates are abrasive is removed as unsourced here.", "25 September 2026 (before v2.2): Removed 'most ice within reach at 30 to 60° latitude': where the ice lies belongs to 02-03 (a third of the surface, 02-03 F-01, quoted in F-36).", "25 September 2026 (before v2.2): Raised S-15 (static) from Medium to High, citing 02-02 F-26 (recorded sparks). Reworded S-14: 'visibility a few metres' was unsourced (02-02 W-04).", "25 September 2026 (before v2.2): Deleted open questions already fixed in other files (00-01 and 00-02 gravity, 03-01's S-23 citation, 01-01's radiation citation, 02-04's Olympus wording). Links now cite 00 (the rulebook), 04.01 Cities, 05 Tours and missions.", "25 September 2026 (before v2.2): Added years to every source name. Diagram labels now stay at 11 px or more on a phone (diagrams scroll sideways inside their card).", "25 September 2026 (before v2.2): 25 September 2026: folder 05 renamed 'Visiting Mars' (decided 25 September 2026); links updated.", "25 September 2026 (v2.2): Corrected the Olympus open question: we use 21.3 km above datum, not 22 km.", "25 September 2026 (v2.2): Corrected S-12: grit kicked at the same speed stays up about 2.6 times as long (Earth's gravity over Mars's); 1.6 is only for things dropped from the same height. Both worked out on the page.", "25 September 2026 (v2.2): Corrected S-17: outdoor kit is rated to about -130°C, just below the -125°C at which dry ice forms (02-02 F-08), because 02-02 W-06 puts dry-ice frost on parked vehicles. Was -100°C.", "25 September 2026 (v2.2): Changed F-25 and F-26 to round the yearly dose the same way: about 235 mSv a year near solar maximum (was shown as 234 in one place and 235 in the other).", "25 September 2026 (v2.2): Corrected F-52 to quote 02-03 F-28's words: collapse chains 40 to 400 m wide, tubes up to about 450 m. The version 2.1 line above that says '20 to 450 m' was wrong; 02-03 never gave 20 m.", "25 September 2026 (v2.2): Changed F-04: 400 to 870 Pa is the range at average height with season and weather (NASA Fact Sheet), not with height; height is F-05 (72 to 1,240 Pa).", "25 September 2026 (v2.2): Changed copies to live quotes: storm wind from 02-02 F-20 (removed our own 60 mph and 27 m/s), storm length from 02-02 F-16 (up to about four months, was 'weeks'), space station water recycling from 01-01 F-30 (removed our own source), and Leshin's two pints from 02-03, shown as about 0.9 litre (was rounded to 1).", "25 September 2026 (v2.2): Moved S-23 (power) to 02-03 R-06; S-14 (storm life) to 02-02 W-04; S-15 (static) to 02-02 W-07 and S-26 (calendar) to 02-02 W-08. Each keeps its ID as a short pointer, with the physics that is ours.", "25 September 2026 (v2.2): Added 'moves to' notes for engineering choices that belong in folder 03: S-18 (burial depth), S-21 (habitat air), S-22 (mining method, 03-01) and S-24 (farms). S-18 now says burial is High confidence but the exact 3 m is Medium.", "25 September 2026 (v2.2): Added a worked comparison under F-09: at the lead site, about 3.9 km below average level (02-03), the air works out at about 910 Pa, roughly 43% more than average. Added an open question for the engine rather than a typed world spec number.", "25 September 2026 (v2.2): Removed '(03-02)' from the settlement drawing's landing pad label: folder 02 does not lean on folder 03.", "25 September 2026 (v2.2): Changed the Olympus caption: the race is flown at true scale with no shrinking (00-01), so the stretched view is for reading the shape only.", "25 September 2026 (v2.2): Corrected the links: 02-02 and 02-03 now list their own fact IDs, not ours, and 02-03's use of this file is described as it really is. World spec entries now name the number they copy with a 'path'. Page title now matches the catalogue: Physical constraints.", "25 September 2026 (v2.2): pointer assumptions now show their owners' confidence (S-14 and S-15 Medium like 02-02 W-04 and W-07; S-23 High like 02-03 R-06). S-29 says 05 Visiting Mars, S-12 says visitors, S-08 says periscopes. used_by reasons now match what 02-04, 03-01 and 03-02 actually read.", "25 September 2026 (v2.3): links made two-way for the new files 03-03 Power, 03-04 Fuel plant and 03-05 Vehicles and port (and older one-sided links), each reason taken from the other file's own link.", "25 September 2026 (v2.3): S-23 now points straight to 03-03 G-01 (the power file), instead of through 02-03 R-06.", "25 September 2026 (v2.4): link reason no longer says the power plan points to 02-03 R-06 (S-23 points straight to 03-03 G-01).", "26 September 2026 (v2.5): F-40 now reads the conjunction dates live from 01-05, which owns them (01-05 F-26); this file's own copies (numbers.comms.conj_2021, conj_2025) and the 2021 source are removed. 01-05 added to quotes and leans_on. The open question on the soil depth for an Earth-like dose notes 02-06 HB-02's planning ceiling for the buried town. S-04 (deconditioning) gets moves_to 02-06, where HB-05 now carries it. F-42, F-43 and F-44 now say their Phobos and Deimos figures are as seen from the equator, and point to 02-07 F-08, F-09 and F-13 for our site (Phobos never overhead at 39.8°N), so the two files no longer read as disagreeing. The moons drawing now labels the Phobos and Deimos crossing times as seen from the equator. used_by lists 02-05, 02-06 and 02-07, each with what it reads.", "26 September 2026 (v2.6): the town's burial depth now belongs to 03-06 HA-01: S-18 keeps the world rule that the town is buried (now High) and points there for the depth (moved_to 03-06 HA-01); F-28's compare cites 03-06 HA-01. The shielding drawing and F-28 read the depth from a sanctioned copy (numbers.copies_of_03_06.cover_m, listed in file 00) instead of a typed 3. S-21 (habitat air) moved to 03-09 LS-01 and S-24 (farms and diet) to 03-10 (GF-01, GF-05); both are now short pointers. S-05 notes that 03-08 SS-01 picks the hard-torso gas suit. The depth open question now points to 03-06 HA-01. used_by adds 03-06 to 03-12, each with what it reads.", "26 September 2026 (v2.7): S-19 now says the outpost's tube is a rock roof over closed pressure shells (04-01-02 LT-04), no longer sealed and pressurised, and that 04-01-02 LT-01 places it at Jeanne on Arsia Mons. Open questions: exact settlement location and population deleted as answered (04-01-01 FC-01 makes the pin the centre of the first modules; people per era is 01-01 E-12 and the town's size by era 04-01-01 FC-13); the governance question now leaves only money and ownership beyond the ground for 04-02-02 (governance: 04-02-01). S-04 no longer moves to 02-06, which has no matching assumption: it stays here, and 04-02-03 SG-03 builds on it. used_by: the old 04.01 line becomes 04-01-02; adds 04-01-01, 04-02-01, 04-02-03, 03-13, 03-14, 03-15 and 05-02.", "26 September 2026 (v2.8): Deleted the open question on who owns what and how people pay: answered by 04-02-02 MT-04 (what people own) and MT-05 (credits). used_by adds 04-02-02. S-26 points to 04-03-01 The calendar and festivals, not the old 04.03 placeholder.", "26 September 2026 (v2.9): S-26 names 04-03-01 CF-03 and CF-04 as the calendar's owner and 04-03-03 for its customs. used_by: back-links for 04-03-01, 04-03-02, 04-03-03, 04-04-01, 04-04-02, 04-04-03, 04-05-01, 04-05-02 (what each reads, from its leans_on). Also back-links for 05-03, 05-04, 05-05, 05-06, 05-07, 05-08 (wave 6 pages, from their leans_on as written today).", "26 September 2026 (v2.10): Shelf life names a re-check date (September 2027), as the Research log (90-04) audit asked. Back-links for 00-04 and 00-05, which read the sol, year, pressures, doses and sunlight live.", "26 September 2026 (v2.11): Beauty pass: a new opening picture, a suited person mid-leap over the plain, labelled as art.", "26 September 2026 (v2.12): Final fix round: S-22: moves_to cleared: 03-01 reads it where it is. used_by: the folder-level '05 Visiting Mars' line removed; the 05 pages that really read this file are listed one by one. Citations: '(02-02 W-04; S-15)' and '(02-03 R-06; S-14)' now separate this file's own IDs from the other file's with a semicolon. The opening picture's sky colours are now read live from 02-07 SK-01 instead of typed; leans_on and quotes add 02-07", "26 September 2026 (v2.13): The owner changed the stack's direction (00 now at the top): the 'Where it fits' heading no longer calls this file the foundation; it now says it sits near the top of the stack, with almost everything below leaning on it.", "28 September 2026 (v2.14): Now used by the new 02-08 Jezero Crater, which reads it live.", "28 September 2026 (v2.15): Used by the Jezero science town (04-01-03) and the Stand in Jezero viewer (05-10).", "29 September 2026 (v2.16): Used by the Mars Through Time globe (05-11), through 02-04's gazetteer. No facts changed.", "30 September 2026 (v2.17): Added where the planets are on any date (F-53, JPL's orbit elements), Mars's spin (F-54, the IAU model) and astronomers' time (F-55, leap seconds, now owned here and read by 03-13), with world spec entries planet_orbits, mars_clock, year_days and light_speed_kms. The engine's sky model (00-02) reads them to put the Sun, Earth and the moons where they really are, first used by the globe's Right now view (05-11). Checked against JPL Horizons: Earth's distance within about 11,000 km and the point where the Sun is overhead within 0.04° (00-02). The Mars Year count stays with 02-02 F-02.", "1 October 2026 (v2.18): used_by adds 03-16 and 04-02-04, the new pages on computing and on needing nothing from Earth.", "1 October 2026 (v2.19): Used by the Mars Atlas (05-13).", "1 October 2026 (v2.20): used_by adds 05-12, which now reads gravity, sol length and tilt for the solar-led power plan.", "3 October 2026 (v2.21): Now also used by 04-01-04 The cities of Mars, which places the towns of Many Cities and Self-sustaining Mars.", "3 October 2026 (v2.22): Now also read by 05-15 Engine lab: Mars's air, gravity and carbon dioxide for its Mars setting, and the Vostok record.", "4 October 2026 (v2.23): Added F-56 (inside Mars: crust and core, from InSight) and F-57 (Mars's iron-rich mantle against Earth's), with numbers.interior, for the atlas's How Mars turned red story (05-13).", "4 October 2026 (v2.24): Used by 05-17 Living on Mars: its Weekends card works out how high people jump from the two gravities (S-02).", "5 October 2026 (v2.25): Mars Atmosphere reads the canonical planet or gazetteer data.", "9 October 2026 (v2.26): Used by 05-19 Playable Arcadia, which reads this file live.", "10 October 2026 (v2.27): Added numbers.look, the four dangers' look book (S-31, 00-05 ST-20), and F-58, the 2014 wind events that cleaned Opportunity's solar panels (NASA PIA18079), for The four dangers stop of 05-17's explainer." ], "sources": { "nasa_mars": { "name": "NASA NSSDCA (D. R. Williams), Mars Fact Sheet, revised 19 May 2025", "url": "https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html" }, "nasa_earth": { "name": "NASA NSSDCA, Earth Fact Sheet, revised 15 November 2024", "url": "https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html" }, "nasa_moon": { "name": "NASA NSSDCA, Moon Fact Sheet (accessed September 2026)", "url": "https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html" }, "nasa_facts": { "name": "NASA Science, Mars: Facts, updated July 2026", "url": "https://science.nasa.gov/mars/facts/" }, "us_std_atm": { "name": "U.S. Standard Atmosphere 1976, layer table (Wikipedia summary, 2026)", "url": "https://en.wikipedia.org/wiki/U.S._Standard_Atmosphere" }, "wiki_armstrong": { "name": "Wikipedia, Armstrong limit, 2026", "url": "https://en.wikipedia.org/wiki/Armstrong_limit" }, "nasa_vacuum": { "name": "NASA Goddard, Imagine the Universe: Ask an Astrophysicist, the human body in a vacuum (accessed September 2026)", "url": "https://imagine.gsfc.nasa.gov/ask_astro/space_travel.html" }, "wiki_olympus": { "name": "Wikipedia, Olympus Mons (MOLA height 21.287 km; area about 300,000 km², the size of Italy), 2026", "url": "https://en.wikipedia.org/wiki/Olympus_Mons" }, "britannica_olympus": { "name": "Encyclopaedia Britannica, Olympus Mons, 2026", "url": "https://www.britannica.com/place/Olympus-Mons" }, "asu_themis": { "name": "Arizona State University THEMIS team, Olympus Mons image release, 2002", "url": "https://themis.mars.asu.edu/zoom-20020405a" }, "wiki_hellas": { "name": "Wikipedia, Hellas Planitia, 2026", "url": "https://en.wikipedia.org/wiki/Hellas_Planitia" }, "jpl_sound_2022": { "name": "NASA JPL, What sounds captured by NASA's Perseverance rover reveal about Mars (Maurice et al., Nature), 1 April 2022", "url": "https://www.jpl.nasa.gov/news/what-sounds-captured-by-nasas-perseverance-rover-reveal-about-mars/" }, "cnrs_2022": { "name": "CNRS via EurekAlert, Perseverance records the first ever sounds from Mars, 2022", "url": "https://www.eurekalert.org/news-releases/948453" }, "jpl_sunset_2015": { "name": "NASA JPL, NASA's Curiosity rover views serene sundown on Mars, 2015", "url": "https://www.jpl.nasa.gov/news/nasas-curiosity-rover-views-serene-sundown-on-mars/" }, "wiki_southpole": { "name": "Wikipedia, Amundsen-Scott South Pole Station (climate table), 2026", "url": "https://en.wikipedia.org/wiki/Amundsen%E2%80%93Scott_South_Pole_Station" }, "wmo_vostok": { "name": "WMO Archive of Weather and Climate Extremes, lowest temperature (Vostok, 21 July 1983; verified by WMO 2011)", "url": "https://wmo.int/asu-map?map=Temp_020" }, "hassler_2014": { "name": "Hassler et al., Mars' surface radiation environment measured with the Mars Science Laboratory's Curiosity rover, Science 343, 2014", "url": "https://www.science.org/doi/10.1126/science.1244797" }, "swri_2013": { "name": "Southwest Research Institute, SwRI scientists publish first radiation measurements from the surface of Mars, 9 December 2013", "url": "https://www.swri.org/newsroom/press-releases/swri-scientists-publish-first-radiation-measurements-the-surface-of-mars" }, "guo_2021": { "name": "Guo et al., Radiation environment for future human exploration on the surface of Mars: the current understanding based on MSL/RAD dose measurements, Astronomy and Astrophysics Review, 2021", "url": "https://link.springer.com/article/10.1007/s00159-021-00136-5" }, "zhang_2022": { "name": "Zhang, Guo et al., From the top of Martian Olympus to deep craters and beneath (model study, cosmic rays only), JGR Planets, 2022", "url": "https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021JE007157" }, "space_2022": { "name": "Space.com, Digging deep on Mars could protect future astronauts from radiation, 2022 (summary of Zhang et al.)", "url": "https://www.space.com/mars-radiation-protection-astronauts-underground" }, "radiologyinfo": { "name": "RadiologyInfo.org (ACR and RSNA), Radiation dose from X-ray and CT exams, reviewed 15 April 2025", "url": "https://www.radiologyinfo.org/en/info/safety-xray" }, "cdc_flight": { "name": "US CDC, Radiation and air travel, fact sheet (accessed September 2026)", "url": "https://www.cdc.gov/radiation-health/data-research/facts-stats/air-travel.html" }, "irr17": { "name": "UK Ionising Radiations Regulations 2017, Schedule 3 (dose limits)", "url": "https://www.legislation.gov.uk/uksi/2017/1075/schedule/3" }, "lemmon_2004": { "name": "Lemmon et al., Atmospheric imaging results from the Mars Exploration Rovers: Spirit and Opportunity, Science, 2004", "url": "https://experts.arizona.edu/en/publications/atmospheric-imaging-results-from-the-mars-exploration-rovers-spir/" }, "epa_pm": { "name": "US EPA, Particulate Matter (PM) Basics (accessed September 2026)", "url": "https://www.epa.gov/pm-pollution/particulate-matter-pm-basics" }, "nasa_dust_2012": { "name": "NASA Technical Reports Server, Mars dust: characterization of particle size and electrostatic charge distribution (citing Mazumder et al. 2004), 2012", "url": "https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120003263.pdf" }, "epa_2026": { "name": "US EPA, National Primary Drinking Water Regulation for Perchlorate (proposed rule), Federal Register, 6 January 2026", "url": "https://www.federalregister.gov/documents/2026/01/06/2026-00021/national-primary-drinking-water-regulation-for-perchlorate" }, "nasa_storms_2015": { "name": "NASA, The fact and fiction of Martian dust storms, 2015", "url": "https://www.nasa.gov/solar-system/the-fact-and-fiction-of-martian-dust-storms/" }, "jpl_opportunity_2018": { "name": "NASA JPL, Opportunity hunkers down during dust storm, June 2018", "url": "https://www.jpl.nasa.gov/news/opportunity-hunkers-down-during-dust-storm/" }, "metoffice_beaufort": { "name": "Met Office, Beaufort wind force scale (accessed September 2026)", "url": "https://weather.metoffice.gov.uk/guides/coast-and-sea/beaufort-scale" }, "jpl_devil_2012": { "name": "NASA JPL, 12-mile-high Martian dust devil caught in act, 4 April 2012", "url": "https://www.jpl.nasa.gov/news/12-mile-high-martian-dust-devil-caught-in-act/" }, "usgs_ice_2018": { "name": "USGS, 3-D structure of buried ice sheets on Mars revealed (Dundas et al., Science), 12 January 2018", "url": "https://www.usgs.gov/news/national-news-release/3-d-structure-buried-ice-sheets-mars-revealed-high-resolution-images" }, "space_water_2013": { "name": "Space.com, Curiosity rover makes big water discovery in Mars dirt (Leshin et al., Science), 26 September 2013", "url": "https://www.space.com/22949-mars-water-discovery-curiosity-rover.html" }, "nasa_conj_2025": { "name": "NASA Science, Curiosity blog, sols 4750 to 4762: See you on the other side of the Sun, 22 December 2025", "url": "https://science.nasa.gov/blog/curiosity-blog-sols-4750-4762-see-you-on-the-other-side-of-the-sun/" }, "nasa_m2020": { "name": "NASA Science, Mars 2020 Perseverance mission page (accessed September 2026)", "url": "https://science.nasa.gov/mission/mars-2020-perseverance/" }, "wiki_phobos": { "name": "Wikipedia, Phobos (moon), 2026", "url": "https://en.wikipedia.org/wiki/Phobos_(moon)" }, "wiki_deimos": { "name": "Wikipedia, Deimos (moon), 2026", "url": "https://en.wikipedia.org/wiki/Deimos_(moon)" }, "jpl_earth_2014": { "name": "NASA JPL, NASA Mars rover Curiosity sees 'evening star' Earth, 6 February 2014", "url": "https://www.jpl.nasa.gov/news/nasa-mars-rover-curiosity-sees-evening-star-earth/" }, "wiki_manhattan": { "name": "Wikipedia, Manhattan, 2026", "url": "https://en.wikipedia.org/wiki/Manhattan" }, "wiki_earth": { "name": "Wikipedia, Earth (surface area and land area), 2026", "url": "https://en.wikipedia.org/wiki/Earth" }, "britannica_everest": { "name": "Encyclopaedia Britannica, Mount Everest (8,849 m), 2026", "url": "https://www.britannica.com/place/Mount-Everest" }, "noaa_ocean": { "name": "NOAA, How deep is the ocean? (accessed September 2026)", "url": "https://oceanservice.noaa.gov/facts/oceandepth.html" }, "nps_grca": { "name": "US National Park Service, Grand Canyon: nature (accessed September 2026)", "url": "https://www.nps.gov/grca/learn/nature/index.htm" }, "sauro_2020": { "name": "Sauro et al., Lava tubes on Earth, Moon and Mars: a review on their size and morphology, Earth-Science Reviews, 2020", "url": "https://digitalcommons.usf.edu/kip_articles/6191/" }, "phys_2020": { "name": "Phys.org, Lava tubes on Mars and the Moon are so wide they can host planetary bases, 2020", "url": "https://phys.org/news/2020-08-lava-tubes-mars-moon-wide.html" }, "jpl_pavonis_2014": { "name": "NASA JPL, A giant cave on a giant volcano (HiRISE image), 2 July 2014", "url": "https://www.jpl.nasa.gov/images/pia18589-a-giant-cave-on-a-giant-volcano/" }, "wiki_timekeeping": { "name": "Wikipedia, Timekeeping on Mars (Mars clock convention, Darian calendar), 2026", "url": "https://en.wikipedia.org/wiki/Timekeeping_on_Mars" }, "rzymski_2024": { "name": "Rzymski et al., Perchlorates on Mars: occurrence and implications for putative life on the Red Planet, Icarus 421, 2024", "url": "https://www.sciencedirect.com/science/article/pii/S0019103524003063" }, "jpl_approx_pos": { "name": "NASA JPL Solar System Dynamics (E. M. Standish), Approximate Positions of the Planets, Table 1, valid 1800 to 2050 (accessed September 2026)", "url": "https://ssd.jpl.nasa.gov/planets/approx_pos.html" }, "iau_2009": { "name": "Archinal and others, Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2009, Celestial Mechanics and Dynamical Astronomy 109, 2011", "url": "https://doi.org/10.1007/s10569-010-9320-4" }, "iers_c72": { "name": "IERS Earth Orientation Centre, Bulletin C 72, 6 July 2026: no leap second at the end of December 2026; UTC minus TAI is -37 s", "url": "https://datacenter.iers.org/data/latestVersion/bulletinC.txt" }, "insight_crust_2021": { "name": "Knapmeyer-Endrun and others, Thickness and structure of the martian crust from InSight seismic data, Science, 2021 (as reported by DLR, 22 July 2021)", "url": "https://www.dlr.de/en/latest/news/2021/03/20210722_the-red-planet-has-a-larger-core-and-a-thinner-crust" }, "insight_core_2023": { "name": "Samuel and others, Geophysical evidence for an enriched molten silicate layer above Mars's core, Nature, 26 October 2023 (IPGP news)", "url": "https://www.ipgp.fr/en/news-and-agenda/news/insight-seismic-data-reveals-a-molten-layer-at-the-base-of-the-martian-mantle/" }, "yoshizaki_2020": { "name": "Yoshizaki and McDonough, The composition of Mars, Geochimica et Cosmochimica Acta, 2020", "url": "https://arxiv.org/abs/1909.07560" }, "mcdonough_1995": { "name": "McDonough and Sun, The composition of the Earth, Chemical Geology 120, 1995", "url": "https://doi.org/10.1016/0009-2541(94)00140-4" }, "nasa_pia18079": { "name": "NASA JPL Photojournal, PIA18079: Opportunity's self-portrait after cleaning events, 2014", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA18079" } }, "sources_checked": "25 September 2026" }, "02-02": { "file": "02-02", "title": "Weather", "folder": "02", "facts_file": "02-02-weather.json", "version": "2.27", "status": "Active", "last_updated": "9 October 2026", "about": "Facts file for 02-02 Weather. The page is built from this file, the library catalogue and the page template. Change a fact here, then run build.py. Words in curly brackets, like {tau_opp}, are filled in from the numbers in this file when the page is built, so each number is typed once. Numbers owned by 02-01 (tilt, year length in sols and days, sunlight, pressure, record cold, hair, Everest, a person's height) and 02-03 (the lead site, the shallow-ice band and SpaceX's solar latitude limit) are read live from those files when the page is built, never typed here.", "one_line": "What the Martian sky does, day to day and year to year: long lopsided seasons, air that freezes onto the poles, storms that hide the Sun for months, frost, fog and dust devils taller than Everest.", "shelf_life": "Perseverance is still measuring the weather and new storms get added as they happen. Re-check the storm list and the Jezero numbers after each dusty season (southern spring and summer), and by September 2027 at the latest.", "header": { "purpose": "Give every other file one agreed account of Martian weather: how the seasons run, when storms come and how bad they get, what frost, fog and dust devils are like, and what each means for people outside.", "why": "Weather is what Mars fiction most often gets wrong, usually by borrowing Earth storms. The real thing is stranger: storms that dim the Sun for months but could not knock over a bicycle, and dry-ice snow.", "when": "Writing any outdoor scene, deciding when surface work can happen, sizing power reserves, building the sky and storms in the 3D world, or writing a storm, frost or dust devil mission.", "change": "Part One changes only with a citation. Add each new global storm with its date. Part Two assumptions can be challenged one at a time. Edit this facts file, then run build.py.", "writing": "Every number is compared to something people know. Pictures first, short sentences, no walls of text." }, "comparisons": { "shard_m": 309.6, "earth_season_days": 91.3, "kew_july_c": [ 13.2, 23.8 ], "peru_cairo_lat": [ -10, 30 ] }, "numbers": { "season_sols": { "n_spring": 193.3, "n_summer": 178.6, "n_autumn": 142.7, "n_winter": 154 }, "aphelion_ls": 71, "perihelion_ls": 251, "my1_start": "11 April 1955", "dusty_ls": [ 180, 360 ], "global_onset_ls": [ 185, 315 ], "global_total": 11, "global_years": [ 1971, 1977, 1977, 1982, 2001, 2007, 2018 ], "global_every_my": 3, "atm_swing_pct": 30, "atm_pm_pct": 15, "jezero_pa": [ 735, 761, 650 ], "snow_depth_m": [ 1.5, 2 ], "cap_edge_lat": 60, "dry_ice_c": -125, "co2_frost_minutes": 60, "viking_frost_days": 100, "viking_frost_inch": 0.001, "volcano_frost_mm": 0.01, "volcano_water_t": 150000, "volcano_pools": 60, "s2018": { "onset_ls": 185, "global_ls": 197, "clear_ls": 250, "area_jun8_mkm2": 18, "area_jun12_mkm2": 35 }, "s2001": { "onset_ls": [ 177, 185 ], "global_ls": 193, "decay_ls": 263, "clear_ls": 304, "sols": 120 }, "tau_clear": [ 0.4, 0.5 ], "tau_2007": 5.5, "tau_msl_2018": 8.5, "tau_opp_2018": 10.8, "opp_wh": [ 645, 22 ], "uv_drop_pct": 97, "ground_swing_k": [ 100, 40 ], "storm_wind_mph": 60, "viking_gust_ms": 26, "settle_sols": 43, "jezero_ground_c": [ -83, 5 ], "jezero_air_c": [ -83, -23 ], "wind_afternoon_ms": 7, "wind_gust_ms": 25, "wind_night_ms": [ 2, 4 ], "dd_diam_m": [ 5, 135 ], "dd_2021": { "width_m": 25, "height_m": 118, "speed_kmh": 19, "date": "27 September 2021" }, "dd_record": { "height_km": 20, "width_m": 70, "date": "14 March 2012" }, "sparks": [ 55, 16 ], "clean_boost_pct": 10, "spirit_wh": [ 210, 240 ], "opp_life_x": 60, "cloud_lat": [ -10, 30 ], "cloud_ls": [ 60, 100 ], "phoenix_snow_km": 4, "jezero_ls_end": 125, "co2_frost_um": 300, "viking2_lat": 48, "phoenix_lat": 68, "mcs": { "archive_start": "2006-09-24", "archive_through": "2025-07-31", "dust_wavelength_um": 21.6, "ice_wavelength_um": 11.9, "levels_per_profile": 105, "product": "2015041500_DDR.TAB", "sample_date": "2015-04-15", "sample_start_utc": "00:00:22.056", "sample_end_utc": "03:59:36.412", "sample_profiles": 379 } }, "sections": [ { "id": "2.1", "title": "The Mars year" }, { "id": "2.2", "title": "The winter freeze-out" }, { "id": "2.3", "title": "Dust storms" }, { "id": "2.4", "title": "Everyday weather" } ], "facts": [ { "id": "F-01", "section": "2.1", "text": "A Mars year is {year_sols} sols (02-01). Mars is tilted {tilt}° (Earth {earth_tilt}°, both 02-01 F-19), so it has four seasons. Northern spring lasts {sp} sols, summer {su}, autumn {au} and winter {wi}.", "compare": "Each season is about {season_x} times an Earth season. A northern winter is about {wi_months} months; a northern summer about {su_months}.", "sources": [ "wiki_astro_mars", "wiki_timekeeping" ] }, { "id": "F-02", "section": "2.1", "text": "Scientists date the Mars year by solar longitude, Ls: 0 at the northern spring equinox, 90 at northern midsummer, 180 at the northern autumn equinox, 270 at northern midwinter. Mars Year 1 began on {my1}, so the 2018 storm happened in Mars Year 34.", "compare": "Ls is Mars's version of a calendar date: 'Ls 180' is like saying 'late September'.", "sources": [ "wiki_timekeeping" ] }, { "id": "F-03", "section": "2.1", "text": "The orbit is stretched. Mars is farthest from the Sun at Ls {aph} (northern spring) and closest at Ls {peri} (late southern spring). Sunlight at the top of the air ranges from about {sun_wlo} to {sun_whi} W/m² over the year (worked out from 02-01's orbit and sunlight figures).", "compare": "Near the Sun, Mars gets about {peri_boost} percent more sunlight than far from it. So the south has short, hot summers and the north long, mild ones.", "sources": [ "lmd_ls" ] }, { "id": "F-04", "section": "2.2", "text": "Each winter, as much as a third of Mars's carbon dioxide air freezes out onto the winter pole. The atmosphere grows and shrinks by about {atm_swing} percent each year.", "compare": "On Earth, air {atm_swing} percent thinner means climbing about {p_alt} km up a mountain. Mars does that, and comes back, every year.", "sources": [ "nasa_snow_2001", "jpl_gale_2013" ] }, { "id": "F-05", "section": "2.2", "text": "Air pressure is lowest near the end of southern winter, when the south cap is biggest, and highest in southern spring and summer. The yearly swing is about {atm_pm} percent either side of the average. At Jezero, Perseverance's daily average rose from {jz_a} to a peak of {jz_b} Pa around sol 100, then fell to {jz_c} Pa by sol 250 (Ls {jz_ls}).", "compare": "A {jz_drop} percent drop in under a Mars season. Jezero sits low, so its pressures are above Mars's {mean_pa} Pa average (02-01).", "sources": [ "tillman_1998", "jpl_gale_2013", "rodriguez_2023" ] }, { "id": "F-06", "section": "2.2", "text": "The seasonal dry-ice layer reaches {snow_lo} to {snow_hi} m deep near both poles, measured by laser from orbit.", "compare": "Up to about a person's height of frozen air.", "sources": [ "nasa_snow_2001" ] }, { "id": "F-07", "section": "2.2", "text": "In northern winter the seasonal cap reaches down to about {cap_lat}°N, then shrinks back to its small water-ice core by summer.", "compare": "{cap_lat}°N on Earth runs through Oslo and the Shetland Islands.", "sources": [ "hubble_1997" ] }, { "id": "F-08", "section": "2.2", "text": "Carbon dioxide snow falls in the south polar winter. It is the only known carbon dioxide snow anywhere in the solar system. Dry ice needs about {dry_ice}°C to form.", "compare": "Colder than the coldest temperature ever measured on Earth ({earth_low}°C at Vostok, 02-01).", "sources": [ "jpl_co2snow_2012" ] }, { "id": "F-09", "section": "2.2", "text": "Thin carbon dioxide frost also forms overnight at middle and low latitudes, especially on high ground, up to several hundred micrometres thick, and turns back to gas within an hour after sunrise.", "compare": "A few hair-widths thick (a hair is about {hair} µm, 02-01), gone by breakfast.", "sources": [ "eos_piqueux_2016" ] }, { "id": "F-10", "section": "2.2", "text": "Viking Lander 2, in Utopia Planitia at about {vk_lat}°N, photographed a thin frost of water ice and dust, perhaps {vk_inch} inch thick. It stayed on the ground for about {vk_days} days.", "compare": "Thinner than a sheet of paper, lasting about three Earth months.", "sources": [ "jpl_viking_frost" ] }, { "id": "F-11", "section": "2.2", "text": "Water frost forms on the summits of the giant Tharsis volcanoes, including Olympus Mons, in the cold seasons. It is about {vf_mm} mm thick and lasts a few hours around sunrise, but about {vf_t} tonnes of water swap between ground and air each day.", "compare": "About {vf_pools} Olympic swimming pools a day.", "sources": [ "esa_frost_2024" ] }, { "id": "F-12", "section": "2.3", "text": "Big dust storms come in southern spring and summer (Ls {dusty_lo} to {dusty_hi}), when Mars is nearest the Sun. In that half of the year many small local storms, up to a few hundred kilometres across, form and fade over a few days. Every year some bigger storms cover continent-sized areas and last for weeks.", "compare": "Like a hurricane season, but for dust, and it lasts almost a year.", "sources": [ "nasa_dust_2015", "smith_2019" ] }, { "id": "F-13", "section": "2.3", "text": "Only {global_total} global (planet-encircling) storms have been recorded. All began between Ls {gl_lo} and {gl_hi}. NASA (2015) puts it at once every {every_my} Mars years on average: about a 1 in {every_my} chance, or {odds} percent, in any one Mars year.", "compare": "Every {every_my} Mars years is about {storm_years} Earth years (NASA says about 5½), but not on a schedule.", "sources": [ "smith_2019", "nasa_dust_2015" ] }, { "id": "F-14", "section": "2.3", "text": "Global storms in the space age: 1971 (Mariner 9 arrived to find only the south polar cap and a mountain top showing, and waited weeks), two in 1977 and one in 1982 (seen by the Viking landers), 2001 (began near Hellas in June, whole planet by late July), 2007 and 2018.", "compare": "Two came in one Mars year in 1977; later came a 19-year gap, 1982 to 2001.", "sources": [ "nasa_mariner9", "tillman_uw", "jpl_1982", "asu_2001", "smith_2019" ] }, { "id": "F-15", "section": "2.3", "text": "The 2018 storm began in late May (Ls {s18_on}). It covered {s18_a1} million km² by 8 June and {s18_a2} million km² by 12 June, circled the planet by 20 June (Ls {s18_gl}), and the dust was back to normal by mid-September (Ls {s18_off}).", "compare": "{s18_a2} million km² is about a quarter of Mars. Start to clear took about three and a half months.", "sources": [ "smith_2019", "jpl_opp_hunker", "nasa_msl_2018" ] }, { "id": "F-16", "section": "2.3", "text": "The 2001 storm began near the Hellas basin about Ls {s01_on_lo} to {s01_on_hi}, circled the planet by Ls {s01_gl}, and its main decay ended about Ls {s01_decay}, roughly {s01_sols} sols later. The air did not fully clear until about Ls {s01_clear}.", "compare": "About {s01_months} months of thick dust: the longest of the three recent storms.", "sources": [ "wolkenberg_2020" ] }, { "id": "F-17", "section": "2.3", "text": "Dust thickness is measured as optical depth, tau. A normal Jezero day is about {tau_c_lo} to {tau_c_hi}. In 2007 Opportunity saw about {tau_07}. In 2018 Curiosity saw about {tau_msl} and Opportunity a record {tau_opp}.", "compare": "Direct sunlight falls by a factor e for each 1 of tau: at {tau_c_hi} about {direct_clear} percent gets straight through; at 5 about 1 percent; at {tau_opp} about 1 part in {direct_opp}.", "sources": [ "rodriguez_2023", "planetary_2018", "jpl_opp_hunker", "smith_2019" ] }, { "id": "F-18", "section": "2.3", "text": "Opportunity's solar panels made about {opp_hi} watt-hours a day on 1 June 2018 and just {opp_lo} on 10 June. Its last message came that day. After more than a thousand recovery commands the mission was declared over on 13 February 2019.", "compare": "About {opp_pct} percent of normal: a month of sunshine giving one day's energy. Scattered light kept it well above the direct beam's 1 in {direct_opp}.", "sources": [ "planetary_2018", "jpl_opp_end" ] }, { "id": "F-19", "section": "2.3", "text": "At Gale Crater during the 2018 storm, ultraviolet light at the ground fell by {uv} percent, and the ground's day-to-night swing shrank from almost {sw_clear} K to about {sw_storm} K. Dust shades the day and warms the night.", "compare": "A step of 1 K is the same as 1°C. The storm turned a desert swing into a cloudy-day swing.", "sources": [ "smith_2019" ] }, { "id": "F-20", "section": "2.3", "text": "Winds in the strongest storms top out at about {storm_mph} mph (about {storm_ms} m/s). Viking measured gusts of {vk_gust} m/s as a storm arrived. The air is so thin that such a wind pushes with only about {force_pct} percent of the force the same wind would have on Earth (02-01's air densities).", "compare": "Tree-felling speed on the gauge, light breeze on the skin.", "sources": [ "nasa_dust_2015", "wiki_climate" ] }, { "id": "F-21", "section": "2.3", "text": "After a storm the fine dust takes weeks to months to settle. In 2018 the haze thinned on a time scale of about {settle} sols.", "compare": "Roughly half of the extra haze gone every {settle_half} sols: about a month.", "sources": [ "smith_2019" ] }, { "id": "F-22", "section": "2.4", "text": "At Jezero Crater, Perseverance finds the ground typically goes from {jg_lo}°C before dawn to {jg_hi}°C at noon, and the air from {ja_lo}°C to {ja_hi}°C.", "compare": "An {jg_swing}°C swing at the ground, against about {kew_swing}°C on a July day in London: about {swing_x} times bigger.", "sources": [ "nasa_meda_2023", "kew_climate" ] }, { "id": "F-23", "section": "2.4", "text": "Jezero winds usually peak around {w_aft} m/s in the afternoon, with gusts up to {w_gust} m/s near midday. At night they drop to {w_n_lo} to {w_n_hi} m/s.", "compare": "{w_aft} m/s is about {w_kmh} km/h, cycling speed. Thin air makes it feel much gentler.", "sources": [ "rodriguez_2023" ] }, { "id": "F-24", "section": "2.4", "text": "Jezero has more dust devils than any other landing site so far: {dd_lo} to {dd_hi} m across. On {dd21_date} one {dd21_w} m wide and at least {dd21_h} m tall, moving at {dd21_v} km/h, passed right over Perseverance and was recorded by its microphone.", "compare": "{dd21_h} m is more than a third of the Shard; {dd21_v} km/h is a steady run.", "sources": [ "rodriguez_2023", "jpl_dd_2022", "wiki_shard" ] }, { "id": "F-25", "section": "2.4", "text": "The tallest dust devil photographed was about {ddr_km} km high and {ddr_w} m wide, in Amazonis Planitia on {ddr_date}.", "compare": "About {ddr_everest} times the height of Everest ({ev_m} m, 02-01), yet thinner than a football pitch is long.", "sources": [ "jpl_dd_2012" ] }, { "id": "F-26", "section": "2.4", "text": "Perseverance's microphone has recorded {sparks} small electrical discharges in dust devils and dust storms since 2021, {sparks_oh} of them as dust devils passed over it. No harm to spacecraft has been reported in decades of operations.", "compare": "Similar to the snap of a static shock after walking on carpet: sparks, not lightning bolts.", "sources": [ "jpl_sparks_2025" ] }, { "id": "F-27", "section": "2.4", "text": "Wind, from gusts and probably passing dust devils, sometimes blew dust off Spirit's and Opportunity's solar panels, boosting power by up to about {clean} percent. One 2009 event lifted Spirit from {sp_wh_lo} to {sp_wh_hi} watt-hours a day. Which one did it each time was not seen.", "compare": "Cleanings like these are one reason Opportunity lasted about {opp_x} times its planned 90 days.", "sources": [ "jpl_insight_2018", "jpl_spirit_2009", "jpl_opp_end" ] }, { "id": "F-28", "section": "2.4", "text": "Thin water-ice clouds gather in a belt from about {cl_lo} to {cl_hi} around northern spring and summer, thickest from Ls {cl_ls_lo} to {cl_ls_hi}, when Mars is farthest from the Sun.", "compare": "Wispy and high, like cirrus on Earth, over a band as wide as Peru to Cairo.", "sources": [ "wolff_1999" ] }, { "id": "F-29", "section": "2.4", "text": "On the arctic plains at about {ph_lat}°N, Phoenix saw cirrus-like ice clouds, ice clouds near the ground at night in late summer, and snow falling from about {ph_km} km up. At first it turned to vapour before landing; near the end of the mission some ice crystals reached the ground.", "compare": "{ph_km} km is about half the height of Everest (02-01).", "sources": [ "jpl_phoenix_2008", "whiteway_2009" ] }, { "id": "F-30", "section": "2.3", "text": "In 2016 James Shirley of NASA JPL forecast a global dust storm within weeks or months of 29 October 2016, from a pattern linking past global storms to a cycle of about 2.2 years in how Mars's orbit is tugged by the other planets. No global storm came that season; the next one began in 2018 (F-14, F-15).", "compare": "Like a hurricane forecast: the season always comes, but which year brings the big one is still hard to call.", "sources": [ "jpl_shirley_2016" ] }, { "id": "F-31", "section": "2.3", "text": "Mars's dust storms are driven by the Sun's heat: air flows from where it is warm to where it is colder, and the winds lift the fine dust. Mars is closest to the Sun in southern summer, when 'the heating is greatest, the winds are strongest, and traditionally, that's when the big global dust storms occur' (Philip Christensen, THEMIS camera lead, Arizona State University, 2018).", "compare": "The same engine as wind on Earth, turned up when Mars swings nearest the Sun.", "sources": [ "asu_christensen_2018" ] }, { "id": "F-32", "section": "2.4", "text": "Mars Climate Sounder derives temperature, dust and water-ice profiles from infrared limb observations. The certified v6.2 archive starts in September 2006 and extends through July 2025 at this source check. Dust opacity per kilometre is reported at 21.6 micrometres, water ice at 11.9 micrometres. These are infrared retrievals, not visible-light photographs and not live weather.", "compare": "Like scanning the layers of a cake from its side, the instrument reads a vertical slice through the air.", "sources": [ "mcs_pds" ] }, { "id": "F-33", "section": "2.4", "text": "The NASA PDS product 2015041500_DDR.TAB contains 379 atmospheric profiles between 00:00:22.056 and 03:59:36.412 UTC on 15 April 2015. Each has 105 native pressure levels, retrieval uncertainties and quality flags. Its altitude is relative to the DDR surface radius; when no surface sounding exists this is a reference tangent radius, not a measured height above local terrain. Empty retrievals are -9999 in the source and must remain missing in a viewer.", "compare": "A flight across a few strips of a planet does not measure the air in the gaps between those strips.", "sources": [ "mcs_product" ] }, { "id": "F-34", "section": "2.4", "text": "NASA/JPL-Caltech published PIA22737 in October 2018: two opposite hemispheres show daily global column dust during the 2018 storm, from late May into September. The colour scale is optical depth, tau. This column-integrated view does not locate dust at a particular altitude. Opportunity is marked in red.", "compare": "A column tells you how much dust you look through, like knowing the total thickness of every window in a building without knowing which floor each is on.", "sources": [ "mcs_storm_animation" ] }, { "id": "F-35", "section": "2.3", "text": "Around each solstice a strong eastward wind, a westerly jet, circles the planet in the winter hemisphere, as one does on Earth (Guendelman, Waugh and Kaspi, Journal of the Atmospheric Sciences, 2021).", "compare": "Like the jet stream that speeds up flights from New York to London.", "sources": [ "guendelman_2021" ] } ], "storm_record": [ { "year": 1971, "label": "1971", "note": "Mariner 9 waits weeks", "facts": [ "F-14" ] }, { "year": 1977, "label": "1977 A and B", "note": "two in one year", "facts": [ "F-14" ] }, { "year": 1982, "label": "1982", "note": "Viking", "facts": [ "F-14" ] }, { "year": 2001, "label": "2001", "note": "about {s01_months} months", "facts": [ "F-16" ] }, { "year": 2007, "label": "2007", "note": "tau about {tau_07}", "facts": [ "F-17" ] }, { "year": 2018, "label": "2018", "note": "tau {tau_opp}, ends Opportunity", "facts": [ "F-15", "F-18" ] } ], "assumptions": [ { "id": "W-01", "confidence": "Medium", "text": "The settlement sits in the northern mid-latitudes, at {pin_lat}°N, just inside SpaceX's {sun_hi}° solar limit (the pin is SpaceX's AP-1 site) (02-03 R-02 holds the lead candidate site, {site_name}; 04-01-01 lays the town out round the pin). So it gets the long mild northern summer ({su} sols) and the shorter northern winter ({wi} sols). Winter still means long nights colder than {ja_lo}°C and a low, weak sun.", "why": "Follows from the season lengths (F-01) and the orbit (F-03). {ja_lo}°C is Jezero's typical pre-dawn air at about 18°N (F-22); at about {site_lat}°N in winter the nights will be colder still, as Viking 2 found on the northern plains in late winter (02-05 F-17). The site's latitude is read live from 02-03. Lowered from High because the original's 'solar cut by half or more' had no source.", "moves_to": "" }, { "id": "W-02", "confidence": "High", "text": "A global storm is the settlement's defining emergency. It comes about once every {storm_years} Earth years (F-13), can last up to about {s01_months} months (F-16) and cuts solar power to a few percent of normal (F-18). How power copes: see 03-03 G-01.", "why": "Frequency from F-13, length from the 2001 storm (F-16), power from Opportunity's {opp_pct} percent (F-18). The power plan itself belongs to 03-03 G-01 (Power).", "moves_to": "" }, { "id": "W-03", "confidence": "Medium", "text": "Storm warning comes in days, not hours. Orbiters watch storms grow, so the settlement gets roughly 3 to 7 days to bring equipment in, top up reserves and get people inside. 'Storm called' is a phrase everyone knows.", "why": "In 2018 the storm went from first sighting in late May to {s18_a1} million km² by 8 June and around the planet by 20 June (F-15). With orbital cameras that lead time is reliable; without them it is not.", "moves_to": "" }, { "id": "W-04", "confidence": "Medium", "text": "During a global storm the outside is not dangerous to walk in, only dim, gritty and cold-to-work-in. Light is an orange dusk at noon, shadows fade, and distant hills vanish into haze. People go out for essential work, roped and lit.", "why": "Wind pushes with about {force_pct} percent of Earth's force (F-20). Curiosity's view of the crater rim 30 km away faded in 2018, so it is the distance that goes, not the ground at your feet. Replaces the original 'visibility a few metres', which had no source. Lowered from High.", "moves_to": "" }, { "id": "W-05", "confidence": "Medium", "text": "Dust devils are a familiar sight on spring and summer afternoons: seen through periscopes and from the few viewing rooms, tracked on cameras, sometimes welcomed for cleaning panels. Children are taught not to chase them because of the grit and static they carry, not because they hurt.", "why": "Matches F-24, F-26 and F-27. The town is buried, with periscopes and a few viewing rooms (02-01 S-18, S-08). The friendly tone is a world-building choice.", "moves_to": "" }, { "id": "W-06", "confidence": "Medium", "text": "On autumn and winter mornings a thin frost covers the ground outside airlocks and on parked vehicles. The dry-ice part is gone within an hour of sunrise; patches of water frost can linger in shade. Ice haze sometimes fills low ground on cold nights.", "why": "Carbon dioxide frost at mid-latitudes (F-09), Viking 2's long-lasting water frost (F-10) and Phoenix's night-time ground clouds (F-29). How often at our exact latitude is a guess.", "moves_to": "" }, { "id": "W-07", "confidence": "Medium", "text": "Static sparks in dust devils and storms are a known, small hazard. Surface structures and suits are earthed, electronics are shielded, and nobody expects lightning bolts.", "why": "Perseverance has recorded {sparks} small discharges (F-26), so sparks are now confirmed. Big lightning has still never been seen. Raised from Low and narrowed from 'lightning' to 'sparks'. The grains' charge is 02-01 F-31.", "moves_to": "" }, { "id": "W-08", "confidence": "High", "text": "The settlement's calendar is built on Ls, not Earth months: people say 'storm season starts at 180' the way Earth people say 'autumn starts in September'. See 04-03-01 CF-03, CF-04 and CF-09, which now own the calendar: the year that starts at Ls 0, its seasons and its season days.", "why": "Ls is how every weather fact is keyed (F-02, F-12), so that reason stays here. The calendar moved on 26 September 2026 so it is written once; 02-01 S-26 points here.", "moved_to": "04-03-01 CF-03, CF-04, CF-09" }, { "id": "W-09", "confidence": "Medium", "text": "For world-building, Mars weather falls into bands. Equator to {sun_lo}°: warmest, driest, no shallow ice found. {sun_lo} to {sun_hi}°: inside SpaceX's solar limit, with shallow ice from about {ice_lo}°. {sun_hi} to {cap_lat}°: ice-rich but less sun and darker winters; our lead pin at {pin_lat}°N sits just inside the {sun_hi}° line. Above {cap_lat}°: buried under dry ice every winter.", "why": "Moved from Part One because it blends several facts into a judgement: the cap edge at {cap_lat}° (F-07), 02-03's shallow-ice band ({ice_lo} to {ice_hi}°, lowest exposed ice at about {ice_lo}°N) and SpaceX's {sun_hi}° solar limit (both read live from 02-03), frost (F-09, F-10) and the temperature range in 02-01.", "moves_to": "" }, { "id": "W-10", "confidence": "Low", "text": "In the 3D world, the sky is driven by one number, tau: about {tau_c_hi} on a clear day, rising over about {rise} sols to 10 or more in a global storm, then fading over months. Everyday dust devils are drawn {dd_lo} to {dd_hi} m wide and up to a few hundred metres tall; rare giants reach kilometres.", "why": "Numbers from F-15, F-17, F-21, F-24 and F-25. The rise time copies the 2018 storm's spread (late May to 20 June). The exact way tau maps to sky colour is the engine's choice (00-02).", "moves_to": "" } ], "world_spec": { "about": "The weather table the engine reads to draw the sky, storms and dust devils. The format belongs to the engine (00-02); the numbers belong to this file. Each names the fact or assumption it comes from.", "tau_clear": { "value": [ 0.4, 0.5 ], "from": "F-17", "path": "numbers.tau_clear" }, "tau_global_storm": { "value": 10.8, "from": "F-17", "path": "numbers.tau_opp_2018" }, "global_storm_start_ls": { "value": [ 185, 315 ], "from": "F-13", "path": "numbers.global_onset_ls" }, "global_storm_odds_pct": { "value": 33, "from": "F-13", "worked_out": "100 / numbers.global_every_my, rounded (1 in 3); the page checks it" }, "pressure_swing_pct": { "value": 30, "from": "F-04", "path": "numbers.atm_swing_pct" }, "dust_devil_width_m": { "value": [ 5, 135 ], "from": "F-24", "path": "numbers.dd_diam_m" }, "co2_frost_gone_min": { "value": 60, "from": "F-09", "path": "numbers.co2_frost_minutes" }, "storm_rise_sols": { "value": 20, "from": "W-10" }, "mars_year_one": { "value": "11 April 1955", "unit": "date (UTC) of Mars Year 1's northern spring equinox", "from": "F-02", "path": "numbers.my1_start" } }, "latitude_bands": [ { "band": "Above {cap}°N", "lat": [ "cap", "pole" ], "text": "Dry ice every winter, months of dark", "kind": "cold" }, { "band": "{sun_hi} to {cap}°N", "lat": [ "sun_hi", "cap" ], "text": "Ice-rich, less sun, dark winters", "kind": "cool" }, { "band": "{sun_lo} to {sun_hi}°N", "lat": [ "sun_lo", "sun_hi" ], "text": "Inside SpaceX's solar limit", "kind": "best" }, { "band": "0 to {sun_lo}°", "lat": [ "-sun_lo", "sun_lo" ], "text": "Warmest, driest, no shallow ice found", "kind": "warm" }, { "band": "{sun_lo} to {sun_hi}°S", "lat": [ "-sun_hi", "-sun_lo" ], "text": "Solar limit, long cold winters", "kind": "good" }, { "band": "{sun_hi} to {cap}°S", "lat": [ "-cap", "-sun_hi" ], "text": "Ice, very dark winters", "kind": "cool" }, { "band": "Above {cap}°S", "lat": [ "-pole", "-cap" ], "text": "Dry ice every winter", "kind": "cold" } ], "links": { "leans_on": [ { "ref": "02-01", "why": "Tilt, year length, orbit, sunlight, mean pressure, air densities, record cold, hair, Everest: read live, not copied" }, { "ref": "02-01 F-34", "why": "Wind force: a storm wind pushes like a light breeze (W-04)" }, { "ref": "02-01 F-31", "why": "Dust grains are charged (W-07)" }, { "ref": "02-01 S-18", "why": "The town is buried, seen through periscopes and a few viewing rooms (W-05)" }, { "ref": "02-03 R-02", "why": "The lead candidate site and its latitude, read live for W-01" }, { "ref": "02-03", "why": "The shallow-ice band and SpaceX's solar latitude limit, read live for W-09 and the band drawing" }, { "ref": "02-05", "why": "SU-06 answers, as far as it can, where the dust-carrying wind comes from at the pin; F-17 (Viking 2's late-winter frost night) backs W-01's colder nights" }, { "ref": "02-07 SK-01", "why": "The sky colours, for the opening picture's sky and the clear and storm skies in section 2.3 (read live)" } ], "used_by": [ { "ref": "02-04", "why": "The yearly swing in air pressure (F-04), for the south ice cap's story on the place cards (read live)" }, { "ref": "05-10", "why": "Jezero's air temperatures, for the viewer's night fact card (read live)" }, { "ref": "02-01", "why": "Quotes the season lengths, storm frequency, storm wind (F-20), storm length (F-16), 2018 opacity and the record dust devil; S-17 cites the dry-ice temperature (F-08)" }, { "ref": "02-03 R-06", "why": "Storm length, cited by R-06's short planetary reason (the power plan itself is 03-03 G-01)" }, { "ref": "03 Structures", "why": "Storm-proofing, earthing, power reserves, panel cleaning" }, { "ref": "00-02 The engine", "why": "Draws the sky and storms from the weather table; its sky model reads mars_year_one to number Mars years" }, { "ref": "03-03 Power", "why": "Reads F-16, F-18, F-17, F-27, F-03: How long a global storm lasts (read live); Opportunity's power in the 2018 storm (read live); The 2018 storm's record dust, tau 10.8 (read live); Wind cleaning solar panels, and Opportunity's long life (read live); Mars's stretched orbit, for sunlight by season (read live)" }, { "ref": "03-04 Fuel plant", "why": "Reads F-08, W-02: Dry ice forms at about -125°C: freezing out carbon dioxide, and frost on cold pipes (read live); A global storm is the settlement's defining emergency" }, { "ref": "03-05 Vehicles and port", "why": "Reads W-03: Days of storm warning to bring vehicles in" }, { "ref": "02-05 The site up close", "why": "Reads the Ls calendar, season lengths, perihelion, the dusty season, the global storm window, frost, dust devils and dry ice (read live)" }, { "ref": "02-07 The Mars sky", "why": "Reads dust opacity (F-17) and storm frequency (F-13) (read live); cites clouds (F-28, F-29), the storm sky (W-04) and W-10" }, { "ref": "03-07 Airlocks, suitports and dust", "why": "Reads F-27: wind cleaning rover panels (read live). Cites W-06: frost outside the airlocks on winter mornings" }, { "ref": "03-10 Greenhouses and food", "why": "Reads F-18: Opportunity's light in the 2018 storm (read live)" }, { "ref": "03-13 Local communications", "why": "Cites W-07: static sparks, so masts and cables are earthed" }, { "ref": "05-02 The Olympus race", "why": "Reads summit frost (F-11) and the 1971 global storm (F-14), for the Dawn and 1971 modes (read live)" }, { "ref": "04-03-01", "why": "The calendar and festivals: seasons (F-01), Ls and Mars Year 1 (F-02), aphelion and perihelion (F-03), frost (F-10, W-06), the dust season and global storms (F-12, F-13) and the Ls calendar (W-08), read live" }, { "ref": "04-04-03 Safety and emergencies", "why": "W-02: A global dust storm is the defining emergency; W-03: days of warning before a dust storm, for Condition 2" }, { "ref": "05-03 Guided tours", "why": "Summit frost on Olympus Mons (F-11), for the flyover's best season" }, { "ref": "05-06 Free roam", "why": "Clear-sky and storm dust (tau) and the global storm season (F-13), for the season dial (read live)" }, { "ref": "00-04 Glossary and units", "why": "F-02: Ls, the season angle, and Mars Year 1 (read live); F-17: tau on clear days and in storms, for the dust strip (read live)" }, { "ref": "02-08", "why": "Jezero's air temperatures (F-22) and dust devil sizes (F-24) (read live)" }, { "ref": "05-11", "why": "Mars Year 1's start (F-02, through mars_year_one) and the season lengths (F-01), for the Right now date (read live)" }, { "ref": "05-13 Mars Atlas", "why": "Mars Year 1 and the season dates, for the atlas's live night side (read live)" }, { "ref": "04-02-04 Needing nothing from Earth", "why": "F-13 and F-16: how often global storms come and the 2001 storm's length, for the storm store (read live)" }, { "ref": "05-12 A Living City", "why": "Perihelion and the 2001 storm, for the solar-led power sums the city view draws (read live)" }, { "ref": "05-15 Engine lab", "why": "Dry ice frost on cold engine lines on Mars (F-08)" }, { "ref": "05-18 Mars Atmosphere", "why": "Owns the MCS archive, profile units, sampling limitations and the NASA 2018 storm replay (F-32 to F-34)." }, { "ref": "05-19", "why": "Playable Arcadia: dust devils, dust-storm days and frost on the plain" }, { "ref": "05-20", "why": "Mars games: dust devils, snow, storms and the air that freezes, for Fact or Fiction? and the Mars Quiz (worked_out)" }, { "ref": "05-17 Living on Mars", "why": "The Mars Year count (Mars Year 1) for the shared sky model, which dates the blueprint's Checked stamp on the Living on Mars explainer" } ] }, "open_questions": [ "02-01 gives -153°C as Mars's lowest temperature. NASA gives about -125°C for dry ice to form (F-08), and the ground under a growing winter cap sits near that. 02-01 could say where -153°C was measured.", "NASA's 2016 angular-momentum chart also lists 1994 as a global dust storm year. Other sources used here do not; if it is confirmed, add it to F-14 and the storm record.", "The pressure-through-the-year drawing is a sketch through measured turning points. Replace it with a full measured year from Perseverance (Sanchez-Lavega 2023, Harri 2024) once those papers can be read.", "How surface structures stand up to freeze-thaw: no 03 file covers it yet. Storms, dust and earthing are answered in 03: vehicles come in on a storm warning (03-05), masts and cables are earthed (03-13), dust is stopped at the doors (03-07)." ], "changes": [ "25 September 2026 (before v2.2): Rebuilt as twin files (this facts file plus the page), with diagrams and the library bar. Version 1.0 was 16 September 2026.", "25 September 2026 (before v2.2): Corrected the share of air that freezes each winter from 25 percent to up to a third (about 30 percent), per NASA.", "25 September 2026 (before v2.2): Corrected the tallest dust devil from 8 km to about 20 km (and 70 m wide, not hundreds of metres).", "25 September 2026 (before v2.2): Corrected the 2018 storm: circled the planet on 20 June, dust back to normal by mid-September; removed 'North America-sized within a week' (it was 18 million km² by 8 June). The original's length, about 3.5 months, was right.", "25 September 2026 (before v2.2): Corrected 'perpetual night at noon': Opportunity still got about 3 percent of its usual solar energy, from scattered light.", "25 September 2026 (before v2.2): Corrected the 2001 storm: main decay over about 120 sols (Ls 185 to 263), fully clear about Ls 304; and Mariner 9's wait in 1971 to several weeks (not three months).", "25 September 2026 (before v2.2): Corrected the storm season: global storms have only started between Ls 185 and 315; the dusty half-year is Ls 180 to 360.", "25 September 2026 (before v2.2): Corrected Viking 2's frost: it was water ice and dust and stayed about 100 days, not dry ice gone by mid-morning.", "25 September 2026 (before v2.2): Corrected everyday winds to Perseverance's measurements: afternoon peaks near 7 m/s, gusts to 25 m/s.", "25 September 2026 (before v2.2): Corrected the clouds: the water-ice cloud belt forms near aphelion (Ls 60 to 100), from about 10°S to 30°N.", "25 September 2026 (before v2.2): Corrected panel cleaning: wind, from gusts and probably dust devils, cleaned Spirit's and Opportunity's panels; which did it each time was not seen.", "25 September 2026 (before v2.2): Updated lightning: small electrical sparks were confirmed by Perseverance in 2025 (F-26). W-07 raised from Low to Medium and narrowed to sparks.", "25 September 2026 (before v2.2): Updated season lengths to 193, 179, 143 and 154 sols.", "25 September 2026 (before v2.2): Removed unverified claims: regional storms born at Chryse and the polar edge, dust devils lasting a few minutes, Phoenix frost on its legs, the sky staying butterscotch for months.", "25 September 2026 (before v2.2): Added frost on the Tharsis volcanoes (2024), overnight carbon dioxide frost at low latitudes, dry-ice snow, the 2018 storm's effects on light and temperature, dust settling, and the Jezero temperature and dust devil records.", "25 September 2026 (before v2.2): Moved the latitude table from facts to assumption W-09. Added W-10 and a weather table for the engine.", "25 September 2026 (before v2.2): Lowered W-01 and W-04 from High to Medium. Replaced W-04's 'visibility a few metres'. W-08 marked to move to 04 Culture.", "25 September 2026 (before v2.2): Replaced the Sahara comparison with London's measured July day (Kew Gardens, Met Office).", "25 September 2026 (before v2.2): Updated 25 September 2026 (version 2.1): numbers owned by 02-01 (tilt, year, orbit, sunlight, pressure, air densities, record cold, hair, Everest, a person) and 02-03 (the lead site) are now read live, not typed. The quoted mean pressure is now 02-01's 636 Pa; sunlight now works out at about 490 to 713 W/m²; wind force at about 1.3 percent.", "25 September 2026 (before v2.2): Added the 1982 global storm (Viking; NASA 2016) and corrected the gap to 19 years (1982 to 2001), in F-14 and the storm record.", "25 September 2026 (before v2.2): Corrected F-05 with Perseverance's full early pressure record (735 up to 761, down to 650 Pa) and noted that Jezero sits low.", "25 September 2026 (before v2.2): Corrected F-29: near the end of Phoenix's mission some snow reached the ground.", "25 September 2026 (before v2.2): Added continent-sized storms lasting weeks every year (F-12), 'especially on high ground' (F-09), and restored Viking 2 at 48°N and Phoenix at 68°N.", "25 September 2026 (before v2.2): Updated W-01 to 38 to 40°N from 02-03's lead site, and W-08 to move to 04.03 Culture. Used-by links now name 02-01, the Interactive map and 05 Tours and missions.", "25 September 2026 (before v2.2): Removed stale open questions that 02-01 has since fixed (winter length, dust devils, the Sahara), and the unused London January figures.", "25 September 2026 (before v2.2): Updated the diagrams so every label is at least 11 px on a phone.", "25 September 2026 (before v2.2): 25 September 2026: folder 05 renamed 'Visiting Mars' (decided 25 September 2026); links updated.", "25 September 2026 (v2.2): Corrected F-13. NASA (2015) says once every three Mars years on average, which is about a 33 percent (1 in 3) chance a year, not 25 percent. The chance is now worked out from the three years, and the engine table's 25 is now 33.", "25 September 2026 (v2.2): The year length (668.6 sols) is now read live from 02-01, not kept here; the dry-ice temperature, storm wind and storm length stay owned here for 02-01 to quote.", "25 September 2026 (v2.2): Redrew the latitude bands and W-09 as 30 to 40° (inside SpaceX's solar limit) and 40 to 60° (ice-rich, less sun), read from 02-03. Our lead pin sits right on the 40° line. Removed 'ice mostly above 30°': 02-03's ice band starts at about 35°.", "25 September 2026 (v2.2): Correction to the earlier line 'Updated W-01 to 38 to 40°N': W-01 now reads the lead pin live from 02-03, about 40°N, right on SpaceX's solar limit.", "25 September 2026 (v2.2): W-02 now points to 02-03 R-06 for the power plan, instead of claiming to match 02-03 R-06 and 02-01 S-23 (they differed). W-05 now says periscopes, viewing rooms and cameras, not windows, to match 02-01 S-18.", "25 September 2026 (v2.2): Links: removed the Interactive map (02-04) from used-by, since it does not use this file; 02-01 now quotes storm wind and length and cites the dry-ice temperature. Removed the open question about 02-01's storm wind; added one on the lead site's prevailing wind direction. Engine table rows now name the number they copy. Page title is now 'Weather'.", "25 September 2026 (v2.2): W-01 now says the pin is a hair over SpaceX's 40° limit; W-08 no longer says 02-01 S-26 assumes a 24-month calendar.", "25 September 2026 (v2.2): leans_on no longer points at 02-01 S-14 and S-15 (they now point back here); it cites the physics facts 02-01 F-34 and F-31 instead. W-07 cites F-31.", "25 September 2026 (v2.3): the city pin moved to AP-1 (02-03 R-02), just inside SpaceX's 40° solar limit; W-01 and the latitude bands now say so.", "25 September 2026 (v2.3): W-01 gives the pin's exact latitude (39.8°N) rather than a rounded 40; the band drawing says 'just inside' the 40° limit.", "25 September 2026 (v2.4): links made two-way for the new files 03-03 Power, 03-04 Fuel plant and 03-05 Vehicles and port (and older one-sided links), each reason taken from the other file's own link.", "25 September 2026 (v2.4): W-02 points to 03-03 G-01 for how power copes with storms; it is a weather statement in its own right, so it no longer carries a moved_to marker.", "25 September 2026 (v2.4): removed the leans_on link to 02-03 R-06, which is now only a signpost to 03-03 G-01.", "25 September 2026 (v2.5): the open question on storing power through a storm is answered by 03-03 Power (G-08, G-09); only the social side (rationing) stays open, for 04.02.", "26 September 2026 (v2.6): Open question on the prevailing wind at the lead site deleted: answered, as far as it can be, by 02-05 SU-06 (no single prevailing wind; the dust-carrying winds come from the north-west, Low confidence until the Mars Climate Database is run at the pin; 02-05 holds that follow-up). W-01 cites Viking 2's late-winter night (02-05 F-17). 02-05 added to leans_on. used_by lists 02-05 and 02-07, which read the Ls calendar, seasons, dust and storms.", "26 September 2026 (v2.7): used_by adds 03-07 and 03-10, each with what it reads.", "26 September 2026 (v2.8): The open question on rationing power in a storm is deleted as answered by 04-02-01 CR-10, the shortage ladder. The structures question now names what 03 answers (03-05, 03-07, 03-13) and leaves only freeze-thaw open. The site text now points to 04-01-01 for the town's layout. used_by adds 03-13 and 05-02.", "26 September 2026 (v2.9): The old 04.03 placeholder is now 04-03-01 The calendar and festivals: W-08 moves_to, used_by and the calendar open question.", "26 September 2026 (v2.10): W-08 has moved to 04-03-01 CF-03, CF-04 and CF-09 (the calendar); the weather reason stays here. Open question on named seasons, months and festivals deleted as answered there. used_by: back-links for 04-03-01, 04-04-03 (what each reads, from its leans_on). Also back-links for 05-03, 05-06 (wave 6 pages, from their leans_on as written today).", "26 September 2026 (v2.11): Shelf life names a re-check date (September 2027), as the Research log (90-04) audit asked. Back-link for 00-04, which reads Ls and tau live.", "26 September 2026 (v2.12): Beauty pass: a new opening picture, a dust devil crossing the plain under thin ice clouds, labelled as art; the pin label on the latitude bands is split onto two lines so it no longer runs off its frame.", "26 September 2026 (v2.13): Final fix round: used_by: the folder-level '05 Visiting Mars' line removed; the 05 pages that really read this file are listed one by one. The opening picture's sky colours are now read live from 02-07 SK-01 instead of typed (and section 2.3 clear and storm skies); leans_on and quotes add 02-07", "28 September 2026 (v2.14): Now used by the new 02-08 Jezero Crater, which reads it live.", "28 September 2026 (v2.15): Used by the Stand in Jezero viewer (05-10).", "30 September 2026 (v2.16): World spec entry mars_year_one (F-02's Mars Year 1 start), so the engine's sky model (00-02) numbers Mars years from this file, not a copy. Read by the globe's Right now view (05-11). No facts changed.", "1 October 2026 (v2.17): used_by adds 04-02-04, which reads F-13 and F-16 for its storm store (links made symmetric).", "1 October 2026 (v2.18): used_by adds 05-12.", "3 October 2026 (v2.19): Now also used by 05-13 Mars Atlas, whose chart shades where it is night on Mars right now with the same sky model as the globe's Right now.", "3 October 2026 (v2.20): Now also read by 05-15 Engine lab: dry ice on cold engine lines on Mars (F-08).", "4 October 2026 (v2.21): Added F-30, the 2016 forecast of a global dust storm that came two years late, for the atlas's story of the next great dust storm (05-13).", "4 October 2026 (v2.22): Added F-31, what drives the dust storms (the Sun's heat, strongest in southern summer), for the atlas's Red only skin-deep card and How Mars turned red (05-13).", "5 October 2026 (v2.23): Added MCS archive and product provenance, native vertical coordinates and the column-versus-profile distinction for Mars Atmosphere.", "9 October 2026 (v2.24): Added F-35, the winter hemisphere's westerly jet (Guendelman, Waugh and Kaspi 2021), for the globe's wind belts (05-11 TT-13).", "9 October 2026 (v2.25): 05-19 (Playable Arcadia) now quotes this file, for dust devils, storm days and frost; used_by updated.", "10 October 2026 (v2.26): 02-04 now reads the yearly air swing (F-04) for the south ice cap's place-card story; added to used_by.", "10 October 2026 (v2.27): Used by 05-17 Living on Mars: the explainer's blueprint stamp is dated with today's Mars date from the shared sky model." ], "sources": { "guendelman_2021": { "name": "Guendelman, Waugh and Kaspi, The emergence of a summer hemisphere jet in planetary atmospheres, Journal of the Atmospheric Sciences, 2021", "url": "https://arxiv.org/abs/2108.00457" }, "wiki_astro_mars": { "name": "Wikipedia, Astronomy on Mars (season lengths), 2026", "url": "https://en.wikipedia.org/wiki/Astronomy_on_Mars" }, "wiki_timekeeping": { "name": "Wikipedia, Timekeeping on Mars (Ls, Mars Year numbering), 2026", "url": "https://en.wikipedia.org/wiki/Timekeeping_on_Mars" }, "lmd_ls": { "name": "LMD Mars Climate Database team, Mars solar longitude and seasons (accessed September 2026)", "url": "https://www-mars.lmd.jussieu.fr/mars/time/solar_longitude.html" }, "nasa_snow_2001": { "name": "NASA, Laser altimeter provides first measurements of seasonal snow depth on Mars (Smith, Zuber and Neumann, Science), 2001", "url": "https://science.nasa.gov/solar-system/planets/mars/laser-altimeter-provides-first-measurements-of-seasonal-snow-depth-on-mars/" }, "jpl_gale_2013": { "name": "NASA JPL, Seasonal pressure curve peaks at Gale Crater (PIA16912), 2013", "url": "https://science.nasa.gov/photojournal/seasonal-pressure-curve-peaks-at-gale-crater" }, "tillman_1998": { "name": "Tillman, University of Washington, Live from Earth and Mars: Viking pressure overview, 1998", "url": "https://www-k12.atmos.washington.edu/k12/resources/mars_data-information/pressure_overview.html" }, "rodriguez_2023": { "name": "Rodriguez-Manfredi et al., The diverse meteorology of Jezero crater over the first 250 sols of Perseverance on Mars, Nature Geoscience, 2023", "url": "https://www.nature.com/articles/s41561-022-01084-0" }, "hubble_1997": { "name": "NASA/Hubble, Seasonal changes in Mars' north polar ice cap, 1997", "url": "https://science.nasa.gov/asset/hubble/seasonal-changes-in-mars-north-polar-ice-cap/" }, "jpl_co2snow_2012": { "name": "NASA JPL, NASA observations point to 'dry ice' snowfall on Mars, 2012", "url": "https://www.jpl.nasa.gov/news/nasa-observations-point-to-dry-ice-snowfall-on-mars/" }, "eos_piqueux_2016": { "name": "Eos (Shultz), Carbon dioxide frost may keep Martian soil dusty, reporting Piqueux et al., 2016", "url": "https://eos.org/research-spotlights/carbon-dioxide-frost-may-keep-martian-soil-dusty" }, "jpl_viking_frost": { "name": "NASA JPL, Ice on Mars: Utopia Planitia again (PIA00571), Viking Lander 2, 1979", "url": "https://www.jpl.nasa.gov/images/pia00571-ice-on-mars-utopia-planitia-again/" }, "esa_frost_2024": { "name": "ESA, Frosty volcanoes discovered in Mars's tropics (Valantinas et al., Nature Geoscience), 2024", "url": "https://www.esa.int/Science_Exploration/Space_Science/Mars_Express/Frosty_volcanoes_discovered_in_Mars_s_tropics" }, "nasa_dust_2015": { "name": "NASA, The fact and fiction of Martian dust storms, 2015", "url": "https://www.nasa.gov/solar-system/the-fact-and-fiction-of-martian-dust-storms/" }, "smith_2019": { "name": "Smith and Guzewich (NASA Goddard), The Mars global dust storm of 2018, ICES 2019", "url": "https://ntrs.nasa.gov/api/citations/20190027303/downloads/20190027303.pdf" }, "nasa_mariner9": { "name": "NASA History, 50 years ago: Mariner 9 enters Mars orbit, 2021", "url": "https://www.nasa.gov/history/50-years-ago-mariner-9-enters-mars-orbit/" }, "tillman_uw": { "name": "Tillman, University of Washington, Mars annual pressure cycle (the 1977 A and B storms) (accessed September 2026)", "url": "https://atmos.uw.edu/~mars/pressure_annual_cycle/annual_cycle_for_netlander_rev_4/node4.html" }, "jpl_1982": { "name": "NASA JPL, 2016 resembles past global dust storm years on Mars (PIA20855), 2016", "url": "https://www.jpl.nasa.gov/images/pia20855-2016-resembles-past-global-dust-storm-years-on-mars/" }, "asu_2001": { "name": "Christensen Research Group (Arizona State University), TES monitored the growth and decay of the 2001 global dust storm (accessed September 2026)", "url": "https://christensen.asu.edu/discovery/tes-monitored-the-growth-and-decay-of-the-2001-global-dust-storm/" }, "jpl_opp_hunker": { "name": "NASA JPL, Opportunity hunkers down during dust storm, 2018", "url": "https://www.jpl.nasa.gov/news/opportunity-hunkers-down-during-dust-storm/" }, "wolkenberg_2020": { "name": "Wolkenberg et al., Similarities and differences of global dust storms in MY 25, 28 and 34, 2020 (MY 25 began at Hellas)", "url": "https://ntrs.nasa.gov/api/citations/20210012819/downloads/21-56.pdf" }, "planetary_2018": { "name": "The Planetary Society, Mars Exploration Rovers update: Opportunity and the 2018 dust storm, 2018", "url": "https://www.planetary.org/articles/06-mer-update-opportunity-dust-storm-sleep" }, "jpl_opp_end": { "name": "NASA JPL, NASA's Opportunity rover mission on Mars comes to end, 2019", "url": "https://www.jpl.nasa.gov/news/nasas-opportunity-rover-mission-on-mars-comes-to-end/" }, "nasa_msl_2018": { "name": "NASA, Martian dust storm grows global: Curiosity captures photos of thickening haze, 2018", "url": "https://www.nasa.gov/missions/martian-dust-storm-grows-global-curiosity-captures-photos-of-thickening-haze/" }, "wiki_climate": { "name": "Wikipedia, Climate of Mars (Viking storm wind gusts), 2026", "url": "https://en.wikipedia.org/wiki/Climate_of_Mars" }, "nasa_meda_2023": { "name": "NASA Science, Daily records of atmospheric temperature with Perseverance, 2023", "url": "https://science.nasa.gov/blog/daily-records-of-atmospheric-temperature-with-perseverance/" }, "kew_climate": { "name": "Met Office 1991-2020 averages for Kew Gardens, via Wikipedia, Climate of London, 2026", "url": "https://en.wikipedia.org/wiki/Climate_of_London" }, "jpl_dd_2022": { "name": "NASA JPL, NASA's Perseverance records a Martian dust devil (PIA25657), 2022", "url": "https://www.jpl.nasa.gov/images/pia25657-nasas-perseverance-records-a-martian-dust-devil/" }, "jpl_dd_2012": { "name": "NASA JPL, 12-mile-high Martian dust devil caught in act, 2012", "url": "https://www.jpl.nasa.gov/news/12-mile-high-martian-dust-devil-caught-in-act/" }, "jpl_sparks_2025": { "name": "NASA JPL, NASA rover detects electric sparks in Mars dust devils, storms (Chide et al., Nature), 2025", "url": "https://www.jpl.nasa.gov/news/nasa-rover-detects-electric-sparks-in-mars-dust-devils-storms/" }, "jpl_insight_2018": { "name": "NASA JPL, For InSight, dust cleanings will yield new science, 2018", "url": "https://www.jpl.nasa.gov/news/for-insight-dust-cleanings-will-yield-new-science/" }, "jpl_spirit_2009": { "name": "NASA JPL, Spirit gets energy boost from cleaner solar panels, 2009", "url": "https://www.jpl.nasa.gov/news/spirit-gets-energy-boost-from-cleaner-solar-panels/" }, "wolff_1999": { "name": "Wolff et al., Some characteristics of the Martian aphelion global cloud belt, Fifth International Conference on Mars (LPI), 1999", "url": "https://www.lpi.usra.edu/meetings/5thMars99/pdf/6173.pdf" }, "jpl_phoenix_2008": { "name": "NASA JPL, NASA Mars lander sees falling snow, 2008", "url": "https://www.jpl.nasa.gov/news/nasa-mars-lander-sees-falling-snow-soil-data-suggest-liquid-past/" }, "whiteway_2009": { "name": "Whiteway et al., Mars water-ice clouds and precipitation, Science, 2009", "url": "https://ui.adsabs.harvard.edu/abs/2009Sci...325...68W" }, "wiki_shard": { "name": "Wikipedia, The Shard (309.6 m), 2026", "url": "https://en.wikipedia.org/wiki/The_Shard" }, "jpl_shirley_2016": { "name": "NASA JPL, Study predicts next global dust storm on Mars, 2016 (Shirley, Icarus 2015)", "url": "https://www.jpl.nasa.gov/news/study-predicts-next-global-dust-storm-on-mars/" }, "asu_christensen_2018": { "name": "Arizona State University news, ASU Mars camera keeps a watchful eye for dust (Philip Christensen), 2018", "url": "https://news.asu.edu/content/asu-mars-camera-keeps-watchful-eye-dust" }, "mcs_pds": { "name": "NASA PDS Atmospheres Node, MCS DDR v6.2 archive and instrument definitions, 2025, checked 2026", "url": "https://pds-atmospheres.nmsu.edu/data_and_services/atmospheres_data/MARS/atmosphere_temp_prof.html" }, "mcs_product": { "name": "NASA/JPL-Caltech, MCS DDR v6.2 product 2015041500_DDR.TAB, observations 2015, reprocessed 2024; unmodified public mirror", "url": "https://github.com/yunusemresenoll/MARS/tree/1fe9f6be281fa0e77026d79d3989f7e99949520d/resources/archive/nasa-pds-mro-mcs-ddr-v6.2-sample" }, "mcs_storm_animation": { "name": "NASA/JPL-Caltech, Mars Climate Sounder Studies 2018 Dust Storm, PIA22737, 2018", "url": "https://science.nasa.gov/photojournal/mars-climate-sounder-studies-2018-dust-storm/" } }, "sources_checked": "25 September 2026", "latitude_bands_about": "Band edges are names, not numbers: cap is this file's winter cap edge (F-07), sun_lo and sun_hi are 02-03's numbers.sun_limits_deg, pole is 90. A minus sign means south." }, "02-07": { "file": "02-07", "title": "The Mars sky", "folder": "02", "facts_file": "02-07-the-mars-sky.json", "version": "1.21", "status": "Active", "last_updated": "10 October 2026", "about": "Facts file for 02-07 The Mars sky. The page is built from this file, the library catalogue and the page template. Change a fact here, then run build.py. Words in curly brackets, like {sun_am}, are filled in from the numbers in this file and from the files it quotes when the page is built, so each number is typed once. Numbers owned by other files (the orbits, the sol, the tilt, the Sun's size and sunlight, the moons' sizes, the dust, the solar conjunction in 02-01; the dust opacity and clouds in 02-02; the site's latitude in 02-03; the era plan in 01-01; the era names in 00-01) are read live, never retyped here.", "one_line": "Everything above the horizon at our site: a butterscotch day and a blue sunset, a Sun two thirds as wide, Phobos racing backwards twice a sol, Earth as an evening star, green auroras, meteors and clouds of dry ice.", "shelf_life": "The sky itself does not change on human time scales, but the science of it moves fast. Mars's visible aurora was first seen in 2024, and Japan's MMX mission, due to launch in October 2026 to land on Phobos (01-01), may refine its orbit and fate. The Phobos eclipse seasons on this page are our own geometry, not yet checked against a published ephemeris. Re-check auroras, Phobos and the cloud sources by September 2027.", "header": { "purpose": "Describe everything a person at our site would see above the horizon: the colour of the sky through a sol, the Sun, the two moons, Earth and the planets, the stars and the pole, auroras, meteors and clouds, and how each one looks from 39.8°N rather than from a rover's site.", "why": "The sky is the one view every resident shares, even from a buried town. The 3D world has to draw it right, and tours, stories and culture keep reaching for it: blue sunsets, Phobos crossing backwards, Earth as a small bright star. 02-01 holds the physics; this file holds the sky itself.", "when": "Drawing the sky, moons or stars in the 3D world, writing a night or sunset scene, planning a sky tour or festival, or checking what can really be seen from our site and when.", "change": "Part One changes only with a citation. Part Two assumptions can be challenged one at a time. Edit this facts file, then run build.py.", "writing": "Every number is compared to something people know. Pictures first, short sentences, no walls of text." }, "comparisons": { "about": "Familiar yardsticks used only to compare. Each one either has a source below or is marked as our own round figure.", "life_years": 80, "life_note": "a long human life, our own round figure", "light_year_km": { "value": 9460730472580.8, "source": "wiki_ly" }, "eye_arcmin": { "value": 1, "source": "wiki_acuity", "note": "normal (20/20) vision resolves about one arcminute" }, "glare_deg": 15, "glare_note": "our assumption for how close to the Sun a bright star can be seen in a dusty twilight sky (SK-04)" }, "numbers": { "sun_radius_km": 695700, "sun_mag_earth": -26.74, "moon_mag_full": -12.74, "mars_max_mag_from_earth": -2.94, "venus_a_mkm": 108.21, "mercury_a_mkm": 57.909, "proxima_ly": 4.25, "phobos": { "a_km": 9378, "period_days": 0.31891, "v10": 11.8, "above_km": 6000, "fall_m_century": 2, "breakup_myr": [ 30, 50 ], "eclipse_s": 40, "eclipse_date": "2 April 2022", "eclipse_sol": 397, "wiki_mag": [ -9, -10 ], "albedo": 0.07, "transit_2026": { "date": "12 August 2026", "sol": 1948 } }, "deimos": { "a_km": 23459, "period_days": 1.26244, "v10": 12.89, "wiki_mag": -5, "albedo": 0.08 }, "earth_view": { "mgs_date": "8 May 2003", "mgs_au": 0.93, "earth_mag": -2.5, "moon_mag": 0.9, "sep_arcmin": [ 3.5, 25 ], "transit_last": "11 May 1984", "transits_next": [ "10 November 2084", "15 November 2163" ], "clarke_year": 1971 }, "pole": { "north_ra_deg": 317.681, "north_dec_deg": 52.887, "north_ra_hms": "21h 10m 42s", "deneb": [ 310.358, 45.28 ], "alderamin": [ 319.645, 62.586 ], "polaris": [ 37.955, 89.264 ] }, "extinction_mag_per_tau": 1.086, "twilight_h": 2, "spirit_sunset": { "date": "19 May 2005", "sol": 489, "time": "6:07 in the evening" }, "curiosity_sunset": { "date": "15 April 2015", "sol": 956 }, "viking_color_date": "21 July 1976", "aurora": { "date": "18 March 2024", "sol": 1094, "nm": 557.7, "rayleigh": 101, "rayleigh_pm": 14, "eye_rayleigh": 250, "clear_rayleigh": 200, "clear_tau": 0.3 }, "meteor": { "spirit_date": "7 March 2004", "siding_date": "19 October 2014", "siding_km": 139500, "siding_kms": 56 }, "craters": { "per_year": 200, "min_m": 3.9 }, "clouds": { "water_max_km": 60, "shine_year": 2021, "rays_date": "2 February 2023", "hood_lat": [ 30, 40 ], "hood_recede_deg": 20, "hood_images": 585, "amec_km": 1800, "amec_w_km": 150, "amec_kmh": 600, "amec_alt_km": 45, "amec_h": 2.5 }, "sky_colours": { "day_zenith": "#C49A6C", "day_horizon": "#D9B98F", "day_near_sun": "#E8D6B8", "sunset_near_sun": "#8FB1CF", "sunset_far": "#8A6E57", "twilight": "#3E4656", "night": "#0C0E15", "storm_noon": "#9C6A3E" }, "moon_anchors": { "jd_tdb": 2461314.5, "date": "1 October 2026", "frame": "Earth's equator of 2000 (ICRF), km from Mars's centre", "phobos_km": [ -829.7237209655841, -8492.736219971477, -3901.224391547381 ], "deimos_km": [ -18353.44795933891, 7086.994209146845, 12766.16024817138 ], "check_years": [ 2020, 2036 ], "check_deg": 4, "about": "Where JPL Horizons puts each moon at midnight (TDB) on 1 October 2026. check_deg: the largest gap between our moons and JPL's on 1 January 2020, 2 October 2026 and 1 January 2036." }, "look": { "from": "SK-11", "about": "How the sky over the pin looks, so every picture, film and 3D scene draws the same sky (00-05 ST-20). Colours are numbers.sky_colours (SK-01); sizes are facts named beside them. Shown in The First Martian City unless a part says otherwise.", "words": { "tw": "02-07:numbers.twilight_h" }, "places": { "day": { "name": "The day sky", "outside": "Butterscotch overhead, paler and browner near the horizon, whitish round a small Sun about two thirds as wide as from Earth (F-05, SK-01). High thin water-ice clouds now and then (F-31)." }, "dusk": { "name": "Sunset and twilight", "outside": "A cool blue glow round the setting Sun while the rest of the sky darkens to grey-brown (F-02, F-03); the glow lingers for up to {tw} hours (F-04). Earth shows as a bright blue-white evening star above the glow, with the Moon a faint dot beside it, in its evening-star seasons (F-15 to F-18)." }, "night": { "name": "The night sky", "outside": "Black and packed with stars on clear nights (02-01 S-09), the same constellations as Earth's (F-21). Phobos, a dark lumpy moon, rises in the west and climbs low over the southern sky (F-07, F-08); Deimos is a bright star creeping the other way (F-13, F-14). Now and then a faint green aurora (F-26)." }, "viewing_room": { "name": "A viewing room", "inside": "One of the town's few surface rooms (02-01 S-18, SK-06): a low room with a long window facing west and south across the plain, soft benches, people in everyday clothes, the room's own lights dimmed so the sky shows (SK-07)." } }, "palette": { "day_zenith": "#C49A6C", "day_horizon": "#D9B98F", "day_near_sun": "#E8D6B8", "sunset_near_sun": "#8FB1CF", "sunset_far": "#8A6E57", "twilight": "#3E4656", "night": "#0C0E15", "storm_noon": "#9C6A3E" }, "light": "The ground takes the sky's colour: warm tan by day, cooling to grey-blue at dusk. Shadows are soft under dust and sharp on the clearest days.", "people": "Indoors in everyday clothes at the viewing-room window, small against it; outside, crews in pairs in white suits, small against the sky.", "eras": { "city": "The sky is watched from viewing rooms and periscopes, and on suited walks.", "far": "Under the domes' glass and water roofs, the sky is overhead every day, softened and blue-tinged through the water (03-10 GF-17)." }, "never": [ "A blue daytime sky (F-01)", "A big Sun: it is two thirds as wide as from Earth (F-05)", "Phobos or Deimos as big, bright, Earth-Moon-like discs (F-09, F-14)", "Rainbows, rain clouds or thunderstorms", "A red or orange glow round the setting Sun: on Mars the colours flip and the glow is blue (F-02)", "Anyone outside without a suit, or working outside alone (03-08 SS-05)", "People posed for the camera or staring at it", "Brass, copper or old-fashioned gauges and lamps" ], "shots": [ { "id": "blue_sunset_room", "name": "A blue sunset from a viewing room", "frame": "Inside a viewing room at the edge of the town, looking west through its long window: the small Sun setting over a flat plain inside a cool blue glow, the far sky grey-brown, Earth a bright evening star above the glow. A few people in everyday clothes sit and stand at the window, small and in silhouette. The buried rows' skylight collars glow outside." }, { "id": "phobos_night", "name": "Phobos over the plain", "frame": "Night over the plain: a sky packed with stars, Phobos small and low in the south, the town's skylight collars glowing faintly, a suited pair walking home." } ], "open": [] } }, "sections": [ { "id": "1.1", "title": "The day sky and the blue sunset", "short": "Day and sunset" }, { "id": "1.2", "title": "The Sun", "short": "Sun" }, { "id": "1.3", "title": "Phobos and Deimos", "short": "Moons" }, { "id": "1.4", "title": "Earth, the Moon and the planets", "short": "Earth" }, { "id": "1.5", "title": "Stars and the pole", "short": "Stars" }, { "id": "1.6", "title": "Auroras and meteors", "short": "Auroras" }, { "id": "1.7", "title": "Clouds", "short": "Clouds" } ], "facts": [ { "id": "F-01", "section": "1.1", "text": "Viking 1 took the first colour picture from the surface of Mars on {viking_date}. The first versions released to the public showed a blue sky. Properly calibrated versions showed the truth: a dust-laden, reddish sky.", "compare": "The first picture of an alien sky was painted in Earth's colours by mistake, because blue was what people expected.", "sources": [ "drew_viking" ] }, { "id": "F-02", "section": "1.1", "text": "Why the colours flip, in the words of NASA's Mark Lemmon: 'the very fine dust is the right size so that blue light penetrates the atmosphere slightly more efficiently.' Normal daylight makes the rusty colour of the dust stand out; sunset makes the blue near the Sun stand out. Curiosity photographed it in Gale crater on sol {cur_sol} ({cur_date}).", "compare": "The grains average about {dust_um} µm across (02-01 F-30), about 1/{hair_x} of a hair's width. 02-01 F-16 holds the blue sunset itself.", "sources": [ "jpl_sunset_2015" ] }, { "id": "F-03", "section": "1.1", "text": "Spirit watched the Sun sink below the rim of Gusev crater on {spirit_date} (sol {spirit_sol}, about {spirit_time}). NASA says the bluish glow above the Sun 'would be visible to us if we were there'. The published colours are slightly exaggerated.", "compare": "Ten years before Curiosity's famous sunset, a human-eye blue glow had already been recorded.", "sources": [ "nasa_spirit_2005" ] }, { "id": "F-04", "section": "1.1", "text": "Twilight is long. Spirit's images show the glow staying visible, but fainter and fainter, for up to {tw_h} hours before sunrise and after sunset, because dust high in the air scatters sunlight round to the night side.", "compare": "Up to {tw_both} hours of twilight in every sol: about {tw_pct}% of the sol spent in the glow.", "sources": [ "nasa_spirit_2005" ] }, { "id": "F-05", "section": "1.2", "text": "The Sun is {sun_r} km in radius. Worked out from Mars's average distance (02-01 F-13), it looks about {sun_am} arcminutes across from Mars, against {sun_am_e} from Earth. Mars's stretched orbit makes it swell and shrink over the year, from about {sun_lo} arcminutes at the far point to {sun_hi} at the near point.", "compare": "About {sun_moon_pct}% of the width of the full Moon from Earth ({moon_am} arcminutes). 02-01 F-15 gives the same answer as 'two thirds as wide'.", "sources": [ "nssdc_sun", "nssdc_moon" ] }, { "id": "F-06", "section": "1.2", "text": "From Earth the Sun shines at magnitude {sun_mag_e}. Worked out from the extra distance, from Mars it shines at about {sun_mag}: only {irr_pct}% of Earth's sunlight (02-01 F-14), but still a blinding disc.", "compare": "Still about {sun_vs_moon} times brighter than the full Moon seen from Earth. Nobody looks straight at it.", "sources": [ "nssdc_sun", "nssdc_moon" ] }, { "id": "F-07", "section": "1.3", "text": "Phobos circles {ph_a} km from Mars's centre, only about {ph_above} km above the surface: closer to its planet than any other moon in the solar system. One orbit takes {ph_period}, faster than Mars turns, so it rises in the west and sets in the east (02-01 F-42).", "compare": "Our Moon is {ph_moon_x} times further from Earth. Phobos laps Mars about three times while the ground turns once.", "sources": [ "nssdc_mars", "nasa_phobos_2015" ] }, { "id": "F-08", "section": "1.3", "text": "Worked out for our site at {lat}°N (02-03 R-02): Phobos never passes overhead. It rises in the west, climbs to only about {ph_alt}° above the southern horizon, and sets in the east about {ph_vis} later. It comes round again every {ph_syn}.", "compare": "From the equator it would pass straight overhead and stay up about {ph_vis_eq} (02-01 F-42). From our site it is a low arc across the south, about {ph_per_sol} passes a sol.", "sources": [ "nssdc_mars" ] }, { "id": "F-09", "section": "1.3", "text": "Worked out from its size (02-01 F-42) and distance: from our site Phobos looks about {ph_rise} arcminutes across as it rises, growing to about {ph_culm} at its highest point, because it is then {ph_d_culm} km away rather than {ph_d_rise} km.", "compare": "About a third of the full Moon from Earth ({moon_am} arcminutes), and it visibly swells as it climbs. Our Moon does the same, but by far less.", "sources": [ "nssdc_mars", "nssdc_moon" ] }, { "id": "F-10", "section": "1.3", "text": "Phobos is one of the darkest bodies known, reflecting only about {ph_albedo_pct}% of the sunlight that hits it, and it shows phases like our Moon. Worked out from NASA's brightness figure, a full Phobos at its highest over our site shines at about magnitude {ph_mag}; reference works give about {ph_wiki_lo} to {ph_wiki_hi} for the best case.", "compare": "About 1/{ph_moon_light} of the full Moon's light on Earth: enough to notice, not enough to read by.", "sources": [ "nssdc_mars", "wiki_astro_mars", "nssdc_moon" ] }, { "id": "F-11", "section": "1.3", "text": "On {ecl_date} (sol {ecl_sol}) Perseverance filmed Phobos crossing the Sun. The eclipse lasted a little over {ecl_s} seconds. Spirit and Opportunity took the first time-lapse pictures of such an eclipse in 2004.", "compare": "Phobos ({ph_culm} arcminutes at best from our site) is too small to cover the Sun ({sun_am} arcminutes): every eclipse is a dark bite crossing the disc, never a total eclipse.", "sources": [ "jpl_eclipse_2022" ] }, { "id": "F-12", "section": "1.3", "text": "Phobos is falling. Mars's gravity draws it in by about {ph_fall} m every hundred years, and NASA scientists expect it to be pulled apart in {ph_brk_lo} to {ph_brk_hi} million years. Its long grooves may be the first cracks.", "compare": "In an {life}-year life it drops about {ph_life_m} m, less than a person's height. The sky of our City era is the sky of today.", "sources": [ "nasa_phobos_2015" ] }, { "id": "F-13", "section": "1.3", "text": "Deimos circles {de_a} km from Mars's centre, once every {de_period}: barely faster than Mars turns. So it rises in the east and crawls west. Worked out for our site, it stays up about {de_vis} days at a time and comes back every {de_syn} sols.", "compare": "02-01 F-44 gives {de_vis_eq} days at the equator. Deimos is the slow moon, Phobos the fast one.", "sources": [ "nssdc_mars" ] }, { "id": "F-14", "section": "1.3", "text": "Worked out: Deimos ({de_d} km across, 02-01 F-44) looks only about {de_am} arcminutes wide from our site, and at full it shines at about magnitude {de_mag}. Reference works say it looks star-like, 'with a disk barely discernible if at all', at about {de_wiki}.", "compare": "Normal eyesight resolves about {eye} arcminute, so Deimos sits right at the edge: a star you might just see is round. It is about {de_vs_earth} times brighter than Earth in the Mars sky (F-15).", "sources": [ "nssdc_mars", "wiki_astro_mars", "wiki_acuity" ] }, { "id": "F-15", "section": "1.4", "text": "Mars Global Surveyor photographed Earth and the Moon from Mars on {mgs_date}, from {mgs_au} AU (astronomical units) away, near Earth's greatest distance from the Sun in the Mars sky. Their brightness was given as magnitude {earth_mag} for Earth and {moon_mag} for the Moon.", "compare": "Earth from Mars is a little fainter than Mars at its very brightest from Earth ({mars_mag}). Curiosity photographed the pair from the ground in 2014 (02-01 F-45).", "sources": [ "wiki_astro_mars", "nssdc_mars" ] }, { "id": "F-16", "section": "1.4", "text": "Earth orbits inside Mars, so it can never stray far from the Sun in the Mars sky. Worked out from the two orbits (02-01 F-13): up to about {e_elong_max}° from the Sun when Mars is near perihelion, about {e_elong}° on average. It is only ever an evening star after sunset or a morning star before dawn, never high in a midnight sky.", "compare": "Mars sees Earth the way we see Venus: a bright star in the twilight, low in the west or east.", "sources": [ "nssdc_mars" ] }, { "id": "F-17", "section": "1.4", "text": "The Moon hangs beside Earth. Worked out at Earth's greatest distance from the Sun in the Mars sky, the two sit about {moon_sep} arcminutes apart; reference works give a range of {sep_lo} to {sep_hi} arcminutes as the distance between the planets changes.", "compare": "About a quarter of the full Moon's width: easy to see as two points with normal eyes (about {eye} arcminute). A bright star with a faint companion.", "sources": [ "nssdc_moon", "wiki_astro_mars", "wiki_acuity" ] }, { "id": "F-18", "section": "1.4", "text": "Earth's show repeats every {syn} days (02-01 F-41). It passes between Mars and the Sun and is lost in the glare, then rises as a morning star, then goes behind the Sun (the solar conjunction, when radio contact stops, 02-01 F-40), then returns as an evening star.", "compare": "The same {syn_mo}-month rhythm as the launch windows (01-01 F-15): the sky and the ships run on one clock.", "sources": [ "nssdc_mars" ] }, { "id": "F-19", "section": "1.4", "text": "Now and then Earth crosses the face of the Sun as seen from Mars. The last transit was on {tr_last}; the next are on {tr_next} and {tr_next2}. The Moon can almost always be seen crossing too. Arthur C. Clarke's {clarke} story 'Transit of Earth' imagines an astronaut on Mars watching the 1984 one.", "compare": "A once-in-a-lifetime sight: the next one is {tr_wait} years after this page was written.", "sources": [ "wiki_transit" ] }, { "id": "F-20", "section": "1.4", "text": "Worked out from NASA's orbit sizes (Venus {venus_a}, Mercury {merc_a} million km from the Sun): from Mars, Venus never strays more than about {v_elong}° from the Sun and Mercury no more than about {m_elong}°.", "compare": "Mercury gets only about a third as far from the Sun as Earth does ({e_elong}°): lost in the dusty twilight glow most of the time.", "sources": [ "nssdc_venus", "nssdc_mercury", "nssdc_mars" ] }, { "id": "F-21", "section": "1.5", "text": "The constellations are the same as Earth's. Mars is never more than about {d_max} million km from Earth (02-01 F-39), while the nearest star is {prox_ly} light-years away.", "compare": "The nearest star is about {prox_x} times further off than Mars ever is from Earth. Worked out, the biggest shift in its position is about {prox_as} arcseconds, far below the {eye_as} arcseconds the eye can resolve.", "sources": [ "wiki_proxima", "wiki_ly" ] }, { "id": "F-22", "section": "1.5", "text": "Mars's north pole points at {pole_hms}, {pole_dec}° north, in Cygnus, the Swan. There is no bright pole star: Deneb is about {deneb_deg}° away and Alderamin about {alder_deg}°. The south pole lies a couple of degrees from Kappa Velorum.", "compare": "Worked out: Polaris, Earth's pole star, sits {polaris_deg}° from Mars's pole. On Mars it is just another star, wheeling round with the rest.", "sources": [ "nssdc_mars", "wiki_astro_mars", "simbad" ] }, { "id": "F-23", "section": "1.5", "text": "Worked out for our site: the north pole of the sky stands {lat}° above the northern horizon, so every star within {lat}° of it never sets. That includes Deneb, Alderamin and Polaris. Stars near the south pole never rise.", "compare": "The same tilt of the sky as anywhere at {lat}° north on Earth, but the wheel of stars turns about Cygnus instead of Polaris.", "sources": [ "nssdc_mars", "simbad" ] }, { "id": "F-24", "section": "1.5", "text": "Dust dims the stars. Starlight is dimmed by about {ext_k} magnitudes for each unit of optical depth (tau) it passes through. On a normal clear day tau is about {tau_lo} to {tau_hi} (02-02 F-17), so stars overhead lose about {ext_clear} magnitudes; in the 2018 storm (tau {tau_opp}) they would have lost about {ext_storm}.", "compare": "On a clear night about {ext_pct}% of a star's light gets through overhead, less near the horizon. In a global storm the night sky goes blank: even the brightest star would be far too faint to see.", "sources": [ "wiki_optical_depth" ] }, { "id": "F-25", "section": "1.6", "text": "Mars has three kinds of aurora. Discrete auroras glow over patches of magnetised crust (first seen by Mars Express, reported 2005). Diffuse auroras spread across the night side when solar particles hit the air (found by MAVEN in 2014). Proton auroras shine on the day side (MAVEN, reported 2018). The Emirates Mars Mission has since seen long sinuous auroras.", "compare": "Earth's auroras hug the poles, where its magnetic field funnels particles. Mars has no global field (02-01 F-24), so a diffuse aurora can cover the whole night side.", "sources": [ "knutsen_2025" ] }, { "id": "F-26", "section": "1.6", "text": "On {au_date} (sol {au_sol}) Perseverance recorded the first visible-light aurora from the surface of another planet: green light at {au_nm} nm, the same oxygen line as Earth's green aurora, at {au_r} ± {au_pm} rayleighs. The team puts the naked-eye limit at about {au_eye} rayleighs; in clearer air (tau {au_tau}) it would have reached about {au_clear}.", "compare": "About {au_pct}% of what the eye needs. Even in the clearer air it would have been 'just below the threshold' of what a person could see; a stronger storm on a clear night would put it within reach.", "sources": [ "knutsen_2025", "jpl_aurora_2025" ] }, { "id": "F-27", "section": "1.6", "text": "See 02-06 F-08, which owns the dose from the solar storm of 20 May 2024: Curiosity measured {st_ugy} micrograys, the biggest surge since it landed. The sky stays here: in that storm MAVEN saw aurora engulf the whole planet.", "compare": "About {st_xray} chest X-rays in one event, by NASA's comparison (02-06 F-08; 02-01 F-27 covers such spikes). On Mars the brightest auroras and the worst radiation arrive together.", "sources": [ "jpl_storm_2024" ], "moved_to": "02-06 F-08" }, { "id": "F-28", "section": "1.6", "text": "Spirit caught a streak across the Martian sky on {sp_met}: the first meteor seen from another planet. Scientists linked it to a stream of dust from comet 114P/Wiseman-Skiff, a Martian meteor shower.", "compare": "Mars has its own meteor showers, from its own comet streams, on its own calendar.", "sources": [ "selsis_2005" ] }, { "id": "F-29", "section": "1.6", "text": "Comet Siding Spring passed within {ss_km} km of Mars on {ss_date}. MAVEN found metals from its dust high in the air, which hit at {ss_kms} km/s. Scientist Nick Schneider estimates a watcher on the ground would have seen tens of thousands of shooting stars an hour, for hours.", "compare": "The comet passed at about {ss_moon_pct}% of the Moon's distance from Earth. Schneider compares it to the great Leonid meteor storm of 1833.", "sources": [ "nasa_siding_2014", "space_siding_2015" ] }, { "id": "F-30", "section": "1.6", "text": "More than {cr_n} small rocks a year strike Mars hard enough to leave craters at least {cr_m} m across (Daubar and others, 2013). Rocks too small to reach the ground on Earth get through Mars's thin air.", "compare": "Worked out over Mars's whole surface ({mars_area} million km², from 02-01's radius): one such crater a year for every {cr_area} km². Within {cr_r} km of any one spot, that is about one every {cr_years} years.", "sources": [ "jpl_craters_2013" ] }, { "id": "F-31", "section": "1.7", "text": "Most Martian clouds are water ice and float no more than about {cl_max} km up. Higher and colder, clouds of carbon dioxide ice (dry ice) form. In {cl_year} Curiosity photographed 'night-shining' clouds glowing after sunset and iridescent 'mother-of-pearl' clouds; Mark Lemmon described their 'shimmery pastel set of colors'.", "compare": "Thin, wispy clouds like Earth's cirrus. 02-02 F-28 holds the belt of water-ice clouds that gathers each northern summer, and F-29 Phoenix's falling snow.", "sources": [ "jpl_clouds_2021" ] }, { "id": "F-32", "section": "1.7", "text": "On {rays_date} Curiosity saw sun rays (crepuscular rays) fanning through clouds at sunset: the first time they were seen so clearly on Mars. The clouds were probably high dry-ice clouds.", "compare": "The same beams of light through gaps in cloud that people photograph at sunset on Earth.", "sources": [ "jpl_rays_2023" ] }, { "id": "F-33", "section": "1.7", "text": "In northern late summer, autumn and winter a cloud cap, the north polar hood, spreads over the north. A 2018 study of {hood_n} telescope images (2001 to 2016) found the hood thinner in the afternoon than in the morning, and cites earlier work (Akabane and others) placing its edge at {hood_lo} to {hood_hi}°N in the early morning, pulling back about {hood_back}° further north by afternoon.", "compare": "Our site at {lat}°N sits right on that edge: on autumn and winter mornings a pale cloud bank may lie over the northern sky, gone by afternoon.", "sources": [ "schmude_2018" ] }, { "id": "F-34", "section": "1.7", "text": "Around southern spring and summer a cloud up to {amec_km} km long and {amec_w} km wide grows each morning from Arsia Mons, racing west at over {amec_kmh} km/h about {amec_alt} km up, for about {amec_h} hours before it drifts off and fades.", "compare": "Worked out: a cloud {amec_alt} km up can be seen from about {amec_hz} km away, so it is a sight for an Arsia Mons outpost (02-01 S-19), not our city.", "sources": [ "esa_amec_2021" ] }, { "id": "F-35", "section": "1.3", "text": "At midnight on {moon_date}, JPL Horizons put Phobos {ph_now_km} km from Mars's centre and Deimos {de_now_km} km. From there the engine carries each moon round at its true period (F-07, F-13). Checked against JPL for {moon_chk_a}, {moon_date} and {moon_chk_b}, both stay within about {moon_err}° of JPL's positions.", "compare": "{moon_err}° is where Phobos will be about {moon_err_min} minutes later: close enough that a moon on screen sits where the real one is.", "sources": [ "jpl_horizons_2026" ] }, { "id": "F-36", "section": "1.3", "text": "On {ph26_date} (sol {ph26_sol}) Perseverance filmed Phobos crossing the Sun again from Jezero. NASA tinted the film to show what a person would see through eclipse glasses. Comparing its films of these crossings lets scientists refine Phobos's orbit and how it is changing.", "compare": "Like the eclipses on Earth that people travel to see, except that on Mars they come round several times a year, each over in under a minute (F-11).", "sources": [ "nasa_pia26811" ] } ], "firsts": { "about": "Firsts in the Mars sky, for the timeline drawing. Each points to the fact that holds it.", "list": [ { "year": 1976, "what": "First colour picture of the sky (Viking 1), first released blue by mistake", "ref": "F-01" }, { "year": 2004, "what": "First meteor seen from another planet (Spirit); first time-lapse of a Phobos eclipse", "ref": "F-28" }, { "year": 2005, "what": "Discrete aurora reported (Mars Express); Spirit's blue sunset and two-hour twilight", "ref": "F-25" }, { "year": 2014, "what": "Diffuse aurora found (MAVEN); Comet Siding Spring's meteor storm", "ref": "F-29" }, { "year": 2015, "what": "Curiosity's colour-calibrated blue sunset", "ref": "F-02" }, { "year": 2018, "what": "Proton aurora reported (MAVEN)", "ref": "F-25" }, { "year": 2021, "what": "Night-shining and mother-of-pearl clouds (Curiosity)", "ref": "F-31" }, { "year": 2022, "what": "Close-up video of a Phobos eclipse (Perseverance)", "ref": "F-11" }, { "year": 2023, "what": "First clear sun rays (Curiosity)", "ref": "F-32" }, { "year": 2024, "what": "First visible-light aurora (Perseverance); whole-planet aurora (MAVEN)", "ref": "F-26" } ] }, "sky_by_era": { "about": "Who watches the sky in each era, and from where. The sky itself is the same in every era (F-12); what changes is the watchers. People per era are read live from 01-01's era plan; where they watch from is our assumption (SK-06, SK-07).", "rows": [ { "era": "today", "where": "Rover cameras at other sites, such as Gale and Jezero. Nobody is at our site (02-04).", "new": "Everything on this page was first seen by robots: sunsets, eclipses, the aurora, a meteor." }, { "era": "robots", "where": "Cameras on the landers and robots at our site.", "new": "Our own site's sky recorded for the first time." }, { "era": "crew", "where": "Suit visors on surface walks, and screens fed by outside cameras.", "new": "The first human eyes on a blue sunset and on Earth as an evening star." }, { "era": "town", "where": "Periscopes and a few viewing rooms (02-01 S-18, 02-02 W-05), plus surface walks.", "new": "Sunsets become an outing (02-01 S-07); people start to watch for Phobos and the evening star." }, { "era": "city", "where": "Viewing rooms and periscopes facing west, south and north (SK-06), and sky cameras on screens.", "new": "A skywatching culture with its own clock (SK-09); port lights on landing nights (SK-07)." } ] }, "assumptions": [ { "id": "SK-01", "confidence": "Medium", "title": "Sky colours for the 3D world", "text": "The 3D world paints the clear-day sky butterscotch overhead, paler and browner near the horizon, and whitish around the Sun. At sunset a cool blue halo forms round the Sun while the far sky darkens to brown; twilight is grey-blue, night near-black. The colours in the engine's list are our reading of calibrated rover pictures. The sky's dustiness is driven by tau (02-02 W-10).", "why": "The directions of change are measured (F-02, F-03, 02-01 F-16). The exact colours are a judgement from calibrated images, not a measurement, so Medium. Brightness comes from 02-01 S-06." }, { "id": "SK-02", "confidence": "High", "title": "Long twilight", "text": "After sunset the 3D world keeps a glow in the sky for up to {tw_h} hours, fading slowly, and the same before dawn. Stars come out one by one through it; the evening star (Earth) shows while the west is still pale.", "why": "Spirit's images (F-04). High dust (02-02 W-10) lengthens it; a dustier sky makes a longer, dimmer glow." }, { "id": "SK-03", "confidence": "Medium", "title": "Phobos eclipse seasons at our site", "text": "Seen from our site, Phobos's track across the sky lies between about {ph_dec_hz}° and {ph_dec_culm}° south of the sky's equator. The Sun only sits in that band twice a Mars year, around Ls {ecl_ls1} and Ls {ecl_ls2} (northern autumn and winter). Those are the Phobos eclipse seasons: on many sols in them, a dark bite crosses the Sun for under a minute.", "why": "Worked out from Phobos's orbit (F-07), our latitude (02-03 R-02) and Mars's tilt (02-01 F-19). The geometry is simple, but we have not checked it against a published eclipse table, so Medium." }, { "id": "SK-04", "confidence": "Low", "title": "When Earth can be seen", "text": "Earth can be picked out when it stands more than about {glare}° from the Sun. On that rule it is visible for about {e_vis_days} days of every {syn}-day cycle, split between a morning-star season and an evening-star season, and hidden for the rest: around the solar conjunction and when it passes between Mars and the Sun.", "why": "The elongations are worked out from the orbits (F-16, F-18). The {glare}° glare limit is our guess for a dusty twilight sky (F-04, F-24), so Low. The site's typical dust is still an open question in 02-05 (no lander has measured tau in Arcadia); when 02-05 has a figure, this limit moves there." }, { "id": "SK-05", "confidence": "High", "title": "The sky and the radio go quiet together", "text": "When Earth slips behind the Sun, residents lose both its light in the sky and its voice on the radio for a few weeks. Earth comes back as the evening star, and its return is also the return of messages from home.", "why": "The solar conjunction that stops radio contact (02-01 F-40) is the same event that hides Earth in the Sun's glare (F-18). The feeling is our story choice; the timing is geometry." }, { "id": "SK-06", "confidence": "Medium", "title": "Where people see the sky", "text": "The viewing rooms and periscopes (02-01 S-18) look mainly west and south. West catches the sunset, the blue halo and the evening star; south catches Phobos's low arc and its eclipses. A north-facing periscope shows the pole in Cygnus, the stars that never set, and the polar hood on winter mornings.", "why": "Where each sight appears is worked out here (F-08, F-16, F-23, F-33). Which way the rooms face is now set by 03-06 HA-08: viewing rooms look west and south, with some periscopes turned north, as above. Where each room sits is 04-01-01 FC-07: the South window opens first, in the First Town, on the Old town's south corner; the City adds Port, South-west and Sunset rooms and a north periscope.", "moves_to": "" }, { "id": "SK-07", "confidence": "Medium", "title": "A dark sky over a buried town", "text": "See 04-01-01 FC-15, which now owns the outdoor lighting rules (enforced under 04-02-01 CR-15). The sky stays here: the town is buried, so almost no light leaks upward, and from the viewing rooms the night sky is as dark as a remote desert on Earth, except towards the port on landing nights.", "why": "Moved in version 1.4 so the lighting rules are written once. Living buried (02-01 S-18) means little light spills upward, and the port and plant stand apart from the town.", "moves_to": "", "moved_to": "04-01-01 FC-15" }, { "id": "SK-08", "confidence": "Medium", "title": "Aurora nights are shelter nights", "text": "A strong solar storm brings both the rare naked-eye aurora and a radiation spike. The alert that sends surface crews underground also tells sky-watchers to go to the viewing rooms. At our site, far from the strong crustal fields in the south, the aurora seen is the diffuse, sky-wide green kind.", "why": "The same storms cause both (F-25 to F-27, 02-01 F-27). Discrete auroras need magnetised crust, which lies in the southern hemisphere (02-01 F-24), far from our northern site; that the site sees mostly the diffuse kind is our reading, so Medium." }, { "id": "SK-09", "confidence": "Low", "title": "A sky with its own clock", "text": "Residents tell time by the sky: Phobos's two passes a sol, the Phobos eclipse seasons, the {syn_mo}-month return of the evening star, and the storm years that hide it all. See 04-03-03 LG-16, which now owns the sky culture built on these rhythms; the sky days are 04-03-01 CF-12.", "why": "The rhythms are worked out on this page (F-08, F-18, SK-03; storm years from 02-02 F-13) and stay here. The culture moved on 26 September 2026 so it is written once.", "moved_to": "04-03-03 LG-16" }, { "id": "SK-10", "confidence": "High", "title": "The engine draws the real sky", "text": "The 3D world draws the real star catalogue, turning about Mars's pole in Cygnus once a sol, with the Sun, Phobos, Deimos, Earth, the Moon and the planets placed from their orbits. Phobos grows as it climbs, Deimos is a star, and Earth is never far from the Sun.", "why": "Every position follows from the numbers in the engine's list and in 02-01 (F-07, F-13, F-16, F-22). Nothing here needs inventing." }, { "id": "SK-11", "confidence": "Medium", "title": "The sky's look book", "text": "How the sky looks is fixed in numbers.look: the day, sunset, night and the viewing rooms, their colours, each era, what must never appear and the signature shots. Every picture, film and 3D scene of the sky is made from it and checked against it.", "why": "00-05 ST-20 (owner, 10 October 2026). Built from F-01 to F-35 and SK-01 to SK-10, choosing the most beautiful option they allow (00 L-19)." } ], "world_spec": { "about": "The numbers the engine (00-02) reads to draw the sky. The format belongs to the engine; the numbers belong to this file. The Sun's size, the moons' sizes, the sol and the tilt come from 02-01's own world spec and numbers; the dust (tau) from 02-02 W-10.", "phobos_orbit_km": { "value": 9378, "unit": "km from Mars's centre", "from": "F-07", "path": "numbers.phobos.a_km" }, "phobos_period_days": { "value": 0.31891, "unit": "Earth days", "from": "F-07", "path": "numbers.phobos.period_days" }, "deimos_orbit_km": { "value": 23459, "unit": "km from Mars's centre", "from": "F-13", "path": "numbers.deimos.a_km" }, "deimos_period_days": { "value": 1.26244, "unit": "Earth days", "from": "F-13", "path": "numbers.deimos.period_days" }, "north_pole_ra_deg": { "value": 317.681, "unit": "degrees", "from": "F-22", "path": "numbers.pole.north_ra_deg" }, "north_pole_dec_deg": { "value": 52.887, "unit": "degrees", "from": "F-22", "path": "numbers.pole.north_dec_deg" }, "twilight_hours": { "value": 2, "unit": "h", "from": "SK-02", "path": "numbers.twilight_h" }, "sky_colours": { "value": { "day_zenith": "#C49A6C", "day_horizon": "#D9B98F", "day_near_sun": "#E8D6B8", "sunset_near_sun": "#8FB1CF", "sunset_far": "#8A6E57", "twilight": "#3E4656", "night": "#0C0E15", "storm_noon": "#9C6A3E" }, "unit": "hex colours", "from": "SK-01", "path": "numbers.sky_colours" }, "aurora_green_nm": { "value": 557.7, "unit": "nm", "from": "F-26", "path": "numbers.aurora.nm" }, "moon_positions": { "value": { "jd_tdb": 2461314.5, "date": "1 October 2026", "frame": "Earth's equator of 2000 (ICRF), km from Mars's centre", "phobos_km": [ -829.7237209655841, -8492.736219971477, -3901.224391547381 ], "deimos_km": [ -18353.44795933891, 7086.994209146845, 12766.16024817138 ], "check_years": [ 2020, 2036 ], "check_deg": 4, "about": "Where JPL Horizons puts each moon at midnight (TDB) on 1 October 2026. check_deg: the largest gap between our moons and JPL's on 1 January 2020, 2 October 2026 and 1 January 2036." }, "unit": "km from Mars's centre, Earth's equator of 2000", "from": "F-35", "path": "numbers.moon_anchors" } }, "links": { "leans_on": [ { "ref": "00", "why": "The rulebook: twin files, facts versus assumptions, who owns what" }, { "ref": "00-01", "why": "Era names, for the sky by era (read live)" }, { "ref": "01-01 E-12", "why": "People in each era, for who is watching the sky (read live); the 26-month window rhythm (F-15, read live)" }, { "ref": "02-01", "why": "Read live: orbits (F-13), sunlight (F-14), the Sun's size (F-15), the blue sunset (F-16), tilt and sol (F-17, F-19), dust size (F-30), the solar conjunction (F-40), Earth-Mars distance (F-39, F-41), the moons (F-42 to F-44), Earth as evening star (F-45). Builds on S-06, S-07, S-09 (daylight, sunsets, night) and S-18 (viewing rooms and periscopes)" }, { "ref": "02-02", "why": "Read live: dust opacity (F-17), storm frequency (F-13); cited: clouds (F-28, F-29), the storm sky (W-04), tau drives the sky (W-10)" }, { "ref": "02-03 R-02", "why": "The site's latitude, 39.8°N at AP-1, for every sky position on this page (read live)" }, { "ref": "01-02", "why": "The Moon's distance from Earth, for the Moon's size and its gap from Earth in the Mars sky (read live)" }, { "ref": "02-06 F-08", "why": "The dose from the 20 May 2024 solar storm and NASA's chest X-ray comparison, for F-27 (read live)" } ], "used_by": [ { "ref": "05-20", "why": "Mars games: Phobos and the Martian sky, for Fact or Fiction? (worked_out)" }, { "ref": "05-19", "why": "The night sky in the playable city: Phobos, Deimos, Earth as the evening star and the night's colours (05-19 PA-13)" }, { "ref": "05-10", "why": "The blue sunset, Phobos, Earth as a star and the aurora, for the viewer's sky pins (read live)" }, { "ref": "00-02", "why": "The engine draws the sky from this file's world spec: moon orbits, the pole, twilight, sky colours, aurora colour; reads SK-01's sky colours for the opening picture's sky (read live); its sky model reads the pole and the moons' positions and periods (F-22, F-35) to place the moons where they really are" }, { "ref": "03-06 Habitats", "why": "Cites SK-06: HA-08 turns the viewing rooms west and south and some periscopes north, to the sights worked out here; reads SK-01's sky colours for the opening scene's sky (read live)" }, { "ref": "04-01-01 The first city", "why": "Reads SK-06, what each direction shows from the viewing rooms, and Phobos's height (read live). SK-07's lighting rules moved there as FC-15" }, { "ref": "04-01-02 The lava-tube outpost", "why": "Reads F-34: the Arsia Mons morning cloud (read live)" }, { "ref": "03-13 Local communications", "why": "Cites F-22: no pole star in the Mars sky; reads SK-01's sky colours for the opening scene's sky (read live)" }, { "ref": "04-03-01", "why": "The calendar and festivals: Earth's cycle and transits (F-18, F-19), Phobos's orbit for the eclipse seasons (SK-03), Earth's return (SK-05) and the skywatching culture (SK-09)" }, { "ref": "04-03-03 Language and culture", "why": "SK-09: A skywatching culture; moves here as LG-16; F-18: Earth as morning and evening star (LG-16)" }, { "ref": "04-04-02 A day in the life", "why": "F-03: the blue sunset, for the Sunset room; F-04: how long twilight lasts (read live)" }, { "ref": "04-05-02 Arrival day", "why": "F-18: Earth's show in the Mars sky; SK-04 on seeing it through glare" }, { "ref": "05-03 Guided tours", "why": "The sky colours (SK-01), the blue sunset and twilight (F-02 to F-04), Earth as evening star (F-16) and the pole in Cygnus (F-22) (read live)" }, { "ref": "05-04 Missions", "why": "The sky's colours for every mission's palette (SK-01, read live)" }, { "ref": "05-05 The Q&A guide", "why": "The sky colours the guide's card is tinted with (SK-01), the blue sunset's cause (F-02) and the viewing directions (SK-06) (read live)" }, { "ref": "05-06 Free roam", "why": "Sky colours (SK-01), twilight (F-04), the blue sunset (F-02), sun rays (F-32) and the star catalogue (SK-10) (read live)" }, { "ref": "05-07 First-time onboarding", "why": "Viking's blue sky (F-01), the blue glow and twilight (F-03, F-04), Earth as morning star (F-16) and the sky colours (SK-01) (read live)" }, { "ref": "05-08 The journey experience", "why": "Sky colours and twilight (SK-01, SK-02), used for the landing dawn (read live)" }, { "ref": "05-09 Sign-ups and business", "why": "The sky colours (SK-01) that grade the boarding pass and every share card, read live" }, { "ref": "00-04 Glossary and units", "why": "F-18: the sky colours, for the dust strip (read live)" }, { "ref": "00-05 Writing and visual standard", "why": "SK-01: the sky's colours through a sol, for the art direction strip (read live)" }, { "ref": "02-01 Physical constraints", "why": "Reads SK-01's sky colours for the opening picture's sky (read live)" }, { "ref": "02-02 Weather", "why": "Reads SK-01's sky colours for the opening picture's sky and the clear and storm skies in section 2.3 (read live)" }, { "ref": "02-03 Resource survey", "why": "Reads SK-01's sky colours for the opening picture's sky (read live)" }, { "ref": "02-04 Interactive map", "why": "Reads SK-01's sky colours for the opening picture's sky (read live); and Phobos's and Deimos's orbits, for their gazetteer entries (read live)" }, { "ref": "02-05 The site up close", "why": "Reads SK-01's sky colours for the opening picture's sky (read live)" }, { "ref": "02-06 The human body on Mars", "why": "Reads SK-01's sky colours for the opening picture's sky (read live)" }, { "ref": "03-01 Water extraction", "why": "Reads SK-01's sky colours for the opening scene's sky (read live)" }, { "ref": "03-02 Landing pads", "why": "Reads SK-01's sky colours for the opening scene's sky (read live)" }, { "ref": "03-03 Power", "why": "Reads SK-01's sky colours for the opening scene's sky (read live)" }, { "ref": "03-04 Fuel plant", "why": "Reads SK-01's sky colours for the opening scene's sky (read live)" }, { "ref": "03-05 Vehicles and port", "why": "Reads SK-01's sky colours for the opening scene's sky (read live)" }, { "ref": "03-07 Airlocks, suitports and dust", "why": "Reads SK-01's sky colours for the opening scene's sky (read live)" }, { "ref": "03-08 Spacesuits", "why": "Reads SK-01's sky colours for the opening scene's sky (read live)" }, { "ref": "03-09 Life support", "why": "Reads SK-01's sky colours for the opening scene's sky (read live)" }, { "ref": "03-10 Greenhouses and food", "why": "Reads SK-01's sky colours for the opening scene's sky (read live)" }, { "ref": "03-11 Construction and materials", "why": "Reads SK-01's sky colours for the opening scene's sky (read live)" }, { "ref": "03-12 Manufacturing", "why": "Reads SK-01's sky colours for the opening scene's sky (read live)" }, { "ref": "03-14 Medical bay", "why": "Reads SK-01's sky colours for the opening scene's sky (read live)" }, { "ref": "03-15 Waste and recycling", "why": "Reads SK-01's sky colours for the opening scene's sky (read live)" }, { "ref": "02-08", "why": "The aurora Perseverance saw from Jezero (F-26) (read live)" }, { "ref": "05-11", "why": "Phobos's and Deimos's orbits and periods, so the globe moves them at their true speeds; the pole and the moons' positions (F-22, F-35) for its Right now view (read live)" }, { "ref": "05-13 Mars Atlas", "why": "Mars's pole and spin frame, for where the Sun is overhead in the atlas's live night side (read live)" }, { "ref": "03-16", "why": "Dusk sky colours in the opening scene (read live)" }, { "ref": "04-02-04", "why": "Dusk sky colours in the opening scene (read live)" }, { "ref": "05-12", "why": "Its sky colours (SK-01) light and colour the first city's Blender proof." }, { "ref": "05-02 The Olympus race", "why": "Phobos's and Deimos's orbits and the pole, for the sky over the race at the moment of flight (read live by the sky model)" }, { "ref": "05-18 Mars Atmosphere", "why": "Its sky colours colour the atmosphere's glow and the Beside Opportunity scene, and Curiosity's sunset date links the 2015 readings to a photo (read live)." }, { "ref": "05-17 Living on Mars", "why": "The pole and moons for the shared sky model, which dates the explainer's Checked stamp" } ] }, "open_questions": [ "Phobos eclipse seasons at our site (SK-03) are our own geometry. Check them against a published ephemeris (for example JPL Horizons) and give exact sols in 04-03-01's calendar (CF-12).", "How dusty the clear-day sky is at Arcadia Planitia: no lander has measured tau there. 02-05 The site up close now holds this question too: a Mars Climate Database run at the pin (planned there for its wind, SU-06) can give a first figure. SK-04 and F-24 then move with it.", "How often an aurora bright enough to see with the naked eye would reach our site: one event has been measured (F-26). Watch for more Perseverance and MAVEN results." ], "changes": [ "25 September 2026 (v0.1): Placeholder created.", "25 September 2026 (v1.0): Written. The day sky and blue sunset, the Sun, Phobos and Deimos seen from our site, Earth and the planets, the stars and the pole, auroras, meteors and clouds, with 34 sourced facts (F-01 to F-34), 10 assumptions (SK-01 to SK-10) and a world spec for the engine. The Sun's size, the moons' sizes, the blue sunset and Earth as evening star stay owned by 02-01 and are quoted, not copied.", "25 September 2026 (v1.1): Independent check against the sources. F-02: removed a claim about colour calibration that the cited JPL page does not make. F-14: Deimos's size and brightness are now worked out from our site, not from the equator (2.0 arcminutes, magnitude -5.5, about 15 times Earth). F-13 and the rhythms chart: the time between Deimos passes now uses Mars's turn against the stars, not the sol (5.3 sols, not 5.4). F-26: the 'just below the threshold' quote belongs to the clearer-air figure, not the measured one. F-31: Lemmon's quote corrected to the one on the cited page. F-33: the 30 to 40°N edge is earlier work cited by the 2018 study. The day-length caption in 1.1 now gives Mars-clock hours, matching 02-05.", "26 September 2026 (v1.2): F-27 is now a signpost to 02-06 F-08, which owns the 20 May 2024 storm dose; the dose and the 30 chest X-rays (labelled NASA's comparison) are read live from 02-06, and this file's copies (numbers.aurora.storm_*) are removed. 02-06 added to quotes and leans_on. The Moon's distance from Earth (384,400 km) is now read live from 01-02, which owns it; this file's copy is removed and 01-02 added to quotes and leans_on. The open question on dust at the site and SK-04 now point to 02-05's own open question on tau at the pin (not yet answered; a Mars Climate Database run there can give a first figure). 02-05 is not added to leans_on, because this page reads nothing from it yet.", "26 September 2026 (v1.3): The open question on which way the viewing rooms and periscopes face is answered by 03-06 HA-08 (west and south, some periscopes north), so it is removed; SK-06 now points there and no longer moves to 03-06, and exactly where each room sits is left to 04-01-01. The 03-06 used_by line says what it cites.", "26 September 2026 (v1.4): SK-07 is now a pointer to 04-01-01 FC-15, which owns the outdoor lighting rules (enforced under 04-02-01 CR-15); the dark sky stays here. The lighting open question is deleted as answered by FC-15 and CR-15. SK-06 now points to 04-01-01 FC-07 for where each viewing room sits. used_by adds 04-01-02 and 03-13 and says what 04-01-01 reads.", "26 September 2026 (v1.5): SK-09's culture has moved to 04-03-03 LG-16 (sky days: 04-03-01 CF-12); the sky rhythms stay. Open question on sky names, customs and festivals deleted as answered (04-03-01 CF-11, CF-12; 04-03-03 LG-16). The ephemeris question now asks for exact sols in 04-03-01's calendar (CF-12). used_by: back-links for 04-03-01, 04-03-03, 04-04-02, 04-05-02 (what each reads, from its leans_on). Also back-links for 05-03, 05-04, 05-05, 05-06, 05-07, 05-08, 05-09 (wave 6 pages, from their leans_on as written today).", "26 September 2026 (v1.6): Back-links for 00-04 and 00-05, which read the sky's colours live.", "26 September 2026 (v1.7): Beauty pass: a new opening picture, the blue sunset with Earth as the evening star and Phobos, in this file's SK-01 colours, labelled as art.", "26 September 2026 (v1.8): Final fix round: SK-05: after the conjunction Earth returns as the evening star (as F-18 says). F-16 and its tile: Earth strays up to about 47° from the Sun near Mars's perihelion, about 41° on average, worked out live from 02-01's orbits. used_by: the folder-level '05 Visiting Mars' line removed; the 05 pages that really read this file are listed one by one. The opening picture reads SK-01 live; used_by adds the 00-02, 02 and 03 pages whose opening pictures and scenes now read the sky colours live", "28 September 2026 (v1.9): Now used by the new 02-08 Jezero Crater, which reads it live.", "28 September 2026 (v1.10): Used by the Stand in Jezero viewer (05-10).", "29 September 2026 (v1.11): The moons' orbits here are now read by 02-04's gazetteer and the Mars Through Time globe (05-11). No facts changed.", "30 September 2026 (v1.12): Added F-35, where JPL Horizons put Phobos and Deimos on 1 October 2026, with a world spec entry, moon_positions. The engine's sky model (00-02) carries them round at their true periods, so the globe's Right now view (05-11) shows each moon where it really is, within about 4°.", "1 October 2026 (v1.13): used_by adds 03-16 and 04-02-04, the new pages on computing and on needing nothing from Earth.", "1 October 2026 (v1.14): Used by 05-12, whose first city proof is lit with these sky colours.", "3 October 2026 (v1.15): Era names follow the owner's new names (00-01): Mars Today, Robots First, First Town, Many Cities; First Human Landing and The First Martian City, Arcadia, where an era is named as such.", "3 October 2026 (v1.16): Now also used by 05-13 Mars Atlas, whose chart shades where it is night on Mars right now with the same sky model as the globe's Right now.", "4 October 2026 (v1.17): Used by 05-02 The Olympus race, whose website reads it live for the real sky over the race.", "6 October 2026 (v1.18): Used by 05-18 Mars Atmosphere for its sky colours and Curiosity's same-day sunset.", "9 October 2026 (v1.19): Used by 05-19 Playable Arcadia, which reads this file live.", "10 October 2026 (v1.20): Used by 05-17 Living on Mars: the explainer's blueprint stamp is dated with today's Mars date from the shared sky model.", "10 October 2026 (v1.21): Added numbers.look, the sky's look book (SK-11, 00-05 ST-20), and F-36, Perseverance's film of Phobos crossing the Sun on 12 August 2026 (NASA PIA26811), for The sky and the day stop of 05-17's explainer." ], "sources": { "drew_viking": { "name": "Andrew LePage, Drew Ex Machina (history blog), First pictures: Viking 1 on Mars, 20 July 2021", "url": "https://www.drewexmachina.com/2021/07/20/first-pictures-viking-1-on-mars-july-20-1976/" }, "jpl_sunset_2015": { "name": "NASA JPL, NASA's Curiosity rover views serene sundown on Mars, 8 May 2015", "url": "https://www.jpl.nasa.gov/news/nasas-curiosity-rover-views-serene-sundown-on-mars/" }, "nasa_spirit_2005": { "name": "NASA Science, Sunset at Mars' Gusev crater (Spirit), image of 19 May 2005", "url": "https://science.nasa.gov/resource/sunset-at-mars-gusev-crater-spirit/" }, "nssdc_sun": { "name": "NASA NSSDCA (D. R. Williams), Sun Fact Sheet (accessed September 2026)", "url": "https://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html" }, "nssdc_moon": { "name": "NASA NSSDCA (D. R. Williams), Moon Fact Sheet (accessed September 2026)", "url": "https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html" }, "nssdc_mars": { "name": "NASA NSSDCA (D. R. Williams), Mars Fact Sheet, with satellites and pole, revised 2025", "url": "https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html" }, "nssdc_venus": { "name": "NASA NSSDCA (D. R. Williams), Venus Fact Sheet (accessed September 2026)", "url": "https://nssdc.gsfc.nasa.gov/planetary/factsheet/venusfact.html" }, "nssdc_mercury": { "name": "NASA NSSDCA (D. R. Williams), Mercury Fact Sheet (accessed September 2026)", "url": "https://nssdc.gsfc.nasa.gov/planetary/factsheet/mercuryfact.html" }, "nasa_phobos_2015": { "name": "NASA Goddard (T. Hurford and others), Mars' moon Phobos is slowly falling apart, 10 November 2015", "url": "https://www.nasa.gov/solar-system/mars-moon-phobos-is-slowly-falling-apart/" }, "jpl_eclipse_2022": { "name": "NASA JPL, NASA's Perseverance rover captures video of solar eclipse on Mars, 20 April 2022", "url": "https://www.jpl.nasa.gov/news/nasas-perseverance-rover-captures-video-of-solar-eclipse-on-mars/" }, "wiki_astro_mars": { "name": "Wikipedia, Astronomy on Mars, 2026", "url": "https://en.wikipedia.org/wiki/Astronomy_on_Mars" }, "wiki_acuity": { "name": "Wikipedia, Visual acuity, 2026", "url": "https://en.wikipedia.org/wiki/Visual_acuity" }, "wiki_transit": { "name": "Wikipedia, Transit of Earth from Mars, 2026", "url": "https://en.wikipedia.org/wiki/Transit_of_Earth_from_Mars" }, "wiki_proxima": { "name": "Wikipedia, Proxima Centauri (Gaia DR3 distance, 2020), 2026", "url": "https://en.wikipedia.org/wiki/Proxima_Centauri" }, "wiki_ly": { "name": "Wikipedia, Light-year (IAU definition), 2026", "url": "https://en.wikipedia.org/wiki/Light-year" }, "simbad": { "name": "CDS Strasbourg, SIMBAD astronomical database: Deneb, Alderamin, Polaris J2000 positions (accessed September 2026)", "url": "https://simbad.cds.unistra.fr/simbad/" }, "wiki_optical_depth": { "name": "Wikipedia, Optical depth (optical depth and astronomical magnitude), 2026", "url": "https://en.wikipedia.org/wiki/Optical_depth" }, "knutsen_2025": { "name": "E. W. Knutsen and others, Detection of visible-wavelength aurora on Mars, Science Advances 11(20), 14 May 2025", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC12077521/" }, "jpl_aurora_2025": { "name": "NASA JPL, NASA observes first visible-light auroras at Mars, 14 May 2025", "url": "https://www.jpl.nasa.gov/news/nasa-observes-first-visible-light-auroras-at-mars/" }, "jpl_storm_2024": { "name": "NASA JPL, NASA watches Mars light up during epic solar storm, 10 June 2024", "url": "https://www.jpl.nasa.gov/news/nasa-watches-mars-light-up-during-epic-solar-storm/" }, "selsis_2005": { "name": "F. Selsis, M. T. Lemmon, J. Vaubaillon and J. F. Bell III, A martian meteor and its parent comet, Nature 435, 581, 2005", "url": "https://www.nature.com/articles/435581a" }, "nasa_siding_2014": { "name": "NASA Science, Comet meteor shower put magnesium and iron into Martian atmosphere, 2014", "url": "https://science.nasa.gov/resource/comet-meteor-shower-put-magnesium-and-iron-into-martian-atmosphere/" }, "space_siding_2015": { "name": "Space.com, October comet flyby caused 'mind-blowing' Martian meteor shower, 30 June 2015", "url": "https://www.space.com/29804-comet-siding-spring-mars-meteor-shower.html" }, "jpl_craters_2013": { "name": "NASA JPL, NASA probe counts space rock impacts on Mars (Daubar and others, Icarus), May 2013", "url": "https://www.jpl.nasa.gov/news/nasa-probe-counts-space-rock-impacts-on-mars/" }, "jpl_clouds_2021": { "name": "NASA JPL, NASA's Curiosity rover captures shining clouds on Mars, 28 May 2021", "url": "https://www.jpl.nasa.gov/news/nasas-curiosity-rover-captures-shining-clouds-on-mars/" }, "jpl_rays_2023": { "name": "NASA JPL, NASA's Curiosity views first 'sun rays' on Mars, 6 March 2023", "url": "https://www.jpl.nasa.gov/news/nasas-curiosity-views-first-sun-rays-on-mars/" }, "schmude_2018": { "name": "R. W. Schmude Jr., The north polar hood of Mars, Journal of the British Astronomical Association, 22 November 2018", "url": "https://britastro.org/journal_contents_ite/the-north-polar-hood-of-mars" }, "esa_amec_2021": { "name": "ESA, Mars Express unlocks the secrets of curious cloud (Hernández-Bernal and others, JGR Planets 2021), March 2021", "url": "https://www.esa.int/Science_Exploration/Space_Science/Mars_Express/Mars_Express_unlocks_the_secrets_of_curious_cloud" }, "jpl_horizons_2026": { "name": "NASA JPL Horizons, Phobos (401) and Deimos (402) positions from Mars's centre, retrieved 30 September 2026", "url": "https://ssd.jpl.nasa.gov/horizons/" }, "nasa_pia26811": { "name": "NASA JPL Photojournal, PIA26811: Perseverance captures another Phobos transit, 24 August 2026", "url": "https://photojournal.jpl.nasa.gov/catalog/PIA26811" } }, "sources_checked": "25 September 2026" }, "01-01": { "file": "01-01", "title": "Getting to Mars", "folder": "01", "facts_file": "01-01-getting-to-mars.json", "version": "2.40", "status": "Active", "last_updated": "9 October 2026", "about": "Facts file for 01-01 Getting to Mars. The page is built from this file, the library catalogue and the page template. Change a fact here, then run build.py. Words in curly brackets, like {ss_h}, are filled in from the numbers in this file when the page is built, so each number is typed once. The 'rockets' list is clean data that the website (05-01) can read directly.", "one_line": "The real rockets, the real calendar and the real price list: how much can reach Mars, how often, and how sure anyone can be.", "shelf_life": "This is the fastest-changing file in the library. Japan's MMX is due on 19 October 2026, days after this check. Re-check the flight record, dates and prices by December 2026. Treat anything here older than three months as possibly out of date, and treat every future date as a hope, not a plan: every Mars landing date announced so far has been missed or pushed back, apart from the website's 2025 date, which moved from 2030 to 2028. Each rocket's next_launch (F-37 to F-39) changes week to week: re-check it every month and after every launch or slip.", "header": { "purpose": "Set the ceiling on what our settlement can have. Everything on Mars came from Earth or was made from something that did, so ships, tonnes and years between trips decide how fast the city grows.", "why": "It is easy to picture a hundred ships landing every year. The real numbers are smaller and less certain, and the dates keep slipping, so no other file should bet on a year.", "when": "Deciding how much material or how many people the settlement has, writing about the journey, choosing which real companies exist in the backstory, or building the website's rocket screens.", "change": "Part One changes only with a citation and a date. Part Two assumptions can be challenged one at a time. Edit this facts file, then run build.py.", "writing": "Every number is compared to something people know. Company promises are labelled as claims. Pictures first, short sentences, no walls of text." }, "comparisons": { "storey_m": 3.2, "tower_m": 96, "tower_source": "parliament_tower", "tower_draw_width_m": 12, "tower_width_note": "Drawing only: the tower width is approximate and not a sourced fact.", "eiffel_frame_t": 7300, "eiffel_source": "eiffel", "gold_usd_per_oz": 4360, "gold_date": "21 September 2026", "gold_source": "fortune_gold", "oz_per_kg": 32.1507, "days_per_month": 30.44 }, "rockets": [ { "id": "starship", "name": "Starship", "version": "Version 3 (Block 3)", "maker": "SpaceX", "country": "United States", "character_select": true, "height_m": 124, "width_m": 9, "upper_stage_height_m": 52, "booster_height_m": 72, "propellant_t": 1600, "booster_propellant_t": 3650, "dry_mass_t": null, "dry_mass_note": "SpaceX publishes no Version 3 dry mass. The Version 2 ship's empty mass was about 85 t (Wikipedia, SpaceX Starship (spacecraft)).", "payload_leo_t": 100, "payload_leo_note": "over 100 t, fully reusable (SpaceX). Version 2 carried about 35 t.", "payload_mars_t": 100, "payload_mars_note": "SpaceX says refilling in orbit lets each ship carry 'several hundred tonnes' all the way to Mars (F-32): a company claim, not yet shown. This library uses about 100 t landed per cargo ship (E-09).", "propellant": "Liquid methane and liquid oxygen", "reusable": "Both stages, by design", "status": "Test flights", "status_detail": "14 flights by 28 September 2026. First Version 3 flight 22 May 2026. Flight 14 on 28 September 2026 reached orbit for the first time and released 26 Starlink satellites, but one ship engine shut down early and the flight was cut short. Refilling in orbit not yet attempted.", "status_date": "3 October 2026", "mars_role": "The only vehicle being built for Mars settlement. SpaceX lists Mars cargo flights no earlier than 2028.", "drawn": "real", "sources": [ "spacex_starship", "wiki_starship", "wiki_f13", "nsf_f14", "zu_f14", "sn_f14" ], "payload_mars_from": "E-09", "maker_profile": { "name": "SpaceX", "founded": "14 March 2002", "founder": "Elon Musk", "home": "Starbase, Texas", "people": "22,621 (April 2026)", "line": "The company that made landing and reusing rockets normal, and the only one building a ship for Mars settlement.", "fact": "In May 2020 SpaceX became the first private company to fly astronauts to the International Space Station. By 10 September 2026 its Falcon rockets had launched 699 times, with 696 full successes.", "sources": [ "wiki_spacex" ], "leader": { "name": "Elon Musk", "role": "Founder, CEO and chief engineer", "line": "Started SpaceX in 2002 to make humanity a multiplanetary species, and still runs it. Mars is why the company exists.", "sources": [ "wiki_spacex" ], "label": "Led by" } }, "next_launch": { "mission": "Flight 15", "short": "Flight 15", "site": "Starbase, Texas", "site_short": "Starbase", "kind": "net", "date": "2026-10-19", "words": "No earlier than 19 October 2026", "refs": [ "F-37" ], "checked": "4 October 2026" } }, { "id": "new_glenn", "name": "New Glenn", "version": "7x2", "maker": "Blue Origin", "country": "United States", "character_select": true, "height_m": 98, "width_m": 7, "payload_leo_t": 45, "payload_leo_note": "45 t with a reusable booster. The announced 9x4 version: over 70 t.", "payload_mars_t": null, "payload_mars_note": "No published figure. Launched NASA's two ESCAPADE Mars probes (535 kg each) in 2025.", "payload_mars_words": { "value": "2", "unit": "probes", "line": "NASA's twin ESCAPADE probes, sent on their way in 2025" }, "propellant": "Liquid methane and liquid oxygen (first stage)", "reusable": "First stage, designed for at least 25 flights", "status": "Grounded: pad being rebuilt", "status_detail": "3 flights. Booster first reused 19 April 2026. A rocket exploded on the pad during a test on 28 May 2026. Blue Origin targets flying again by the end of 2026; NASA's administrator said the pad may not be restored until 2028.", "status_date": "25 September 2026", "mars_role": "Launched ESCAPADE. Picked to build and launch NASA's Mars Telecommunications Network orbiter, due for delivery by the end of 2028 (contract under protest, F-27).", "drawn": "real", "sources": [ "wiki_newglenn", "nsf_ng3", "wiki_ng_explosion", "cnbc_isaacman", "space_mtn" ], "maker_profile": { "name": "Blue Origin", "founded": "8 September 2000", "founder": "Jeff Bezos", "home": "Kent, Washington", "people": "11,000 (2023)", "line": "Jeff Bezos's rocket company: small rockets that fly tourists to the edge of space, and now New Glenn to orbit.", "fact": "Blue Origin was founded two years before SpaceX, but first reached orbit on 16 January 2025, with New Glenn's very first launch.", "sources": [ "wiki_blue_origin" ], "leader": { "name": "Jeff Bezos", "role": "Founder", "line": "Started Blue Origin in 2000 and has funded it ever since. Its chief executive, Dave Limp, has run the company day to day since December 2023.", "sources": [ "wiki_blue_origin" ], "label": "Founded by" } }, "next_launch": { "mission": "Back to flight with 48 Amazon Leo satellites", "short": "Amazon Leo", "site": "Cape Canaveral, Florida", "site_short": "Cape Canaveral", "kind": "by", "date": "2026-12-31", "words": "By the end of 2026, Blue Origin says", "refs": [ "F-38" ], "checked": "4 October 2026" } }, { "id": "long_march_5", "name": "Long March 5", "version": "CZ-5 / CZ-5B", "maker": "China Academy of Launch Vehicle Technology (CALT)", "country": "China", "character_select": true, "height_m": 57, "width_m": 5, "booster_count": 4, "booster_width_m": 3.35, "booster_height_m": 27.6, "booster_note": "Four strap-on boosters, each 3.35 m wide and 27.6 m tall (Wikipedia, Long March 5). width_m is the core.", "payload_leo_t": 25, "payload_leo_note": "25 t (CZ-5B version)", "payload_mars_t": 6, "payload_mars_note": "About 6 t sent on the way to Mars (trans-Mars injection).", "propellant": "Liquid hydrogen, kerosene and liquid oxygen", "reusable": "No", "status": "Flying", "status_detail": "18 launches by 11 June 2026, 17 successes. Launched Tianwen-1 (orbiter, lander and the Zhurong rover) in July 2020.", "status_date": "11 June 2026", "mars_role": "Two launches will carry Tianwen-3, China's Mars sample-return mission, around 2028.", "drawn": "real", "sources": [ "wiki_lm5", "wiki_tw3" ], "maker_profile": { "name": "China Academy of Launch Vehicle Technology (CALT)", "founded": "16 November 1957", "founder": "Qian Xuesen", "home": "Fengtai, Beijing", "people": "More than 33,000 (May 2020)", "line": "China's main rocket builder, part of the state space company CASC, and maker of the whole Long March family.", "fact": "CALT was founded in 1957 and builds every rocket in the Long March family, the rockets behind China's space station, Moon landings and Mars rover.", "sources": [ "wiki_calt", "wiki_lm2f", "wiki_tianwen1" ], "leader": { "name": "Qian Xuesen", "role": "Founding father of Chinese rocketry", "line": "The scientist who founded the institute that became CALT. Today CALT is led by its president, Wang Xiaojun, and its chief designer, Long Lehao, has set out the Long March 9 plans for Mars.", "sources": [ "wiki_calt" ], "label": "Founded by" } }, "next_launch": { "mission": "Chang'e 7, to the Moon's south pole", "short": "Chang'e 7", "site": "Wenchang, Hainan", "site_short": "Wenchang", "kind": "window", "date": "2027-02-01", "words": "A February or March 2027 window", "refs": [ "F-39" ], "checked": "4 October 2026" } }, { "id": "falcon_heavy", "name": "Falcon Heavy", "version": "", "maker": "SpaceX", "country": "United States", "character_select": false, "height_m": 70, "width_m": 12.2, "payload_leo_t": 63.8, "payload_leo_note": "63.8 t with every core thrown away. Falcon 9 alone: 22.8 t.", "payload_mars_t": 16.8, "payload_mars_note": "16.8 t sent towards Mars, fully expendable.", "propellant": "Kerosene and liquid oxygen", "reusable": "Side boosters and core can be recovered", "status": "Flying", "status_detail": "In service since 2018.", "status_date": "25 September 2026", "mars_role": "Chosen to launch Europe's Rosalind Franklin rover in late 2028.", "drawn": "real", "sources": [ "wiki_fh", "wiki_rfr" ] }, { "id": "long_march_9", "name": "Long March 9", "version": "2024 design", "maker": "China Academy of Launch Vehicle Technology (CALT)", "country": "China", "character_select": false, "height_m": 114, "width_m": 10.6, "payload_leo_t": 150, "payload_leo_note": "At least 150 t (design target)", "payload_mars_t": null, "payload_mars_note": "No published figure.", "propellant": "Liquid methane and liquid oxygen", "reusable": "First stage planned reusable", "status": "In development", "status_detail": "First flight targeted for 2033. Design has changed several times.", "status_date": "25 September 2026", "mars_role": "No announced Mars mission.", "drawn": "planned", "sources": [ "wiki_lm9", "space_lm9" ] } ], "perseverance": { "mass_kg": 1025, "curiosity_diff_kg": 126, "mission_cost_usd_bn": 2.7, "sources": [ "jpl_perseverance", "planetary_perse" ] }, "refuel": { "propellant_t": 1200, "tanker_load_t": 100, "ships_2026_plan": 5, "musk_full_refill_launches": 8, "nasa_lunar_launches": 16, "sources": [ "aero_america", "wiki_starship", "spacex_starship", "spacedaily_refuel" ] }, "calendar": { "window_months": 26, "cruise_days": 200, "perseverance_launch": "2020-07-30", "perseverance_land": "2021-02-18", "msl_cruise_days": 253, "next_window": "November 2026", "next_window_start": [ 2026, 11 ], "earth_orbit_mkm": 149.598, "mars_orbit_mkm": 227.956, "earth_year_days": 365.256, "mars_year_days": 686.98, "sources": [ "nasa_timeline", "nasa_marsfact", "k1945", "aero_america", "nasa_dra5" ], "surface_stay_days": 500, "crew_trip_days": 900, "nasa_crew": 6 }, "era_plan": { "about": "Ships, people and returning ships in each era. This file owns these numbers because folder 01 answers who is going and how they get there. Era names and their order come from the Project map (00-01). Years in the plan count from the first crew landing in {first_crew_year}. Pages show calendar years, worked out from that one number (00 L-18). The eras after the City are in after_city. Every number here is an assumption: the order is E-10, who goes home is E-11, the sizes are E-12. crewed_ship_cargo_t is the cargo a crewed ship lands besides its people (E-13); whether the City's people and cargo both fit is E-14.", "first_crew_year": 2036, "eras": [ { "era": "robots", "windows_before_crew": [ 1, 2 ], "ships_per_window": [ 2, 5 ], "people": [ 0, 0 ], "returning_ships_per_window": [ 0, 0 ], "what": "Uncrewed ships land reactors, the ice drill, the fuel plant and building robots. The first ship lands on natural ground; robots build the first pad. The plant starts making fuel." }, { "era": "crew", "years": [ 0, 2 ], "ships_per_window": [ 3, 6 ], "people": [ 6, 12 ], "returning_ships_per_window": [ 1, 2 ], "what": "The first crew lands beside a working fuel plant, lives in the first habitat and flies home in the next return window." }, { "era": "town", "years": [ 2, 20 ], "ships_per_window": [ 5, 10 ], "people": [ 50, 200 ], "returning_ships_per_window": [ 1, 3 ], "what": "A new crew lands every window; most stay two windows, so crews overlap. Greenhouses, more habitats and a busier port." }, { "era": "city", "years": [ 20, 30 ], "ships_per_window": [ 10, 30 ], "people": [ 1000, 5000 ], "returning_ships_per_window": [ 2, 5 ], "what": "The city we show. Most people stay for good; a few ships each window fly home." } ], "after_city_note": "Eras after the City sit apart in 'after_city', because the kit pages (folder 03) and most of folder 04 size their numbers by era only up to the City. How Mars gets from the City to needing nothing from Earth is 04-02-04, which reads these. The last era, Self-sustaining Mars, has no plan of ships: it begins when Many Cities ends.", "after_city": [ { "era": "cities", "years": [ 30, 60 ], "ships_per_window": [ 200, 600 ], "people": [ 50000, 200000 ], "returning_ships_per_window": [ 5, 20 ], "what": "More towns and cities, each built for its own reason. Factories learn to make what the ships used to bring, so a growing share of every window's ships carry people. The era ends when Mars needs nothing from Earth (04-02-04)." } ], "crewed_ship_cargo_t": [ 20, 40 ] }, "cost": { "spacex_usd_per_t": 100000000, "spacex_mars_from": 2028, "spacex_mars_from_2025": 2030, "sources": [ "spacex_starship", "benzinga_2025", "planetary_perse", "fortune_gold" ], "mtn_usd_m": 700, "msr_fund_usd_m": 110 }, "life": { "oxygen_kg": 0.89, "drink_kg": 2.79, "food_kg": 2.39, "iss_water_pct": 98, "iss_water_before_pct": [ 93, 94 ], "cruise_msv_day": 1.8, "round_trip_sv": 0.66, "ct_every_days": [ 5, 6 ], "sources": [ "ewert_2019", "nasa_water", "swri_2013" ] }, "promises": [ { "said": 2016, "target": 2018, "what": "Red Dragon: an uncrewed landing", "outcome": "missed" }, { "said": 2017, "target": 2022, "what": "First cargo ships", "outcome": "missed" }, { "said": 2024, "target": 2026, "what": "Five uncrewed Starships; crews in 2028 if they land", "outcome": "dropped", "outcome_note": "no Starship is planned for the 2026 window (F-25)" }, { "said": 2026, "target": 2028, "what": "SpaceX website: Mars cargo 'no earlier than 2028'", "outcome": "current" } ], "moon_shift": { "date": "8 February 2026", "mars_start_years": [ 5, 7 ], "moon_city_years": 10, "mars_city_years": 20, "sources": [ "nbc_2026", "spacepolicy_2026", "cnn_2026" ] }, "events": [ { "date": "2026-02-08", "label": "SpaceX puts the Moon first", "kind": "shift", "ref": "F-24" }, { "date": "2026-05-22", "label": "First Starship Version 3 flight", "kind": "rocket", "ref": "F-14" }, { "date": "2026-05-28", "label": "New Glenn explodes on its pad", "kind": "rocket", "ref": "F-06" }, { "date": "2026-09-01", "label": "Blue Origin wins the Mars phone line", "kind": "mars", "ref": "F-27" }, { "date": "2026-09-28", "label": "Starship reaches orbit for the first time (Flight 14)", "kind": "rocket", "ref": "F-14" }, { "date": "2026-10-19", "label": "Japan's MMX launches to Phobos (planned)", "kind": "planned", "ref": "F-25" }, { "date": "2026-11-15", "label": "Window opens; ESCAPADE swings past Earth", "kind": "window", "ref": "F-17", "display": "November 2026" } ], "future": [ { "year": 2027.7, "label": "ESCAPADE reaches Mars", "ref": "F-25" }, { "year": 2028.5, "label": "SpaceX Mars cargo, no earlier than", "ref": "F-19", "claim": true }, { "year": 2028.75, "label": "Rosalind Franklin launches (planned, late 2028)", "ref": "F-28" }, { "year": 2028.95, "label": "Tianwen-3 launches (window, about Dec 2028 to Jan 2029)", "ref": "F-28" }, { "year": 2030, "label": "Mars phone line working (planned; paused by a protest)", "ref": "F-27" }, { "year": 2031, "label": "Tianwen-3 and MMX samples reach Earth", "ref": "F-28" }, { "year": 2033, "label": "Long March 9 first flight (target)", "ref": "F-09" } ], "players": [ { "who": "SpaceX", "what": "Starship; the only human settlement plan", "when": "Mars cargo no earlier than 2028; city work 'in about 5 to 7 years' (said February 2026)", "kind": "People and cargo", "refs": [ "F-19", "F-24" ] }, { "who": "Blue Origin", "what": "New Glenn; picked for the Mars Telecommunications Network orbiter (contract under protest, F-27)", "when": "Planned: orbiter delivered by end 2028, working at Mars by 2030", "kind": "Cargo and infrastructure", "refs": [ "F-06", "F-27", "F-36" ], "people_later": "Part of Blue Origin's long-term plan, on a far bigger rocket still on paper, with no date set" }, { "who": "China (CNSA)", "what": "Tianwen-3 sample return on two Long March 5s; Long March 9 later", "when": "Launch around 2028, samples home around 2031", "kind": "Robots", "refs": [ "F-08", "F-28", "F-35" ], "people_later": "China plans its first crews from 2033, on bigger rockets still to come" }, { "who": "NASA", "what": "ESCAPADE; Mars phone line; a small landing-technology fund after Sample Return was cancelled", "when": "Ongoing; people go to the Moon first", "kind": "Robots and infrastructure", "refs": [ "F-25", "F-26", "F-27" ] }, { "who": "JAXA (Japan)", "what": "MMX: land on the moon Phobos and bring back a sample", "when": "Launch planned 19 October 2026, sample home 2031", "kind": "Robots", "refs": [ "F-25" ] }, { "who": "ESA (Europe)", "what": "Rosalind Franklin rover, on a Falcon Heavy", "when": "Planned: launch late 2028, landing 2030", "kind": "Robots", "refs": [ "F-28" ] }, { "who": "Impulse Space", "what": "A small commercial Mars lander on Relativity's Terran R", "when": "No earlier than 2028", "kind": "Cargo", "refs": [ "F-28" ] }, { "who": "Rocket Lab", "what": "Built the ESCAPADE probes; lost the phone-line bid and protested", "when": "No Mars rocket", "kind": "Robots", "refs": [ "F-25", "F-27" ] } ], "sections": [ { "id": "1.1", "title": "The rockets" }, { "id": "1.2", "title": "Filling up in orbit" }, { "id": "1.3", "title": "The calendar" }, { "id": "1.4", "title": "What it costs" }, { "id": "1.5", "title": "Where the timeline stands" }, { "id": "1.6", "title": "Everyone with a Mars plan" }, { "id": "1.7", "title": "What a person costs to carry" } ], "facts": [ { "id": "F-01", "section": "1.1", "text": "Starship Version 3, booster and ship together, is {ss_h} m tall and {ss_w} m wide. The ship on top is {ss_ship_h} m tall. SpaceX lists its payload as over {ss_leo} tonnes, fully reusable.", "compare": "{ss_vs_tower} times the height of Big Ben's Elizabeth Tower ({tower} m), or about a {ss_storeys}-storey building.", "sources": [ "spacex_starship", "parliament_tower" ] }, { "id": "F-02", "section": "1.1", "text": "The earlier Version 2 was rated for about {ss_v2_leo} tonnes to low Earth orbit. Version 3 aims at {ss_leo} tonnes with both stages reused. The ship holds {ss_prop} tonnes of liquid methane and liquid oxygen.", "compare": "{ss_leo} tonnes is about {ss_perse} Perseverance rovers. The fuel alone weighs about a fifth of the Eiffel Tower's iron frame.", "sources": [ "wiki_starship", "spacex_starship", "eiffel" ] }, { "id": "F-03", "section": "1.1", "text": "NASA's Perseverance rover weighs {perse_kg} kg, {curio_diff} kg more than Curiosity before it.", "compare": "About a small car. A full Starship load would be around {ss_perse} of them.", "sources": [ "jpl_perseverance", "nasa_timeline" ] }, { "id": "F-04", "section": "1.1", "text": "Blue Origin's New Glenn is {ng_h} m tall and {ng_w} m wide and carries {ng_leo} tonnes to low Earth orbit. Its first stage lands on a ship at sea and is designed for at least 25 flights.", "compare": "Almost exactly the height of the Elizabeth Tower ({tower} m). It lifts about twice what a Falcon 9 does ({f9_leo} t).", "sources": [ "wiki_newglenn", "parliament_tower", "wiki_fh" ] }, { "id": "F-05", "section": "1.1", "text": "New Glenn reached orbit on its first flight (16 January 2025). Its second flight (13 November 2025) sent NASA's two ESCAPADE Mars probes on their way and landed its booster. On its third (19 April 2026) it reused a booster for the first time, but the upper stage left the satellite in too low an orbit.", "compare": "Three flights, three firsts, one lost satellite.", "sources": [ "wiki_newglenn", "nsf_ng3" ] }, { "id": "F-06", "section": "1.1", "text": "On 28 May 2026 a New Glenn exploded during an engine test on its pad at Cape Canaveral, badly damaging the pad. The cause was traced to a main oxygen valve on one engine. Blue Origin aims to fly again by the end of 2026; NASA's administrator said the pad might not be restored until 2028.", "compare": "Until the pad is back, New Glenn cannot fly.", "sources": [ "wiki_ng_explosion", "cnbc_isaacman" ] }, { "id": "F-07", "section": "1.1", "text": "In November 2025 Blue Origin announced a bigger New Glenn '9x4' (over 70 tonnes to low Earth orbit, nearly as tall as Starship) and showed a full-scale folding aerobrake, a heat shield meant for delivering heavy cargo to places including Mars.", "compare": "Announcements, not hardware on a pad.", "sources": [ "wiki_newglenn", "blue_aerobrake" ] }, { "id": "F-08", "section": "1.1", "text": "China's Long March 5 is {lm5_h} m tall with a {lm5_w} m core. It lifts {lm5_leo} tonnes to low Earth orbit or about {lm5_mars} tonnes on the way to Mars. By 11 June 2026 it had flown 18 times with one failure, and it launched Tianwen-1 and the Zhurong rover in 2020.", "compare": "About an {lm5_storeys}-storey building. Its Mars load is about {lm5_perse} Perseverances.", "sources": [ "wiki_lm5" ] }, { "id": "F-09", "section": "1.1", "text": "China's Long March 9, a super-heavy rocket like Starship, is still on the drawing board: {lm9_h} m tall, {lm9_w} m wide, at least {lm9_leo} tonnes to orbit, first flight targeted for 2033.", "compare": "Wider than Starship. Planned, not built.", "sources": [ "wiki_lm9", "space_lm9" ] }, { "id": "F-10", "section": "1.1", "text": "SpaceX's Falcon Heavy lifts {fh_leo} tonnes to low Earth orbit, or {fh_mars} tonnes towards Mars, if every core is thrown away. Falcon 9 lifts {f9_leo} tonnes.", "compare": "Falcon Heavy's Mars load is about {fh_perse} Perseverances.", "sources": [ "wiki_fh" ] }, { "id": "F-11", "section": "1.2", "text": "A Starship that reaches orbit has used almost all its fuel. To leave for Mars it must be refilled by tanker Starships. Donald Rapp, a consultant to NASA's Jet Propulsion Laboratory, estimated about {prop_t} tonnes of propellant to refill a ship in Earth orbit before it leaves, for an earlier, smaller ship, at about {tanker_t} tonnes per tanker: about {tankers} tanker launches per Mars ship. The Version 3 ship holds {ss_prop} tonnes when full (F-02). The five ships once planned for 2026 would have needed about {tankers_5}.", "compare": "Like filling a car from a jerry can, {tankers} trips to the petrol station for one journey.", "sources": [ "aero_america" ] }, { "id": "F-12", "section": "1.2", "text": "Other estimates differ: Musk has said 8 launches to fill a Starship completely; NASA has estimated 16 launches in quick succession to fill one for a Moon landing. Some fuel boils off during transfer, so the real number is uncertain.", "compare": "The answer is 'about a dozen', give or take half.", "sources": [ "wiki_starship", "aero_america" ] }, { "id": "F-13", "section": "1.2", "text": "As of Flight 13 (24 July 2026) SpaceX had not yet tried moving propellant between two Starships. The demonstration, first aimed at March 2025, is now 'targeted for 2026'. A March 2026 NASA inspector-general report called it one of the most significant technical challenges.", "compare": "Until this works, no Starship can go to Mars.", "sources": [ "spacedaily_refuel" ] }, { "id": "F-14", "section": "1.2", "text": "Starship had flown 13 test flights by 24 July 2026: 8 successes, 5 failures. The first Version 3 flew on 22 May 2026. On Flight 13 the ship released 20 Starlink satellites and splashed down as planned, but the booster was lost at sea. On Flight 14, on 28 September 2026, a Version 3 Starship reached orbit for the first time and released 26 Starlink satellites; one of the ship's engines shut down early, so it came down after about 3 hours instead of 10.", "compare": "Still in testing: Starship has now reached orbit, but has not yet refilled in orbit or been caught after an orbital flight.", "sources": [ "wiki_starship", "wiki_f12", "wiki_f13", "nsf_f14", "zu_f14", "sn_f14" ] }, { "id": "F-32", "section": "1.2", "text": "Company claim: SpaceX's Starship page says refilling in orbit lets each ship carry 'several hundred tonnes of cargo per ship all the way to Mars'.", "compare": "Even 200 t, the low end of 'several hundred', would be about {sev_perse} Perseverances. Not yet shown: no ship has been refilled (F-13).", "sources": [ "spacex_starship", "jpl_perseverance" ] }, { "id": "F-15", "section": "1.3", "text": "Earth and Mars line up for the most energy-efficient trip about once every {window_months} months. NASA puts the cruise to Mars at about {cruise_days} days.", "compare": "A bus that leaves every two years and two months and takes over half a year to arrive.", "sources": [ "nasa_timeline", "nasa_marsfact" ] }, { "id": "F-16", "section": "1.3", "text": "Perseverance launched on 30 July 2020 and landed on 18 February 2021, {perse_days} days later. Curiosity's cruise took {msl_days} days. China expects Tianwen-3 to take 7 to 8 months.", "compare": "About {perse_months} and {msl_months} months: longer than a school term, shorter than a pregnancy.", "sources": [ "nasa_timeline", "swri_2013", "govcn_tw3" ] }, { "id": "F-17", "section": "1.3", "text": "The current window opens in November 2026 and closes about a month later. The next opens in late 2028 or early 2029.", "compare": "Miss the bus and the next one is more than two years away.", "sources": [ "k1945" ] }, { "id": "F-18", "section": "1.3", "text": "Robert Moses, a retired NASA engineer, says a Starship with a full propellant load could cut the trip to 3 to 4 months, reducing radiation for crews.", "compare": "About half the usual trip. An estimate, not yet shown: it needs full tanks after refilling (F-13).", "sources": [ "aero_america" ] }, { "id": "F-33", "section": "1.3", "text": "NASA's reference plan for a crewed Mars trip (Design Reference Architecture 5.0) keeps the crew about {stay_days} days on the surface, waiting for the planets to line up for the trip home. The crew is away about {crew_days} days in all.", "compare": "{stay_days} days is about {stay_months} months on Mars; {crew_days} days is about {crew_years} years away from home, long enough to miss {crew_bdays} birthdays.", "sources": [ "nasa_dra5" ] }, { "id": "F-19", "section": "1.4", "text": "Company price: SpaceX's Starship page lists cargo flights to Mars 'no earlier than {mars_from}' at ${price_m} million per metric ton. In October 2025 the same site said Mars flights would start in {mars_from_2025}.", "compare": "${usd_kg} per kilogram, about {gold_pct}% of the price of a kilogram of gold ({gold_kg} on {gold_date}).", "sources": [ "spacex_starship", "benzinga_2025", "fortune_gold" ] }, { "id": "F-20", "section": "1.4", "text": "Real past cost: Perseverance's whole mission, including building, launch and two years of work, cost about ${perse_bn} billion.", "compare": "About ${perse_per_t} billion per tonne landed: {perse_vs_spacex} times SpaceX's advertised price. One is a real bill; the other is a price list for flights that have not happened.", "sources": [ "planetary_perse", "jpl_perseverance" ] }, { "id": "F-21", "section": "1.4", "text": "SpaceX's published price is for cargo. It lists no price for carrying a person.", "compare": "Like a delivery firm that publishes its parcel rates but no passenger fare: nobody can yet buy a seat to Mars.", "sources": [ "spacex_starship" ] }, { "id": "F-22", "section": "1.5", "text": "SpaceX's Mars dates so far: in 2016, a landing in 2018; in 2017, cargo ships in 2022; in 2024, five uncrewed Starships in 2026 with crews in 2028; now, 'no earlier than 2028'.", "compare": "Four dates: two missed, one dropped before its window opened, one current. Each slipped by at least one bus (26 months).", "sources": [ "scienceblog_2026", "nightly_2024", "spacex_starship" ] }, { "id": "F-23", "section": "1.5", "text": "In May 2025 Musk put the chance of sending an uncrewed Starship in the 2026 window at 50-50, with Optimus humanoid robots aboard the first ship.", "compare": "A coin toss. Since dropped: no Starship is planned for the 2026 window (F-25).", "sources": [ "aljazeera_2025" ] }, { "id": "F-24", "section": "1.5", "text": "On {shift_date} Musk said SpaceX had shifted focus to a 'self-growing city' on the Moon, possible in under {moon_yrs} years, while Mars would take {mars_yrs}+ years. SpaceX would still begin a Mars city in about {mars_start} years. The Wall Street Journal reported SpaceX told investors it was aiming for an uncrewed Moon landing in March 2027. On 27 July 2026 Musk posted 'I will not forget about Mars' and repeated the 5 to 7 years for a Mars city.", "compare": "{mars_start} years is about {mars_start_windows} Mars buses away.", "sources": [ "nbc_2026", "spacepolicy_2026", "cnn_2026", "benzinga_2026" ] }, { "id": "F-25", "section": "1.5", "text": "No Starship is heading to Mars in the late-2026 window. What is: Japan's MMX, due to launch on 19 October 2026 on Japan's H3 rocket to land on the moon Phobos and return a sample by 2031, and NASA's two ESCAPADE probes, built by Rocket Lab, which swing past Earth in November 2026 and reach Mars in September 2027.", "compare": "The 2026 bus carries two small robotic missions, not a fleet.", "sources": [ "spacex_starship", "nsf_2026preview", "wiki_mmx", "wiki_escapade" ] }, { "id": "F-26", "section": "1.5", "text": "NASA's Mars Sample Return was cancelled by the spending bill the US Senate passed on 15 January 2026. Congress gave $110 million to a 'Mars Future Missions' fund for landing and other technology instead. Perseverance's 30-plus rock samples stay on Mars.", "compare": "The rocks are packed and waiting, with no ride home booked. $110 million is about {msr_pct}% of what Perseverance cost.", "sources": [ "livescience_msr" ] }, { "id": "F-27", "section": "1.5", "text": "On 1 September 2026 NASA picked Blue Origin to build, launch and run the Mars Telecommunications Network, a relay orbiter on its Blue Ring design, for about ${mtn_m} million. Delivery is due by 31 December 2028 and service at Mars by 2030. It would replace relays launched in 2001 (Mars Odyssey) and 2005 (Mars Reconnaissance Orbiter). On 11 September 2026 Rocket Lab, a losing bidder, filed a protest with the US Government Accountability Office; work is paused until a ruling due by mid-December 2026.", "compare": "The phone line every later mission will depend on. ${mtn_m} million is about {mtn_pct}% of Perseverance's cost, roughly a quarter.", "sources": [ "nasa_mtn", "space_mtn", "satnews_protest", "wiki_mto", "wiki_odyssey" ] }, { "id": "F-28", "section": "1.5", "text": "China's Tianwen-3 is planned to launch on two Long March 5 rockets around 2028, work on the surface for about a year, and bring at least 500 g of Mars back by about 2031. Its landing zone lies between 17° and 30°N; three final sites are due by the end of 2026. Europe's Rosalind Franklin rover is planned to launch in late 2028 on a Falcon Heavy; Impulse Space plans a small lander no earlier than 2028.", "compare": "500 g is half a 1 kg bag of sugar. If it holds, China brings Mars rock home first.", "sources": [ "govcn_tw3", "space_tw3", "wiki_tw3", "wiki_rfr", "nsf_impulse" ] }, { "id": "F-29", "section": "1.7", "text": "NASA's reference astronaut uses about {o2} kg of oxygen, {drink} kg (litres) of drinking water, raised from a 2.0 kg baseline for a heavy exercise schedule, and {food} kg of packaged food a day: about {daily} kg in all.", "compare": "Over a {cruise_days}-day trip that is about {trip_t} tonnes per person without recycling, more than a Perseverance.", "sources": [ "ewert_2019" ] }, { "id": "F-30", "section": "1.7", "text": "The International Space Station now recycles {iss_water}% of its water, up from 93 to 94% before a new brine processor (2023).", "compare": "Out of 50 bottles, only one is lost.", "sources": [ "nasa_water" ] }, { "id": "F-31", "section": "1.7", "text": "Curiosity measured about {rad_day} millisieverts of radiation a day on its way to Mars, about {rad_rt} sievert for a round trip with today's rockets.", "compare": "Like a whole-body CT scan every 5 or 6 days: about {ct_lo} to {ct_hi} scans on a {cruise_days}-day trip. A whole-body CT (about 10 mSv, implied by that comparison) is several times the chest CT that 02-01 uses as its yardstick.", "sources": [ "swri_2013" ] }, { "id": "F-34", "section": "1.3", "text": "NASA's reference plan (Design Reference Architecture 5.0) sends the cargo one launch window ahead of the crew, and makes the ascent fuel's oxygen on Mars before the crew leaves Earth. It plans for a crew of about {nasa_crew}.", "compare": "One window ahead means the cargo waits on Mars about {window_months} months, over two years, before anyone arrives.", "sources": [ "nasa_dra5" ] }, { "id": "F-35", "section": "1.6", "text": "In June 2021 the head of the China Academy of Launch Vehicle Technology, Wang Xiaojun, said China plans crewed launches to Mars in 2033, 2035, 2037, 2041 and beyond, after robot missions to study base sites. The rocket was not named, and Long March 5 is not built to carry people.", "compare": "China's first crew date comes before this library's first landing, but China has not yet flown a person beyond Earth orbit.", "sources": [ "aljazeera_china_mars" ] }, { "id": "F-36", "section": "1.6", "text": "Blue Origin has called Mars part of Jeff Bezos's long-term vision, to be reached on a much bigger rocket, New Armstrong, over decades. It has announced no crewed Mars plan or date.", "compare": "New Glenn builds the phone line to Mars; Blue Origin's passengers wait for a rocket still on paper.", "sources": [ "yahoo_blue_mars" ] }, { "id": "F-37", "section": "1.6", "text": "After Flight 14 reached orbit on 28 September 2026, Starship Flight 15 (Booster 22 and Ship 42, from Starbase's second pad) was pencilled in for no earlier than 19 October 2026. The date comes from air traffic planning, not from SpaceX, and is described as highly provisional; Flight 16 from Florida was pencilled in for no earlier than 30 October 2026.", "compare": "Flight 14 itself slipped six days, from 22 to 28 September.", "sources": [ "wiki_sf15", "nsf_f15", "fox_f15" ] }, { "id": "F-38", "section": "1.6", "text": "New Glenn has not flown since its third flight on 19 April 2026, and a static fire blew up the vehicle meant for its next mission on its pad on 28 May 2026. Blue Origin says it will return to flight by the end of 2026, carrying 48 Amazon Leo satellites; no date has been set.", "compare": "Some observers expect the return to slip into early 2027.", "sources": [ "blue_rtf", "wiki_ng_launches" ] }, { "id": "F-39", "section": "1.6", "text": "China's Chang'e 7 Moon mission on a Long March 5 was rolled to its pad on 19 August 2026, then called off on 23 August: it cannot fly in this year's window and is reported for a February or March 2027 window. No other Long March 5 launch is announced for 2026, though China often flies military satellites on it at a few days' notice.", "compare": "Long March 5 last flew on 11 June 2026, carrying a communications test satellite.", "sources": [ "caixin_ce7", "nsf_next_ce7" ] } ], "assumptions": [ { "id": "E-01", "confidence": "Medium", "text": "Our world's timeline starts from real hardware and aims ambitious but believable. Uncrewed landings (the Robots First era) begin in the early 2030s and the first crew lands in {first_crew_year}, ending a flight launched in the mid-2035 window. The city we show is about {city_lo} to {city_hi} years after that. Every page shows calendar years, worked out from this one landing year (00 L-18), so if the real landing slips only this number changes.", "why": "SpaceX says Mars cargo 'no earlier than 2028' (F-19), Musk says Mars city work begins in about 5 to 7 years (F-24), and every date has slipped or been dropped (F-22). Calendar years make the world feel real; keeping them all worked out from one landing year keeps every file consistent however the real dates move. The owner chose {first_crew_year} on 28 September 2026. The era names come from the Project map (00-01); the years for each era are in the era plan (E-12)." }, { "id": "E-02", "confidence": "High", "text": "Cargo arrives in batches every {window_months} months, never continuously. Between windows nothing new can arrive: a broken part cannot be reordered; it is repaired, improvised or done without until the next window. The settlement's rhythm, its stock-taking, repairs and worries, follows this two-year pulse.", "why": "Fixed by orbital mechanics (F-15). No current rocket can change it." }, { "id": "E-03", "confidence": "Medium", "text": "In the city era, a typical window brings {city_ships_lo} to {city_ships_hi} ships. A cargo ship lands about {ss_mars} tonnes (E-09), so if every ship carried cargo a window would land {e03_lo} to {e03_hi} tonnes, spread over a month of landings. Most City ships carry people instead, and land far less (E-13, E-14): about {cargo_lo} to {cargo_hi} t at the low end. Earlier eras land fewer (E-12).", "why": "That is {eif_lo} to {eif_hi}% of the Eiffel Tower's iron frame per window. We stay low because every number so far has been optimistic (F-22), and because at about {tankers} tanker launches per ship (Rapp's estimate for refilling in Earth orbit, F-11), {city_ships_lo} to {city_ships_hi} ships already means {tank_lo} to {tank_hi} tanker launches in a few weeks, far beyond any launch rate yet achieved." }, { "id": "E-04", "confidence": "Medium", "text": "Ships burn methane and oxygen, and ships going home are refilled with propellant made on Mars from ice and the carbon dioxide air. That makes water mining a strategic industry, not just a utility (03-01 builds on this; the ice itself is surveyed in 02-03).", "why": "Starship already burns methane and oxygen (F-02). A full ship holds {ss_prop} tonnes of propellant (F-02); shipping that from Earth would take about {e04_ships} full ships' cargo ({ss_prop} t / {ss_mars} t landed, E-09) for every ship going home (our working-out)." }, { "id": "E-05", "confidence": "Low", "text": "See 04-02-01 CR-01, which now owns who governs the settlement: a mixed venture, run on the ground by a Settlement Authority set up by the partner countries. 01-04 LM-01 to LM-03 set the Earth-side limits it works inside.", "why": "Moved in version 2.8 so who governs is written once. The real examples that suggested a mixed venture stay here: a NASA-paid Blue Origin orbiter (F-27), a European rover on a SpaceX rocket (F-28), a Japanese mission on a Japanese rocket (F-25).", "moved_to": "04-02-01 CR-01" }, { "id": "E-06", "confidence": "High", "text": "Every object in the city was either landed at about ${price_m} million a tonne or made on Mars. People are visibly careful with mass: nothing is disposable, packaging is reused, and 'Earth-made' is a mark of value.", "why": "Follows from the published price (F-19): ${usd_kg} a kilogram, about {gold_pct}% of the price of gold. Even a tenfold fall leaves ${usd_kg10} a kilogram, so a spare part is worth shipping only if Mars cannot make it." }, { "id": "E-07", "confidence": "Medium", "text": "In the early eras the trip takes about 7 months (6 to 9). Faster 3 to 4 month crossings appear only in later eras, as an upgrade people remember arriving.", "why": "Real missions take about {cruise_days} days (F-15, F-16). The 3 to 4 month trip is an engineer's estimate that needs full tanks after refilling (F-18), which has not yet been tried (F-13)." }, { "id": "E-08", "confidence": "Medium", "text": "Downstream files draw the arriving ship with Starship's published size (F-01): a ship about {ss_ship_h} m tall and {ss_w} m wide landing about {ss_mars} tonnes of cargo (E-09). We do not name the company in the world.", "why": "It is the only Mars ship being built with published dimensions. Keeping the company unnamed fits E-05 and survives changes in the real industry." }, { "id": "E-09", "confidence": "Medium", "text": "Each cargo ship lands about {ss_mars} tonnes on Mars.", "why": "SpaceX's own target to low Earth orbit is over {ss_leo} tonnes (F-01). Its Mars claim of several hundred tonnes (F-32) is not yet shown, and every past SpaceX Mars date has been optimistic (F-22), so we use the lower figure." }, { "id": "E-10", "confidence": "Medium", "text": "Robots First come first. One or two launch windows before the first crew, uncrewed ships land the reactors, the ice drill, the fuel plant and building robots. The first ship lands on natural ground and robots build the first pad (03-02). The plant starts making fuel before the crew leaves Earth, so the crew's way home is being made before they set off.", "why": "This is NASA's own pattern: cargo one window ahead, and the ascent fuel's oxygen made on Mars before the crew departs (F-34). SpaceX's plans have always sent uncrewed ships first (F-22). A crew should never land without a proven way home. Decided by the owner on 25 September 2026." }, { "id": "E-11", "confidence": "Medium", "text": "The first crew stays about {stay_days} days and flies home in the next return window, on fuel made on Mars (F-33, E-10). In the early town, a new crew lands every window and most people stay for two, so crews overlap and hand over (01-03 WG-14). In the city, most people stay for good and only a few ships a window fly home.", "why": "A surface stay of about {stay_days} days is set by the planets (F-33), and NASA's reference plan brings its crew home on fuel made partly on Mars (F-34). A town grows only if some people stay longer. Who stays for life, and why, is now 04-02-03 Staying for good (SG-01 to SG-03), which takes over this assumption's social side. Decided by the owner on 25 September 2026.", "moves_to": "" }, { "id": "E-12", "confidence": "Low", "text": "Ships, people and returning ships in each era follow the era plan: {plan_line}", "why": "Robots First: SpaceX's own last plan was five uncrewed ships in one window (F-22). First crew: NASA plans for about {nasa_crew} people (F-34); Starship is far bigger, so up to twice that. First Town: a hundred or so people, the size of a large research station. City: {city_ships_lo} to {city_ships_hi} ships (E-03). People and returns are kept low because every number so far has been optimistic (F-22). Many Cities: {cities_p_lo} to {cities_p_hi} people by its end, so that Mars can stand on its own (04-02-04 works out that these ships close the plan). The sizes are guesses; the order (E-10) and who goes home (E-11) are firmer. Decided by the owner on 25 September 2026. At the top of the City's range the people the plan needs and the cargo do not both fit (E-14): the owner decides how to close it (00-01)." }, { "id": "E-13", "confidence": "Low", "text": "A crewed ship lands about {cc_lo} to {cc_hi} tonnes of cargo besides its people: a fifth to two-fifths of a cargo ship's {ss_mars} t (E-09).", "why": "The cabin, seats, life support and storm shelter take much of the ship's load, and the crossing's packaged food alone is about {food_crew_t} t for {pp_hi} people ({food} kg a day each for {cruise_days} days, F-29), before spares; water and air are mostly recycled (F-30). No published figure splits a crewed Starship's load between people and cargo, so this is our judgement, kept Low." }, { "id": "E-14", "confidence": "Low", "text": "In the City, ships carry mostly people. Growing from the First Town's {town_hi} people to {city_p_lo} to {city_p_hi} by {city_end} (about {city_win} windows), and replacing the {home_lo} to {home_hi} who fly home each window, needs about {need_lo} to {need_hi} arrivals a window. At {pp_lo} to {pp_hi} people a ship (01-02 JN-04), the low end fills about {pships_lo} of the {city_ships_lo} ships and lands about {cargo_lo} to {cargo_hi} t of cargo, not {e03_lo} t. The high end needs {pships_hi_lo} to {pships_hi_hi} ships of people, more than the {city_ships_hi} planned: at the top of its range the era plan does not close.", "why": "Worked out from this file's era plan (E-12), the cargo a crewed ship lands (E-13) and 01-02's people per ship. Births are left out: they start late and are few. The owner decides how to close the gap (00-01): more ships a window, more people a ship, a longer City era, or a smaller City. The numbers in E-12 stay as the owner set them until then." } ], "links": { "leans_on": [ { "ref": "00", "why": "Library rules: folders, IDs, facts versus assumptions, eras" }, { "ref": "00-01", "why": "Era names and their order, for the era plan (read live)" }, { "ref": "01-04 LM-01, LM-02, LM-03", "why": "The Earth-side limits on E-05's mixed venture: no ownership of the ground, ownership of what is extracted, Earth jurisdiction and supervision" } ], "used_by": [ { "ref": "05-19", "why": "Starship's size, for the ship standing on the plain in the playable world" }, { "ref": "05-13 Mars Atlas", "why": "People per era at the city and across Mars, for the atlas's settlement cards, and the ships waiting to fly the first crew home, for the home page key (read live)" }, { "ref": "04-01-03", "why": "The first crew's landing year, for the science town's calendar years (read live)" }, { "ref": "05-10", "why": "The first crew's landing year and Starship's height, for the Stand in Jezero viewer (read live)" }, { "ref": "03-02 F-01", "why": "Starship's size" }, { "ref": "03-02 F-02", "why": "Perseverance's mass (F-03)" }, { "ref": "03-02 F-15", "why": "Moon-first shift and the 26-month window" }, { "ref": "03-02 P-02", "why": "Ships stay about 500 days before the trip home (F-33); ships per window per era (E-12)" }, { "ref": "03-02 P-05", "why": "Cargo landed per ship (E-09)" }, { "ref": "03-02 P-06", "why": "Reuse-everything culture (E-06)" }, { "ref": "03-02 P-07", "why": "Cargo landed per ship (E-09)" }, { "ref": "03-01", "why": "Crew's surface stay (F-33)" }, { "ref": "03-01", "why": "Space station water recovery (F-30, life.iss_water_pct)" }, { "ref": "02-01", "why": "Quotes Perseverance's launch and landing dates" }, { "ref": "02-01", "why": "Space station water recovery (F-30, life.iss_water_pct)" }, { "ref": "04 Settled world", "why": "Years since the first crew landed (E-01)" }, { "ref": "04-02-01 How the city is run", "why": "Reads E-12 and F-15: people per era and how long until a ship home (read live). E-05, the mixed venture and its Settlement Authority, is taken over as CR-01; cites E-11 (crews rotate in the First Town); F-29: NASA's drinking water per astronaut, for CR-11 (read live)" }, { "ref": "05-01 The website", "why": "Rocket character-select reads the rockets list" }, { "ref": "03-01", "why": "Return fuel is made on Mars (E-04), from the ship's full propellant load (F-02); the plant lands and starts before the first crew (E-10); cargo landed per ship, for reactor mass (E-09)" }, { "ref": "03-02 F-15", "why": "SpaceX's Mars timing and first ships (F-23, F-24) and the window (F-15)" }, { "ref": "03-02 P-02", "why": "Ships stay about 500 days before the trip home (F-33); ships per window per era (E-12)" }, { "ref": "03-02 P-09", "why": "A full ship's propellant, for take-off mass (F-02)" }, { "ref": "02-03", "why": "SpaceX's Moon-first shift dates its site choice (F-24, in 02-03's shelf life)" }, { "ref": "00-01", "why": "The era plan: when each era is, and its ships and people (E-10 to E-12, read live)" }, { "ref": "03-01", "why": "Returning ships and people per era, for water and power (E-12, read live)" }, { "ref": "03-02", "why": "Ships per window per era, for pads (E-12, read live); the first ship and the robots (E-10)" }, { "ref": "03-02 P-04", "why": "The first crew flies home in the next return window (E-11)" }, { "ref": "03-03 Power", "why": "Reads E-09, E-12, E-10, F-33: About 100 t landed per cargo ship, for the mass of the power kit (read live); People, ships and returning ships in each era, for power by era (read live); Reactors and the fuel plant land before the first crew; About 500 days on the surface, the fuel plant's deadline (read live); Starship's propellant load and the launch window (read live)" }, { "ref": "03-04 Fuel plant", "why": "Reads F-02, F-15, F-33, F-29, F-06, E-04, E-09, E-10, E-12: A full Starship's propellant, 1,600 t (read live); The 26-month gap between launch windows (read live); About 500 days on the surface before the trip home (read live); Oxygen breathed per person per day, for the spare oxygen (read live); The 2026 New Glenn pad explosion, for safety; Ships going home are refilled with propellant made on Mars; About 100 t landed per cargo ship, for plant and reactor mass (read live); The plant lands and starts before the first crew leaves Earth; People and returning ships per era, for the plant by era (read live)" }, { "ref": "03-05 Vehicles and port", "why": "Reads E-09, E-12, E-06, E-10, F-23, F-15: About 100 t landed per cargo ship, to unload (read live); Ships, people and returning ships per era, for the port by era and the yard (read live); Reuse everything: ships that stay are stripped; Robots First land before any crew; SpaceX's plan to send Optimus robots on the first Mars ships; The 26-month launch window, for windows per era (read live); Starship height and the Eiffel Tower yardstick (read live)" }, { "ref": "01-02 The journey", "why": "Reads F-01, F-11, F-13, F-15, F-29, F-31, F-33, E-07, E-09, E-12 and the calendar: Starship's size, refilling, the cruise, food, radiation per day, the surface stay, trip length by era, cargo per ship, people per era and the orbits for the path (read live)" }, { "ref": "01-03 Who goes", "why": "Reads E-05, E-10, E-11, E-12, F-19, F-21, F-29, F-31, F-33, F-34: who chooses the crews, robots first, who goes home, people per era, the cargo price, food per day, the round-trip dose, time away and NASA's crew of six (read live)" }, { "ref": "01-04 Law, money and governance", "why": "Reads E-05, E-09, E-10, E-12, F-15, F-19, F-20, F-29: the mixed venture whose Earth-side limits it sets, cargo per ship, robots first, ships per era, the window, the cargo price, Perseverance's cost and a person's daily needs (read live)" }, { "ref": "01-05 The Earth-Mars link", "why": "Reads the calendar, F-27, F-33, E-12 and the comparisons: orbit sizes and years for the delay and the conjunction cycle, the relay network and its price, the blackout during the stay, the link per person (read live)" }, { "ref": "02-05 The site up close", "why": "Starship's height and width, and people per era (read live)" }, { "ref": "02-06 The human body on Mars", "why": "Reads F-15, F-31, F-33, E-07, E-12: the cruise and window, the journey dose, the stay and time away, months weightless and people per era, for the dose table (read live)" }, { "ref": "02-07 The Mars sky", "why": "Reads E-12 and F-15: people per era, and the 26-month window rhythm (read live)" }, { "ref": "03-06 Habitats", "why": "Reads E-09, E-12, F-33: cargo per ship, people per era and the surface stay, for living space and habitat counts (read live). Cites E-10 and F-34: cargo lands first, so the first modules are in place before the crew leaves" }, { "ref": "03-07 Airlocks, suitports and dust", "why": "Reads E-12, F-29, F-33: people per era, oxygen breathed a day and the first crew's stay, for trips outside and air lost at the doors (read live). Cites E-10: no doors while only robots are there" }, { "ref": "03-08 Spacesuits", "why": "Reads E-12, F-15, F-33: people per era, the 26-month window and the first crew's stay, for suit-hours and suit counts (read live)" }, { "ref": "03-09 Life support", "why": "Reads F-29, F-30, F-15, E-12: oxygen per person per day (read live, never copied), the station's water recovery, the window gap, and people and returning ships per era" }, { "ref": "03-10 Greenhouses and food", "why": "Reads F-29, F-15, F-33, E-09, E-12: food eaten a day, the window, the first crew's stay, cargo per ship and people per era, for shipped food and farm area and power by era (read live). Cites E-10: the first food lands with the cargo" }, { "ref": "03-11 Construction and materials", "why": "Reads E-09, E-10, E-12: cargo per ship, robots first, and people, ships and windows per era, for construction by era (read live)" }, { "ref": "03-12 Manufacturing", "why": "Reads F-19, E-09, E-12: the cargo price per tonne, cargo per ship, and ships, people and returning ships per era, for hulls to remelt and the City's power (read live). Cites E-06: 'Earth-made' is a mark of value" }, { "ref": "03-13 Local communications", "why": "Reads E-12: people in each era, for the network per person (read live)" }, { "ref": "03-14 Medical bay", "why": "Reads E-12, F-15, F-33: people per era, the window and cruise, and the first crew's time away, for the medical load, staff and medicine shelf life (read live). Cites E-10: stores land before the first crew" }, { "ref": "03-15 Waste and recycling", "why": "Reads E-12, F-15, F-33, E-09: people and ships per era, the window, the first crew's stay and cargo per ship, for waste by era (read live). Cites E-11: returning ships are few, so no waste goes home" }, { "ref": "04-01-01 The first city", "why": "Reads E-12 and Starship's height and cargo: people, ships and returning ships per era, for the town's size, the views and the landing field (read live). Cites E-10: robots, reactors and plant first, the first ship on natural ground" }, { "ref": "04-01-02 The lava-tube outpost", "why": "Reads E-12, F-02, F-29: ships and people per era, a full Starship's propellant for the hop, and drinking water per person (read live). Cites E-11: nobody is spare before the First Town" }, { "ref": "04-02-03 Staying for good", "why": "Reads E-12, F-15, F-31: people and returning ships per era, the window and the crossing's dose (read live). SG-01 takes over E-11's social side; cites E-10 (a way home is ready first)" }, { "ref": "04-02-02 Money and trade", "why": "Reads F-19 (the price per tonne and the gold price), E-12 (ships, people and returning ships per era), F-15 (the window and cruise) and F-29 (a day's food) and Starship's propellant load (MT-14), live, to price everything; cites E-02 (nothing arrives between windows), E-06 (Earth-made is a mark of value) and F-26 (Sample Return cancelled)" }, { "ref": "04-03-01", "why": "The calendar and festivals: the launch window and cruise (F-15), the surface stay (F-33), the first crew going home (E-11) and people per era (E-12), all read live" }, { "ref": "04-03-02 Food and home life", "why": "E-09: about 100 t landed per cargo ship, for the clothes sum (read live); E-12: people per era, for the era table and the City's clothes sum (read live); F-15: the 26-month window, for food per person per window (read live); F-19: SpaceX's price per tonne to Mars, for what shipped food and coffee cost (read live); F-29: packaged food per person per day, for food shipped by era (read live); F-33: the surface stay, against the station's menu cycle (read live)" }, { "ref": "04-03-03 Language and culture", "why": "E-12: people per era, for the era table (read live); F-15: the 26-month window and the crossing's length, for the window customs (read live); F-33: about 500 days on the surface before going home, for the window customs (read live)" }, { "ref": "04-04-01 Jobs", "why": "E-12: people per era, which every headcount must equal (read live); E-11, who goes home" }, { "ref": "04-04-02 A day in the life", "why": "E-12: people per era, for the table by era (read live)" }, { "ref": "04-04-03 Safety and emergencies", "why": "E-12: people per era, for who responds (read live)" }, { "ref": "04-05-01 Characters", "why": "E-12: people per era and each era's years, for the cast by era and every age (read live); E-11: the First crew flies home after its surface stay (read live), and rotations in the First Town; F-15: the window and the crossing, for arrival years and ages (read live)" }, { "ref": "04-05-02 Arrival day", "why": "E-12: the eras and their people (read live); F-15: the crossing's length, the orbits and Perseverance's dates, for the sky on arrival (read live); F-31: radiation a day on the crossing, for the dose on arrival (read live)" }, { "ref": "05-03 Guided tours", "why": "The era plan (E-10, E-11, E-12) behind the first landing and the era switch, and the ship's height for the port tour (read live)" }, { "ref": "05-04 Missions", "why": "The era plan and the First crew's stay, for comparisons (E-11, E-12, read live)" }, { "ref": "05-05 The Q&A guide", "why": "The era plan's years (E-12), the launch window and surface stay for who is on Mars when, and the robots-first order (E-10) (read live)" }, { "ref": "05-06 Free roam", "why": "The era plan (E-12): people and ships shown in each era (read live)" }, { "ref": "05-07 First-time onboarding", "why": "The era plan: people in each era, for the era doors (E-12) (read live)" }, { "ref": "05-08 The journey experience", "why": "Cruise days and the launch window (F-15), orbit sizes for the path, the era plan's people and ships (E-10, E-12), faster later crossings (E-07), the ship's height (read live)" }, { "ref": "05-09 Sign-ups and business", "why": "The next launch window and the window length for the boarding pass and seasons, and the era plan's people per era, read live" }, { "ref": "00-04 Glossary and units", "why": "E-12: the era plan: when each era falls and how many people (read live); F-15: the launch window, every 26 months (read live); F-33: the surface stay, about 500 days (read live); E-09: Starship's propellant and cargo landed on Mars (read live)" }, { "ref": "02-08", "why": "Sample Return's cancellation (F-26), for what happens to Perseverance's samples (read live)" }, { "ref": "05-12", "why": "City experience reads this source live through the generated library bundle." }, { "ref": "03-16", "why": "People per era for computing by era, and the surface stay (read live)" }, { "ref": "04-02-04", "why": "The era plan, including Many Cities, and Musk's 2026 Moon-first plan (read live); checks that Many Cities' ships seat its people" }, { "ref": "04-01-04 The cities of Mars", "why": "People across Mars in Many Cities (the era plan's after_city), for the later towns' page (read live)" }, { "ref": "01-06 Rocket engines", "why": "Which rocket each engine flies on (rocket ids)" }, { "ref": "05-15 Engine lab", "why": "The rockets' names" }, { "ref": "01-07", "why": "Earth's and Mars's orbit sizes, for how far Mars is at its closest on the ladder of ways to space (read live)" }, { "ref": "05-16", "why": "The rocket pages read each home page rocket, its maker, its race to Mars and its part in going to Mars (rockets/library.json)" }, { "ref": "01-08", "why": "Inside the rockets reads each rocket's height, stage heights, width, loads and boosters, and the storey and Eiffel Tower yardsticks" }, { "ref": "05-17", "why": "The home page's Living on Mars cards: what this part looks like in each era" }, { "ref": "01-10", "why": "The first crew's landing year, for the last stop on Who got us here, and the cruise to Mars for its comparisons (read live)" }, { "ref": "05-20", "why": "Mars games: starship's height, the launch window and the trip time, for the Mars Quiz (worked_out)" } ] }, "open_questions": [ "Re-check after 19 October 2026 (MMX launch) and mid-December 2026 (the ruling on Rocket Lab's protest).", "05-01 The website: read the 'rockets' list in this file for the character-select screen. Starship, New Glenn and Long March 5 carry character_select: true. New Glenn's status is 'Grounded'; Long March 5's figures are for the CZ-5 and CZ-5B versions.", "02-01 owns Mars's orbit. 01-01 keeps its own NASA-sourced copy of the two orbit sizes (calendar.earth_orbit_mkm and calendar.mars_orbit_mkm) for the orbit drawing, because 01 may not lean on 02. It is a sanctioned copy, checked by build.py (00 L-17).", "No independent estimate of the cost of landing a tonne on Mars by Starship was found. Add one when a credible study appears.", "The era plan does not close at the top of the City's range (E-14): the arrivals the City needs each window take more ships than the plan allows. For the owner, on the Project map (00-01): more ships a window, more people a ship, a longer City era or a smaller City." ], "changes": [ "25 September 2026 (before v2.2): Rebuilt as twin files (this facts file plus the page), with a to-scale rocket line-up, an orbit picture, a timeline and the library bar. Version 1.1 was 16 September 2026.", "25 September 2026 (before v2.2): Added a clean 'rockets' list (height, width, payload, status, sources) for the website's rocket screens.", "25 September 2026 (before v2.2): Updated Starship to Version 3: 124 m tall, 9 m wide, over 100 t (SpaceX), 1,600 t of propellant. Added the Flight 12 and 13 results and Flight 14's date.", "25 September 2026 (before v2.2): Corrected 'about a 40-storey block' to about 39 storeys, now worked out from the height.", "25 September 2026 (before v2.2): Corrected Long March 9: first flight is targeted for 2033, not around 2028.", "25 September 2026 (before v2.2): Corrected MMX: it launches in the 2026 window (19 October 2026), not 2028.", "25 September 2026 (before v2.2): Corrected Musk's broken dates: the verified list is 2018, 2022, 2026, and now 'no earlier than 2028'. Removed '2024 promised in 2020' and the 'three years per slip' average, which could not be sourced.", "25 September 2026 (before v2.2): Corrected the Wall Street Journal report: it said SpaceX told investors it was aiming for an uncrewed Moon landing in March 2027.", "25 September 2026 (before v2.2): Corrected daily needs to NASA's 2019 reference astronaut: 0.89 kg oxygen, 2.79 kg drinking water, 2.39 kg packaged food.", "25 September 2026 (before v2.2): Corrected the ISS recycling claim: water recovery reached 98% in 2023. Removed the unsourced '90 percent less oxygen and water'.", "25 September 2026 (before v2.2): Corrected E-06's reasoning: at $100,000 a kilogram, Mars cargo costs about 70% of gold, not more. A tenfold fall would not keep it above gold.", "25 September 2026 (before v2.2): Corrected E-03's comparison: 1,000 to 3,000 t is 14 to 41% of the Eiffel Tower's iron frame, not the whole tower.", "25 September 2026 (before v2.2): Added New Glenn's third flight (first booster reuse, lost satellite), the cause of the pad explosion, and the aerobrake.", "25 September 2026 (before v2.2): Added Long March 5 and Falcon Heavy figures, the cost of Perseverance as a real benchmark, Tianwen-3's sample size and site timeline, Rosalind Franklin, Impulse Space, and Rocket Lab's protest.", "25 September 2026 (before v2.2): Added E-07 (trip length in our eras) and E-08 (which ship downstream files draw).", "25 September 2026 (before v2.2): Removed claims that could not be sourced: 'all Mars landings total a few tonnes', entry at 7.5 km/s, the Premier League and Crossrail cost comparisons, '20 ships in the second window and 100 in the third', and 'carrying return fuel would halve the payload'.", "25 September 2026 (before v2.2): Removed the comparison with the dose on the Mars surface (owned by 02-01); the trip dose is now compared with CT scans.", "25 September 2026 (before v2.2): Moved the link to 03-02 landing pads from 'see 03-02' in the text to 'used by', since 01 may not lean on 03.", "25 September 2026 (before v2.2): Updated E-01 and E-05 reasoning to the September 2026 facts. E-03 and E-06 keep their meaning.", "25 September 2026 (before v2.2): Updated the at-a-glance panel (in 2.0): '100+ t' became Starship's 124 m height, '6 to 9 months' became about 200 days, and '5 to 7 yrs' moved into section 1.5.", "25 September 2026 (before v2.2): Corrected F-18 (25 September 2026, 2.1): the 3 to 4 month trip is Robert Moses's estimate, a retired NASA engineer, not a SpaceX claim.", "25 September 2026 (before v2.2): Corrected the shelf-life wording (2.1): not every date slipped; SpaceX's website moved Mars cargo from 2030 to 2028.", "25 September 2026 (before v2.2): Added (2.1): Rocket Lab's protest of 11 September 2026 pausing the Mars phone line, the 2001 and 2005 relay orbiters it replaces, Musk's 27 July 2026 'I will not forget about Mars', Donald Rapp by name, MMX's H3 rocket, dollar comparisons for the $110 million fund and the $700 million contract, and the whole-body versus chest CT note.", "25 September 2026 (before v2.2): Added (2.1): Starship's Version 3 propellant (1,600 t), booster figures and a clear note that no Version 3 dry mass is published, for 03-01 and 03-02.", "25 September 2026 (before v2.2): Restored (2.1): the relay-orbiter ages and, in E-02, 'a broken part cannot be reordered'.", "25 September 2026 (before v2.2): Updated (2.1): E-04 reasoning (about 12 ships' cargo per return), E-07 trip length (about 7 months, 6 to 9), F-12 wording, source years, links, open questions and timeline dates. Removed unused data fields. Mobile drawings now scroll sideways with a hint so labels stay readable.", "25 September 2026 (before v2.2): 25 September 2026: folder 05 renamed 'Visiting Mars' (decided 25 September 2026); links updated.", "25 September 2026 (v2.2): Corrected E-04: a ship going home needs its full 1,600 t load (F-02), about 16 ships' cargo at 100 t landed each (E-09), not Rapp's 1,200 t. F-11 now says 1,200 t is Rapp's Earth-orbit refill estimate for an earlier, smaller ship. E-03 labels its tanker count as that estimate.", "25 September 2026 (v2.2): Added F-32 (SpaceX's 'several hundred tonnes' Mars claim), F-33 (NASA's 500-day surface stay, 900 days away) and E-09 (about 100 t landed per cargo ship). E-03 and E-08 now cite E-09. Starship's payload_mars_note updated; added payload_mars_from.", "25 September 2026 (v2.2): Corrected future plans stated as done: the 2026 promise is 'dropped' (F-25), not missed; F-22 and F-23 comparisons reworded. New Glenn is 'picked' for the Mars orbiter (contract under protest, F-27); ESA, Tianwen-3 and the phone line marked planned.", "25 September 2026 (v2.2): Updated E-01: count 'years since the first crew landed (Year 0)'; uncrewed landings come before. The no-year rule is marked as proposed for file 00, with an open question.", "25 September 2026 (v2.2): Moved E-05 (who governs) towards 04.02 Societies (moves_to).", "25 September 2026 (v2.2): Removed two stale open questions about 03-02 (Starship's size, and bare '01-01' citations). The orbit-copy note now says it is a sanctioned copy for build.py to check.", "25 September 2026 (v2.2): Updated links: 02-01 reads Perseverance's dates; added 03-02 F-02, 03-01 for F-33 and life.iss_water_pct, 02-01 for life.iss_water_pct; 03-02 P-05 and P-07 cite E-09; no numbers in link reasons.", "25 September 2026 (v2.2): the year lengths in calendar (earth_year_days, mars_year_days) are also labelled sanctioned copies of 02-01, checked by build.py (file 00 L-17).", "25 September 2026 (v2.2): deleted two answered open questions (L-17 and L-18 now exist in file 00). used_by now lists every file that reads this one, including 02-03 and more of 03-01 and 03-02.", "25 September 2026 (v2.3): the owner decided the eras and the crew-return plan. Added the era plan (ships, people and returning ships per era), F-34 (NASA sends cargo a window ahead and makes fuel before the crew leaves), E-10 (robots and cargo first; the fuel plant works before the crew leaves Earth), E-11 (the first crew goes home after about 500 days; the city mostly stays) and E-12 (sizes per era). E-01 and E-03 now read the era plan. Removed the open question on whether anyone goes home.", "25 September 2026 (v2.3): E-10 now says only the ascent fuel's oxygen is made on Mars in NASA's plan (F-34); E-12 no longer leans on a folder-03 example; used_by lists 03-01's use of E-10 and 03-02's use of E-11.", "25 September 2026 (v2.4): links made two-way for the new files 03-03 Power, 03-04 Fuel plant and 03-05 Vehicles and port (and older one-sided links), each reason taken from the other file's own link.", "25 September 2026 (v2.5): 03-05's link no longer claims it reads F-02 (tanker runs were dropped; fuel moves by pipeline, 03-04 C-07).", "26 September 2026 (v2.6): The ship-interiors open question now points to 01-02 The journey and 05-08 The journey experience. E-05 cites 01-04 LM-01 to LM-03 for the Earth-side limits on the mixed venture (01-04 added to leans_on). used_by lists the wave 1 pages that read this file: 01-02, 01-03, 01-04, 01-05, 02-05, 02-06 and 02-07, each with what it reads.", "26 September 2026 (v2.7): used_by adds 03-06 to 03-12 (habitats, airlocks, suits, life support, farms, construction and manufacturing), each with what it reads. 03-09 now reads the oxygen per person (F-29) live instead of keeping a copy. F-29's 2.39 kg of food was checked against Ewert and Stromgren 2019: it is the planning figure including 0.43 kg of packaging and a 10% allowance for unopened food, as 'packaged food' says, so it stands.", "26 September 2026 (v2.8): E-05 (who governs) is now a pointer to 04-02-01 CR-01, which took it over. E-11 moves_to now names 04-02-03 Staying for good, which takes over its social side (SG-01). Three open questions deleted as answered: where the first ships land (04-01-01 FC-01 makes the pin the centre of the first modules, FC-10 lands the first ship to the south as First Landing), taking over E-05 (04-02-01 CR-01) and why people stay for life (04-02-03 SG-01 to SG-03). F-29 now says its drinking water is in kg and litres alike and was raised from a 2.0 kg baseline for exercise (Ewert and Stromgren 2019, checked): it is drinking water only, so 03-01's 2 to 2.5 litres (food and drink, EFSA) is a different measure. used_by adds 03-13, 03-14, 03-15, 04-01-01, 04-01-02 and 04-02-03, and the old 04.02 Societies line becomes 04-02-01.", "26 September 2026 (v2.9): used_by adds 04-02-02 Money and trade, which reads F-19, E-12, F-15 and F-29 live.", "26 September 2026 (v2.10): The 04-02-01 used_by line adds F-29 (drinking water per astronaut, read live for CR-11). used_by: back-links for 04-03-01, 04-03-02, 04-03-03, 04-04-01, 04-04-02, 04-04-03, 04-05-01, 04-05-02 (what each reads, from its leans_on). Also back-links for 05-03, 05-04, 05-05, 05-06, 05-07, 05-08, 05-09 (wave 6 pages, from their leans_on as written today).", "26 September 2026 (v2.11): F-21 has a comparison line; the shelf life names a re-check date (December 2026), as the Research log (90-04) audit asked. Back-link for 00-04, which reads the era plan, window, stay and cargo live.", "26 September 2026 (v2.12): Beauty pass: a new opening picture, Earth's and Mars's orbits to scale with the transfer arc, labelled as art.", "26 September 2026 (v2.13): Final fix round: New E-13 (cargo a crewed ship lands, Low) and E-14 (in the City ships carry mostly people; at the top of the City's range the era plan does not close), worked out live from the era plan and 01-02's people per ship; E-12's why points to E-14 and the owner's decision on 00-01 (E-12's numbers unchanged); a new open question for it; the pointer-only open question on ship interiors removed. E-11 and the era plan's Early town line: most people stay two windows so crews overlap (01-03 WG-14); the plan's numbers unchanged. used_by 04-02-02: it now reads Starship's propellant load too. E-11: moves_to cleared: the social side has moved to 04-02-03 SG-01 to SG-03, as its why already says; the owner's decision stays here. used_by: the folder-level '05 Visiting Mars' line removed; the 05 pages that really read this file are listed one by one", "28 September 2026 (v2.14): The owner chose calendar years with the first crew landing in 2036 (era_plan.first_crew_year). E-01 now names that year and says pages show calendar years worked out from it (00 L-18 changed the same day). The era plan table and E-14 now show calendar years; wording about fiction removed (00 L-21). Now also used by the new 02-08 Jezero Crater.", "28 September 2026 (v2.15): Used by the Jezero science town (04-01-03) and the Stand in Jezero viewer (05-10). The era plan's note no longer says 'Year 0' (00 L-18).", "30 September 2026 (v2.16): Added the city experience to the files that read this source.", "1 October 2026 (v2.17): The era plan gains Many cities, years 30 to 60 after the first landing, with 200 to 600 ships a window and 50,000 to 200,000 people at its end, at the owner's request for a last era in which Mars needs nothing from Earth (00-01). 04-02-04 checks that these ships seat the arrivals the plan needs. It sits in the plan's 'after_city' list, because the kit pages size their numbers only up to the City. The era after it, Self-sustaining Mars, has no plan of ships: it begins when Many cities ends.", "1 October 2026 (v2.18): used_by adds 03-16 and 04-02-04, the new pages on computing and on needing nothing from Earth.", "1 October 2026 (v2.19): Used by the Mars Atlas (05-13).", "1 October 2026 (v2.20): E-14's cargo sum now comes from the library's one cargo rule (shared-rules.js, LIB.cargoByEra), which 03-03, 03-12 and 03-15 also use, so their cargo per window matches E-14 (in the City about 360 to 1,200 t a window, not 1,000 to 3,000 t). E-03 now says its 1,000 to 3,000 t is what a window would land if every ship carried cargo, and points to E-14 for what it really lands.", "3 October 2026 (v2.21): Long March 5's four strap-on boosters added (3.35 m wide, 27.6 m tall, Wikipedia), so the website's rocket line-up can draw it to scale with its boosters.", "3 October 2026 (v2.22): Added F-35 (China's planned crewed Mars launches from 2033, Al Jazeera 2021) and F-36 (Blue Origin's long-term Mars vision on New Armstrong, no crewed plan or date, 2016), and a people_later line on those two players, for the home page's Pick your rocket screen.", "3 October 2026 (v2.23): Now also used by 04-01-04 The cities of Mars, which places the towns of Many Cities and Self-sustaining Mars.", "3 October 2026 (v2.24): Flight 14 result added to F-14, the Starship status and the timeline: on 28 September 2026 Starship reached orbit for the first time and released 26 Starlink satellites, ending early after one ship engine shut down (Zendar Universe; SpaceNexus). Found while checking the Rocket Engine Lab against this file.", "3 October 2026 (v2.25): Added 'race': the same six steps for each home page rocket (first flight, reached orbit, flew again, refilled in orbit, sent a mission to Mars, carried people) with the date each first happened, from Wikipedia and Flight 14's sources, for the home page's race to Mars.", "3 October 2026 (v2.26): Now also read by 01-06 Rocket engines (which rocket each engine flies on) and 05-15 Engine lab (the rockets' names).", "3 October 2026 (v2.27): race.details added: for each of the 18 steps on the home page's race to Mars, a short plain description and one interesting fact, with sources (Wikipedia pages for Starship, New Glenn, Long March 5, Tianwen-1, ESCAPADE, New Shepard and Long March 2F; Flight 14's sources; F-24, F-35, F-36).", "3 October 2026 (v2.28): Now also used by 01-07 Ways to space today, which works out how far Mars is from the orbit sizes in calendar.", "3 October 2026 (v2.29): Each home page rocket now has a maker_profile (founded, founder, home, people, one line and one fact, from Wikipedia's SpaceX, Blue Origin and CALT pages) for the new rocket pages (05-16), which also read it.", "4 October 2026 (v2.30): used_by: 05-13 now also reads the First Human Landing era's returning ships (E-12) for the home page atlas key.", "4 October 2026 (v2.31): Now also used by 01-08 Inside the rockets.", "4 October 2026 (v2.32): Owner: the home page counts down to each rocket's next launch. New F-37 (Starship Flight 15, no earlier than 19 October 2026), F-38 (New Glenn back to flight by the end of 2026) and F-39 (Long March 5's next named flight, Chang'e 7, early 2027), with each rocket's next_launch and seven sources. shelf_life says to re-check them monthly.", "4 October 2026 (v2.33): sources_checked updated for the next-launch check (F-37 to F-39).", "4 October 2026 (v2.34): Used by 05-17 Living on Mars, the home page's cards on how each part of a Mars city works in each era.", "5 October 2026 (v2.35): New Glenn's rocket gets payload_mars_words (NASA's twin ESCAPADE probes, 2025), so the home page no longer says it has taken nothing to Mars while its race says it has. Race details no longer start 'Never:': the website now says 'Not built for it', which is what the step means.", "5 October 2026 (v2.36): Each home page rocket's maker profile now names its leading person (`leader`: name, role, one line), for the rocket pages' Who builds it: Elon Musk (SpaceX), Jeff Bezos (Blue Origin, with CEO Dave Limp named in the line) and Qian Xuesen (CALT's founder; its president Wang Xiaojun and chief designer Long Lehao are named in the line, because China's rocket programme has no single public figure like the other two) (owner). Each leader has a `label` (Led by, or Founded by where the person is the founder and not the current head).", "5 October 2026 (v2.37): Each race step in race.details gets a `punch`: one short line drawn only from its own text and fact, for the rocket pages' six race cards (owner: much less text).", "9 October 2026 (v2.38): Owner: each rocket's next_launch gains short (the mission in a word or two) and site_short (the pad's town), so the home page's Pick your rocket shows the launch as a big countdown with two short tags instead of sentences.", "9 October 2026 (v2.39): Used by 05-19 Playable Arcadia, which reads this file live.", "9 October 2026 (v2.40): Used by 01-10 Who got us here, which reads the landing year and the cruise live." ], "sources": { "spacex_starship": { "name": "SpaceX, Starship vehicle page (specifications and Moon and Mars cargo pricing) (accessed September 2026)", "url": "https://new.spacex.com/vehicles/starship" }, "wiki_starship": { "name": "Wikipedia, SpaceX Starship, 2026", "url": "https://en.wikipedia.org/wiki/SpaceX_Starship" }, "wiki_f12": { "name": "Wikipedia, Starship flight test 12, 2026", "url": "https://en.wikipedia.org/wiki/Starship_flight_test_12" }, "wiki_f13": { "name": "Wikipedia, Starship flight test 13, 2026", "url": "https://en.wikipedia.org/wiki/Starship_flight_test_13" }, "nsf_f14": { "name": "Next Spaceflight, Starship Flight 14, 2026", "url": "https://nextspaceflight.com/launches/details/8346/" }, "zu_f14": { "name": "Zendar Universe, Starship Flight 14 result, 2026", "url": "https://zendaruniverse.com/updates/starship-flight-14-result-first-orbit-why-it-ended-early/" }, "sn_f14": { "name": "SpaceNexus, Today in Space, 29 September 2026", "url": "https://spacenexus.us/briefing/2026-09-29" }, "jpl_perseverance": { "name": "NASA JPL, Perseverance rover press kit, 2020", "url": "https://www.jpl.nasa.gov/news/press_kits/mars_2020/landing/mission/spacecraft/perseverance_rover" }, "planetary_perse": { "name": "The Planetary Society, Cost of Perseverance, 2020", "url": "https://www.planetary.org/space-policy/cost-of-perseverance" }, "wiki_newglenn": { "name": "Wikipedia, New Glenn, 2026", "url": "https://en.wikipedia.org/wiki/New_Glenn" }, "nsf_ng3": { "name": "NASASpaceFlight, New Glenn launches on third mission, successfully reuses booster, April 2026", "url": "https://www.nasaspaceflight.com/2026/04/ng-3-launch/" }, "wiki_ng_explosion": { "name": "Wikipedia, 2026 New Glenn rocket explosion, 2026", "url": "https://en.wikipedia.org/wiki/2026_New_Glenn_rocket_explosion" }, "cnbc_isaacman": { "name": "CNBC, Blue Origin launchpad may not be restored until 2028, NASA's Isaacman says, 1 June 2026", "url": "https://www.cnbc.com/2026/06/01/blue-origin-launchpad-may-not-be-restored-until-2028-nasas-isaacman.html" }, "blue_aerobrake": { "name": "Blue Origin, full-scale deployable aerobrake unit (post on X), November 2025", "url": "https://x.com/blueorigin/status/1991251070979391796" }, "wiki_lm5": { "name": "Wikipedia, Long March 5, 2026", "url": "https://en.wikipedia.org/wiki/Long_March_5" }, "wiki_lm9": { "name": "Wikipedia, Long March 9, 2026", "url": "https://en.wikipedia.org/wiki/Long_March_9" }, "space_lm9": { "name": "Space.com, China planning to build its own version of SpaceX's Starship, 8 November 2024", "url": "https://www.space.com/china-long-march-9-spacex-starship-rocket" }, "wiki_fh": { "name": "Wikipedia, Falcon Heavy, 2026", "url": "https://en.wikipedia.org/wiki/Falcon_Heavy" }, "aero_america": { "name": "Jon Kelvey, A Closer Look at SpaceX's Mars Plan, Aerospace America (AIAA), undated (accessed September 2026)", "url": "https://aerospaceamerica.aiaa.org/aiaa-spacex/" }, "spacedaily_refuel": { "name": "Space Daily, Starship after 13 test flights: orbital refuelling is the Mars hurdle, 27 August 2026 (updated 17 September 2026)", "url": "https://spacedaily.com/t-starship-13-test-flights-orbital-refueling-mars-hurdle/" }, "nasa_timeline": { "name": "NASA Science, Mars Exploration: mission timeline (accessed September 2026)", "url": "https://science.nasa.gov/planetary-science/programs/mars-exploration/mission-timeline/" }, "nasa_marsfact": { "name": "NASA NSSDCA, Mars Fact Sheet (accessed September 2026)", "url": "https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html" }, "k1945": { "name": "Harrison Kass, The Mars launch window opens in November 2026 and closes about a month later, 19FortyFive, 9 August 2026", "url": "https://www.19fortyfive.com/2026/08/the-mars-launch-window-opens-in-november-2026-and-closes-about-a-month-later-the-next-one-is-in-2029/" }, "benzinga_2025": { "name": "Benzinga, SpaceX eyes $100 million-per-ton Mars cargo missions, 13 October 2025", "url": "https://www.benzinga.com/news/space/25/10/48168768/elon-musks-spacex-eyes-100-million-per-ton-mars-cargo-missions-by-2030-as-11th-starship-launch-approaches" }, "fortune_gold": { "name": "Fortune, Current price of gold: 21 September 2026", "url": "https://fortune.com/article/current-price-of-gold-09-21-2026/" }, "scienceblog_2026": { "name": "ScienceBlog, SpaceX Mars deadlines 2016 to 2028, 15 August 2026", "url": "https://scienceblog.com/t-spacex-mars-deadlines-2016-2018-2022-2026-2028/" }, "nightly_2024": { "name": "The Nightly, Musk to send five uncrewed Starships to Mars by 2026, crews as soon as 2028, September 2024", "url": "https://thenightly.com.au/business/spacex-mission-to-mars-elon-musk-to-send-five-uncrewed-starships-to-mars-by-2026-crews-to-follow-as-soon-as-2028-c-16147336" }, "aljazeera_2025": { "name": "Al Jazeera, Musk says 50-50 chance of sending uncrewed Starship to Mars by late 2026, 30 May 2025", "url": "https://www.aljazeera.com/news/2025/5/30/musk-says-50-50-chance-of-sending-uncrewed-starship-to-mars-by-late-2026" }, "nbc_2026": { "name": "NBC News, In a reversal, SpaceX prioritizes 'city' on the moon over Mars project, February 2026", "url": "https://www.nbcnews.com/science/space/spacex-prioritizes-moon-before-mars-musk-says-rcna258168" }, "spacepolicy_2026": { "name": "SpacePolicyOnline, Musk embraces the Moon, February 2026", "url": "https://spacepolicyonline.com/news/musk-embraces-the-moon/" }, "cnn_2026": { "name": "CNN, Elon Musk says SpaceX prioritizing the moon, pivots away from his Mars settlement ambition, 8 February 2026", "url": "https://www.cnn.com/2026/02/08/science/elon-musk-spacex-priorities-moon-intl-hnk" }, "nsf_2026preview": { "name": "NASASpaceFlight, Space science in 2026: Mars missions preview, January 2026", "url": "https://www.nasaspaceflight.com/2026/01/space-science-2026-preview/" }, "wiki_mmx": { "name": "Wikipedia, Martian Moons eXploration, 2026", "url": "https://en.wikipedia.org/wiki/Martian_Moons_eXploration" }, "wiki_escapade": { "name": "Wikipedia, ESCAPADE, 2026", "url": "https://en.wikipedia.org/wiki/ESCAPADE" }, "livescience_msr": { "name": "Live Science, NASA's Mars Sample Return is dead, 16 January 2026", "url": "https://www.livescience.com/space/mars/nasas-mars-sample-return-is-dead-leaving-china-to-retrieve-signs-of-life-from-the-red-planet" }, "nasa_mtn": { "name": "NASA, NASA selects Blue Origin as Mars Telecommunications Network provider, 1 September 2026", "url": "https://www.nasa.gov/news-release/nasa-selects-blue-origin-as-mars-telecommunications-network-provider/" }, "space_mtn": { "name": "Space.com, Blue Origin wins $700 million contract to build NASA's next Mars orbiter, 2 September 2026", "url": "https://www.space.com/space-exploration/missions/blue-origin-wins-usd700-million-contract-to-build-nasas-next-mars-orbiter" }, "satnews_protest": { "name": "SatNews, Rocket Lab files GAO bid protest over NASA's $700M Mars orbiter award, 14 September 2026", "url": "https://satnews.com/2026/09/14/rocket-lab-files-gao-bid-protest-over-nasas-700m-mars-orbiter-award-to-blue-origin/" }, "govcn_tw3": { "name": "Xinhua via gov.cn, Chinese scientist details first planned Mars sample-return mission Tianwen-3, 23 July 2025", "url": "https://english.www.gov.cn/news/202507/23/content_WS68803af3c6d0868f4e8f45d3.html" }, "space_tw3": { "name": "Space.com, China on track to launch Mars sample-return mission in 2028, 9 September 2026", "url": "https://www.space.com/astronomy/mars/china-on-track-to-launch-mars-sample-return-mission-in-2028-if-accurate-this-represents-a-sputnik-moment" }, "wiki_tw3": { "name": "Wikipedia, Tianwen-3, 2026", "url": "https://en.wikipedia.org/wiki/Tianwen-3" }, "wiki_rfr": { "name": "Wikipedia, Rosalind Franklin (rover), 2026", "url": "https://en.wikipedia.org/wiki/Rosalind_Franklin_(rover)" }, "nsf_impulse": { "name": "Next Spaceflight, Impulse Space's Mars mission on Terran R, 2026", "url": "https://nextspaceflight.com/launches/details/7164/" }, "ewert_2019": { "name": "Ewert and Stromgren, Astronaut Mass Balance for Long Duration Missions, NASA, 2019", "url": "https://ntrs.nasa.gov/api/citations/20190027563/downloads/20190027563.pdf" }, "nasa_water": { "name": "NASA, NASA achieves water recovery milestone on International Space Station, 20 June 2023", "url": "https://www.nasa.gov/missions/station/iss-research/nasa-achieves-water-recovery-milestone-on-international-space-station" }, "swri_2013": { "name": "Southwest Research Institute, SwRI-led team calculates the radiation exposure associated with a trip to Mars, 30 May 2013", "url": "https://www.swri.org/newsroom/press-releases/swri-led-team-calculates-the-radiation-exposure-associated-trip-mars" }, "parliament_tower": { "name": "UK Parliament, Big Ben and Elizabeth Tower: facts and figures (accessed September 2026)", "url": "https://www.parliament.uk/about/living-heritage/building/palace/big-ben/facts-figures/" }, "eiffel": { "name": "Société d'exploitation de la tour Eiffel, The Eiffel Tower: key figures (accessed September 2026)", "url": "https://www.toureiffel.paris/en/the-monument/key-figures" }, "benzinga_2026": { "name": "Benzinga, Elon Musk says 'I will not forget about Mars', 27 July 2026", "url": "https://www.benzinga.com/news/space/26/07/60689644/elon-musk-says-i-will-not-forget-about-mars-reaffirms-spacexs-multiplanetary-vision" }, "wiki_mto": { "name": "Wikipedia, Mars Telecommunications Orbiter (accessed September 2026)", "url": "https://en.wikipedia.org/wiki/Mars_Telecommunications_Orbiter" }, "wiki_odyssey": { "name": "Wikipedia, 2001 Mars Odyssey (accessed September 2026)", "url": "https://en.wikipedia.org/wiki/2001_Mars_Odyssey" }, "nasa_dra5": { "name": "NASA, Human Exploration of Mars Design Reference Architecture 5.0, executive summary presentation, 4 December 2008 (full report 2009)", "url": "https://www.nasa.gov/pdf/373669main_2008-12-04_Mars_DRA5_Executive_Summary-Presentation.pdf" }, "aljazeera_china_mars": { "name": "Al Jazeera, China plans for first manned mission to Mars in 2033, 24 June 2021", "url": "https://www.aljazeera.com/news/2021/6/24/china-plans-for-first-manned-mission-to-mars-in-2033" }, "yahoo_blue_mars": { "name": "GeekWire via Yahoo News, Jeff Bezos' Blue Origin space venture sets its sights on trips to Mars and the moon, September 2016", "url": "https://ca.news.yahoo.com/jeff-bezos-blue-origin-space-175956962.html" }, "wiki_starship_reuse": { "name": "Wikipedia, SpaceX Starship (Flight 9, first reflown Super Heavy booster), 2026", "url": "https://en.wikipedia.org/wiki/SpaceX_Starship" }, "wiki_tianwen1": { "name": "Wikipedia, Tianwen-1, 2026", "url": "https://en.wikipedia.org/wiki/Tianwen-1" }, "wiki_new_shepard": { "name": "Wikipedia, New Shepard, 2026", "url": "https://en.wikipedia.org/wiki/New_Shepard" }, "wiki_lm2f": { "name": "Wikipedia, Long March 2F, 2026", "url": "https://en.wikipedia.org/wiki/Long_March_2F" }, "wiki_spacex": { "name": "Wikipedia, SpaceX, 2026", "url": "https://en.wikipedia.org/wiki/SpaceX" }, "wiki_blue_origin": { "name": "Wikipedia, Blue Origin, 2026", "url": "https://en.wikipedia.org/wiki/Blue_Origin" }, "wiki_calt": { "name": "Wikipedia, China Academy of Launch Vehicle Technology, 2026", "url": "https://en.wikipedia.org/wiki/China_Academy_of_Launch_Vehicle_Technology" }, "wiki_sf15": { "name": "Wikipedia, Starship flight 15 (edited 2 October 2026)", "url": "https://en.wikipedia.org/wiki/Starship_flight_15" }, "nsf_f15": { "name": "NASASpaceflight, Starship makes orbit, Flight 15 preps in full swing, 30 September 2026", "url": "https://www.nasaspaceflight.com/2026/09/starship-14-orbit-flight-15/" }, "fox_f15": { "name": "FOX Weather, After milestone flight, SpaceX targets next Starship launch, 30 September 2026", "url": "https://www.foxweather.com/earth-space/after-fiery-splashdown-spacex-sets-sights-next-starship-launch-kalshi" }, "blue_rtf": { "name": "Blue Origin, New Glenn Return to Flight, 30 June 2026", "url": "https://www.blueorigin.com/news/new-glenn-return-to-flight" }, "wiki_ng_launches": { "name": "Wikipedia, List of New Glenn launches (edited 21 September 2026)", "url": "https://en.wikipedia.org/wiki/List_of_New_Glenn_launches" }, "caixin_ce7": { "name": "Caixin (Xinhua report), Chang'e 7 launch called off, 24 August 2026", "url": "https://companies.caixin.com/m/2026-08-24/102477229.html" }, "nsf_next_ce7": { "name": "Next Spaceflight, Chang'e 7 launch page (checked 4 October 2026)", "url": "https://nextspaceflight.com/launches/details/4723/" } }, "sources_checked": "4 October 2026 (the next launches, F-37 to F-39; other facts as dated in their sources)", "numbers": { "ss_v2_leo_t": 35, "f9_leo_t": 22.8 }, "race": { "note": "The race to Mars: the same steps for every rocket on the home page. Each value is the date it first happened; null means not yet; 'never' means the rocket is not built for it. Refilling comes before the Mars step because a Starship must refill in orbit before it can leave for Mars.", "steps": [ { "id": "fly", "label": "First flight" }, { "id": "orbit", "label": "Reached orbit" }, { "id": "reuse", "label": "Flew again" }, { "id": "refill", "label": "Refilled in orbit" }, { "id": "mars", "label": "Sent a mission to Mars" }, { "id": "crew", "label": "Carried people" } ], "rockets": { "starship": { "fly": "20 April 2023", "orbit": "28 September 2026", "reuse": "27 May 2025", "refill": null, "mars": null, "crew": null, "sources": [ "wiki_starship", "wiki_starship_reuse", "zu_f14" ] }, "new_glenn": { "fly": "16 January 2025", "orbit": "16 January 2025", "reuse": "19 April 2026", "refill": "never", "mars": "13 November 2025", "crew": "never", "sources": [ "wiki_newglenn" ] }, "long_march_5": { "fly": "3 November 2016", "orbit": "3 November 2016", "reuse": "never", "refill": "never", "mars": "23 July 2020", "crew": "never", "sources": [ "wiki_lm5", "wiki_tw3" ] } }, "details": { "starship": { "fly": { "text": "Flight 1 lifted off from Starbase in Texas: the biggest rocket ever launched. About 3 minutes in, the booster and ship failed to separate and it was destroyed.", "fact": "Its 33 engines push about twice as hard as the Saturn V that sent Apollo to the Moon. The launch smashed the concrete under the pad.", "sources": [ "wiki_starship" ], "punch": "The biggest rocket ever launched. It blew apart 3 minutes in." }, "orbit": { "text": "On Flight 14 a Version 3 Starship reached orbit for the first time, about 275 km up, and released 26 Starlink satellites.", "fact": "One engine shut down early, so SpaceX brought it home after about 3 hours instead of the planned 10. It splashed down in the Pacific, north of Hawaii.", "sources": [ "zu_f14" ], "punch": "Flight 14 finally made orbit, 275 km up, and dropped off 26 Starlinks." }, "reuse": { "text": "Flight 9 used Booster 14, the first Super Heavy booster to fly a second time.", "fact": "Starship's boosters fly back to the launch tower and are caught in mid-air by two giant mechanical arms. The first catch was on 13 October 2024.", "sources": [ "wiki_starship", "wiki_starship_reuse" ], "punch": "Booster 14 became the first Super Heavy to fly a second time." }, "refill": { "text": "Not tried yet. A Starship that reaches orbit has used almost all its fuel, so before it can leave for Mars, tanker Starships must fly up and fill it.", "fact": "Elon Musk has said a full refill takes about {musk_tankers} tanker launches for every ship going to Mars.", "sources": [ "aero_america", "spacedaily_refuel" ], "punch": "The make-or-break step: tankers must fill it up in orbit before Mars." }, "mars": { "text": "Not yet. {mars_role}", "fact": "Earth and Mars line up for the shortest trip only once every {window_months} months. Miss a window and the next ship waits more than two years.", "sources": [ "spacex_starship", "nasa_timeline" ], "punch": "Not yet. Mars only lines up once every {window_months} months." }, "crew": { "text": "No one has flown on Starship yet. It is the only rocket being built to carry people to Mars.", "fact": "On {moon_date} Elon Musk said SpaceX had shifted its focus to a city on the Moon first, with Mars to follow.", "sources": [ "nbc_2026", "spacepolicy_2026", "cnn_2026", "benzinga_2026" ], "punch": "Nobody yet, but it is the only rocket being built to fly people to Mars." } }, "new_glenn": { "fly": { "text": "New Glenn lifted off from Cape Canaveral in Florida and reached orbit on its very first launch, carrying Blue Origin's Blue Ring Pathfinder.", "fact": "It is named after John Glenn, the first American to orbit the Earth. The booster was lost while trying to land.", "sources": [ "wiki_newglenn" ], "punch": "Reached orbit on its very first launch, from Cape Canaveral." }, "orbit": { "text": "Orbit on the first try, with the upper stage and its cargo placed far above the Earth.", "fact": "Reaching orbit on a first flight is rare: Starship took 14 flights to get there.", "sources": [ "wiki_newglenn", "zu_f14" ], "punch": "First try. Starship needed 14 flights to get there." }, "reuse": { "text": "The booster that landed after the ESCAPADE launch flew again, the first New Glenn booster to be reused. A fault in the upper stage left that flight's satellite in the wrong orbit.", "fact": "New Glenn's boosters land on a ship at sea nicknamed Jacklyn. A month later, in May 2026, a New Glenn exploded on its pad during a test.", "sources": [ "wiki_newglenn", "wiki_ng_explosion" ], "punch": "A booster that landed on a ship at sea flew again." }, "refill": { "text": "New Glenn is not built to be refilled in space.", "fact": "Blue Origin's plans for people beyond Earth rest on a far bigger rocket, New Armstrong, which is still on paper.", "sources": [ "yahoo_blue_mars" ], "punch": "Not built for it. Blue Origin's bigger dreams rest on New Armstrong." }, "mars": { "text": "Launched NASA's twin ESCAPADE probes, Blue and Gold, which will study how Mars lost most of its air to space.", "fact": "They did not head straight for Mars. They wait about 1.6 million km from Earth until the window opens in late 2026, and arrive by September 2027.", "sources": [ "wiki_escapade" ], "punch": "Sent NASA's twin probes, Blue and Gold, on their way to Mars." }, "crew": { "text": "New Glenn is not built to carry people. Blue Origin flies passengers on New Shepard, a small rocket that hops above the edge of space.", "fact": "A New Shepard flight lasts about 10 minutes. Jeff Bezos flew on its first crewed flight, on 20 July 2021.", "sources": [ "wiki_new_shepard" ], "punch": "No seats. Blue Origin flies people on its small New Shepard." } }, "long_march_5": { "fly": { "text": "Lifted off from Wenchang, China's southernmost launch site, on the island of Hainan.", "fact": "In China its nickname is Pang Wu, \"Fat Five\", for its wide body.", "sources": [ "wiki_lm5" ], "punch": "\"Fat Five\" roared off China's tropical island of Hainan." }, "orbit": { "text": "Reached orbit on its first flight.", "fact": "Its second flight, in July 2017, failed because of a fault in one engine, and it did not fly again for 28 months.", "sources": [ "wiki_lm5" ], "punch": "Orbit first time. Then a failure grounded it for 28 months." }, "reuse": { "text": "Every Long March 5 is used once.", "fact": "Its four strap-on boosters fall away after about 3 minutes and are not recovered.", "sources": [ "wiki_lm5" ], "punch": "Used once. Its four boosters fall away and are never recovered." }, "refill": { "text": "Long March 5 is not built to be refilled in space.", "fact": "China's Mars sample-return mission, Tianwen-3, will use two separate Long March 5 launches instead.", "sources": [ "wiki_tw3" ], "punch": "Not built for it. Tianwen-3 will use two launches instead." }, "mars": { "text": "Launched Tianwen-1: an orbiter, a lander and the Zhurong rover.", "fact": "China became the first country to orbit, land and drive on Mars on its very first try. Zhurong landed on 14 May 2021.", "sources": [ "wiki_tianwen1" ], "punch": "Launched Tianwen-1: orbit, land and drive on Mars, all at the first try." }, "crew": { "text": "Long March 5 does not carry people. China flies its astronauts on the smaller Long March 2F.", "fact": "Yang Liwei became China's first person in space on a Long March 2F in 2003. China plans its first crews to Mars from 2033, on bigger rockets still to come.", "sources": [ "wiki_lm2f", "aljazeera_china_mars" ], "punch": "No people. China's astronauts ride the smaller Long March 2F." } } }, "details_note": "What the home page's race to Mars shows when a step is hovered or tapped: one or two plain sentences and one interesting fact each. {musk_tankers}, {window_months}, {moon_date} and {mars_role} are filled in on the page from this file (refuel, calendar, moon_shift, the rocket's mars_role), so no number is typed twice." } }, "01-05": { "file": "01-05", "title": "The Earth-Mars link", "folder": "01", "facts_file": "01-05-the-earth-mars-link.json", "version": "1.10", "status": "Active", "last_updated": "3 October 2026", "about": "Facts file for 01-05 The Earth-Mars link. The page is built from this file, the library catalogue and the page template. Change a fact here, then run build.py. Words in curly brackets, like {lt_max}, are filled in from the numbers in this file when the page is built, so each number is typed once. Numbers owned by other files (the orbit sizes and years, the launch window, the surface stay, the era plan, the Mars Telecommunications Network and its price, the Elizabeth Tower) are read live from 01-01, and era names from 00-01, never retyped here. Folder 01 may not lean on 02, so the speed of light and the closest and farthest distances are kept here as labelled copies of 02-01's numbers (see numbers.copies_of_02_01); they should be listed as sanctioned copies in file 00.", "one_line": "How the settlement talks to Earth: a chain of relay satellites and giant dishes, a delay of {lt_real_min} to {lt_real_max} minutes each way, a trickle of data, and a fortnight or more of silence every {window} months.", "shelf_life": "Fast-moving. MAVEN was declared lost in June 2026, the Mars Telecommunications Network contract is under protest until about mid-December 2026 (01-01 F-27), Odyssey is low on fuel, and laser links are moving from demonstration to service. Re-check the relay fleet, NASA's relay contract and any SpaceX or other company proposal by March 2027, and the Deep Space Network's load by September 2027.", "header": { "purpose": "Describe the link between the settlement and Earth: how far a signal travels and how long it takes, the chain of relays and dishes it passes through, how much data gets through, the lasers that will carry more, the solar conjunction blackout, the store-and-forward internet that copes with all this, and how the link grows and is shared in each era.", "why": "Every message home, every order for spare parts, every film, every piece of news and every medical second opinion goes through this link. It sets how alone the settlement is. Scenes about calling home, news day, emergencies and the blackout all need the same numbers.", "when": "Writing a scene with a message to or from Earth, a blackout, or a remote-control robot; planning what the settlement can download; sizing the local network (03-13); or checking a delay or data-rate number in another file.", "change": "Part One changes only with a citation. Part Two assumptions can be challenged one at a time. Edit this facts file, then run build.py.", "writing": "Every number is compared to something people know. Pictures first, short sentences, no walls of text." }, "sections": [ { "id": "1.1", "title": "The delay" }, { "id": "1.2", "title": "The relay chain" }, { "id": "1.3", "title": "How much gets through" }, { "id": "1.4", "title": "Lasers" }, { "id": "1.5", "title": "The next network" }, { "id": "1.6", "title": "The blackout" }, { "id": "1.7", "title": "An internet that waits" } ], "numbers": { "copies_of_02_01": { "note": "Labelled copies of numbers owned by 02-01 (numbers.comms.light_kms and numbers.comms.dist_mkm). Folder 01 may not quote 02 (00 L-03), so they are listed as sanctioned copies in file 00 (L-17) and build.py checks they still match.", "light_kms": 299792.458, "dist_mkm": [ 54.6, 401.4 ] }, "perse_delay_s": 682, "perse_edl_min": 7, "mars500_min": 20, "iss_delay_s": 50, "neemo_min": [ 5, 10 ], "hera_delay_s": 180, "hera_done": [ 1, 4 ], "uhf_mbps": 2, "pass_min": 8, "hga_kbps": 32, "cmd_kbit_day": 225, "cmd_kbps": [ 1, 2 ], "cmd_window_min": 15, "relay_launch": { "odyssey": 2001, "mex": 2003, "mro": 2005, "maven": 2013, "tgo": 2016 }, "relay_mb_day_2026": { "tgo": 2228.1, "mro": 850.6, "odyssey": 107.3 }, "relay_mb_day_to_2025": { "tgo": 1562.7, "maven": 897.5, "mro": 447.5, "odyssey": 170.4 }, "relay_sessions_week": 12, "relay_session_gbit": 1, "mro_mbps": 6, "mro_dish_m": 3, "mro_tbit_2010": 100, "dsn_sites": 3, "dsn_big_m": 70, "dsn_mid_m": 34, "dsn_start_year": 1958, "dsn_missions": 60, "dsn_over_pct": 40, "dsn_over_2030s_pct": 50, "dsn_short_hours": [ 8500, 15000 ], "dsn_hours_year": 77000, "dss23_date": "25 August 2026", "dss_new_planned": 6, "dss_project_year": 2009, "esa_dsa": 4, "esa_dsa_m": 35, "esa_nno3_eur_m": 62.3, "esa_cold_c": -263, "m4_bps": 8.333, "m4_year": 1965, "m4_photos": 22, "m4_hours_per_photo": 10, "netflix_fhd_mbps": 5, "netflix_4k_mbps": 15, "uk_line_mbps": 285, "uk_gb_month": 583, "dsoc_near": { "date": "11 December 2023", "mbps": 267, "mkm": 31 }, "dsoc_mid": { "date": "8 April 2024", "mbps": 25, "mkm": 226, "goal_mbps": 1 }, "dsoc_far": { "date": "June 2024", "mbps": 6.25, "max_mbps": 8.3, "mkm": 390 }, "dsoc_record_mmi": 307, "dsoc_passes": 65, "dsoc_tbit": 13.6, "dsoc_tele_cm": 22, "dsoc_laser_w": 4, "dsoc_vs_radio": [ 10, 100 ], "mtn_req": { "rtn_mbps": 1, "fwd_mbps": 0.1, "far_mkm": 400, "best_mbps": 100, "uhf_mbps": 2, "adv_mbps": 25, "store_tb": 10, "years": 5 }, "study_usd_k": [ 200, 300 ], "study_weeks": 12, "marslink_mbps": 4, "marslink_au": 1.5, "conjunctions": [ { "start": "2023-11-11", "end": "2023-11-25", "label": "11 to 25 November 2023" }, { "start": "2025-12-27", "end": "2026-01-20", "label": "27 December 2025 to 20 January 2026" } ], "dark_days": 2, "ascend": { "deg": [ 1, 2, 3, 10 ], "days": [ 2.9, 11.8, 19.6, 66.9 ], "l45_extra_min": 5 }, "cerf_year": 1998, "epoxi": { "year": 2008, "mkm": 32, "nodes": 10 }, "iss_dtn": "May 2016", "mcmurdo_people": 1000, "pole_rtt_ms": 750, "link_by_era_mbps": { "note": "Our assumption EL-03: the settlement's average link to Earth in each era, in megabits per second, averaged over the 26-month cycle. Not a fact.", "robots": [ 1, 100 ], "crew": [ 25, 250 ], "town": [ 100, 1000 ], "city": [ 1000, 10000 ] }, "film_hours": 2 }, "facts": [ { "id": "F-01", "section": "1.1", "text": "Radio and light travel at {c_kms} km a second. The number is exact, because the metre itself is defined by it.", "compare": "Nothing travels faster, so no better radio or laser can ever shorten the delay. Only a faster link, never a quicker one.", "sources": [ "nist_c" ] }, { "id": "F-02", "section": "1.1", "text": "Worked out from the average orbits (01-01's copies of the orbit sizes), Earth and Mars are {d_avg_min} to {d_avg_max} million km apart, so a signal takes {lt_avg_min} to {lt_avg_max} minutes one way. Both orbits are ovals, so the real extremes are {d_real_min} and {d_real_max} million km: {lt_real_min} to {lt_real_max} minutes.", "compare": "A question and its answer take {rt_min} to {rt_max} minutes at best. No live calls, ever.", "sources": [ "nasa_mrn", "nist_c", "nasa_marsfact" ] }, { "id": "F-03", "section": "1.1", "text": "When Perseverance landed on 18 February 2021, everything at Mars happened {perse_delay} before Earth heard of it. Entry, descent and landing took about {perse_edl} minutes.", "compare": "When the first signal of entry reached Earth, the rover had already been standing on Mars for about {perse_early} minutes.", "sources": [ "jpl_m2020_landing" ] }, { "id": "F-04", "section": "1.1", "text": "Mars500, the {mars500_days}-day mock Mars mission in a sealed building in Moscow (2010 to 2011, owned by 01-03 F-14), built a {mars500_min}-minute one-way delay into every exchange with its control centre.", "compare": "Every reply at least {mars500_rt} minutes away, for a year and a half.", "sources": [ "esa_mars500" ] }, { "id": "F-05", "section": "1.1", "text": "The only delay study flown in space (Kintz and others, 2016) gave three space station astronauts and their ground team a {iss_delay}-second one-way delay. Stress and frustration rose, tasks took longer, and the astronauts turned to each other instead of the ground.", "compare": "Mars's shortest delay is about {iss_x} times that test's.", "sources": [ "nasa_tm_delay" ] }, { "id": "F-06", "section": "1.1", "text": "In NASA's undersea NEEMO missions with {neemo_lo} to {neemo_hi} minute delays, crews preferred text and data to voice, because text does not interrupt. In a HERA study, with a {hera_s}-second delay only {hera_lo} message in 5 was completed, against {hera_hi} in 5 with none.", "compare": "On Mars the delay is {hera_x_lo} to {hera_x_hi} times HERA's {hera_s} seconds. Mars talk is written, like email.", "sources": [ "nasa_tm_delay" ] }, { "id": "F-07", "section": "1.2", "text": "Rovers send almost everything by a short UHF radio hop to a passing orbiter, at up to {uhf_mbps} Mbps. Each orbiter is in view of a rover for only about {pass_min} minutes at a time.", "compare": "A full pass at the top rate carries about {pass_mb} MB, the size of a few dozen phone photos.", "sources": [ "nasa_mrn", "wiki_msl" ] }, { "id": "F-08", "section": "1.2", "text": "A rover can also talk to Earth directly with its own small dish: Curiosity sends at up to {hga_kbps} kbit a second. Its orders usually go up this way, about {cmd_kbit} kbit a day at {cmd_lo} to {cmd_hi} kbit a second in a {cmd_min}-minute window.", "compare": "A day's orders are about {cmd_kb} KB: less than a short email with one small photo.", "sources": [ "wiki_msl" ] }, { "id": "F-09", "section": "1.2", "text": "The relay fleet in 2026 is four orbiters: NASA's Mars Odyssey (launched {l_ody}) and Mars Reconnaissance Orbiter ({l_mro}), and Europe's Mars Express ({l_mex}) and Trace Gas Orbiter ({l_tgo}). NASA's MAVEN ({l_mav}), the second-busiest relay, stopped answering on 6 December 2025 and was declared lost on 3 June 2026.", "compare": "Odyssey has been passing messages home for {ody_age} years. The whole Mars internet rests on four ageing science orbiters.", "sources": [ "nasa_mrn", "sciam_maven" ] }, { "id": "F-10", "section": "1.2", "text": "From February to May 2026 the fleet relayed on average {r_tgo} megabits a day through the Trace Gas Orbiter, {r_mro} through MRO and {r_ody} through Odyssey: about {relay_mb} megabits a day in all.", "compare": "About {relay_MB} MB a day from every lander and rover on Mars together: {film_pct}% of one {film_h}-hour film at Netflix's Full HD rate.", "sources": [ "nasa_mrn" ] }, { "id": "F-11", "section": "1.2", "text": "NASA says the relay network brings rover data home about {sessions} times a week, each time roughly {session_gbit} gigabit.", "compare": "Like a village post office with a dozen collections a week.", "sources": [ "nasa_mrn" ] }, { "id": "F-12", "section": "1.2", "text": "MRO's {mro_dish}-metre dish sends to Earth at up to {mro_mbps} Mbps. By March 2010 it had sent {mro_tbit} terabits, more than three times all other missions beyond the Moon put together.", "compare": "{mro_mbps} Mbps is a little more than Netflix asks for a Full HD film ({nf_fhd} Mbps), and only when Mars is close.", "sources": [ "jpl_mro_2010", "netflix" ] }, { "id": "F-13", "section": "1.2", "text": "NASA's Deep Space Network has {dsn_sites} sites spaced round the world: Goldstone in California, near Madrid and near Canberra. Before a spacecraft sets at one, the next can pick it up. Each site has one {dsn_big}-metre dish and several {dsn_mid}-metre dishes. Its forerunner began in January {dsn_year}.", "compare": "A {dsn_big} m dish is about {dish_tower_pct}% of the height of the Elizabeth Tower ({tower} m, 01-01).", "sources": [ "nasa_dsn" ] }, { "id": "F-14", "section": "1.2", "text": "In 2023 NASA's inspector general found the network oversubscribed: demand beat supply by about {dsn_over}% at times, heading for about {dsn_over30}% by the 2030s. Over five years missions got {short_lo} to {short_hi} fewer hours than they asked for. It serves about {dsn_missions} missions, and Perseverance is one of its biggest users.", "compare": "Like a phone line where nearly one call in three cannot get through at the busiest times.", "sources": [ "nasa_oig_2023" ] }, { "id": "F-15", "section": "1.2", "text": "A new {dsn_mid}-metre dish, DSS-23, opened at Goldstone on {dss23}. It is one of {dss_new} new dishes planned since {dss_year}.", "compare": "{dss_span} years after that plan began, it is still being built: Earth's end of the link grows slowly.", "sources": [ "nasa_dss23" ] }, { "id": "F-16", "section": "1.2", "text": "Europe runs its own deep space dishes. Its fourth {esa_m}-metre antenna, at New Norcia in Western Australia, was opened on 4 October 2025 for about €{esa_eur} million. Parts of its receiver are cooled to about {esa_c}°C to hear faint signals. Its dishes serve Mars Express and the Trace Gas Orbiter.", "compare": "Colder than anywhere on Mars, just to listen.", "sources": [ "sd_esa_nno3" ] }, { "id": "F-17", "section": "1.3", "text": "Mariner 4, the first spacecraft to photograph Mars, sent its pictures at {m4_bps} bits a second in {m4_year}. Each of its {m4_photos} photos took {m4_h} hours. Staff at JPL could not wait: they printed the first picture's numbers on strips and coloured them in by hand.", "compare": "MRO's top rate is about {mro_vs_m4} times faster. One Mariner 4 photo would now take a fraction of a second.", "sources": [ "nasa_mariner4", "jpl_mro_2010" ] }, { "id": "F-18", "section": "1.3", "text": "Netflix recommends {nf_fhd} Mbps for Full HD films and {nf_4k} Mbps for 4K.", "compare": "A {film_h}-hour Full HD film is about {film_gb} GB.", "sources": [ "netflix" ] }, { "id": "F-19", "section": "1.3", "text": "In July 2025 British home broadband lines averaged a top download speed of {uk_mbps} Mbps, and each connection used about {uk_gb} GB of data in the month.", "compare": "At the 2026 rate (F-10), the whole Mars relay fleet would need about {uk_years} years to carry one British home's month of data.", "sources": [ "ofcom_2025" ] }, { "id": "F-20", "section": "1.4", "text": "NASA's laser link on the Psyche probe (Deep Space Optical Communications) sent data at up to {dn_mbps} Mbps from {dn_mkm} million km on {dn_date}, including a 15-second ultra-high-definition video of a cat called Taters.", "compare": "{dn_x} times MRO's top radio rate, from about {dn_pct}% of the distance to Mars at its closest.", "sources": [ "wiki_dsoc", "jpl_dsoc_2024" ] }, { "id": "F-21", "section": "1.4", "text": "On {dm_date} the same laser sent {dm_mbps} Mbps from {dm_mkm} million km, where the goal had been {dm_goal} Mbps. NASA says laser links can be {dr_lo} to {dr_hi} times faster than the best deep space radio.", "compare": "{dm_mkm} million km is well inside Mars's range; {dm_mbps} Mbps is enough for a 4K film ({nf_4k} Mbps).", "sources": [ "jpl_dsoc_apr24" ] }, { "id": "F-22", "section": "1.4", "text": "At {df_mkm} million km, about Mars's farthest, it kept up {df_mbps} Mbps with bursts to {df_max} Mbps ({df_date}). It reached {rec_mmi} million miles in December 2024, and ended in September 2025 after {passes} passes and {tbit} terabits. Its telescope is {tele} cm wide and its laser {laser_w} watts.", "compare": "A {laser_w}-watt laser through a {tele} cm telescope carried more than MRO's best radio rate, from about as far as Mars ever gets.", "sources": [ "jpl_dsoc_2024", "jpl_dsoc_2025", "wiki_dsoc" ] }, { "id": "F-23", "section": "1.5", "text": "NASA's draft requirements for the Mars Telecommunications Network (March 2026) ask for at least {req_rtn} Mbps home and {req_fwd} Mbps out even at {req_far} million km, up to {req_best} Mbps when conditions are good, {req_uhf} Mbps by UHF and {req_adv} Mbps by newer links for each user on Mars, {req_tb} TB of storage, the Bundle Protocol (F-30) and {req_y} years of service.", "compare": "The worst-case floor is a sixth of MRO's best; the best case is enough for several 4K films at once.", "sources": [ "milaero_mtn" ] }, { "id": "F-24", "section": "1.5", "text": "In May 2024 NASA paid Blue Origin, Lockheed Martin and SpaceX ${st_lo},000 to ${st_hi},000 each for {st_w}-week studies of commercial Mars relays. SpaceNews expected SpaceX's study to use a version of its Starlink satellites.", "compare": "Pocket money beside the ${mtn_m} million later offered for the relay itself (01-01 F-27).", "sources": [ "spacenews_2024" ] }, { "id": "F-25", "section": "1.5", "text": "Company proposal: in November 2024 SpaceX's plan, 'Marslink', was shown in a NASA presentation: Starlink-based relays sending {ml_mbps} Mbps or more across {ml_au} times Earth's distance from the Sun. Musk called it a first step towards 'greater than petabit per second' between Earth and Mars.", "compare": "{ml_au} times Earth's distance from the Sun is about {ml_mkm} million km. A proposal, not built; a petabit a second is about {pb_x} British home lines.", "sources": [ "nbf_marslink", "spacenews_2024" ] }, { "id": "F-26", "section": "1.6", "text": "Worked out from the two planets' years (01-01), the Sun passes between Earth and Mars every {syn_d} days. Missions stop sending commands for two to three and a half weeks: {conj0}; {conj1}.", "compare": "Once every {syn_mo} months, a fortnight or more when nobody on Earth can give an order.", "sources": [ "jpl_conj_2023", "nasa_conj_2025" ] }, { "id": "F-27", "section": "1.6", "text": "The reason: hot, charged gas thrown out by the Sun's corona can scramble a radio signal, and a garbled command could make a spacecraft do something unexpected. For about {dark} days nothing gets through at all, while Mars is behind the Sun's disc.", "compare": "Messages still trickle home most days; the silence runs the other way.", "sources": [ "jpl_conj_2023" ] }, { "id": "F-28", "section": "1.6", "text": "A 2022 NASA study (McBrayer, Chai and Judd) found every crewed Mars mission meets one two-to-three-week disruption. How long depends on how close to the Sun a radio can work: about {a1} days within {g1}°, {a2} within {g2}°, {a3} within {g3}°. Long-stay crews meet it on Mars. A relay near a point 60° ahead of or behind Earth could avoid it, adding about {l45} minutes of delay.", "compare": "Planning around it is easy; living through it is the hard part.", "sources": [ "ntrs_ascend" ] }, { "id": "F-29", "section": "1.7", "text": "The internet expects an unbroken path from sender to receiver. Delay-Tolerant Networking does not: each stop holds the data until the next one is ready. NASA began it with internet pioneer Vint Cerf around {cerf}. In {ep_year} it was tested on the EPOXI spacecraft, {ep_mkm} million km away, with {ep_nodes} network stops, sending dozens of pictures.", "compare": "A post office, not a phone call: each sorting office keeps the parcel until the next van comes.", "sources": [ "sd_epoxi" ] }, { "id": "F-30", "section": "1.7", "text": "The space station has had a Delay-Tolerant Networking service since {iss_dtn}. Its standard, the Bundle Protocol, is what NASA now asks Mars relays to speak (F-23).", "compare": "Tested in orbit for a decade before Mars needs it.", "sources": [ "nasa_hdtn", "upi_2016" ] }, { "id": "F-31", "section": "1.7", "text": "Blog account by an Antarctic IT worker (2024): at McMurdo nearly {mc_people} people shared a few dozen megabits a second; at the South Pole there was internet only a few hours a day, when satellites rose above the horizon, with a round trip of about {pole_ms} milliseconds. 'Operational needs are aggressively prioritized, and the community soaks up whatever is left.' Apps with short time-outs simply failed.", "compare": "A Mars round trip is {pole_x_lo} to {pole_x_hi} times the South Pole's: software written for Earth breaks.", "sources": [ "brr_2024" ] } ], "assumptions": [ { "id": "EL-01", "confidence": "High", "text": "Nothing between Mars and Earth is live, in any era. People send messages, video letters and files, and read replies later. Voice calls, video calls and live games with Earth do not exist.", "why": "The delay is {lt_real_min} to {lt_real_max} minutes each way and cannot be shortened (F-01, F-02). Crews under delay prefer text (F-06), and the only delay test in space showed stress rising with even {iss_delay} seconds (F-05)." }, { "id": "EL-02", "confidence": "High", "text": "The link is a chain: antennas and laser terminals on the surface, relay satellites round Mars, and big dishes and telescopes on Earth, on sites spread round the world so one always faces Mars. Almost everything goes through the relays; the settlement can also talk to Earth directly, slowly, as a backup.", "why": "This is how every Mars lander works today (F-07, F-08, F-13). A relay overhead is closer and bigger than any dish a lander carries, and one Earth site cannot see Mars all day (F-13)." }, { "id": "EL-03", "confidence": "Low", "text": "The settlement's average link to Earth grows by era: {era_links}. It is fastest when Mars is close and slowest when it is far.", "why": "Robots First: shares relays like NASA's planned network, with a floor of {req_rtn} Mbps and a best of {req_best} (F-23). First crew: its own laser relays, as proven by Psyche at {dm_mbps} Mbps from {dm_mkm} million km with a {laser_w} W laser (F-21, F-22). First Town and the First Martian City: bigger lasers, telescopes and more relays, still far below the petabit a second SpaceX has talked about (F-25). The sizes are guesses; that it grows by factors of ten is firmer. A laser link carries far more when Mars is close (F-20, F-22)." }, { "id": "EL-04", "confidence": "Medium", "text": "The link is shared in a fixed order: safety and health first, then running the settlement (ships, the fuel plant, power), then science, then personal messages (each person has a daily allowance), and last a bulk feed of news, software, books and films sent in quiet hours. Nothing personal can push out a safety message.", "why": "The same order the Antarctic stations use: 'operational needs are aggressively prioritized' (F-31). At the low end of EL-03 a City dweller's equal share would be only about {city_share}% of what one British home uses in a day (F-19), before safety and operations take theirs. The council sets each person's equal allowance, and the safety officer decides what counts as safety (04-02-01 CR-14)." }, { "id": "EL-05", "confidence": "Medium", "text": "The settlement keeps its own copy of the parts of Earth's internet people use most: encyclopaedias, maps, manuals, news, software updates, books, music and films, refreshed by the bulk feed. A page that is not in the copy is ordered from Earth and arrives, at the earliest, one round trip later, often the next day.", "why": "A round trip of {rt_min} to {rt_max} minutes (F-02) and a shared, limited link (EL-03, EL-04) make browsing Earth live impossible. Delay-Tolerant Networking already stores and forwards (F-29, F-30), and South Pole apps with short time-outs failed (F-31)." }, { "id": "EL-06", "confidence": "Medium", "text": "Every {window} months the settlement plans for the blackout: no landings, launches or risky work while the Sun is between the planets, spare parts and medicines stocked beforehand, and messages queued to send afterwards. From the First Town on, a relay placed away from the Sun-Earth line (near one of the points 60° ahead of or behind Earth) keeps a thin link open, at the cost of a few extra minutes of delay.", "why": "Conjunctions are regular and predictable (F-26), last two to three weeks (F-26, F-28), and NASA's study names a relay near those points as a fix (F-28). The first crew's stay of about {stay} days is {stay_pct}% of one {window}-month cycle, so they live through one blackout on Mars (F-28, 01-01 F-33)." }, { "id": "EL-07", "confidence": "Medium", "text": "In the Robots First era the link carries one plan of work up to the robots each sol and their pictures and results down. Robots do the work on their own; nobody on Earth steers them live.", "why": "A joystick is useless with a delay of {lt_real_min} to {lt_real_max} minutes (F-02). Today's rovers get about {cmd_kbit} kbit of orders a day and send their results through relays (F-08, F-10)." }, { "id": "EL-08", "confidence": "Low", "text": "Every screen in the settlement shows two small numbers: the current one-way delay to Earth, and the days until the next blackout. People plan a message home by them.", "why": "Both change slowly and predictably over each cycle (F-02, F-26), and everyone needs them. A story choice that makes the distance visible." }, { "id": "EL-09", "confidence": "Medium", "text": "Earth's end grows too. At first the settlement buys time on NASA's and Europe's dishes. By the First Town it has its own receiving stations, radio dishes and laser telescopes on three continents, so one always faces Mars.", "why": "NASA's network is already oversubscribed and new dishes arrive slowly (F-14, F-15); Europe runs its own (F-16). Laser links need large telescopes on the ground, as Psyche's did (F-20). Three sites spaced round the world is the pattern that works (F-13)." }, { "id": "EL-10", "confidence": "Low", "text": "On Mars, the link's dishes and laser terminals stand on the surface in a fenced antenna field outside the buried town, pointing at the sky, with spares, and the town can switch to a direct slow link to Earth if every relay fails.", "why": "Antennas must see the sky and the relays (EL-02); a direct link is the backup today's rovers keep (F-08). Where exactly they stand is now 03-13 LC-13 (the antenna field) and 04-01-01 FC-08 (its place on the map); the local network is 03-13.", "moves_to": "" } ], "links": { "leans_on": [ { "ref": "00", "why": "Library rules: folders, IDs, facts versus assumptions, sanctioned copies" }, { "ref": "00-01", "why": "Era names and their order (read live)" }, { "ref": "01-01 calendar", "why": "Orbit sizes and years (sanctioned copies of 02-01) for the delay and the conjunction cycle; the 26-month window (read live)" }, { "ref": "01-01 F-27", "why": "The Mars Telecommunications Network and its price, quoted (read live)" }, { "ref": "01-01 F-33", "why": "About 500 days on the surface, so the first crew lives through a blackout (read live)" }, { "ref": "01-01 E-12", "why": "People in each era, for the link per person (read live)" }, { "ref": "01-01 comparisons", "why": "The Elizabeth Tower yardstick and days per month (read live)" }, { "ref": "01-03 F-14", "why": "Mars-500's length, for F-04 (read live)" } ], "used_by": [ { "ref": "05-10", "why": "The signal delay to Earth, for the photo-of-Earth pin in the Stand in Jezero viewer" }, { "ref": "02-01 Physical constraints", "why": "Reads F-26: the conjunction dates and pause lengths, for 02-01 F-40 (read live)" }, { "ref": "03-13 Local communications", "why": "Reads F-07, F-18, F-19 and EL-03 (read live); cites F-09, EL-05, EL-07 and EL-08; places EL-10's dishes and laser terminals in its antenna field (LC-13)" }, { "ref": "04-02-01 How the city is run", "why": "Sets each person's daily allowance, in EL-04's order (CR-14)" }, { "ref": "03-14 Medical bay", "why": "Reads F-26: the blackout dates (read live). Cites EL-04 (health messages go first) and EL-06 (planning for the blackout)" }, { "ref": "04-01-02 The lava-tube outpost", "why": "Cites EL-02: relay orbiters carry all the outpost's long-distance traffic (LT-09)" }, { "ref": "04-02-02 Money and trade", "why": "Reads EL-03: the link to Earth by era, the pipe for data exports (read live)" }, { "ref": "04-03-01", "why": "The calendar and festivals: the solar blackout's dates and length (F-26, F-27), and the settlement's blackout plan and screens (EL-06, EL-07, EL-08), read live" }, { "ref": "04-03-03 Language and culture", "why": "F-02: the light delay to Earth (worked out live from 02-01's distances); EL-01: nothing live with Earth (LG-13); EL-05: the local copy of Earth's media (LG-13); EL-06: the blackout, 'going dark' (LG-04); EL-08: the delay on every screen, 'the lag' (LG-04)" }, { "ref": "04-04-02 A day in the life", "why": "EL-01: nothing is live: messages, not calls; EL-04: the order of traffic on the link and the daily allowance; EL-06: the blackout and the queue; EL-07: one plan a sol in the Robots First era; EL-08: screens show the delay" }, { "ref": "04-04-03 Safety and emergencies", "why": "EL-06: the blackout and how the town prepares for it (SE-12)" }, { "ref": "04-05-01 Characters", "why": "EL-04: the order the Earth link is shared in: Anand's night shift" }, { "ref": "04-05-02 Arrival day", "why": "EL-01: nothing is live; messages, not calls; EL-04: the link's order and each person's daily allowance" }, { "ref": "05-04 Missions", "why": "Nothing is live (EL-01), the uplink window and the delay studies (F-04, F-05, F-08, read live)" }, { "ref": "05-05 The Q&A guide", "why": "The one-way delay worked out from the speed of light (F-01, F-02), cited in the 'Ask Earth' answer" }, { "ref": "03-16", "why": "The delay, the conjunction break, the bulk feed and the town's copy of Earth's internet (F-02, F-28, EL-04, EL-05)" }, { "ref": "05-20", "why": "Mars games: mariner 4's photo time and Perseverance's signal delay, for the Mars Quiz (worked_out)" } ] }, "open_questions": [], "changes": [ "25 September 2026 (v1.0): Written. The light delay worked out from 01-01's orbit sizes, the relay chain from rover to Deep Space Network, how much data gets through, laser links, the next relay network, the solar conjunction blackout, Delay-Tolerant Networking and the link by era, with 31 sourced facts and 10 assumptions (EL-01 to EL-10). The Mars Telecommunications Network is quoted from 01-01 F-27, not retyped.", "25 September 2026 (v1.0): Keeps labelled copies of 02-01's speed of light and closest and farthest distances (numbers.copies_of_02_01), because folder 01 may not quote 02. To be listed as sanctioned copies in file 00.", "25 September 2026 (v1.1): Independent check. MAVEN's loss, DSS-23 (25 August 2026), NASA's March 2026 draft relay requirements, the relay volumes, the Deep Space Network audit, the Psyche laser results, the conjunction dates and the delay studies all confirmed at their sources. F-09 now gives MAVEN's exact dates (last signal 6 December 2025, declared lost 3 June 2026). F-24 now says SpaceX's Starlink-based study was SpaceNews's expectation, as the source words it. The sanctioned copies of 02-01's numbers are still not listed in file 00.", "26 September 2026 (v1.2): Mars-500 length is now read live from 01-03, which owns it (01-03 F-14): F-04 cites it and the copies (mars500_days, mars500_years) are removed; 01-03 added to quotes and leans_on. The labelled copies of 02-01 (light speed, Earth-Mars distances) are now listed as sanctioned copies in file 00, and the note says so. F-26 conjunction dates are now quoted by 02-01 F-40. used_by lists 02-01, which reads F-26.", "26 September 2026 (v1.3): Two open questions deleted as answered: where the dishes stand and how the town's network works (03-13 LC-13 and LC-01 to LC-04), and who sets each person's allowance (04-02-01 CR-14). EL-04 cites CR-14. used_by: 03-13 and 04-02-01 lose \"(planned)\" and say what they read; adds 03-14 and 04-01-02.", "26 September 2026 (v1.4): used_by adds 04-02-02 Money and trade (reads EL-03 live); the 04-04-02 and 04-04-03 lines are no longer marked planned.", "26 September 2026 (v1.5): Open questions deleted as answered: a message home and the blackout as lived (04-04-02 DL-08) and an emergency during the blackout (04-04-03 SE-12). used_by: back-links for 04-03-01, 04-03-03, 04-04-02, 04-04-03, 04-05-01, 04-05-02 (what each reads, from its leans_on). Also back-links for 05-04, 05-05 (wave 6 pages, from their leans_on as written today).", "26 September 2026 (v1.6): Beauty pass: a new opening picture, a dish at dusk on Mars aimed at Earth as the evening star, labelled as art.", "26 September 2026 (v1.7): Final fix round: EL-10: the placement has moved to 03-13 LC-13, so moves_to is cleared and the dishes stand in a fenced antenna field outside the town, not 'a short walk' from it. The delay chart and era table give the Earth-Mars cycle as about 26 months, the figure the library plans with (00-04)", "28 September 2026 (v1.8): Used by the Stand in Jezero viewer (05-10).", "1 October 2026 (v1.9): used_by adds 03-16, the new pages on computing and on needing nothing from Earth.", "3 October 2026 (v1.10): Era names follow the owner's new names (00-01): Mars Today, Robots First, First Town, Many Cities; First Human Landing and The First Martian City, Arcadia, where an era is named as such." ], "sources": { "nist_c": { "name": "NIST, CODATA value: speed of light in vacuum (exact), 2022", "url": "https://physics.nist.gov/cgi-bin/cuu/Value?c" }, "nasa_marsfact": { "name": "NASA NSSDCA, Mars Fact Sheet (accessed September 2026)", "url": "https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html" }, "nasa_mrn": { "name": "NASA Science, Mars Relay Network, 2025, updated 5 June 2026", "url": "https://science.nasa.gov/mars/mars-relay-network/" }, "jpl_m2020_landing": { "name": "NASA JPL, Mars 2020 Perseverance landing press kit: mission overview, 2021", "url": "https://www.jpl.nasa.gov/news/press_kits/mars_2020/landing/mission/" }, "esa_mars500": { "name": "ESA, Mars500: study overview, 2011", "url": "https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Mars500/Mars500_study_overview" }, "nasa_tm_delay": { "name": "NASA, Assessment of the state of communication delay research, Technical Memorandum 20250003885, 2025", "url": "https://ntrs.nasa.gov/api/citations/20250003885/downloads/NASA%20TM20250003885.pdf" }, "wiki_msl": { "name": "Wikipedia, Mars Science Laboratory: communications (accessed September 2026)", "url": "https://en.wikipedia.org/wiki/Mars_Science_Laboratory" }, "sciam_maven": { "name": "Scientific American, NASA's Mars mission MAVEN is lost forever, June 2026", "url": "https://www.scientificamerican.com/article/nasas-mars-mission-maven-is-lost-forever/" }, "jpl_mro_2010": { "name": "NASA JPL, NASA Mars orbiter speeds past data milestone, 3 March 2010", "url": "https://www.jpl.nasa.gov/news/nasa-mars-orbiter-speeds-past-data-milestone/" }, "netflix": { "name": "Netflix Help Center, Netflix-recommended internet speeds (accessed September 2026)", "url": "https://help.netflix.com/en/node/306" }, "nasa_dsn": { "name": "NASA, Deep Space Network, updated 16 June 2026", "url": "https://www.nasa.gov/communicating-with-missions/dsn/" }, "nasa_oig_2023": { "name": "NASA Office of Inspector General, Audit of NASA's Deep Space Network (IG-23-016), 12 July 2023", "url": "https://oig.nasa.gov/wp-content/uploads/2023/12/ig-23-016.pdf" }, "nasa_dss23": { "name": "NASA Science, NASA Deep Space Network's new Goldstone antenna goes online, August 2026", "url": "https://science.nasa.gov/photojournal/nasa-deep-space-networks-new-goldstone-antenna-goes-online/" }, "sd_esa_nno3": { "name": "ScienceDaily (ESA release), ESA's new super antenna in Australia, 6 October 2025", "url": "https://www.sciencedaily.com/releases/2025/10/251006051109.htm" }, "nasa_mariner4": { "name": "NASA History, 55 years ago: Mariner 4 first to explore Mars, 2020", "url": "https://www.nasa.gov/history/55-years-ago-mariner-4-first-to-explore-mars/" }, "ofcom_2025": { "name": "Ofcom, Connected Nations UK report 2025, 19 November 2025", "url": "https://www.ofcom.org.uk/siteassets/resources/documents/research-and-data/multi-sector/infrastructure-research/connected-nations-2025/connected-nations-uk-report-2025.pdf" }, "wiki_dsoc": { "name": "Wikipedia, Deep Space Optical Communications (accessed September 2026)", "url": "https://en.wikipedia.org/wiki/Deep_Space_Optical_Communications" }, "jpl_dsoc_2024": { "name": "NASA JPL, NASA's laser comms demo makes deep space record, completes first phase, 2024", "url": "https://www.jpl.nasa.gov/news/nasas-laser-comms-demo-makes-deep-space-record-completes-first-phase/" }, "jpl_dsoc_apr24": { "name": "NASA JPL, NASA's optical comms demo transmits data over 140 million miles, April 2024", "url": "https://www.jpl.nasa.gov/news/nasas-optical-comms-demo-transmits-data-over-140-million-miles/" }, "jpl_dsoc_2025": { "name": "NASA JPL, NASA's deep space communications demo exceeds project expectations, 18 September 2025", "url": "https://www.jpl.nasa.gov/news/nasas-deep-space-communications-demo-exceeds-project-expectations/" }, "milaero_mtn": { "name": "Military and Aerospace Electronics, NASA outlines requirements for Mars Telecommunications Network spacecraft, 5 March 2026", "url": "https://www.militaryaerospace.com/communications/news/55361810/nasa-outlines-requirements-for-high-performance-mars-telecommunications-network-spacecraft" }, "spacenews_2024": { "name": "SpaceNews, NASA awards studies for commercial Mars missions, May 2024", "url": "https://spacenews.com/nasa-awards-studies-for-commercial-mars-missions/" }, "nbf_marslink": { "name": "NextBigFuture (blog), SpaceX will create Marslink as a first step for Earth-Mars communication, 8 November 2024", "url": "https://www.nextbigfuture.com/2024/11/spacex-will-create-marslink-as-a-first-step-for-earth-mars-communication.html" }, "jpl_conj_2023": { "name": "NASA JPL, NASA's Mars fleet will still conduct science while lying low, 10 November 2023", "url": "https://www.jpl.nasa.gov/news/nasas-mars-fleet-will-still-conduct-science-while-lying-low/" }, "nasa_conj_2025": { "name": "NASA Science, Curiosity blog, sols 4750 to 4762: See you on the other side of the Sun, 22 December 2025", "url": "https://science.nasa.gov/blog/curiosity-blog-sols-4750-4762-see-you-on-the-other-side-of-the-sun/" }, "ntrs_ascend": { "name": "McBrayer, Chai and Judd, Communication delays, disruptions and blackouts for crewed Mars missions, NASA (AIAA ASCEND), 2022", "url": "https://ntrs.nasa.gov/api/citations/20220013418/downloads/ASCEND-Communication%20Delays,%20Disruptions,%20and%20Blackouts%20for%20Crewed%20Mars%20Missions.pdf" }, "sd_epoxi": { "name": "ScienceDaily (NASA release), NASA tests first deep-space internet, 19 November 2008", "url": "https://www.sciencedaily.com/releases/2008/11/081118160432.htm" }, "nasa_hdtn": { "name": "NASA Glenn, High-Rate Delay Tolerant Networking, 2025", "url": "https://www.nasa.gov/glenn/glenn-expertise-space-exploration/scan/high-rate-delay-tolerant-networking/" }, "upi_2016": { "name": "UPI, NASA reveals solar system internet for interplanetary communication, 28 June 2016", "url": "https://www.upi.com/Science_News/2016/06/28/NASA-reveals-solar-system-Internet-for-interplanetary-communication/4191467120455/" }, "brr_2024": { "name": "brr.fyi (blog by an Antarctic station IT worker), Engineering for slow internet, 30 May 2024", "url": "https://brr.fyi/posts/engineering-for-slow-internet" } }, "sources_checked": "25 September 2026" }, "03-06": { "file": "03-06", "title": "Habitats", "folder": "03", "facts_file": "03-06-habitats.json", "version": "1.22", "status": "Active", "last_updated": "11 October 2026", "about": "Facts file for 03-06 Habitats. The page is built from this file, the library catalogue and the page template. Change a fact here, then run build.py. Words in curly brackets, like {cover}, are filled in from the numbers in this file, or from other files, when the page is built, so each number is typed once. Numbers owned by other files (the era plan and people per era, era names, NASA's volume minimum and the station's volume, Starship's claimed cabin, Mars-500's chamber, gravity, sea-level pressure, the surface dose and how soil shields it, the dose ceiling in the town, the cabin pressure, the refuge days, the pad distance, the ice depth at the site) are read live from 00-01, 01-01, 01-02, 01-03, 02-01, 02-05, 02-06, 03-02 and 03-09, never retyped here.", "one_line": "How the buried town is built and what it is like inside: why it is under 3 m of soil, why the air pushes up harder than the soil pushes down, the kinds of home from landed ship to steel vault, how much room each person gets in each era, and the light, sound, privacy, fire and storm rules that make it livable.", "shelf_life": "Inflatable habitats are being tested every year (Sierra Space's burst tests, BEAM still on the space station) and NASA revises its habitability standard (NASA-STD-3001) every few years. SpaceX has published no Mars habitat design. No published study gives the radiation dose under exactly 3 m of ice-rich soil. Re-check BEAM's status, inflatable burst tests, NASA's volume guidance, any SpaceX habitat plan and any new subsurface dose model by September 2027.", "header": { "purpose": "Describe how the settlement's living spaces are built and what they are like inside: the burial depth and why, the pressure the walls must hold, the kinds of module in each era, room per person, the layout of a home vault, light, noise, privacy, fire and leak sections, the storm shelter, the viewing rooms and periscopes, and how many habitats each era needs.", "why": "People spend almost all of their lives inside these walls. The habitat sets the radiation dose, the feel of every indoor scene, the shape of the town seen from above (almost nothing, because it is buried) and much of the cargo list. If it is vague, every home, hall and emergency scene is vague.", "when": "Placing or drawing the town in 3D, writing any indoor scene, sizing air, water or power per person, checking a dose, or deciding what a first-crew, early-town or city home looks like.", "change": "Part One changes only with a citation. Part Two assumptions can be challenged one at a time. Airlocks belong to 03-07, the air and water machines to 03-09, farms to 03-10, digging and bricks to 03-11 and the city map to 04-01-01. Edit this facts file, then run build.py.", "writing": "Every number is compared to something people know. Pictures first, short sentences, no walls of text." }, "comparisons": { "about": "Yardsticks used only to compare. Others (a person's height, a storey, a tennis court, standard gravity) are read from 02-01, 01-03 and 01-02.", "tonne_kg": 1000 }, "numbers": { "cover_m": 3, "cover_note": "Burial depth of every living space, from the top of the pressure shell to the surface. 02-01 S-18 chose 3 m and said the depth moves to this file; HA-01 now owns it.", "soil_kg_m3": [ 1200, 1600 ], "ring": { "d_m": 9, "h_m": 1.83, "t_mm": 3.97, "density_t_m3": 8.0, "density_note": "Stainless steel weighs about 8 t per cubic metre (Wikipedia, SAE 304 stainless steel), used only for HA-03's rough shell mass." }, "ss304_mpa": [ 210, 1050 ], "beam": { "launch": "8 April 2016", "expand": "28 May 2016", "hours": 7, "bursts": 25, "burst_s": 147, "kg": 1413, "l_m": 4.01, "d_m": 3.23, "m3": 16, "nasa_owns": "December 2021", "test_years": 2, "grow_cm": 170 }, "transhab": { "d_m": 8.2, "packed_d_m": 4.3, "l_m": 11, "m3": 339.8, "kg": 13154, "floors": 4, "ban_year": 2000 }, "b330_m3": 330, "genesis_years": [ 2006, 2007 ], "bigelow_staff": 88, "cohen_lighter_pct": [ 30, 50 ], "cohen_year": 1997, "sierra": { "margin_pct": 27, "year": 2024 }, "ice_house": { "year": 2015, "light_pct": 50, "people": [ 2, 4 ] }, "hab_challenge": { "usd": 2061023, "years": [ 2015, 2019 ] }, "spacex": { "domes_year": 2012, "ships_year": 2018 }, "nhv_cq_m3": 5.4, "iss_cq_m3": 2.1, "nhv_areas": 7, "cq_test": { "l_m": 2, "h_m": 0.85, "w_m": 0.9, "people": 8, "days": 11, "year": 2021 }, "m500_module": { "d_m": 3.6, "l_m": 20, "cabins": 6, "cabin_m2": 3 }, "nakagin": { "year": 1972, "capsules": 140, "dims_m": [ 2.5, 2.5, 4.0 ], "window_m": 1.3, "demolished": 2022 }, "capsule_inn_year": 1979, "uk_min_m2": { "shower": 37, "bath": 39, "year": 2015 }, "b2": { "m2": 12700, "years": [ 1991, 1993 ] }, "ohio": { "officers": 15, "enlisted": 140, "patrol_days": [ 70, 90 ], "per_bunk": [ 2, 3 ] }, "pole": { "year": 2008, "m2": 7400, "summer": 150, "winter": [ 39, 50 ], "snow_cm": 20 }, "halley": { "year": 2013, "modules": 8, "moved_km": 23, "moved_year": 2017 }, "cq_acoustic": { "vol_pct": 13, "mass_pct": 6, "nc": 40 }, "spektr_year": 1997, "permafrost": { "pile_m": 15, "gravel_m": [ 1, 2 ], "damaged_pct": 80, "year": 2022 }, "m3_per_person": { "value": 120, "first_crew": 50, "town": 80, "source": "HA-04", "note": "Habitable living space per person, not counting farms, workshops, machine rooms or airlocks. 'value' is the City (the world we show); 'first_crew' and 'town' are the earlier eras. 03-09 reads this for air volume per person." }, "hab_share": 0.6, "hab_share_note": "Share of a module's pressurised volume that is living space (HA-03). The space station's share is read live from 01-02.", "vault": { "d_m": 9, "l_m": 50, "sections": 4, "floor_below_centre_m": 2.25, "floor_note": "How far the floor sits below the shell's centre line (HA-03): a quarter of the diameter, so the floor is about 7.8 m wide where it meets the shell and the room is about 6.75 m tall in the middle. 03-10 reads it for the farm racks (GF-15) and the city viewer for its floors." }, "private_m3": { "crew": 9, "town": 20, "city": 60 }, "viewing_h_per_sol": 1, "section_exits": 2, "cover_deep_m": 5, "cover_deep_note": "Cover over the deep family rows (HA-13): the trench is cut 2 m deeper into frozen ground, so the mound on top, and the spacing of the rows, stay the same.", "look": { "from": "HA-16", "about": "How Arcadia City's homes look, so every picture, film and 3D scene draws the same places (00-05 ST-20). Sizes are our design unless a fact or assumption is named; they pass the glance test within about a quarter. Shown in The First Martian City unless a part says otherwise.", "words": { "cover": "03-06:numbers.cover_m", "vd": "03-06:numbers.vault.d_m", "vl": "03-06:numbers.vault.l_m", "roof": "03-10:worked_out.roof_water_m" }, "places": { "rows": { "name": "The buried rows", "outside": "Long, low, rounded mounds of rust-red soil about {vl} m long, in parallel rows, each over a steel vault {vd} m across under {cover} m of soil (HA-01, HA-03). Along each mound's crest stand skylight wells: a raised white collar with a glass cap over a mirror-lined shaft. At each end an entrance porch: a printed airlock with a lamp, a small window, and a canopy over a grille where you stamp and brush dust off a suit that is already sealed (03-07). No spare suit hangs in the open. Graded paths with boot prints between the rows. Close up the mound is never smooth: lumpy, sandbag-like soil with stones in it, wind ripples and boot paths, the skylight collars standing on low steel rims with a hinged dust cover and a bolted glass dome.", "inside": "A round steel vault: the floor about 7.8 m wide where it meets the curved shell and about 6.75 m tall in the middle (numbers.vault). Just inside the hatch, still in the row's air, the suit room holds the rack of spare suits (03-07): you dress there and seal the helmet before the outer door opens. Beyond it, white and warm-wood panels, soft white light, daylight falling from a skylight well, screens and periscopes showing the sky outside (HA-08), doors into private rooms down both sides (HA-06). Quiet, curved and well lit. Down the middle a street of wooden boards with a long runner, trees in round planters under each skylight well where the daylight falls, benches, and string lights crossing the ceiling; the homes' fronts face each other along both sides, each with its door, a lit window, a house plate and a pot by the door, and a terrace with plants on its roof." }, "domes": { "name": "The dome neighbourhoods", "outside": "A great glass dome on a low sealed rim, its roof two skins of glass holding about {roof} m of water that glows deep blue (03-10 GF-17, HA-14), white printed homes visible through it, joined to the buried town by a tunnel (HA-15). The dome stands on a heavy foundation ring wall of printed soil about 1.5 m tall, with an earth berm heaped against it outside; its glass is carried by a triangulated frame of slim white struts, and its walk-in locks (03-07 AD-13) stand out from the ring wall.", "inside": "One- and two-storey homes printed from Mars soil, soft curves with fine ribbed print lines, flat roofs used as terraces and roof gardens, big windows, in a ring round a small square or park with paved streets of pressed soil and lamps (HA-15). People in everyday clothes. Light comes through the water roof softened and moving, rippling across walls and paving like light under a shallow sea. In The First Martian City the first dome is still filling: some plots empty, a home being printed (HA-15). Close up the homes show their printed layers, deep-set window and door frames, sills, door numbers, lamps by the doors and the clutter of living: pots, bikes, boots by the door, chalk on the paving." }, "your_room": { "name": "Your room", "inside": "A small bedroom at the back of a home in the first dome, its big window looking out over the plain to the ship: a low wooden bed with a white duvet and a rust-coloured throw, a bedside table with a lamp, a tall plant, a wall shelf with books and a photograph of Earth, a wall screen saying good morning. Soft light from the window, warm from the lamp." } }, "palette": { "printed_wall": "#D9A07A", "white": "#F4F2EE", "graphite": "#2E2C31", "coral": "#E0825E", "warm_wood": "#B98A5E", "water_roof": "#3F8FC9", "soil": "#B4643C", "lamp": "#FFD9A8" }, "light": "Outside: butterscotch sky by day, blue round the Sun at dusk (02-07 F-02), skylight collars and porch lamps glowing warm, the domes glowing blue from within. Inside the domes: daylight through the water roof, blue and moving, warm lamps at dusk.", "eras": { "city": "Mostly buried rows; the first dome neighbourhood, still filling up (HA-14, HA-15).", "far": "About half the people under three full domes with grown trees, a park and a lake; the buried rows remain for families with young children (HA-14)." }, "never": [ "Windows in a buried row's walls (only skylight wells and periscopes, HA-08)", "Homes standing in the open air outside a dome, or a dome without its water roof", "Soil heaped straight on a home with no shell under it (HA-02)", "Pitched roofs, chimneys or gutters: it never rains", "Brass, copper or old-fashioned gauges and lamps", "A blue daytime sky, snow, rain or puddles outside", "Anyone outside without a suit, or working outside alone (03-08 SS-05)", "People posed for the camera or staring at it", "A smooth, perfect mound or a dome rising straight out of bare ground with no ring wall" ], "shots": [ { "id": "two_ways", "name": "Two ways to live, at dusk", "frame": "From the plain at dusk: the buried rows' long mounds in front, skylight collars and porch lamps glowing warm, a suited person walking to a porch; behind them the first dome neighbourhood glowing blue through its water roof, printed homes and terraces visible inside, the sky blue round the setting Sun." }, { "id": "square", "name": "The square under the water roof", "frame": "Inside a dome at street level: printed homes round a small square, roof gardens, people in everyday clothes, rippling blue light on the paving." }, { "id": "row", "name": "Inside a row", "frame": "Down the length of a vault: warm panels, doors either side, a shaft of daylight from a skylight well." }, { "id": "cut_row", "name": "Two ways to live, with a row cut open", "frame": "The two_ways shot at dusk, with the nearest buried row sliced open crosswise near its front end: the round steel vault mostly below ground level, a thick band of soil over its top about a third of the vault's width, a skylight shaft rising through the soil to its collar, and inside a warm room with a wooden floor a little below the middle of the circle and people at a table, small against the room. Used for How Arcadia does it, where the room under the soil is otherwise out of sight." } ], "open": [], "weathering": "Everything outside wears the plain: red dust banked against its foot and settled on every upward face, paler wind streaks running down from edges and bolt heads, thin dark panel seams, and scuffs where boots, hands and wheels touch. Dust is finer and lighter on what is cleaned often (hatches, grilles), heavy on what is not (radiators' feet, tank legs). Inside the domes things are clean but lived in." } }, "sections": [ { "id": "1.1", "title": "Why bury it, and how deep" }, { "id": "1.2", "title": "The push from inside" }, { "id": "1.3", "title": "Kinds of home" }, { "id": "1.4", "title": "Room to live" }, { "id": "1.5", "title": "Inside: light, sound and privacy" }, { "id": "1.6", "title": "Fire, leaks and storms" }, { "id": "1.7", "title": "Standing on ice" } ], "facts": [ { "id": "F-01", "section": "1.1", "owner": "02-01", "text": "Curiosity measured about {surf_day} mSv a day on the open surface (02-01 F-25). Soil shields, but a thin layer makes things worse at first: a model puts the dose peak about {peak_cm} cm down, and finds about {sh_lo} to {sh_hi} m of soil brings the yearly dose below {sh_target} mSv (02-01 F-28).", "compare": "About {surf_year} mSv a year in the open: {surf_uk_x} times the UK limit for a radiation worker ({uk_lim} mSv). A shallow covering is worse than none.", "sources": [ "hassler_2014", "zhang_2022" ] }, { "id": "F-02", "section": "1.1", "text": "A NASA study of radiation shielding on Mars (Slaba, Mertens and Blattnig, 2013) found that shielding with local soil 'will also be of little help unless several hundred g/cm² of regolith is utilized'.", "compare": "g/cm² is mass above each square centimetre. {cover} m of soil at Viking's densities (F-03) is {ad_lo} to {ad_hi} g/cm²: several hundred, as the study asks.", "sources": [ "slaba_2013" ] }, { "id": "F-03", "section": "1.1", "text": "The Viking landers' arms measured Mars soil at their sites: loose drift material with a bulk density of about {rho_lo} kg/m³, blocky, crusted material of about {rho_hi} kg/m³ (Moore and others, US Geological Survey, 1987).", "compare": "A cubic metre of Mars soil holds {rho_lo_t} to {rho_hi_t} t of mass, but in Mars gravity it weighs what {w_lo} to {w_hi} kg weighs on Earth: about {w_people} adults' worth.", "sources": [ "usgs_1987" ] }, { "id": "F-04", "section": "1.2", "text": "In a thin-walled cylinder, the stress that tries to split the wall along its length (the hoop stress) is the pressure times the radius, divided by the wall's thickness: σ = P r / t.", "compare": "Twice the width needs twice the wall for the same pressure. Wide halls cost steel; narrow tubes are cheap.", "sources": [ "wiki_cylinder" ] }, { "id": "F-05", "section": "1.2", "text": "Starship is built from rolls of 301 stainless steel, unrolled, cut and welded into rings {ring_d} m across, {ring_h} m tall and {ring_t} mm thick.", "compare": "A steel skin under 4 mm thick holds a rocket's tanks. At the town's {cabin} kPa (03-09) a ring like that works its steel at about {ring_mpa} MPa (F-04).", "sources": [ "wiki_starship_ship" ] }, { "id": "F-06", "section": "1.2", "text": "Type 304 stainless steel, a close relative, has a yield strength (the stress at which it starts to stretch for good) from {ss_lo} MPa, when annealed and at its weakest, up to {ss_hi} MPa fully hardened.", "compare": "{ring_mpa} MPa is about {ring_pct}% of the weakest figure. Holding air in is easy for steel. The hard parts are joints, seals, hatches and cold.", "sources": [ "wiki_304" ] }, { "id": "F-07", "section": "1.3", "text": "BEAM, an inflatable room built by Bigelow Aerospace, flew to the space station on {beam_launch} and was expanded on {beam_expand}, over about {beam_h} hours, with air let in {beam_bursts} times for a total of {beam_s} seconds. It weighs {beam_kg} kg and opened to {beam_l} m long and {beam_d} m across: {beam_m3} m³.", "compare": "About a third of an ordinary 50 m³ room ({beam_room}%, 02-01's yardstick), from a package that grew {beam_grow} cm longer. It was let out slowly, a puff at a time.", "sources": [ "wiki_beam" ] }, { "id": "F-08", "section": "1.3", "text": "BEAM was meant as a {beam_test}-year test. Its sensors found cosmic radiation inside 'comparable to those in the rest of the space station', and 'a few probable micrometeoroid debris impacts' that its protective layers stopped. NASA took ownership in {beam_owns} and still uses it as a store room.", "compare": "A fabric room has now outlived its planned life on the station several times over.", "sources": [ "wiki_beam", "wiki_bigelow" ] }, { "id": "F-09", "section": "1.3", "text": "NASA's TransHab, designed in the late 1990s, packed to {th_packed} m across and expanded to {th_d} m across and {th_l} m long, with {th_m3} m³ inside, {th_floors} floors and almost two dozen layers of fabric, foam and Kevlar. It weighed {th_kg} kg. Congress stopped NASA working on it in {th_ban}; Bigelow bought the patents.", "compare": "One TransHab weighs {th_share}% of a cargo ship's {cargo} t on Mars (01-01 E-09), before its fittings.", "sources": [ "wiki_transhab" ] }, { "id": "F-10", "section": "1.3", "text": "Bigelow flew two small inflatable test craft, Genesis I and II, in {gen1} and {gen2}, and designed the B330, named for its {b330} m³ of room. In March 2020 it laid off all {big_staff} staff; the company is now dormant.", "compare": "The biggest inflatable ever designed for flight never flew. The technology outlived the company that carried it.", "sources": [ "wiki_bigelow" ] }, { "id": "F-11", "section": "1.3", "text": "A {cohen_year} NASA roadmap for Mars habitats (Cohen and Kennedy) set a goal for inflatable and composite structures to be {cl_lo} to {cl_hi}% lighter than aluminium hard shells, and called for 'automated delivery and emplacement' of habitats.", "compare": "Robots set out the homes before people arrive: the order our world follows (HA-05).", "sources": [ "cohen_1997" ] }, { "id": "F-12", "section": "1.3", "text": "Company claim: in January {sierra_year} Sierra Space announced a full-scale burst test of its inflatable station module that exceeded the required safety margin by {sierra_pct}%.", "compare": "Burst tests blow a module up until it fails. Fabric walls are now tested to the same rules as metal ones.", "sources": [ "wiki_life" ] }, { "id": "F-13", "section": "1.3", "text": "The Mars Ice House won NASA's {ih_year} Mars habitat design contest: a shell of water ice, 3D-printed inside an inflatable membrane from Earth, meant to let in about {ih_light}% of visible light for {ih_lo} to {ih_hi} people.", "compare": "A home you could see the sky from. Our world chooses soil and periscopes instead (02-01 S-18).", "sources": [ "wiki_icehouse" ] }, { "id": "F-14", "section": "1.3", "text": "NASA's 3D-Printed Habitat Challenge ran in three phases from {hc_y0} to {hc_y1} and paid out ${hc_usd} in prizes. One entry, AI SpaceFactory's MARSHA, is an upright, four-level shell of basalt fibre and plant-made plastic, with an inner and an outer shell so the rooms are isolated from the outer wall swelling and shrinking as the temperature swings.", "compare": "Printed homes stand on the surface. Ours are buried, so a printed shell would still need 3 m of soil on top.", "sources": [ "nasa_3dph", "aisf_marsha" ] }, { "id": "F-15", "section": "1.3", "text": "Company claims: SpaceX's plans have included 'transparent domes for growing crops' ({sx_domes}), and using the first Mars-bound ships themselves as Martian habitats ({sx_ships}). SpaceX has published no habitat design.", "compare": "Our world keeps the ship as a first home for the first days, and leaves out the domes (02-01 S-18).", "sources": [ "wiki_spacex_mars" ] }, { "id": "F-16", "section": "1.4", "owner": "01-02", "text": "NASA's expert panel set a minimum of {nhv} m³ of habitable volume per person for a {nhv_crew}-person, {nhv_months}-month Mars mission (01-02 F-07). The space station gives its crew of {iss_crew} about {iss_hab} m³ of habitable volume inside {iss_press} m³ (01-02 F-06).", "compare": "The station works out at about {iss_pp} m³ each, {iss_x} times NASA's minimum; only {iss_share}% of its pressurised volume is living space.", "sources": [ "nasa_nhv", "nasa_iss" ] }, { "id": "F-17", "section": "1.4", "text": "The same NASA panel split a home into {nhv_areas} kinds of space (sleeping, eating together, work, exercise, washing, passageways, storage) and sized each crew member's private quarters at {nhv_cq} m³, against {iss_cq} m³ on the space station, asking for 'a larger volume for crew quarters... to provide privacy and restoration'.", "compare": "{iss_cq} m³ is about a phone box. {nhv_cq} m³ is a bunk with room to sit, stand and dress.", "sources": [ "nasa_nhv" ] }, { "id": "F-18", "section": "1.4", "text": "In October {cqt_year} NASA tested sleeping pods about {cqt_l} m long, {cqt_h} m high and {cqt_w} m wide, with {cqt_n} people shut in for {cqt_d} days (Howard and Litaker, 2022).", "compare": "About {cqt_m3} m³: a capsule-hotel bed (F-21). Pods like these are for short trips, not a 500-day stay.", "sources": [ "howard_2022" ] }, { "id": "F-19", "section": "1.4", "owner": "01-03", "text": "Mars-500's six men lived in a {m5_vol} m³ chamber for {m5_days} days (01-03 F-14). Their main living module was a tube {m5_d} m across and {m5_l} m long, holding {m5_cabins} crew compartments of about {m5_cab} m² each, a kitchen, a lounge, the control room and a toilet.", "compare": "About {m5_pp} m³ each in all, but a private floor of {m5_cab} m²: about a single bed and a desk.", "sources": [ "basner_plos_2014", "wiki_mars500" ] }, { "id": "F-20", "section": "1.4", "text": "Kisho Kurokawa's Nakagin Capsule Tower in Tokyo ({nk_year}) was {nk_n} capsules, each a factory-made room {nk_a} by {nk_b} by {nk_c} m with one round window {nk_w} m across, used as small flats and offices. It was taken down in {nk_down}.", "compare": "{nk_m3} m³ each: exactly NASA's minimum per person (F-16). People used them for fifty years.", "sources": [ "wiki_nakagin" ] }, { "id": "F-21", "section": "1.4", "text": "The first capsule hotel, the Capsule Inn Osaka, opened in {ci_year}, also designed by Kurokawa. Each capsule is 'roughly the length and width of a single bed, with sufficient height for a hotel guest to crawl in and sit up'.", "compare": "Fine for a night after missing the last train. Our world gives even the first crew a room they can stand up in (HA-06).", "sources": [ "wiki_capsule" ] }, { "id": "F-22", "section": "1.4", "text": "England's national space standard ({uk_year}) sets the smallest new one-bedroom home for one person at {uk_shower} m² of floor with a shower room, or {uk_bath} m² with a bathroom.", "compare": "{uk_shower} m² is about {uk_court}% of a tennis court. A City home in our world gives each person about {city_priv} m³ of their own (HA-06).", "sources": [ "gov_space_std" ] }, { "id": "F-23", "section": "1.4", "text": "Biosphere 2 in Arizona sealed {b2_crew} people inside {b2_m2} m² from 26 September {b2_y0} to 26 September {b2_y1}, with their own farm, ocean, rainforest and desert.", "compare": "About {b2_pp} m² each, far more than any base, because the building was also the farm and the wild. Even so, its air ran short (03-09 F-24).", "sources": [ "wiki_biosphere2" ] }, { "id": "F-24", "section": "1.4", "text": "A US Ohio-class submarine has two complete crews of {oh_off} officers and {oh_enl} enlisted sailors, each serving deterrent patrols of {oh_lo} to {oh_hi} days. On submarines two or even three sailors may share one bunk in turns, called hot racking.", "compare": "A sealed, crowded, sunless home people already live in. It works for weeks, with a known end date. A Mars stay runs {stay_days} days (01-01 F-33).", "sources": [ "wiki_ohio", "wiki_hotrack" ] }, { "id": "F-25", "section": "1.5", "text": "On the space station each private crew quarters needed {aq_vol}% of its volume and about {aq_mass}% of its mass just to quieten it, with a two-fan push-pull system blowing fresh air at the sleeper's head. Inside it had to be quieter than NASA's NC-{aq_nc} noise curve (Broyan and others, 2010).", "compare": "The fans that move the air run day and night, and they are the noise. Quiet has to be designed in, not hoped for.", "sources": [ "broyan_2010" ] }, { "id": "F-26", "section": "1.5", "owner": "02-06", "text": "Without daylight, the body clock runs on a cycle of about {circ} hours; in a 2007 test people were kept in step with a {sch_h}-hour Mars day by light of about {lux} lux in the second half of each waking day (02-06 F-29).", "compare": "About the light of a bright office. Lamps, not windows, keep a buried town on Mars time.", "sources": [ "czeisler_1999", "scheer_2007" ] }, { "id": "F-27", "section": "1.6", "text": "In June {spk_year} the cargo ship Progress M-34 hit Mir's Spektr module and punctured it. Spektr's air fell to a vacuum; the crew's quick work sealing it off meant they did not have to abandon the station.", "compare": "One closed hatch saved the rest of the home. Every habitat in our town is built as sections that can be shut off (HA-07).", "sources": [ "wiki_mir" ] }, { "id": "F-28", "section": "1.6", "owner": "03-09", "text": "In February {mir_year} a faulty oxygen candle set fire to Mir with {mir_crew} people aboard and blocked the way to one of the two lifeboats (03-09 F-26).", "compare": "A fire can sit between you and the way out. So every section in our town has two ways out (HA-07).", "sources": [ "wiki_vika" ] }, { "id": "F-29", "section": "1.7", "text": "On Earth, 'the heat of the building (or pipeline) can spread to the soil, thawing it', until the ground can no longer carry the building. Fixes include piles, pioneered by Mikhail Kim in Norilsk and now advised to reach about {pf_pile} m down, gravel pads {pf_g_lo} to {pf_g_hi} m thick, and ammonia heat pipes. By {pf_year}, up to {pf_pct}% of buildings in some northern Russian cities were damaged.", "compare": "A warm room on frozen ground slowly melts its own foundations. Our town sits just above ice (02-05).", "sources": [ "wiki_permafrost" ] }, { "id": "F-30", "section": "1.7", "text": "The elevated Amundsen-Scott South Pole Station (dedicated {pole_year}) is a {pole_m2} m² building for about {pole_summer} people in summer and {pole_w_lo} to {pole_w_hi} in winter, cut off from mid-February to late October. About {pole_snow} cm of snow builds up each year, so the whole building can be jacked up a full floor.", "compare": "About {pole_pp} m² of building for each winter resident. The ground under it is always changing, so the building is made to move.", "sources": [ "wiki_pole" ] }, { "id": "F-31", "section": "1.7", "text": "Britain's Halley VI station in Antarctica (opened {hal_year}) is a string of {hal_n} modules on hydraulic legs with giant skis. In {hal_moved_year} it was towed {hal_km} km to escape a spreading crack in the ice shelf.", "compare": "A town that can walk away from bad ground. Ours is buried, so it has to get its ground right first time (HA-10).", "sources": [ "wiki_halley" ] }, { "id": "F-32", "section": "1.3", "owner": "01-02", "text": "Company claim (2017 design): Starship's cargo area has a pressurised volume of {sx_m3} m³, to be laid out as cabins for about {sx_people} people on the way to Mars (01-02 F-08).", "compare": "At the station's living share ({iss_share}%), one ship holds about {sx_live} m³ of living space: room for {sx_fit} people at our First crew's {crew_pp} m³ each (HA-04).", "sources": [ "spacex_2017" ] } ], "failures": [ { "icon": "leak", "title": "A slow leak", "text": "Seals and hatches age. A leak that is too small to hear still costs air every hour, and dust makes seals worse.", "refs": [ "F-27", "HA-07" ] }, { "icon": "fire", "title": "Fire", "text": "Air at {o2}% oxygen (03-09) lets things burn more readily. A fire can sit between you and the door.", "refs": [ "F-28", "HA-07" ] }, { "icon": "lift", "title": "Pushed up, not crushed", "text": "A building whose floor is the ground would be lifted by its own air. Every living space is a closed shell.", "refs": [ "F-04", "HA-02" ] }, { "icon": "thaw", "title": "Melting its own ground", "text": "A warm vault over ice-rich ground slowly turns the ice under it to vapour and sinks, unless it is insulated.", "refs": [ "F-29", "HA-10" ] }, { "icon": "walls", "title": "The same four walls", "text": "Monotony, not danger, is what crews say is hardest. Room, privacy, light and views are safety equipment.", "refs": [ "F-19", "HA-06", "HA-08" ] } ], "assumptions": [ { "id": "HA-01", "confidence": "Medium", "text": "Every living space in the town is buried under at least {cover} m of soil, measured from the top of its pressure shell to the surface. This takes over 02-01 S-18's burial depth. Short-stay viewing rooms are the only rooms at the surface (HA-08).", "why": "About {sh_lo} to {sh_hi} m brings the dose below {sh_target} mSv a year (02-01 F-28, F-01); NASA's study asks for several hundred g/cm² (F-02), and {cover} m is {ad_lo} to {ad_hi} g/cm² (F-03). 02-06 HB-02 plans a ceiling of {buried} mSv a year inside, which needs more than the bare minimum. Medium, not High: no source checked gives the dose at exactly {cover} m (open question). The ice-rich ground below {ice_top} m (02-05) probably shields better than dry soil (02-06 HB-02).", "moves_to": "" }, { "id": "HA-02", "confidence": "High", "text": "The air inside is held by closed pressure shells: steel, composite or fabric vessels with their own floors. The soil on top is a blanket against radiation, heat and stones, never a lid holding the air in. No building uses the ground itself as its floor under pressure.", "why": "At {cabin} kPa (03-09 LS-01) the air pushes out with {cabin} kPa; {cover} m of soil presses down with only {soil_lo} to {soil_hi} kPa (F-03, 02-01 F-01). It would take {bal_lo} to {bal_hi} m of soil to balance the push ({bal_atm_lo} to {bal_atm_hi} m at Earth's sea-level pressure). A closed shell carries its own pressure, like a balloon or a tank (F-04).", "moves_to": "" }, { "id": "HA-03", "confidence": "Medium", "text": "Three kinds of home, in order. The landed ship, for the first crew's first days only. Inflatable modules about the size of TransHab ({th_d} m across, about {th_m3_r} m³), for the First crew and early First Town. Buried steel vaults {v_d} m across and {v_l} m long, welded on Mars from rolled steel rings like Starship's, from the First Town on; in the City, many vaults joined by buried tunnels, with a few larger halls. About {share_pct}% of each shell is living space; the rest is machines, stores, ducts and walls. Lava tubes are for outposts, not this town (02-01 S-19).", "why": "Inflatables pack small, and NASA set them a goal of being {cl_lo} to {cl_hi}% lighter than hard shells (F-11); BEAM has flown for years (F-07, F-08) and full-scale burst tests pass (F-12). A {v_d} m steel ring holds the town's air at about {ring_pct}% of weak steel's yield (F-05, F-06), and SpaceX already builds such rings from rolls. {share_pct}% is above the station's {iss_share}% (F-16) because big machines live in their own vaults. Worked out, roughly: a vault's shell alone, rings {ring_t} mm thick with flat ends, is about {v_steel} t of steel at about {ss_rho} t per m³ (stainless steel's weight, Wikipedia), before decks, frames and doors. Medium: no Mars habitat has been built.", "moves_to": "" }, { "id": "HA-04", "confidence": "Low", "text": "Living space per person, by era: about {crew_pp} m³ for the First crew, {town_pp} m³ in the First Town and {city_pp} m³ in the City. This counts homes, halls, kitchens, clinics, schools and passages, but not farms (03-10), workshops or machine rooms.", "why": "The First crew gets twice NASA's {nhv} m³ minimum (F-16), close to the station's {iss_pp} m³, because they stay {stay_days} days, not months, and much of the time underground. The First Town rotates crews every window or two, so it grows from that. City people stay for good, with families: {city_pp} m³ is a small private home (HA-06) plus a share of the town's public rooms. Low: every figure here is a design choice, not a measurement.", "moves_to": "" }, { "id": "HA-05", "confidence": "Low", "text": "The first crew's inflatable modules land in the Robots First era. Robots lay them in a trench, they are inflated and checked from Earth, and robots then cover them with {cover} m of soil, all before the crew leaves Earth. The crew lives in its landed ship for its first rest days (01-02 JN-09), then drives the {pad_lo} to {pad_hi} km (03-02 P-01) to the buried modules and moves in.", "why": "NASA's reference plan lands cargo one window ahead of the crew (01-01 F-34), and our world lands the plant and reactors first for the same reason (01-01 E-10): never land a crew without a proven way home, or a proven home. Inflating before covering matters: soil laid on a flat module would stop it opening. Low: no robot has yet buried a habitat.", "moves_to": "" }, { "id": "HA-06", "confidence": "Medium", "text": "Everyone has a private room with a door, from the First crew on: about {priv_crew} m³ in the First crew (a room you can stand, dress and sit up in), {priv_town} m³ in the First Town and a small home of about {priv_city} m³ per person in the City.", "why": "NASA asks for {nhv_cq} m³ of private quarters, against the station's {iss_cq} m³, for privacy and restoration (F-17). Mars-500's {m5_cab} m² cabins (F-19) and a capsule hotel's crawl-in bed (F-21) show the floor below which people only sleep. Even a City home per person stays smaller than England's smallest legal one-person flat (F-22): space on Mars stays precious. How each era's homes are furnished and shared is 04-03-02 FH-06.", "moves_to": "" }, { "id": "HA-07", "confidence": "Medium", "text": "Every vault is split into {sections} sections by pressure doors, and every section has {exits} ways out: along the vault and into a buried tunnel or the next vault. Every buried cluster of vaults also has at least {ways_out} separate ways out to the surface, each through 03-07's five-stage entrance from porch to living space (03-07 AD-01, AD-09). Air, water and power machines sit in their own vaults or rooms, away from sleeping rooms. Sleeping rooms are kept at or below NC-40 and work areas at NC-50 (01-02 F-10).", "why": "Sections are how the station and submarines survive fires and leaks (03-09 LS-09); Spektr was saved by sealing it off (F-27); Mir's fire blocked one way out (F-28). Quiet costs space: {aq_vol}% of a station sleeping room's volume went on it (F-25), so it is cheaper to keep noisy machines elsewhere.", "moves_to": "" }, { "id": "HA-08", "confidence": "Medium", "text": "Views come by periscope and viewing room. Shared halls have periscopes and screens showing the sky outside. Each district has a viewing room at the surface, roofed with soil, looking out through a thick side window, mostly to the west and south, with some periscopes turned north (02-07 SK-06); people visit it for occasions, arrivals and departures, not daily. Visits count towards each person's surface hours (02-06 HB-03).", "why": "An hour a sol in the open would cost about {view_lo} to {view_hi} mSv a year (02-01 F-25, F-26): {view_share} of the whole {buried} mSv yearly ceiling (02-06 HB-02). A periscope costs no dose. Crews say monotony is hardest (01-03 F-16); 02-01 S-20 asks for views and projected sky, and 03-02 P-01 already expects ships to be watched from the viewing rooms. Which way they face follows what can be seen from the pin: sunsets and the evening star to the west, Phobos to the south, the stars that never set to the north (02-07 SK-06). 04-01-01 FC-07 places each viewing room on the city map.", "moves_to": "" }, { "id": "HA-09", "confidence": "High", "text": "The buried town is its own storm shelter: under {cover} m of soil a solar storm changes nothing inside (02-06 HB-04). While the first crew is still in its landed ship, the ship's water-walled shelter serves (01-02 JN-07). Every section keeps a refuge kit of air, water and food for {refuge} days (03-09 LS-05, LS-09), for fire, leaks and long power cuts in dust storms.", "why": "{cover} m is far thicker than the {shelter_lo} to {shelter_hi} cm of water NASA's radiation brief suggests for a storm shelter (01-02 F-20). The danger in a dust storm is power, not radiation (03-03 G-01, G-08), which the refuge kits answer.", "moves_to": "" }, { "id": "HA-10", "confidence": "Medium", "text": "Every vault sits on a made bed of dry fill, gravel and foam (03-11 CM-04), with temperature sensors in the ice below. Where the ground warms, passive heat pipes carry heat up and away, as on Earth's permafrost.", "why": "Dry soil lies only about {ice_top} m over ice-rich ground at the pin (02-05 SU-02, SU-03), and exposed ice turns to vapour within days (02-05 SU-10). Warm buildings on frozen ground sink unless insulated or cooled (F-29). A buried town cannot be jacked up or towed away like the polar stations (F-30, F-31).", "moves_to": "", "moved_to": "03-11 CM-04 (how the bed is laid)" }, { "id": "HA-11", "confidence": "Medium", "text": "See 04-04-02 DL-10, which now owns what home looks and sounds like: a quiet, curved, well-lit place with no sound from outside, only fans, pumps and footsteps.", "why": "Moved on 26 September 2026 so the feel of home is written once. The physics stays here: {cover} m of soil blocks every sound from outside (02-01 S-10), and fans run all the time (F-25).", "moved_to": "04-04-02 DL-10" }, { "id": "HA-12", "confidence": "Low", "text": "Habitats by era follow from people (01-01 E-12), living space per person (HA-04) and the size of each kind of home (HA-03): none lived in during Robots First, a few inflatables for the First crew, a handful of vaults in the First Town, and hundreds of vault-sized spaces in the City. See the table.", "why": "Worked out, not chosen: change the era plan or HA-04 and the table changes. Low because the era plan itself is a low-confidence guess (01-01 E-12). 04-01-01 FC-13 turns these counts into ground on the city map.", "moves_to": "" }, { "id": "HA-13", "confidence": "Low", "text": "Deep family rows. Where pregnant residents and young children live (04-02-03 SG-06), the vault trench is cut {deep_extra} m deeper into the frozen ground, so {cover_deep} m of soil lies over the shell instead of {cover} m. The mound on top is the same, so these rows sit at the same spacing as every other row; only the trench is deeper. 04-01-01 FC-20 places them.", "why": "Ice-cemented ground stands vertical while frozen (03-11 CM-03), so a deeper cut needs no wider mound and costs only more digging. 04-02-03 SG-06 promised families 'the most deeply buried vaults'; this makes them real on the plan. How much the extra {deep_extra} m cuts the dose is open, like the dose at {cover} m itself (open question), so Low.", "moves_to": "" }, { "id": "HA-14", "confidence": "Low", "text": "Not every home is buried (owner, 9 October 2026). From The First Martian City, Arcadia, the first dome neighbourhoods rise on the surface beside the buried quarters: homes under great glass domes whose roofs carry a layer of water between two skins of glass as their radiation shield (03-10 GF-17). By Self-sustaining Mars about half of Arcadia City's people live under domes, with gardens and paths between the homes, and half in the buried vaults (HA-01). Since 10 October 2026 the water layer is sized to shield as well as the rows' soil (GF-17), so the dose under a dome is no higher than in the buried rows; the deep rows stay the home for families with young children (04-01-01 FC-20).", "why": "The owner's choice, for beauty: daylight through water is the picture of a Mars city people want to see. The water roof is what makes living under glass plausible (02-01 F-28: water and soil both block radiation); without it a glass dome is only a place to visit, as the farm domes are (03-10 GF-16).", "moves_to": "" }, { "id": "HA-15", "confidence": "Medium", "text": "Inside a dome neighbourhood (owner, 9 October 2026). The dome holds the air: its glass and water roof is tied down at the rim to a sealed floor, as the farm domes are (HA-02, 03-10 GF-16), so the air inside is the town's own (03-09 LS-01) and people walk about in everyday clothes. The homes inside never hold air, so they are built like houses, not vaults: one or two storeys, 3D printed from sintered Mars soil (03-11 CM-10, F-19), with the soft curves and fine ribbed print lines of a printed wall (03-11 F-24), flat roofs used as terraces and roof gardens because it never rains or blows indoors, and big windows. They stand in a ring round a small square or park, with gardens behind them, paved streets of pressed soil and lamps for the night. Light comes through the water roof softened and moving, as under a shallow sea (03-10 GF-17). Each dome joins the buried town by a tunnel. A tear in the glass lets the air out slowly, because a dome holds so much of it, so alarms sound and people walk through the tunnel doors into the buried town, the next sealed part (03-07 AD-11). In The First Martian City, Arcadia, the first dome is still filling up, with homes being printed on empty plots; by Self-sustaining Mars three domes are full, with grown trees, a park and a lake.", "why": "The dome neighbourhoods are the most visible part of the city and the place every visitor wakes up, so their look needs one written answer that every picture, film and 3D view can follow. Printing walls that hold no air is what 03-11 CM-10 sets out; a roof with no weather under it needs no pitch; and leaving a breach to the buried town's sealed sections follows 03-07 AD-11. The layout and the look are our best estimate.", "moves_to": "" }, { "id": "HA-16", "confidence": "Medium", "text": "How the homes look is fixed in numbers.look: the buried rows and the dome neighbourhoods, inside and out, their sizes, colours, light, each era, what must never appear and the signature shots. Every picture, film and 3D scene of the homes is made from it and checked against it.", "why": "00-05 ST-20 (owner, 10 October 2026). Built from HA-01 to HA-15, 03-10 GF-17, choosing the most beautiful option they allow (00 L-19)." } ], "world_spec": { "about": "The numbers the engine's 'Place the kit' step can read to draw buried habitats, their cover and their size. The format belongs to the engine (00-02); the numbers belong to this file. Each names the fact or assumption it comes from.", "cover_m": { "value": 3, "from": "HA-01", "path": "numbers.cover_m" }, "vault_diameter_m": { "value": 9, "from": "HA-03", "path": "numbers.vault.d_m" }, "vault_length_m": { "value": 50, "from": "HA-03", "path": "numbers.vault.l_m" }, "inflatable_diameter_m": { "value": 8.2, "from": "HA-03", "path": "numbers.transhab.d_m" }, "inflatable_length_m": { "value": 11, "from": "HA-03", "path": "numbers.transhab.l_m" }, "m3_per_person": { "value": 120, "from": "HA-04", "path": "numbers.m3_per_person.value", "note": "City. First crew and First Town values are in numbers.m3_per_person." }, "m3_per_person_first_crew": { "value": 50, "from": "HA-04", "path": "numbers.m3_per_person.first_crew" }, "living_share": { "value": 0.6, "from": "HA-03", "path": "numbers.hab_share" }, "vault_floor_below_centre_m": { "value": 2.25, "from": "HA-03", "path": "numbers.vault.floor_below_centre_m" }, "cover_deep_m": { "value": 5, "from": "HA-13", "path": "numbers.cover_deep_m" } }, "links": { "leans_on": [ { "ref": "00-01", "why": "Era names (read live)" }, { "ref": "01-01 E-12", "why": "People per era, for volume and habitat counts (read live)" }, { "ref": "01-01 E-10", "why": "Robots First land first, so the first modules are placed before the crew leaves" }, { "ref": "01-01 E-09", "why": "About 100 t landed per cargo ship, against a module's mass (read live)" }, { "ref": "01-01 F-33", "why": "About 500 days on the surface (read live)" }, { "ref": "01-01 F-34", "why": "NASA sends cargo one window ahead of the crew" }, { "ref": "01-02 F-06", "why": "The space station's habitable and pressurised volume and crew (read live)" }, { "ref": "01-02 F-07", "why": "NASA's 25 m³ minimum per person (read live)" }, { "ref": "01-02 F-08", "why": "SpaceX's claimed 825 m³ cabin (read live)" }, { "ref": "01-02 F-10", "why": "NASA's noise limits for sleep and work" }, { "ref": "01-02 F-20", "why": "Storm shelter thickness in water (read live)" }, { "ref": "01-02 JN-07", "why": "The ship's water-walled storm shelter, for the first crew's first days" }, { "ref": "01-02 JN-09", "why": "The rest days after landing, spent in the ship" }, { "ref": "01-03 F-14", "why": "Mars-500's chamber volume (read live)" }, { "ref": "01-03 F-16", "why": "HI-SEAS crews found monotony hardest" }, { "ref": "02-01 F-01", "why": "Mars gravity, for the weight of soil (read live)" }, { "ref": "02-01 F-25", "why": "The surface dose rate (read live)" }, { "ref": "02-01 F-26", "why": "The dose over the solar cycle, for the viewing-room sum (read live)" }, { "ref": "02-01 F-28", "why": "How soil depth cuts the dose (read live)" }, { "ref": "02-01 S-18", "why": "The buried town; its burial depth now lives here (HA-01)" }, { "ref": "02-01 S-08", "why": "Earth-like timed lighting inside" }, { "ref": "02-01 S-10", "why": "Outside sound is thin and dull" }, { "ref": "02-01 S-19", "why": "Lava tubes are for outposts" }, { "ref": "02-01 S-20", "why": "Living enclosed is the main strain: views and projected sky" }, { "ref": "02-05 SU-02", "why": "Dry soil about 0.5 m over ice at the pin (read live)" }, { "ref": "02-05 SU-03", "why": "Ice-rich ground below" }, { "ref": "02-05 SU-10", "why": "Exposed ice turns to vapour within days" }, { "ref": "02-06 HB-02", "why": "The dose ceiling inside the buried town (read live)" }, { "ref": "02-06 HB-03", "why": "Surface hours per sol, which viewing-room visits count towards" }, { "ref": "02-06 HB-04", "why": "A storm changes nothing inside the buried town" }, { "ref": "02-06 F-29", "why": "Light keeps the body clock on the sol (read live)" }, { "ref": "02-07 SK-06", "why": "Which way the viewing rooms and periscopes face; SK-01, the sky colours, for the opening scene's sky (read live)" }, { "ref": "03-02 P-01", "why": "The nearest pad is 3 to 5 km from the habitat (read live)" }, { "ref": "03-03 G-01", "why": "The power plan: dust storms are a power problem, not a radiation one" }, { "ref": "03-09 LS-01", "why": "The cabin pressure and oxygen share, for the push on the walls and fire (read live)" }, { "ref": "03-09 LS-05", "why": "Refuge kits in every section (read live)" }, { "ref": "03-09 LS-09", "why": "Sections with pressure doors" }, { "ref": "03-09 F-26", "why": "The Mir fire (read live)" }, { "ref": "03-07 AD-01", "why": "The five-stage entrance, porch to living space, that every way out of a cluster uses (HA-07)" }, { "ref": "03-07 AD-09", "why": "At least two separate ways out of every buried cluster (HA-07, read live); the airlocks themselves belong to 03-07" }, { "ref": "03-11 CM-04", "why": "How the insulated bed under each vault is laid (HA-10)" }, { "ref": "03-10 GF-17", "why": "The water roof over the dome neighbourhoods and the light it lets through (HA-14, HA-15)" }, { "ref": "03-11 CM-10", "why": "Printed walls that hold no air, used for the homes inside the domes (HA-15)" } ], "used_by": [ { "ref": "05-19", "why": "Dome homes and buried rows, drawn in the playable world's two eras" }, { "ref": "04-01-03", "why": "Buried homes, the viewing room and the landed ship as first home (JT-04, JT-05)" }, { "ref": "03-09", "why": "Reads living space per person, for how fast carbon dioxide builds up, and the sections for its refuges" }, { "ref": "03-07", "why": "Where each habitat's entrances and suit rooms go, and two ways out per cluster" }, { "ref": "03-10", "why": "Farms are buried, sealed rooms built and covered like the habitats" }, { "ref": "03-11", "why": "Reads the burial depth, vault and inflatable sizes, living space per person and soil densities, for how much soil to dig and place" }, { "ref": "04-01-01 The first city", "why": "Reads HA-08 (viewing rooms by district, facing west and south), vault and inflatable sizes and space per person (read live), to place the vaults, halls and viewing rooms (FC-03, FC-07, FC-13)" }, { "ref": "00-02 The engine", "why": "Draws the buried vaults and cover from the world spec" }, { "ref": "03-13 Local communications", "why": "Reads HA-01 (3 m of soil over every living space) and HA-03 (vault sizes and sections) live; cites HA-02, HA-05 and HA-07 for the buried network" }, { "ref": "03-14 Medical bay", "why": "Reads HA-01 (burial depth, for the pharmacy store) and HA-03 (vault and inflatable sizes, for the bay plans) live; cites HA-07 (pressure sections)" }, { "ref": "03-15 Waste and recycling", "why": "Cites HA-07 (machines in their own vaults, away from sleeping rooms) and HA-10 (insulated gravel beds above the ice)" }, { "ref": "04-01-02 The lava-tube outpost", "why": "Cites HA-02 (pressure shells, never the ground, hold the air) and reads module size, for the shells on the tube floor (LT-04)" }, { "ref": "04-02-02 Money and trade", "why": "Reads HA-06: private space per person in each era (read live)" }, { "ref": "04-03-02 Food and home life", "why": "F-17: NASA's and the station's private quarters, for the rooms drawing (read live); F-22: England's smallest one-person flat (read live); HA-01: burial depth, for the dining hall drawing (read live); HA-03: vault size and sections, for the dining hall drawing (read live); HA-05: the first crew's buried inflatables; HA-06: private space per person by era (read live); 04-03-02 says how it is furnished and shared; HA-07: pressure sections and quiet sleeping rooms" }, { "ref": "04-03-03 Language and culture", "why": "HA-03: vault size and halls, where games are played (read live); HA-06: private space, where the First crew prays or reflects (LG-11). What inside feels like is now 04-04-02 DL-10" }, { "ref": "04-04-02 A day in the life", "why": "HA-06: private room size by era (read live); HA-08: viewing rooms are for occasions and count as surface time; DL-10 took over HA-11 (what home looks and sounds like)" }, { "ref": "04-04-03 Safety and emergencies", "why": "HA-07: sections, pressure doors and two ways out (read live for the vault)" }, { "ref": "04-05-01 Characters", "why": "HA-06: private space per person by era, for every home (read live)" }, { "ref": "04-05-02 Arrival day", "why": "HA-05: the first crew lives in its ship for its rest days; HA-06 private space (read live); HA-08 viewing rooms for arrivals" }, { "ref": "05-03 Guided tours", "why": "Burial depth (HA-01)" }, { "ref": "05-04 Missions", "why": "The vault's size, for the night watch leak (read live)" }, { "ref": "05-06 Free roam", "why": "The vaults whose public rooms free roam opens, and the viewing rooms (HA-08)" }, { "ref": "00-04 Glossary and units", "why": "HA-03: vault and inflatable sizes and the burial depth (read live)" }, { "ref": "00-05 Writing and visual standard", "why": "HA-01: the town's burial depth, for a before-and-after example (read live)" }, { "ref": "03-12 Manufacturing", "why": "Reads the vault size, living share, living space per person and the shell's steel (HA-03, HA-04) for the City's steel need against supply (MF-13, read live)" }, { "ref": "05-12", "why": "City experience reads this source live through the generated library bundle." }, { "ref": "04-02-03 SG-06", "why": "HA-13: the deep family rows its families and nursery live in" }, { "ref": "04-01-01 FC-20", "why": "HA-13: the deep family rows and their cover; the vault floor depth for the viewer (read live)" }, { "ref": "03-16", "why": "Soil cover and vault size for the server hall (read live)" }, { "ref": "04-02-04", "why": "Soil cover and vault size in the opening scene (read live)" }, { "ref": "05-17", "why": "Living on Mars's list of the twenty parts a city needs (homes)" }, { "ref": "05-20", "why": "Mars games: how much soil covers a home, for the Mars Quiz's radiation answer (worked_out)" } ] }, "open_questions": [ "The radiation dose under exactly 3 m of ice-rich soil at the pin: no source checked gives it (02-01 F-28 stops at the 100 mSv depth). Replace HA-01's reasoning when a depth profile for ice-rich ground is published. The same answer tells whether the deepest vaults can keep a whole pregnancy under the US limit of 5 mSv for a declared pregnancy (10 CFR 20.1208), as 04-02-03 SG-06 aims.", "How much heat a buried vault loses into ice-rich ground, and how fast the ice under it would turn to vapour: no Mars study found (HA-10).", "Whether an inflatable module can carry 3 m of soil laid on it once inflated: no burial test found (HA-05). Watch for a NASA or company test." ], "changes": [ "26 September 2026 (v1.0): Written. Burial and shielding, the push of the air against the soil, the kinds of home, room per person, light, sound and privacy, fire and leak sections, the storm shelter, standing on ice, and habitats by era, with 32 facts and 12 assumptions (HA-01 to HA-12).", "26 September 2026 (v1.0): Takes over 02-01 S-18's burial depth (3 m, HA-01) and gives the pre-agreed numbers: m3_per_person (value, first_crew, town), cover_m, and the world spec for vault and inflatable sizes. The cabin pressure is read from 03-09, never kept here.", "26 September 2026 (v1.1): Checked against the sources. HA-08 and the tile corrected: an hour a sol in the open costs about 9 to 15 mSv in an Earth year, about half to three quarters of 02-06's 20 mSv yearly ceiling. The page had counted a whole Mars year (668.6 sols) against a ceiling set per Earth year.", "26 September 2026 (v1.1): Deleted the open question on how trenches are dug and how much soil each vault needs: answered by 03-11 CM-03 (cut and cover) and its section 1.4 (the cover). HA-10 no longer says vaults sit 'on dry ground' (at the pin dry ground is only the top 0.5 m, 02-05 SU-02): they sit on a made bed of dry fill, gravel and foam, and how the bed is laid has moved to 03-11 CM-04.", "26 September 2026 (v1.1): HA-07 now says every buried cluster has at least two separate ways out, each through 03-07's five-stage entrance (03-07 AD-01, AD-09, read live); added 03-07 AD-01 and 03-11 CM-04 to leans_on. HA-03 now calls the 30 to 50% lighter inflatables NASA's goal (F-11), not a fact. F-29 reworded: Kim pioneered pile foundations; the 15 m depth is today's advice.", "26 September 2026 (v1.2): Answered by 04-01-01 The first city. Deleted the open question on where the vaults, tunnels, halls and viewing rooms sit (FC-03, FC-07, FC-09) and the one on which vaults hold the farms (03-10 GF-01, GF-02 size them; FC-05 places the farm belt). HA-08 and HA-12 no longer move: they point to FC-07 and FC-13, which place them on the map. The open question on the dose under 3 m of soil notes that 04-02-03 SG-06 (a whole pregnancy under the US worker limit in the deepest vaults) needs the same answer. used_by adds 03-13, 03-14, 03-15 and 04-01-02, and gives 04-01-01 what it reads.", "26 September 2026 (v1.3): used_by adds 04-02-02 Money and trade, which reads HA-06 live.", "26 September 2026 (v1.4): HA-11 has moved to 04-04-02 DL-10 (what home looks and sounds like); this ID is now a pointer. HA-06 no longer moves: its furnishing side is answered by 04-03-02 FH-06 (cited). The dose-at-depth question names the limit: the US 5 mSv for a declared pregnancy (10 CFR 20.1208). used_by: back-links for 04-03-02, 04-03-03, 04-04-02, 04-04-03, 04-05-01, 04-05-02 (what each reads, from its leans_on). Also back-links for 05-03, 05-04, 05-06 (wave 6 pages, from their leans_on as written today).", "26 September 2026 (v1.5): Back-links for 00-04 and 00-05, which read the vault sizes and burial depth live.", "26 September 2026 (v1.6): Beauty pass: an opening scene at the top of At a glance: the buried town cut open at dusk, to scale; the era table fits the page; two chart labels no longer clip. No fact or number changed.", "26 September 2026 (v1.7): Final fix round: used_by: the folder-level '05 Visiting Mars' line removed; the 05 pages that really read this file are listed one by one. used_by: HA-11 is a pointer to 04-04-02 DL-10, so the reasons for 04-03-03, 04-05-02 and 05-03 no longer name it (their citations of the interiors now go to DL-10). The opening scene's sky colours are now read live from 02-07 SK-01 instead of typed; leans_on and quotes add 02-07. HA-03: a rough steel mass per vault shell, worked out from this file's own ring and vault sizes and stainless steel's weight, labelled as rough. used_by adds 03-12, which reads the vault and its steel for the City's steel need", "28 September 2026 (v1.8): Used by the Jezero science town (04-01-03).", "30 September 2026 (v1.9): Added the city experience to the files that read this source.", "1 October 2026 (v1.10): used_by adds 03-16 and 04-02-04, the new pages on computing and on needing nothing from Earth.", "1 October 2026 (v1.11): New HA-13: deep family rows, cut 2 m deeper into frozen ground (numbers.cover_deep_m, 5 m of cover), placed by 04-01-01 FC-20, so 04-02-03 SG-06's 'most deeply buried vaults' exist on the plan. numbers.vault.floor_below_centre_m (2.25 m) now owns the floor depth that 03-10 GF-15 and the city viewer read. used_by adds 04-02-03 SG-06.", "3 October 2026 (v1.12): Era names follow the owner's new names (00-01): Mars Today, Robots First, First Town, Many Cities; First Human Landing and The First Martian City, Arcadia, where an era is named as such.", "4 October 2026 (v1.13): Used by 05-17 Living on Mars, the home page's cards on how each part of a Mars city works in each era.", "4 October 2026 (v1.14): 05-17 Living on Mars no longer has a homes card; the link's reason now names its list of the twenty parts.", "9 October 2026 (v1.15): Owner: about half of Arcadia City's homes are under water-roofed glass domes by Self-sustaining Mars, the first from The First Martian City, Arcadia (HA-14).", "9 October 2026 (v1.16): HA-15 added (owner): what a dome neighbourhood is like inside: printed homes that hold no air, flat roofs and gardens, streets and lamps, the water roof's light, and what happens if the glass tears.", "10 October 2026 (v1.17): HA-14: the water roof is now sized (03-10 GF-17), so the dose under a dome matches the buried rows.", "10 October 2026 (v1.18): The homes' look book (numbers.look, HA-16): the buried rows and the dome neighbourhoods, inside and out, the one source for every picture, film and 3D scene of them (00-05 ST-20).", "10 October 2026 (v1.19): New signature shot, cut_row (two ways to live with a buried row cut open), for the Living on Mars explainer's How Arcadia does it, so the home under the soil can be seen and pinned.", "10 October 2026 (v1.20): The look book (HA-16) now covers close-up detail: the mound's lumpy soil and skylight hardware, the domes' foundation ring wall, berm and triangulated frame, the homes' frames and clutter, your room, and the weathering of everything outside.", "10 October 2026 (v1.21): The look book's inside of a buried row now has its street: trees under the skylight wells, benches, string lights and roof terraces on the homes (HA-16), as walked through in Playable Arcadia (05-19 PA-87).", "11 October 2026 (v1.22): A buried row's porch no longer carries spare suits under the canopy. Those hang in the suit room, in the row's air, and the helmet is sealed before the outer hatch opens (03-07)." ], "sources": { "hassler_2014": { "name": "Hassler et al., Mars' surface radiation environment measured with the Mars Science Laboratory's Curiosity rover, Science 343, 2014", "url": "https://www.science.org/doi/10.1126/science.1244797" }, "zhang_2022": { "name": "Zhang, Guo et al., From the top of Martian Olympus to deep craters and beneath (model study, cosmic rays only), JGR Planets, 2022", "url": "https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021JE007157" }, "slaba_2013": { "name": "Slaba, Mertens and Blattnig (NASA Langley), Radiation Shielding Optimization on Mars, NASA TP-2013-217983, 2013", "url": "https://ntrs.nasa.gov/api/citations/20130012456/downloads/20130012456.pdf" }, "usgs_1987": { "name": "Moore, Hutton, Clow and Spitzer, Physical properties of the surface materials at the Viking landing sites on Mars, US Geological Survey Professional Paper 1389, 1987", "url": "https://pubs.usgs.gov/publication/pp1389" }, "wiki_cylinder": { "name": "Wikipedia, Cylinder stress, 2026", "url": "https://en.wikipedia.org/wiki/Cylinder_stress" }, "wiki_starship_ship": { "name": "Wikipedia, SpaceX Starship (spacecraft), 2026", "url": "https://en.wikipedia.org/wiki/SpaceX_Starship_(spacecraft)" }, "wiki_304": { "name": "Wikipedia, SAE 304 stainless steel, 2026", "url": "https://en.wikipedia.org/wiki/SAE_304_stainless_steel" }, "wiki_beam": { "name": "Wikipedia, Bigelow Expandable Activity Module, 2026", "url": "https://en.wikipedia.org/wiki/Bigelow_Expandable_Activity_Module" }, "wiki_bigelow": { "name": "Wikipedia, Bigelow Aerospace, 2026", "url": "https://en.wikipedia.org/wiki/Bigelow_Aerospace" }, "wiki_transhab": { "name": "Wikipedia, TransHab, 2026", "url": "https://en.wikipedia.org/wiki/TransHab" }, "cohen_1997": { "name": "Cohen (NASA Ames) and Kennedy (NASA Johnson), Habitats and Surface Construction Technology and Development Roadmap, NASA, 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"wiki_halley": { "name": "Wikipedia, Halley Research Station, 2026", "url": "https://en.wikipedia.org/wiki/Halley_Research_Station" }, "spacex_2017": { "name": "SpaceX, Making Life Multiplanetary, Elon Musk's IAC talk, transcript, 29 September 2017", "url": "https://www.spacex.com/media/making_life_multiplanetary_transcript_2017.pdf" } }, "sources_checked": "26 September 2026" }, "01-02": { "file": "01-02", "title": "The journey", "folder": "01", "facts_file": "01-02-the-journey.json", "version": "1.18", "status": "Active", "last_updated": "3 October 2026", "about": "Facts file for 01-02 The journey. The page is built from this file, the library catalogue and the page template. Change a fact here, then run build.py. Words in curly brackets, like {path_mkm}, are filled in when the page is built, from the numbers in this file and from 01-01 (read live), so each number is typed once. The trip's length, its radiation, a person's daily food and the surface stay belong to 01-01 and are quoted, never copied. The path, distances, apparent sizes and signal delay on this page are worked out as the page is built, from 01-01's orbit sizes.", "one_line": "Six to seven months in a ship between Earth and Mars: leaving orbit, the long coast, the body and mind in weightlessness, Earth shrinking to a star, and the seven minutes that end it.", "shelf_life": "SpaceX's only published crewed Mars ship figures are from 2017 (an 825 m³ cabin for about 100 people) and 2020 (the users guide); no crewed Starship has flown and no ship has yet been refilled in orbit (01-01 F-13). Re-check by March 2027 at the latest, and after each Starship design update, after the first refilling test, and when NASA revises its health standards (NASA-STD-3001). The landing record changes with every Mars landing attempt: the next are planned from 2028 (01-01 F-28).", "header": { "purpose": "Describe the trip from Earth orbit to the Mars surface as it really is: each phase from refilling to touchdown, the path through space, living space, food, sleep and noise, what weightlessness and radiation do to the body, the strain on the mind, the view from the window, and how a ship gets down through the thin air.", "why": "Every person in the city made this trip, and it shapes who arrives and in what state: six or seven months weightless, with no way to turn back and no help closer than months away. The visitor's ride (05-08) and arrival day (04-05-02) need a factual journey to stand on.", "when": "Writing anything about the crossing, arrival or the first days on Mars; sizing crews per ship; checking what a newly landed person can do; building the journey experience (05-08).", "change": "Part One changes only with a citation and a date. Part Two assumptions can be challenged one at a time. Trip length, radiation and daily needs change in 01-01, not here. Edit this facts file, then run build.py.", "writing": "Every number is compared to something people know. Company promises are labelled as claims. Pictures first, short sentences, no walls of text." }, "comparisons": { "days_per_month": 30.44, "hours_per_week": 40, "note": "Everyday units used only for comparisons. g0_ms2 is standard gravity, the value that defines '1 g', fixed by the General Conference on Weights and Measures in 1901.", "g0_ms2": 9.80665 }, "numbers": { "copies_note": "Four numbers below are labelled copies of numbers owned by 02-01, because folder 01 may not quote folder 02 (00 L-17): earth_radius_km (02-01 numbers.earth.radius_km), mars_radius_km (02-01 numbers.geography.radius_km), moon_d_km (02-01 numbers.moons.moon_d_km) and light_kms (02-01 numbers.comms.light_kms). They are used only to work out apparent sizes and signal delay.", "earth_radius_km": 6371.0, "mars_radius_km": 3389.5, "moon_d_km": 3474.8, "light_kms": 299792.458, "moon_dist_km": 384400, "acuity_arcmin": 1, "hohmann_year": 1925, "perse": { "cruise_days": 203, "path_mkm": 471, "tcm": 4, "approach_days": 45, "approach_tcm": 2, "cruise_sep_min": 10, "entry_kmh": 19500, "rover_kg": 1025, "peak_c": 1300, "peak_s": 75, "chute_s": 240, "chute_km": 11, "chute_kmh": 1512, "chute_m": 21.5, "hs_after_s": 20, "backshell_km": 2.1, "backshell_kmh": 306, "crane_m": 20, "crane_kmh": 2.7, "crane_lower_m": 7.6, "edl_min": 7, "trn_m": 600, "lvs_m": 40, "lvs_s": 10, "ellipse_km": [ 7.7, 6.6 ], "light_s": 682 }, "pathfinder": { "ellipse_km": [ 200, 70 ], "v_kms": [ 7.3, 0.4 ], "decel_s": 180 }, "msl": { "ei_radius_km": 3522.2, "blackout_s": 40, "light_min": 13.8 }, "iss": { "hab_m3": 388, "press_m3": 1005, "crew": 7, "speed_miles_s": 5, "km_per_mile": 1.609344, "exercise_h": 2 }, "nhv": { "m3_pp": 25, "crew": 6, "months": 30 }, "spacex": { "press_m3": 825, "cabins": 40, "per_cabin": [ 2, 3 ], "people": 100, "entry_kms": 7.5, "trip_months": [ 3, 6 ], "tiles": 18000, "tile_c": 1400, "sn8_date": "9 December 2020" }, "food": { "iss_shelf_yr": [ 1.5, 3 ], "mars_shelf_yr": 5 }, "noise": { "nc_work": 50, "nc_sleep": 40, "spacelab_dba": 68, "spacelab_peak_dba": 84 }, "sleep": { "iss_h": 6.09, "sched_h": 8.5, "meds_pct": 75, "iss_n": 21 }, "body": { "bone_pct_month": [ 1, 1.5 ], "calf_pct": 13, "power_pct": 32, "trappe_n": 9, "trappe_months": 6, "sans_pct": 70, "sans_clin_pct": 18, "taller_pct": 3, "taller_cm": 5, "taller_m": 1.8, "gemini_g": 0.00015, "gemini_date": "14 September 1966", "recover_days": 45 }, "radiation": { "career_msv": 600, "spe_msv": 250, "shelter_cm": [ 10, 20 ], "water_kg_m3": 1000, "orion_build_h": 1, "orion_stay_h": 24, "storm_1972_h": 7 }, "mind": { "m500_sleep_pct": 8.4, "polyakov_days": 437, "flash_min": 2.9 }, "entry": { "lyne_g": 5, "soviet_g": [ 5, 6 ], "soviet_months": 8, "srp_gap_mach": 5 }, "abort": { "apollo13_miles": 200000, "tito_days": 501 }, "refill_weeks": [ 2, 6 ], "rest_days": [ 3, 7 ], "crew_ship_people": { "town": [ 20, 30 ], "city": [ 20, 30 ] } }, "landings": { "about": "Every spacecraft that reached Mars and tried to land, by the year it arrived. Not counted: Mars 7 (1974), whose lander missed the planet by about 1,300 km, and NASA's two Deep Space 2 probes (1999), small penetrators carried by Mars Polar Lander, which were never heard from. Result: 'worked' (landed and did its job), 'partial' (landed, then fell silent within seconds), 'silent' (landed but never called home), 'lost' (crashed or lost during the descent).", "list": [ { "name": "Mars 2", "who": "Soviet Union", "year": 1971, "result": "lost" }, { "name": "Mars 3", "who": "Soviet Union", "year": 1971, "result": "partial" }, { "name": "Mars 6", "who": "Soviet Union", "year": 1974, "result": "lost" }, { "name": "Viking 1", "who": "United States", "year": 1976, "result": "worked" }, { "name": "Viking 2", "who": "United States", "year": 1976, "result": "worked" }, { "name": "Mars Pathfinder", "who": "United States", "year": 1997, "result": "worked" }, { "name": "Mars Polar Lander", "who": "United States", "year": 1999, "result": "lost" }, { "name": "Beagle 2", "who": "United Kingdom and ESA", "year": 2003, "result": "silent" }, { "name": "Spirit", "who": "United States", "year": 2004, "result": "worked" }, { "name": "Opportunity", "who": "United States", "year": 2004, "result": "worked" }, { "name": "Phoenix", "who": "United States", "year": 2008, "result": "worked" }, { "name": "Curiosity", "who": "United States", "year": 2012, "result": "worked" }, { "name": "Schiaparelli", "who": "ESA and Russia", "year": 2016, "result": "lost" }, { "name": "InSight", "who": "United States", "year": 2018, "result": "worked" }, { "name": "Perseverance", "who": "United States", "year": 2021, "result": "worked" }, { "name": "Zhurong (Tianwen-1)", "who": "China", "year": 2021, "result": "worked" } ], "sources": [ "wiki_marslanding", "wiki_landers" ] }, "sections": [ { "id": "1.1", "title": "Leaving Earth" }, { "id": "1.2", "title": "The path and the point of no return" }, { "id": "1.3", "title": "Living aboard" }, { "id": "1.4", "title": "The body without weight" }, { "id": "1.5", "title": "Radiation and solar storms" }, { "id": "1.6", "title": "The mind and the view" }, { "id": "1.7", "title": "Arriving: entry, descent and landing" }, { "id": "1.8", "title": "The landing record" }, { "id": "1.9", "title": "The first steps" } ], "facts": [ { "id": "F-01", "section": "1.1", "text": "Company claim: SpaceX's 2020 users guide says the crew version of Starship 'can transport up to 100 people from Earth into LEO and on to the Moon and Mars', with 'private cabins, large common areas, centralized storage, solar storm shelters and a viewing gallery'. Its Starship page still says 'up to 100 people on long-duration, interplanetary flights'.", "compare": "A design promise: no crewed Starship has flown, and none has yet been refilled in orbit (01-01 F-13).", "sources": [ "spacex_ug", "spacex_page" ] }, { "id": "F-02", "section": "1.2", "text": "The cheapest path from Earth's orbit to Mars's is half an ellipse that just touches both, described by Walter Hohmann in {hohmann_year}. Worked out from 01-01's orbit sizes, it takes about {hohmann_d} days. A ship that burns a little harder at departure takes a steeper path; the one drawn on this page, timed to NASA's {cruise_days}-day cruise (01-01 F-15), travels about {path_mkm} million km.", "compare": "The straight-line gap between the planets when the ship arrives is only about {arr_gap_mkm} million km: the ship travels about {path_x} times that, curving round the Sun.", "sources": [ "wiki_hohmann", "nasa_basics" ] }, { "id": "F-03", "section": "1.2", "text": "Perseverance took {p_days} days to travel about {p_path} million km from Earth to Mars. Engineers planned {p_tcm} course corrections during the cruise, {p_atcm} of them in the final {p_appr} days, the approach. The cruise stage was dropped {p_sep} minutes before the capsule hit the top of the atmosphere.", "compare": "Our worked-out path ({path_mkm} million km in {cruise_days} days) is within {path_diff}% of Perseverance's real one, a check on the drawing.", "sources": [ "jpl_m2020" ] }, { "id": "F-04", "section": "1.2", "text": "On 13 April 1970 an oxygen tank exploded on Apollo 13, about {a13_miles} miles ({a13_km} km) from Earth. The crew used the lunar module as a lifeboat, and burns put them back on a 'free-return' path that swung round the Moon and home. They splashed down on 17 April.", "compare": "Home in four days from the Moon. A week into a Mars trip the ship is already about {d7_mkm} million km out, and its path does not lead home (1.2).", "sources": [ "nasa_apollo13" ] }, { "id": "F-05", "section": "1.2", "text": "Inspiration Mars, a private plan announced in 2013, would have flown a married couple past Mars and back in {tito_days} days from January 2018 on a free-return path: no landing, and no aborts after leaving Earth. The foundation ran out of money and stopped work by the end of 2015.", "compare": "A free return that loops back to Earth takes well over a year. The {cruise_days}-day path drawn here would come back round to Earth's orbit after about {orbit_d} days, with Earth near the far side of the Sun.", "sources": [ "wiki_inspiration" ] }, { "id": "F-06", "section": "1.3", "text": "The International Space Station has {iss_hab} m³ of habitable volume inside {iss_press} m³ of pressurised volume, shared by a crew of {iss_crew}: six sleeping quarters, two bathrooms, a gym and a bay window. It travels at about {iss_miles} miles (about {iss_kms} km) a second.", "compare": "About {iss_pp} m³ of living space each, 'larger than a six-bedroom house' in NASA's words.", "sources": [ "nasa_iss" ] }, { "id": "F-07", "section": "1.3", "text": "In 2014 a NASA expert panel recommended a minimum acceptable net habitable volume of {nhv} m³ per person, for a crew of {nhv_crew} on a {nhv_months}-month Mars mission with about six months each way.", "compare": "{nhv} m³ is a room about 4 m by 2.5 m with a 2.5 m ceiling, per person, for half a year.", "sources": [ "nasa_nhv" ] }, { "id": "F-08", "section": "1.3", "text": "Company claim (2017 design): Musk said the ship's cargo area had a pressurised volume of {sx_m3} m³, 'greater than the pressurized area of an A380', and that for Mars it would be laid out as {sx_cabins} cabins with two or three people each, 'about a hundred people per flight to Mars', plus storage, a galley, a solar storm shelter and an entertainment area. He put the crossing at three months 'in a really good scenario but maybe as much as six months'.", "compare": "{sx_m3} m³ shared by {sx_people} is {sx_pp} m³ each, about a third of NASA's minimum (F-07). At the ISS's share of living space in its pressurised volume ({iss_share}%, F-06), it would be about {sx_live} m³: enough for about {sx_fit} people at NASA's minimum.", "sources": [ "spacex_2017" ] }, { "id": "F-09", "section": "1.3", "text": "Space station food keeps for {iss_shelf_lo} to {iss_shelf_hi} years before its quality and some nutrients fall to unacceptable levels. NASA scientists set a Mars target of at least {mars_shelf} years, whether packaged or grown.", "compare": "At 01-01's {food_kg} kg of packaged food a person a day (01-01 F-29), one person eats about {food_pp} kg on a {cruise_days}-day crossing; {sx_people} people would eat about {food_100} t, {food_100_pct}% of a cargo ship's landed load (01-01 E-09).", "sources": [ "douglas_2021" ] }, { "id": "F-10", "section": "1.3", "text": "NASA's standard limits continuous noise in work areas to its NC-{nc_work} curve (about {nc_work} dB in the middle of hearing's range) and in sleeping quarters on missions over 30 days to NC-{nc_sleep}. On a 1991 Spacelab flight the noise averaged {sl_dba} dBA across the day and rose to {sl_peak} dBA; the crew reported headaches and trouble hearing each other.", "compare": "A ship is never silent: fans, pumps and air handling run for the whole crossing.", "sources": [ "nasa_acoustics" ] }, { "id": "F-11", "section": "1.3", "text": "A ten-year study (Barger and colleagues, 2014) found that {iss_n} space station astronauts slept an average of {sleep_h} hours a night, against {sleep_sched} hours scheduled, and {meds_pct}% used sleep medication at some point.", "compare": "About {sleep_short} hours short each night. Over a {cruise_days}-day crossing that is about {sleep_nights} nights' sleep lost.", "sources": [ "barger_2014" ] }, { "id": "F-12", "section": "1.4", "text": "NASA: 'On the six-month trek between the planets, crews will be weightless', then live in about a third of Earth's gravity on Mars. Weight-bearing bones lose on average {bone_lo} to {bone_hi}% of their mineral density a month; body fluids shift towards the head and may press on the eyes. Moving between gravity fields upsets balance, coordination and walking.", "compare": "Over a {cruise_days}-day crossing ({cruise_months} months) that is about {trip_bone_lo} to {trip_bone_hi}% of the hip and spine's mineral, lost before the first step on Mars.", "sources": [ "nasa_gravity" ] }, { "id": "F-13", "section": "1.4", "text": "{trappe_n} space station crew members, measured before and after {trappe_m}-month stays despite regular exercise, lost {calf}% of their calf muscle volume and {power}% of its peak power (Trappe and colleagues, 2009).", "compare": "About a third less push from the calves on arrival day, after exercising all the way.", "sources": [ "trappe_2009" ] }, { "id": "F-14", "section": "1.4", "text": "To limit muscle and bone loss, space station crews exercise at least {ex_h} hours a day, with a treadmill, an exercise bike and a resistance machine.", "compare": "Over a {cruise_days}-day crossing that is about {ex_total} hours, {ex_weeks} forty-hour working weeks of exercise.", "sources": [ "nasa_iss" ] }, { "id": "F-15", "section": "1.4", "text": "NASA reports that {sans_pct}% of long-stay crew show one or more signs of spaceflight-associated neuro-ocular syndrome (swelling at the back of the eye, a flattened eyeball, folds in the retina, a shift towards long sight), and {sans_clin}% have a clinically concerning case. So far every crew member's vision has been correctable to 20/20 with new glasses.", "compare": "If the station's rates held on the way to Mars, about {sans_of12} of a First crew of {crew_max} (01-01 E-12) would show signs, and about {sans_clin12} would have a concerning case.", "sources": [ "nasa_sans" ] }, { "id": "F-16", "section": "1.4", "text": "Without gravity squeezing the spine, astronauts grow up to {taller_pct}% taller: a {taller_m} m person can gain up to {taller_cm} cm. The height goes again within a few months of returning to gravity.", "compare": "A 1.8 m person arrives about 1.85 m tall, and settles back as gravity returns.", "sources": [ "space_taller" ] }, { "id": "F-17", "section": "1.4", "text": "The only artificial gravity people have made in flight came on {gem_date}, when Gemini XI's crew spun their capsule on a tether to an Agena rocket stage and produced about {gem_g} g. SpaceX's published Mars ship designs (F-01, F-08) describe cabins, common areas and a storm shelter, but no spinning section.", "compare": "At {gem_g} g a 70 kg person would weigh about {gem_grams} grams.", "sources": [ "nasa_gemini11", "spacex_ug", "spacex_2017" ] }, { "id": "F-18", "section": "1.5", "text": "NASA's standard (2022) limits an astronaut's whole career to {career} mSv of spaceflight radiation, the same for all ages and sexes. Curiosity measured about {rad_day} mSv a day on its way to Mars (01-01 F-31).", "compare": "One {cruise_days}-day crossing is about {trip_msv} mSv, {trip_pct}% of a whole career's limit, before a single day on Mars. A round trip with today's rockets, about {rt_msv} mSv (01-01 F-31), is over the limit.", "sources": [ "nasa_radstd", "swri_2013" ] }, { "id": "F-19", "section": "1.5", "text": "In August 1972, between Apollo 16 (April) and Apollo 17 (December), the Sun threw out a storm of fast particles. A US National Research Council book (2002) says astronauts in the command module would have absorbed their 30-day limit of radiation to the skin and eyes within {storm_h} hours.", "compare": "Luck, not planning, kept anyone from being caught out. A Mars crew spends months, not days, beyond Earth's magnetic shield.", "sources": [ "nrc_2002" ] }, { "id": "F-20", "section": "1.5", "text": "NASA's Orion crew are to build a storm shelter within {orion_h} hour of an alert, from stowage bags of supplies, food and water packed round the seats, and stay inside for as long as {orion_stay} hours. NASA's radiation brief recommends a shelter with an extra {sh_lo} cm of water-equivalent shielding for a once-in-a-century storm, {sh_hi} cm for once in a thousand years.", "compare": "{sh_lo} cm of water weighs {sh_kg} kg for every square metre of wall: shelter walls of 20 m² need about {sh_t20} t of water, food or supplies packed round them.", "sources": [ "nasa_orion_2016", "nasa_radstd" ] }, { "id": "F-21", "section": "1.6", "text": "See 01-03 F-14 and F-15, which own Mars-500: {m500_crew} men sealed in a mock spacecraft in Moscow for {m500_days} days (3 June 2010 to 4 November 2011), {m500_prob} of them with sleep problems. The detail for the crossing stays here: sleep rose by {m500_sleep}% across the mission, and one man slipped onto a near-25-hour day (Basner and colleagues, 2013).", "compare": "The authors' lesson: ships and habitats need Earth's daily signals built in: light at set times, meals and exercise.", "sources": [ "basner_2013" ], "moved_to": "01-03 F-14" }, { "id": "F-22", "section": "1.6", "text": "A NASA study of the photographs space station crews choose to take (Robinson and colleagues, 2006) suggests that looking at Earth is part of what keeps them well, and warns that 'Earth out-of-view' may be an important challenge for crews going to Mars, increasing the sense of isolation.", "compare": "About {star_day} days out, Earth shrinks below what the eye can see as a disc (1.6 drawing): from then on home is a bright star.", "sources": [ "robinson_2006" ] }, { "id": "F-23", "section": "1.6", "text": "Cosmonaut and doctor Valeri Polyakov spent {pol_days} days on the Mir space station (8 January 1994 to 22 March 1995), longer than any single flight before or since, to learn how the body copes with a Mars-length mission. His mood fell in the first weeks, then held at its pre-flight level from the second month to the fourteenth.", "compare": "{pol_days} days is a {cruise_days}-day crossing plus about {pol_extra} more days: the one human test that already covers a trip out and most of a trip back.", "sources": [ "wiki_polyakov" ] }, { "id": "F-24", "section": "1.6", "text": "Neil Armstrong and Buzz Aldrin both saw flashes of light with their eyes closed on Apollo 11: cosmic rays passing through the retina and firing its cells. Dark-adapted Apollo crews saw one every {flash_min} minutes on average. Don Pettit described them on the space station as 'luminous dancing fairies'.", "compare": "Beyond Earth's magnetic field, a crew in a dark cabin may see a flash every few minutes: radiation made visible.", "sources": [ "nasa_flashes" ] }, { "id": "F-25", "section": "1.6", "text": "Normal sight (20/20) resolves detail about {acuity} arc minute across. The Moon, {moon_km} km away on average, looks about {moon_arcmin} arc minutes wide from Earth.", "compare": "Worked out on this page: Earth drops below {acuity} arc minute, becoming a point of light, about {star_mkm} million km out; Mars grows past it about {disc_days} days before arrival, and looks as wide as the full Moon only in the last {moon_h} hours or so.", "sources": [ "wiki_acuity", "nasa_moon" ] }, { "id": "F-26", "section": "1.6", "text": "On Perseverance's landing day a radio signal took {p_light} to cross from Mars to Earth; on Curiosity's it took {msl_light} minutes. Radio travels at the speed of light, so the delay grows every day of the crossing.", "compare": "Worked out for the path drawn here: a one-way signal takes about {d30_s} seconds a month out, and about {arr_delay} minutes on arrival. The link itself belongs to 01-05.", "sources": [ "jpl_m2020", "msl_presskit" ] }, { "id": "F-27", "section": "1.7", "text": "Perseverance hit the top of the atmosphere at about {p_entry} km/h. Its heat shield peaked at about {p_peak}°C some {p_peak_s} seconds later. At {p_chute_s} seconds, {p_chute_km} km up and at {p_chute_kmh} km/h, a {p_chute_m} m parachute opened; the heat shield dropped {p_hs} seconds after that. At {p_bs_km} km it left the parachute and flew on rockets from {p_bs_kmh} km/h, slowing to {p_cr_kmh} km/h by {p_cr_m} m, where a sky crane lowered the rover {p_lower} m on cables. Entry to touchdown took about {p_edl} minutes.", "compare": "{p_entry} km/h is about {entry_iss}% of the space station's speed (F-06). By the time the parachute opened, the air alone had taken away about {p_chute_shed}% of that speed and {p_chute_energy}% of its energy of motion, because the energy of a moving thing grows with the square of its speed.", "sources": [ "jpl_m2020" ] }, { "id": "F-28", "section": "1.7", "text": "'Seven minutes of terror': Curiosity's team defined the top of the atmosphere as {msl_ei} km from the centre of Mars, and a plasma cut its radio for about {msl_blackout} seconds on the way in. The landing was over before Earth heard that it had begun. Perseverance steered itself: its camera fixed its position to within about {p_lvs} m in under {p_lvs_s} seconds, and it could move its touchdown by up to {p_trn} m to dodge hazards.", "compare": "The top of the atmosphere is about {ei_alt} km up. Landing target ellipses shrank from {pf_e1} by {pf_e2} km (Pathfinder, 1997) to {p_e1} by {p_e2} km (Perseverance, 2021): about {ell_x} times smaller in area.", "sources": [ "jpl_msl_comm", "jpl_m2020", "nasa_ellipse" ] }, { "id": "F-29", "section": "1.7", "text": "Company claim (2017): 'For Mars entry, you are entering very quickly, going seven and a half kilometers a second', and 'you can remove almost all the energy aerodynamically'. Some heat shield wears away, 'sort of like a brake pad'. The ship lands on its engines, able to land 'with either one of the two center engines' if one fails.", "compare": "{sx_entry} km/s is {sx_entry_kmh} km/h, about {sx_vs_p} times Perseverance's entry speed. 'Almost all the energy' still leaves real speed: when Perseverance's parachute opened, {p_chute_energy}% of its energy was gone but {p_chute_left}% of its speed was left (F-27). The engines still have work to do.", "sources": [ "spacex_2017" ] }, { "id": "F-30", "section": "1.7", "text": "Starship's heat shield is about {tiles} black hexagonal tiles, rated to about {tile_c}°C. Starship comes down belly-first like a skydiver, then flips upright and lights its engines just before touchdown: first tried by the prototype SN8 on {sn8}, which crashed when low fuel-tank pressure starved its engines.", "compare": "The belly flop is Starship's parachute: the whole ship is the airbrake.", "sources": [ "wiki_starship_sc", "wiki_sn8" ] }, { "id": "F-31", "section": "1.7", "text": "Every Mars lander so far has flown straight in from its approach path. Aerocapture, braking into orbit with one pass through the atmosphere, has never been tried on a planetary mission; Mars Odyssey was meant to, but switched to aerobraking, many gentle passes over weeks.", "compare": "Going into orbit first would add a safer pause before landing, but with a technique nobody has flown.", "sources": [ "wiki_aerocapture" ] }, { "id": "F-32", "section": "1.7", "text": "A NASA Ames study (Lyne, 1992) looked at Soviet cosmonauts coming home after {sov_m}-month flights with peak loads of {sov_lo} to {sov_hi} g, and recommended no more than {lyne} g for a crew braking at Mars. Mars Pathfinder slowed from {pf_v0} to {pf_v1} km/s in about three minutes.", "compare": "That is an average of about {pf_g} g for three minutes: robot landers can take far more than a person who has been weightless for months.", "sources": [ "lyne_1992", "wiki_marsentry" ] }, { "id": "F-36", "section": "1.7", "text": "The heaviest thing ever landed on Mars is Perseverance, about {p_kg} kg, in 2021. JPL's chief engineer Rob Manning describes a gap below about Mach {srp_mach} where heavy craft are still too fast for parachutes. A big ship has to fire its engines into the oncoming air while it is still faster than sound: supersonic retropropulsion.", "compare": "A cargo ship lands about {ss_cargo} t of cargo alone (01-01 E-09): {ss_vs_perse} times Perseverance, before counting the ship itself. Parachutes do not grow that far.", "sources": [ "ut_2024", "wiki_perse" ] }, { "id": "F-37", "section": "1.7", "text": "In September 2014 a Falcon 9 first stage relit its engines while falling faster than sound off the coast of Georgia, USA, and NASA filmed it in infrared from an aircraft. NASA called it the first high-quality record of a rocket firing into its direction of travel at supersonic speed in Mars-like conditions. NASA and SpaceX then studied the data together for three years.", "compare": "Every booster that lands on Earth today rehearses the hardest minute of a big Mars landing.", "sources": [ "nasa_srp_2014", "ut_2024" ] }, { "id": "F-38", "section": "1.7", "text": "Entry heat comes mostly from air squeezed in the shock wave in front of the ship, not from friction rubbing on the hull.", "compare": "Like a bicycle pump that warms as you squeeze it, but squeezed at {sx_entry_kmh} km/h. That is why the shield faces the air head-on, belly-first.", "sources": [ "wiki_entry" ] }, { "id": "F-33", "section": "1.8", "text": "{land_n} spacecraft have reached Mars and tried to land. {land_ok} worked. Of the rest, {land_lost} crashed or were lost on the way down, Mars 3 landed in 1971 but fell silent within seconds, and Beagle 2 landed in 2003 but never called home; it was found in photos in 2015.", "compare": "About {land_fail_pct}% of attempts failed. Since Pathfinder in 1997, {since97_ok} of {since97_n} have worked; NASA's own record is {us_ok} of {us_n}.", "sources": [ "wiki_marslanding", "wiki_landers" ] }, { "id": "F-34", "section": "1.9", "text": "NASA tests of people after long bed rest (a stand-in for weightlessness) found that tasks needing balance were the hardest, so crews 'may have difficulty maintaining balance control when landing on Mars'. NASA warns of lightheadedness and fainting at the change of gravity. Back on Earth, most space station crews regain their fitness within {recover} days.", "compare": "{recover} days is about {recover_pct}% of the {stay_days}-day stay on Mars (01-01 F-33).", "sources": [ "nasa_ftt", "nasa_gravity", "nasa_recond" ] }, { "id": "F-35", "section": "1.9", "text": "At the end of his {pol_days}-day flight in 1995, Polyakov chose to walk from the landing capsule rather than be carried, to show that a crew could work on Mars after the long trip.", "compare": "One walk, after more than twice the length of a Mars crossing, onto Earth's full gravity. Mars asks for just over a third of it (NASA, F-12; 02-01 owns the number).", "sources": [ "wiki_polyakov" ] } ], "phases": [ { "id": "launch", "name": "Launch", "text": "Minutes to orbit. The crew go up last, once their ship is full.", "refs": [ "JN-01" ] }, { "id": "refill", "name": "Refilling in orbit", "text": "Tanker ships fly up and refill the crew ship, about a dozen, give or take half (01-01 F-12).", "refs": [ "JN-01" ] }, { "id": "tmi", "name": "Trans-Mars injection", "text": "One long burn out of Earth orbit. After it there is no turning back.", "refs": [ "JN-03" ] }, { "id": "cruise", "name": "The coast", "text": "Months of weightless coasting, with a few small course corrections.", "refs": [ "F-03" ] }, { "id": "approach", "name": "Approach", "text": "The last weeks: final aiming, Mars grows from a star to a disc.", "refs": [ "F-03", "F-25" ] }, { "id": "edl", "name": "Entry, descent and landing", "text": "Minutes from the top of the atmosphere to the pad.", "refs": [ "F-27", "JN-06" ] } ], "assumptions": [ { "id": "JN-01", "confidence": "Low", "text": "A crew ship is refilled in Earth orbit over about {refill_lo} to {refill_hi} weeks before it leaves. The crew launch last, once the ship is full, so they spend days, not weeks, in Earth orbit.", "why": "Refilling takes about a dozen tanker launches, give or take half (01-01 F-11, F-12), and NASA assumed its 16 would fly 'in quick succession'. It has never been done (01-01 F-13). Sending people up last keeps them from using up weightless weeks and supplies before the trip even starts." }, { "id": "JN-02", "confidence": "Medium", "text": "The crossing takes about {cruise_days} days, as in 01-01 (F-15, E-07). The ship coasts weightless, with a handful of small course corrections, most of them in the last six weeks, as on Perseverance.", "why": "Real missions take about {cruise_days} days (01-01 F-15); faster trips need full tanks after refilling (01-01 E-07). Perseverance planned {p_tcm} corrections, {p_atcm} in the last {p_appr} days (F-03)." }, { "id": "JN-03", "confidence": "High", "text": "No turning back after trans-Mars injection. Before the burn, a crew can come home from Earth orbit. After it, every problem is fixed on board with spares and skill, or waited out in the storm shelter, until Mars.", "why": "The {cruise_days}-day path does not come back to Earth on its own: its orbit round the Sun takes about {orbit_d} days, and Earth is then near the far side of the Sun (F-05, worked out). Free-return paths take well over a year (F-05). Apollo 13 had the Moon to swing round (F-04); a Mars crew has nothing between." }, { "id": "JN-04", "confidence": "Low", "text": "People per crewed ship, by era: First crew, {crew_pp_lo} to {crew_pp_hi} (the whole crew of {crew_people}, in the {crew_ships} ships that later fly them home); First Town and the First Martian City, about {city_pp_lo} to {city_pp_hi}. Never the 100 SpaceX has claimed.", "why": "NASA's minimum is {nhv} m³ of living space each (F-07). SpaceX's 2017 cabin of {sx_m3} m³ (F-08) gives {sx_fit} people at the ISS's share of living space, {sx_fit_all} if nearly all of it were living space; 100 people would get {sx_pp} m³ each. So {city_pp_lo} to {city_pp_hi} people is only possible if most of the cabin is living space, far more than the station's share, with stores and machinery kept outside it: one reason confidence is Low. The First crew numbers come from 01-01's era plan (E-12), read live. Who travels is for 01-03." }, { "id": "JN-05", "confidence": "Medium", "text": "No artificial gravity on the way. Everyone exercises about {ex_h} hours a day on the crossing, as on the space station, and people still arrive with weaker bones, legs and balance.", "why": "No published Mars ship design spins (F-17). Even with space-station exercise, crews lose bone (F-12) and about {calf}% of calf muscle in six months (F-13)." }, { "id": "JN-06", "confidence": "Medium", "text": "Ships fly straight into the atmosphere from the approach path, belly-first behind a tiled heat shield, then flip and land on their engines on a pad (03-02). The entry is shaped to keep peak deceleration at or under about {lyne} g for the crew.", "why": "It is how every Mars lander so far has arrived and what SpaceX has described (F-29, F-30, F-31); aerocapture has never been flown (F-31). A ship this heavy cannot use parachutes, so it fires its engines while still faster than sound (F-36), which Falcon 9 boosters already do on Earth (F-37). A NASA study set {lyne} g as the ceiling for people after months weightless (F-32)." }, { "id": "JN-07", "confidence": "Medium", "text": "Every crew ship has a solar storm shelter at its middle, walled by the ship's water, food and supplies, at least {sh_lo} cm water-equivalent thick. The crew can reach it within an hour of a warning and live in it for a day or more.", "why": "SpaceX's designs include one (F-01, F-08); NASA's Orion uses stowed supplies the same way (F-20), and NASA recommends at least {sh_lo} cm of extra water-equivalent (F-20). Storms can deliver a month's safe dose in hours (F-19)." }, { "id": "JN-08", "confidence": "Medium", "text": "The ship keeps a strict day: lights brighten and dim on a schedule, with fixed meals and exercise. In the last weeks the clocks slide towards the Mars day, so crews land already on Mars time.", "why": "Mars-500's crew drifted without strong daily signals, and its authors call for timed light, meals and exercise (F-21). Station crews already sleep short (F-11). The Mars day's length belongs to 02-01." }, { "id": "JN-09", "confidence": "Medium", "text": "A newly landed crew rests and does only light work indoors for about {rest_lo} to {rest_hi} days: medical checks, walking practice, no suited work outside. Full fitness comes back over weeks.", "why": "Balance is the hardest thing after months weightless, and fainting is a risk (F-34). Crews back from the station take up to about {recover} days to recover (F-34). Mars's lower gravity is kinder than Earth's, and Polyakov walked on day one (F-35), so days, not months, before light work. What arrival day is like belongs to 04-05-02." }, { "id": "JN-10", "confidence": "Medium", "text": "Messages, not calls. From about two months out, when a signal takes about {d60_s} seconds each way, talk with Earth is recorded messages; by arrival each reply takes about {arr_rt} minutes there and back.", "why": "Worked out from the path and the speed of light (F-26). The relay network, bandwidth and blackouts belong to 01-05." } ], "links": { "leans_on": [ { "ref": "00", "why": "Library rules: folders, IDs, facts versus assumptions, eras" }, { "ref": "00-01", "why": "Era names and their order (read live)" }, { "ref": "01-01 F-15", "why": "The cruise to Mars, about 200 days, for every trip sum (read live)" }, { "ref": "01-01 E-07", "why": "Trip length in each era" }, { "ref": "01-01 F-01", "why": "Starship's size, for the phase drawing" }, { "ref": "01-01 F-11", "why": "Refilling in orbit: tanker launches per Mars ship" }, { "ref": "01-01 F-13", "why": "Refilling has never been tried" }, { "ref": "01-01 F-29", "why": "Packaged food per person per day, for food on the crossing (read live)" }, { "ref": "01-01 F-31", "why": "Radiation per day in cruise and for a round trip (read live)" }, { "ref": "01-01 F-33", "why": "The surface stay, for recovery time (read live)" }, { "ref": "01-01 E-09", "why": "About 100 t landed per cargo ship, to compare food mass and the heaviest lander so far (read live)" }, { "ref": "01-01 E-12", "why": "People in the First crew and later eras (read live)" }, { "ref": "01-01 calendar", "why": "Orbit sizes and year lengths, for the path, distances and apparent sizes (read live)" }, { "ref": "01-03 F-14, F-15", "why": "Mars-500's crew, length and sleep problems, for F-21 (read live)" } ], "used_by": [ { "ref": "05-20", "why": "Mars games: Perseverance's landing, the body in space and Polyakov's record, for Mars Quiz questions (worked_out)" }, { "ref": "05-08 The journey experience", "why": "The factual trip the visitor's ride is built on: phases, path, views, delay, landing" }, { "ref": "02-06 The human body on Mars", "why": "Reads F-11, F-12, F-14, F-18, F-20, F-23 and F-35: sleep in orbit, bone loss, station exercise, NASA's career limit, the Orion storm shelter and Polyakov's record (read live); cites JN-09 for the first days after landing" }, { "ref": "01-03 Who goes", "why": "Reads F-18 and F-23: NASA's career limit and Polyakov's record (read live)" }, { "ref": "02-07 The Mars sky", "why": "Reads the Moon's distance from Earth (read live)" }, { "ref": "03-06 Habitats", "why": "Reads F-06, F-07, F-08, F-20: the station's volume, NASA's minimum per person, SpaceX's cabin volume and the storm shelter's water thickness (read live). Cites F-10 (noise limits), JN-07 (the ship's storm shelter) and JN-09 (rest days in the ship)" }, { "ref": "03-08 Spacesuits", "why": "Reads JN-09: no suited work in a crew's first days (read live)" }, { "ref": "03-09 Life support", "why": "Cites F-04: the Apollo 13 explosion, before its carbon dioxide problem" }, { "ref": "03-13 Local communications", "why": "Reads F-28: Perseverance's camera fixed its landing position to about 40 m (read live)" }, { "ref": "04-02-03 Staying for good", "why": "Reads JN-04: people per crewed ship, for seats home each window (read live)" }, { "ref": "04-02-02 Money and trade", "why": "Reads JN-04: people per crewed ship, for seats home and visitors (read live)" }, { "ref": "04-03-02 Food and home life", "why": "F-10: NASA's noise limit for sleeping quarters (read live); F-11: astronauts' sleep on the station (read live); F-21: timed light, meals and exercise keep body clocks steady" }, { "ref": "04-04-02 A day in the life", "why": "F-11: astronaut sleep against schedule (read live); F-14: the space station's daily exercise (read live)" }, { "ref": "04-05-01 Characters", "why": "JN-04: the whole First crew fits the ships that fly it home" }, { "ref": "04-05-02 Arrival day", "why": "JN-09: the first days' rest after landing; 04-05-02 tells what arrival day is like; JN-04: people per crewed ship (read live); JN-08: ship clocks already on Mars time; AR-02 proposes the same for the air; F-26: signal delay on landing days (read live); F-30: Starship's belly-flop landing (read live); F-32: the 5 g ceiling for a crew braking at Mars (read live); F-34: balance and fainting after long flights (read live); F-35: Polyakov walked from his capsule (read live)" }, { "ref": "00-04 Glossary and units", "why": "F-18: NASA's career dose limit, for the dose ladder (read live)" }, { "ref": "03-03 Power", "why": "JN-04: people per crewed ship, for the cargo a window lands once crewed ships are counted (read live)" }, { "ref": "03-12 Manufacturing", "why": "JN-04: people per crewed ship, for the cargo a window lands once crewed ships are counted (read live)" }, { "ref": "03-15 Waste and recycling", "why": "JN-04: people per crewed ship, for the cargo a window lands once crewed ships are counted (read live)" }, { "ref": "04-02-04", "why": "People per crewed ship, for the Many Cities arrivals check (read live)" }, { "ref": "01-09", "why": "How the rockets fly reads Earth's radius (a copy kept here) to draw the curve of the Earth under each climb" }, { "ref": "01-10", "why": "Who got us here reads Earth's radius (a copy kept here) to say how far Artemis II went in Earths" }, { "ref": "03-10", "why": "Water's density, to size the water roof (GF-17)" } ] }, "open_questions": [ "02-06 The human body on Mars: how the body recovers from the crossing in Mars gravity over the 500-day stay, and what that means for the trip home.", "Re-check SpaceX's crewed ship figures when a new Starship crew design is published; the 825 m³ figure is from 2017.", "04-05-02 AR-02 proposes bringing the crew ship's cabin air down, a step at a time in the last weeks of the crossing, to the town's air (03-09 LS-01), so nothing changes on arrival day. The ship's cabin air belongs here: accept, change or refuse it (JN-08 already slides the ship's clocks to Mars time)." ], "changes": [ "25 September 2026 (v1.0): Written. The journey from Earth orbit to the Mars surface: phases, the path worked out from 01-01's orbit sizes, living aboard, the body without weight, radiation and storm shelters, the mind and the view, entry, descent and landing, the landing record and the first steps. 35 sourced facts and 10 assumptions (JN-01 to JN-10).", "25 September 2026 (v1.0): The brief's 'roughly half of all Mars landing attempts have failed' checked against a full list: 6 of 16 landers that reached Mars failed (about 4 in 10). Earlier counts that include launch failures and probes that never reached Mars come out nearer half.", "25 September 2026 (v1.1): Independent check. The landing record (10 of 16 worked) re-counted from the list, and the 825 m³ figure, 40 cabins and entry quotes confirmed in SpaceX's 2017 transcript, where 825 m³ is the pressurised volume of the ship's cargo area: F-08 now says so. Perseverance's landing numbers, the ISS, NASA's habitable-volume minimum, SANS, sleep, noise, food, radiation, Mars-500 and Polyakov facts confirmed at their sources. JN-04 now says openly that 20 to 30 people per ship needs far more of the cabin as living space than the station's share; the 1.3 caption no longer implies the station share supports 20 to 30. The by-era caption now says later eras may be faster (01-01 E-07), rather than 200 days in every era. 01-03 and 01-05 removed from used_by: neither reads this file yet, so the links were one-sided; both hand-offs stay in the open questions.", "25 September 2026 (v1.0): SpaceX's '1,000 m³' cabin figure could not be found in any SpaceX source; the page uses SpaceX's own 2017 figure, 825 m³, labelled as a claim.", "26 September 2026 (v1.2): Mars-500 is owned by 01-03 (F-14, F-15): F-21 is now a signpost that reads the crew, days and sleep problems live from 01-03, keeping only its own sleep detail (8.4%); the copies in numbers.mind are removed. 01-03 added to quotes and leans_on. F-15's comparison now reads the largest First crew from 01-01's era plan (E-12) instead of a typed 12. used_by: 03-02 removed (it does not read JN-06; the pointer to 03-02 stays in JN-06's text); 01-03 and 02-07 added (they read F-18, F-23 and the Moon's distance); 02-06's reason now lists what it really reads.", "26 September 2026 (v1.3): used_by adds 03-06, 03-08 and 03-09, each with what it reads.", "26 September 2026 (v1.4): used_by adds 03-13 (Perseverance's landing fix, F-28) and 04-02-03 (people per crewed ship, JN-04, for seats home).", "26 September 2026 (v1.5): used_by adds 04-02-02 Money and trade, which reads JN-04 live.", "26 September 2026 (v1.6): New open question: 04-05-02 AR-02's proposal to bring the ship's cabin air to the town's before landing (with 03-09). used_by: back-links for 04-03-02, 04-04-02, 04-05-01, 04-05-02 (what each reads, from its leans_on).", "26 September 2026 (v1.7): Open question deleted as answered: ship interiors, the visitor's cabin and what the ride shows (05-08 JE-08).", "26 September 2026 (v1.8): Shelf life names a re-check date (March 2027), as the Research log (90-04) audit asked. Back-link for 00-04, which reads NASA's career dose limit (F-18) live.", "26 September 2026 (v1.9): Beauty pass: a new opening picture, the ship coasting between a crescent Earth and Mars, labelled as art.", "26 September 2026 (v1.10): Final fix round: Two open questions deleted as answered: people per crewed ship and the First crew (01-03, 04-05-01 CH-03), and the delay curve, bandwidth and blackout (01-05 section 1.1, EL-03, EL-06). The opening picture's Earth is drawn more than half lit, as it is seen from a ship outbound beyond Earth's orbit, not as a thin crescent", "30 September 2026 (v1.11): Gravity described as 'just over a third' of Earth's, to match 02-01's 38%.", "1 October 2026 (v1.12): used_by adds 04-02-04, the new pages on computing and on needing nothing from Earth.", "1 October 2026 (v1.13): used_by: 03-03, 03-12 and 03-15 now read JN-04's people per crewed ship for the library's cargo rule.", "3 October 2026 (v1.14): Era names follow the owner's new names (00-01): Mars Today, Robots First, First Town, Many Cities; First Human Landing and The First Martian City, Arcadia, where an era is named as such.", "3 October 2026 (v1.15): Landing section checked against a brief that said the air does 99% of the slowing. The 2017 claim is about energy, not speed (F-29), so F-27 and F-29 now show both: at Perseverance's parachute nearly all the energy was gone but a real share of the speed was left. New F-36 (the heaviest lander so far and why heavy ships must fire their engines faster than sound), F-37 (NASA filming a Falcon 9 doing it in 2014) and F-38 (entry heat is squeezed air, not friction). JN-06 now cites them. The height-speed chart shows speed left against energy left.", "4 October 2026 (v1.16): Now also used by 01-09 How the rockets fly, for Earth's radius.", "9 October 2026 (v1.17): Now also used by 01-10 Who got us here, for Earth's radius.", "10 October 2026 (v1.18): 03-10 now quotes this file for water's density, to size the water roof (GF-17); used_by updated." ], "sources": { "spacex_ug": { "name": "SpaceX, Starship Users Guide, revision 1.0, March 2020", "url": "https://www.spacex.com/media/starship_users_guide_v1.pdf" }, "spacex_page": { "name": "SpaceX, Starship vehicle page (accessed September 2026)", "url": "https://new.spacex.com/vehicles/starship" }, "spacex_2017": { "name": "SpaceX, Making Life Multiplanetary, Elon Musk's IAC talk, transcript, 29 September 2017", "url": "https://www.spacex.com/media/making_life_multiplanetary_transcript_2017.pdf" }, "wiki_hohmann": { "name": "Wikipedia, Hohmann transfer orbit, 2026", "url": "https://en.wikipedia.org/wiki/Hohmann_transfer_orbit" }, "nasa_basics": { "name": "NASA Science, Basics of Space Flight, chapter 4: interplanetary trajectories (accessed September 2026)", "url": "https://science.nasa.gov/learn/basics-of-space-flight/chapter4-1/" }, "jpl_m2020": { "name": "NASA JPL, Mars 2020 Perseverance landing press kit: mission overview, February 2021", "url": "https://www.jpl.nasa.gov/news/press_kits/mars_2020/landing/mission/" }, "nasa_apollo13": { "name": "NASA, Apollo 13: mission details (accessed September 2026)", "url": "https://www.nasa.gov/missions/apollo/apollo-13-mission-details/" }, "wiki_inspiration": { "name": "Wikipedia, Inspiration Mars Foundation, 2026", "url": "https://en.wikipedia.org/wiki/Inspiration_Mars_Foundation" }, "nasa_iss": { "name": "NASA, International Space Station facts and figures (accessed September 2026)", "url": "https://www.nasa.gov/international-space-station/space-station-facts-and-figures/" }, "nasa_nhv": { "name": "NASA Human Research Program, Minimum Acceptable Net Habitable Volume for Long-Duration Exploration Missions: expert consensus session report, 2014", "url": "https://ntrs.nasa.gov/api/citations/20140016951/downloads/20140016951.pdf" }, "douglas_2021": { "name": "Douglas and colleagues (NASA), Spaceflight food system: impacts to nutritional adequacy, white paper for the National Academies decadal survey, 2021", "url": "https://science.nasa.gov/wp-content/uploads/2023/05/217_c45375645fac320a40021ce82d71213c_DouglasGraceL.pdf" }, "nasa_acoustics": { "name": "NASA Office of the Chief Health and Medical Officer, NASA-STD-3001 technical brief: acoustics, revision C, October 2023", "url": "https://www.nasa.gov/wp-content/uploads/2023/12/ochmo-tb-035-acoustics.pdf" }, "barger_2014": { "name": "Brigham and Women's Hospital (EurekAlert), Ten-year study highlights sleep deficiency and sleep medication use in astronauts (Barger and colleagues, The Lancet Neurology), 8 August 2014", "url": "https://www.eurekalert.org/news-releases/595450" }, "nasa_gravity": { "name": "NASA Human Research Program, Hazard: gravity fields (accessed September 2026)", "url": "https://www.nasa.gov/hrp/hazard-gravity-fields" }, "trappe_2009": { "name": "Trappe and colleagues, Exercise in space: human skeletal muscle after 6 months aboard the International Space Station, Journal of Applied Physiology, 2009", "url": "https://epublications.marquette.edu/bio_fac/24/" }, "nasa_sans": { "name": "NASA Office of the Chief Health and Medical Officer, Spaceflight associated neuro-ocular syndrome (SANS), medical technical brief, 21 February 2024", "url": "https://www.nasa.gov/wp-content/uploads/2024/02/ochmo-mtb-001-sans.pdf" }, "space_taller": { "name": "Space.com, New study examines why astronauts grow taller in space, 2013", "url": "https://www.space.com/19116-astronauts-taller-space-spines.html" }, "nasa_gemini11": { "name": "NASA, Sept. 14, 1966: Gemini XI artificial gravity experiment (accessed September 2026)", "url": "https://www.nasa.gov/image-article/sept-14-1966-gemini-xi-artificial-gravity-experiment/" }, "nasa_radstd": { "name": "NASA Office of the Chief Health and Medical Officer, Radiation protection technical brief (NASA-STD-3001), 2023", "url": "https://www.nasa.gov/wp-content/uploads/2023/03/radiation-protection-technical-brief-ochmo.pdf" }, "swri_2013": { "name": "Southwest Research Institute, SwRI-led team calculates the radiation exposure associated with a trip to Mars, 30 May 2013 (the figure 01-01 F-31 owns)", "url": "https://www.swri.org/newsroom/press-releases/swri-led-team-calculates-the-radiation-exposure-associated-trip-mars" }, "nrc_2002": { "name": "US National Research Council, Storms from the Sun: The Emerging Science of Space Weather, chapter 9, National Academies Press, 2002", "url": "https://www.nationalacademies.org/read/10249/chapter/11" }, "nasa_orion_2016": { "name": "NASA, Scientists and engineers evaluate Orion radiation protection plan, September 2016", "url": "https://www.nasa.gov/missions/artemis/orion/scientists-and-engineers-evaluate-orion-radiation-protection-plan/" }, "basner_2013": { "name": "Basner and colleagues, Mars 520-d mission simulation reveals protracted crew hypokinesis and alterations of sleep duration and timing, PNAS, 2013", "url": "https://www.med.upenn.edu/uep/assets/user-content/documents/PNAS2013Basner1212646110withSupportingAppendix.pdf" }, "robinson_2006": { "name": "Robinson, Slack and colleagues, Patterns in crew-initiated photography of Earth from ISS: is Earth observation a salutogenic experience?, NASA, 2006", "url": "https://ntrs.nasa.gov/api/citations/20090006921/downloads/20090006921.pdf" }, "wiki_polyakov": { "name": "Wikipedia, Valeri Polyakov, 2026", "url": "https://en.wikipedia.org/wiki/Valeri_Polyakov" }, "nasa_flashes": { "name": "Nancy Atkinson, 'Seeing' cosmic rays in space, Universe Today, 19 April 2012 (archived by NASA)", "url": "https://www.nasa.gov/wp-content/uploads/2021/11/seeingcosmicraysinspace.pdf" }, "wiki_acuity": { "name": "Wikipedia, Visual acuity, 2026", "url": "https://en.wikipedia.org/wiki/Visual_acuity" }, "nasa_moon": { "name": "NASA NSSDCA, Moon fact sheet (accessed September 2026)", "url": "https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html" }, "msl_presskit": { "name": "NASA, Mars Science Laboratory landing press kit, July 2012", "url": "https://solarsystem.nasa.gov/docs/MSL%20Press%20Kit%20Landing%283%29.pdf" }, "jpl_msl_comm": { "name": "Makovsky, Ilott and Taylor, Mars Science Laboratory telecommunications system design, JPL DESCANSO series, chapter 8, 2014", "url": "https://descanso.jpl.nasa.gov/monograph/series13/DeepCommo_Chapter8--141029.pdf" }, "nasa_ellipse": { "name": "NASA Science Photojournal, Zeroing in on the target (landing ellipses of past Mars missions), 2020", "url": "https://science.nasa.gov/photojournal/zeroing-in-on-the-target" }, "wiki_starship_sc": { "name": "Wikipedia, SpaceX Starship (spacecraft), 2026", "url": "https://en.wikipedia.org/wiki/SpaceX_Starship_(spacecraft)" }, "wiki_sn8": { "name": "Wikipedia, Starship SN8, 2026", "url": "https://en.wikipedia.org/wiki/Starship_SN8" }, "wiki_aerocapture": { "name": "Wikipedia, Aerocapture, 2026", "url": "https://en.wikipedia.org/wiki/Aerocapture" }, "lyne_1992": { "name": "J. E. Lyne, NASA Ames Research Center, Physiological constraints on deceleration during the aerocapture of manned vehicles, 1992", "url": "https://ntrs.nasa.gov/citations/19950010336" }, "ut_2024": { "name": "Universe Today, Nancy Atkinson, The new Mars landing approach: how we'll land large payloads on the Red Planet, 18 November 2024", "url": "https://www.universetoday.com/articles/the-new-mars-landing-approach-how-well-land-large-payloads-on-the-red-planet" }, "nasa_srp_2014": { "name": "NASA, New commercial rocket descent data may help NASA with future Mars landings, 17 October 2014", "url": "https://www.nasa.gov/press/2014/october/new-commercial-rocket-descent-data-may-help-nasa-with-future-mars-landings" }, "wiki_perse": { "name": "Wikipedia, Perseverance (rover), 2026", "url": "https://en.wikipedia.org/wiki/Perseverance_(rover)" }, "wiki_entry": { "name": "Wikipedia, Atmospheric entry, 2026", "url": "https://en.wikipedia.org/wiki/Atmospheric_entry" }, "wiki_marsentry": { "name": "Wikipedia, Mars atmospheric entry, 2026", "url": "https://en.wikipedia.org/wiki/Mars_atmospheric_entry" }, "wiki_marslanding": { "name": "Wikipedia, Mars landing, 2026", "url": "https://en.wikipedia.org/wiki/Mars_landing" }, "wiki_landers": { "name": "Wikipedia, List of Mars landers, 2026", "url": "https://en.wikipedia.org/wiki/List_of_Mars_landers" }, "nasa_ftt": { "name": "NASA, Walk the line: NASA studies physical performance after spaceflight, 29 September 2015", "url": "https://www.nasa.gov/humans-in-space/walk-the-line-nasa-studies-physical-performance-after-spaceflight/" }, "nasa_recond": { "name": "NASA, The real story about astronaut health care in space (accessed September 2026)", "url": "https://www.nasa.gov/missions/station/faq-the-real-story-about-astronaut-health-care-in-space/" } }, "sources_checked": "25 September 2026" }, "01-03": { "file": "01-03", "title": "Who goes", "folder": "01", "facts_file": "01-03-who-goes.json", "version": "1.11", "status": "Active", "last_updated": "3 October 2026", "about": "Facts file for 01-03 Who goes. The page is built from this file, the library catalogue and the page template. Change a fact here, then run build.py. Words in curly brackets, like {nasa21_odds}, are filled in from the numbers in this file when the page is built, so each number is typed once. Numbers owned by other files (the era names, people per era, the time away, the round-trip radiation dose, the cargo price and the food eaten per day) are read live from 00-01 and 01-01, never retyped here.", "one_line": "Who is chosen to go to Mars, how, and how the mix changes from a handful of specialists to a city of settlers.", "shelf_life": "Astronaut selections, analogue missions and company claims change every year or two. NASA's CHAPEA 2 crew is due out of its habitat in late 2026, NASA's radiation standard is revised every few years (NASA-STD-3001), ESA and JAXA open new calls every decade or so, and SpaceX has published no crew or ticket plan. Re-check the selection numbers, the radiation limit and any SpaceX statement on crews or ticket prices by September 2027.", "header": { "purpose": "Say who goes to Mars in each era of our world, how they are chosen and why: the real selection systems of NASA, ESA, JAXA and China, what a Mars trip adds (isolation, distance, radiation, age), what analogue missions have taught, the Mars One warning, and the promise of settlers buying tickets.", "why": "Every scene has people in it. Who they are, how old, what they know and how they were picked shapes the characters, the jobs, the tensions and the look of every era. Without one agreed answer, each file invents its own crew.", "when": "Writing a character, a crew, a job or an arrival scene; deciding how many doctors or engineers are on Mars in an era; or checking a selection, age or radiation number in another file.", "change": "Part One changes only with a citation. Part Two assumptions can be challenged one at a time. The number of people in each era belongs to 01-01's era plan (E-12), not here. Edit this facts file, then run build.py.", "writing": "Every number is compared to something people know. Pictures first, short sentences, no walls of text." }, "comparisons": { "pool_m3": 2500, "tennis_court_m2": 260.8, "sqft_m2": 0.0929, "note": "Yardsticks for drawings and comparisons only: an Olympic pool is 50 m by 25 m by 2 m deep; a doubles tennis court is 23.77 m by 10.97 m (International Tennis Federation rules)." }, "numbers": { "mercury": { "stages": [ 508, 110, 32, 7 ], "stage_names": [ "test pilot records screened", "ranked and reviewed", "sent for medical tests", "chosen" ], "max_age": 40, "max_height": "5 ft 11 in", "jet_hours": 1500, "year": 1959 }, "nasa": { "y2017": { "applicants": 18300, "selected": 12 }, "y1978_record": 8000, "y2021": { "applicants": 12000, "selected": 10 }, "y2025": { "applicants": 8000, "selected": 10, "women": 6 }, "since_1959": 370, "training_years": 2, "age_range": [ 26, 46 ], "age_avg": 34 }, "esa": { "stages": [ 22523, 1361, 400, 17 ], "stage_names": [ "applied", "invited to stage two", "tested in Cologne", "chosen" ], "career": 5, "reserve": 11, "disability": 1, "women_pct": 24, "disability_applicants": 257, "months": 17, "months_note": "From applications closing (18 June 2021) to the new class being named (23 November 2022)." }, "jaxa": { "applicants": 4127, "selected": 2 }, "china": [ { "year": 1998, "n": 14 }, { "year": 2010, "n": 7 }, { "year": 2020, "n": 18 }, { "year": 2024, "n": 10 } ], "harvard": { "applicants": 54008, "admitted": 1937 }, "oxford": { "applicants": 23000, "places": 3300 }, "mars_one": { "stages": [ 202586, 4227, 1058, 660, 100 ], "stage_names": [ "claimed", "finished an application", "round two", "round three", "the 'Mars 100'" ], "fee_usd": [ 5, 73 ], "death_days": 68, "falcon_claim": 6, "falcon_mit": 15, "spares_pct": 62, "cost_usd_bn": 6, "debt_eur_m": 1 }, "days": { "iss": 180, "hiseas": 365, "chapea": 378, "mars500": 520, "concordia": 300 }, "mars500": { "crew": 6, "volume_m3": 550, "control_conflicts": 41, "crew_conflicts": 8, "sleep_problems": 4, "rest_up_pct": 50.4, "calm": 2 }, "chapea": { "crew": 4, "area_sqft": 1700, "delay_min": 22, "age": [ 30, 55 ] }, "hiseas": { "crew": 6, "dome_m": 11 }, "concordia": { "winter_max": 16, "no_flights_months": 9, "altitude_m": 3200, "low_c": -80, "nearest_km": 600 }, "sandal": { "crews": 2, "people": 27 }, "mdrs": { "crews": 270, "since": 2001, "crew": 6, "rotation_weeks": 2 }, "exmo": { "covered_pct": 89, "gaps": 16 }, "salotti_min": 110, "smith_founders": [ 14000, 44000 ], "radiation_msv": { "old_woman_30": 180, "old_man_60": 700, "iss_6mo": [ 50, 180 ], "mars_mission": 1070, "exceed_pct": 150 }, "glenn_age": 77, "women_pct_2020": 12, "musk": { "now_usd_bn": 10, "target_usd_k": 200, "ticket_usd_k": [ 100, 500 ], "per_ship": [ 100, 200 ] }, "mars_direct_crew": 4 }, "sections": [ { "id": "1.1", "title": "How astronauts are chosen today" }, { "id": "1.2", "title": "The odds" }, { "id": "1.3", "title": "What Mars adds: the mind and the team" }, { "id": "1.4", "title": "Skills and crew size" }, { "id": "1.5", "title": "Age, sex and radiation" }, { "id": "1.6", "title": "Mars One: a warning" }, { "id": "1.7", "title": "Settlers and the ticket" } ], "facts": [ { "id": "F-01", "section": "1.1", "text": "NASA's first astronaut call, in January {mc_year}, asked for men under {mc_age}, shorter than {mc_height} (to fit the Mercury capsule), with a degree, test pilot school and {mc_hours} hours of jet flying. From {mc_s0} test pilot records, {mc_s1} were reviewed, {mc_s2} went for medical tests and {mc_s3} were chosen, announced on 9 April {mc_year}.", "compare": "1 in {mc_odds} of an already elite pool. The height limit was set by the size of the spacecraft, not the job.", "sources": [ "nasa_mercury7" ] }, { "id": "F-02", "section": "1.1", "text": "To apply to NASA today you must be a US citizen with a master's degree in science, engineering, computing or maths (or a medical degree, doctoral work or test pilot school), have two years of related work or 1,000 hours as pilot in command of jets, and pass NASA's long-duration spaceflight physical.", "compare": "No age limit and no height rule: the spacecraft now fit people, not the other way round.", "sources": [ "nasa_requirements" ] }, { "id": "F-03", "section": "1.1", "text": "More than {n17_a} people applied to join NASA's 2017 astronaut class, a record: the previous best was {n78} in 1978. NASA chose {n17_s}.", "compare": "1 in {nasa17_odds}: about {nasa17_x} times harder to get into than Harvard (F-10).", "sources": [ "nasa_record_2016", "npr_2017" ] }, { "id": "F-04", "section": "1.1", "text": "NASA's 2021 class of {n21_s} was chosen from more than {n21_a} applicants. Its members then spent more than two years in basic training (spacewalks, robotics, station systems, T-38 jets) before they could be given a flight.", "compare": "1 in {nasa21_odds}. Selection is the start of the wait, not the end: about {n_train} years before anyone can be named to a crew.", "sources": [ "nasa_2021_grad", "nasa_requirements" ] }, { "id": "F-05", "section": "1.1", "text": "On 22 September 2025 NASA named its 2025 class: {n25_s} people ({n25_w} women and {n25_m} men) from more than {n25_a} applicants, including pilots, engineers, a geologist and medical people. They bring NASA's total to {n_total} astronaut candidates since 1959.", "compare": "1 in {nasa25_odds}. {n_total} candidates in 66 years: about six a year.", "sources": [ "nasa_2025" ] }, { "id": "F-06", "section": "1.1", "text": "ESA's 2021 to 2022 selection had {esa_s0} applicants, {esa_women}% of them women. {esa_s1} were invited to stage two and just over {esa_s2} were tested in Cologne. Six stages (screening, cognitive and personality tests, psychometric and group exercises, medicals, and two interview rounds) left {esa_s3}: {esa_career} career astronauts, {esa_reserve} in reserve and {esa_dis} astronaut with a disability, named on 23 November 2022.", "compare": "1 in {esa_odds} for any place; 1 in {esa_career_odds} for a career astronaut's job.", "sources": [ "esa_2022", "esa_timeline", "wiki_esa2022", "spacenews_esa" ] }, { "id": "F-07", "section": "1.1", "text": "John McFall, a British orthopaedic surgeon who lost his right leg in a motorcycle accident at 19 and won Paralympic sprint bronze in Beijing in 2008, joined ESA's reserve in 2022 as the first astronaut with a physical disability. In February 2025 ESA cleared him medically for a long-duration space station mission. {esa_dis_apps} people had applied for that place.", "compare": "The rule used to be 'fit the machine'. For the first time an agency asked what it would take to make the machine fit the person.", "sources": [ "smithsonian_mcfall", "wiki_esa2022" ] }, { "id": "F-08", "section": "1.1", "text": "Japan's space agency JAXA chose {jx_s} astronaut candidates on 28 February 2023 from {jx_a} applicants: Makoto Suwa, 46, a World Bank disaster-risk specialist with a geoscience PhD, and Ayu Yoneda, 28, a surgeon. For this call JAXA had dropped its science or engineering degree requirement.", "compare": "1 in {jaxa_odds}. Neither is a pilot: one studies climate and disasters, the other operates on people.", "sources": [ "jaxa_2023", "phys_jaxa" ] }, { "id": "F-09", "section": "1.1", "text": "China has chosen astronauts in four batches: {cn_list}. The first were all air force pilots; the 2020 batch added flight engineers and payload specialists, and in 2024 China chose payload specialists from Hong Kong and Macao for the first time.", "compare": "{cn_total} people in 26 years, about two a year. China now picks scientists and engineers, not only pilots.", "sources": [ "china_2024" ] }, { "id": "F-10", "section": "1.2", "text": "Harvard College admitted {hv_s} of {hv_a} applicants to its class of 2028.", "compare": "1 in {harvard_odds}, one of the hardest places on Earth to get into, and still about {harvard_x} times easier than NASA's 2021 astronaut call.", "sources": [ "crimson_2028" ] }, { "id": "F-11", "section": "1.2", "text": "Over {ox_a} people applied for undergraduate study at the University of Oxford in 2024, for around {ox_s} places a year.", "compare": "About 1 in {oxford_odds}.", "sources": [ "oxford_stats" ] }, { "id": "F-12", "section": "1.3", "text": "NASA's Human Research Program names five hazards of spaceflight: radiation, isolation and confinement, distance from Earth, gravity fields, and hostile closed environments. On isolation it says crews 'must be carefully chosen, trained, and supported to ensure they can work effectively as a team for months or years in space'.", "compare": "Two of the five, isolation and distance, are about the mind and the team, not the body.", "sources": [ "nasa_hazards" ] }, { "id": "F-13", "section": "1.3", "text": "See 01-02 F-23, which owns the record: Valeri Polyakov's {d_poly} days aboard Mir (8 January 1994 to 22 March 1995), still the longest single stay in space.", "compare": "A Mars crew is away about {trip_days} days (01-01 F-33), about {poly_x} times the record, with no way to come home early.", "sources": [ "britannica_polyakov" ], "moved_to": "01-02 F-23" }, { "id": "F-14", "section": "1.3", "text": "In Mars-500, six men (three chosen by Russia, two by ESA, one by China) lived sealed in a {m5_vol} cubic metre chamber in Moscow for {d_m5} days, from 3 June 2010 to 4 November 2011. They reported {m5_ctl} conflicts with mission control and only {m5_crew} with each other. Two of the six showed no disturbances or distress at all.", "compare": "Five times as much friction with the people on the radio as with the people in the room. The chamber was about a fifth of an Olympic pool ({m5_pool}%).", "sources": [ "basner_plos_2014" ] }, { "id": "F-15", "section": "1.3", "text": "The Mars-500 crew grew steadily more sedentary: rest time rose {m5_rest}% over the mission. {m5_sleep} of the six had at least one sleep problem, such as a drifting body clock or chronic short sleep.", "compare": "Without sunrise or a commute, the body slowly winds down. Light and a fixed routine matter as much as the people chosen.", "sources": [ "basner_pnas_2013" ] }, { "id": "F-16", "section": "1.3", "text": "HI-SEAS IV put {hs_crew} people from France, Germany and the United States in a dome {hs_dome} m across on the slopes of Mauna Loa, Hawaii, for a year (August 2015 to August 2016). They said the hardest part was monotony: 'always in the same place, always with the same people'.", "compare": "Not danger, but boredom. A year of powdered cheese and the same five faces.", "sources": [ "phys_hiseas_2016" ] }, { "id": "F-17", "section": "1.3", "text": "NASA's first CHAPEA crew lived {d_ch} days (25 June 2023 to 6 July 2024) in Mars Dune Alpha, a 3D-printed {ch_sqft} sq ft habitat in Houston. The four were a stem-cell research scientist (commander), a structural engineer (flight engineer), an emergency physician specialising in austere medicine (medical officer) and a US Navy microbiologist (science officer).", "compare": "{ch_m2} square metres for four: about {ch_court} of a tennis court. The crew is a job list: command, engineering, medicine, science.", "sources": [ "nasa_chapea1_crew", "nasa_chapea1", "space_chapea" ] }, { "id": "F-18", "section": "1.3", "text": "NASA's call for its next CHAPEA crew asked for healthy, non-smoking US citizens or permanent residents aged {ch_age_lo} to {ch_age_hi} with astronaut-style qualifications. Crews face resource limits, equipment failures and messages to Earth delayed by up to {ch_delay} minutes each way.", "compare": "An older age band than NASA's astronaut classes (average {n_age_avg} at selection, F-27): steadiness counts more than youth for a year shut in.", "sources": [ "nasa_chapea_call", "wiki_chapea" ] }, { "id": "F-19", "section": "1.3", "text": "Concordia, the French-Italian station on the Antarctic plateau, winters up to {co_n} people at {co_alt} m, with no flights for about {co_nf} months (planes can reach it only from November to February), four months of darkness and temperatures down to {co_low}°C. The nearest people are {co_km} km away. ESA sends a doctor every year to study the crew as a stand-in for Mars.", "compare": "More cut off than the space station: in an emergency, nobody can come. ESA's nickname for it is 'White Mars'.", "sources": [ "esa_concordia", "sandal_2018" ] }, { "id": "F-20", "section": "1.3", "text": "A study of {sd_n} people over two Concordia winters of about ten months each (Sandal and others, 2018), all screened medically and psychiatrically, found that everyone's coping efforts fell to their lowest around the third quarter of the stay. The authors call it 'psychological hibernation' and suggest it may be a healthy way to cope, not a breakdown.", "compare": "Polar crews have long talked of a 'third-quarter slump'. It is when the end is not yet in sight.", "sources": [ "sandal_2018" ] }, { "id": "F-21", "section": "1.3", "text": "The Mars Society's Mars Desert Research Station in the Utah desert has hosted over {mdrs_n} crews since {mdrs_y}, usually six volunteers at a time for two-week rotations.", "compare": "Short practice runs, like a fire drill: many people get a taste; few have done a year.", "sources": [ "mdrs_reports", "wiki_mdrs" ] }, { "id": "F-22", "section": "1.4", "text": "NASA's Mars reference plan (DRA 5.0) sends a crew of {nasa_crew} (01-01 F-34) and explains the size: 'a reasonable compromise between the skill mix and level of effort for missions of this complexity and duration balanced with the magnitude of the systems and infrastructure needed to support this crew'.", "compare": "Each extra person needs more air, food, water and room, so every person must cover more than one job.", "sources": [ "nasa_dra5_sp" ] }, { "id": "F-23", "section": "1.4", "text": "Robert Zubrin's Mars Direct plan (1990) sent {md_crew} astronauts: 'the minimum number required so that the team can be split in two without leaving anyone alone'.", "compare": "Two go outside, two stay in. Never one person alone.", "sources": [ "wiki_mars_direct" ] }, { "id": "F-24", "section": "1.4", "text": "A NASA study of the medical officer for Moon and Mars crews found that emergency medicine plus aerospace medicine covers {ex_pct}% of the skills needed, and {ex_gap} skills are taught by no medical specialty today. Getting a patient back to Earth may take up to two weeks from lunar orbit and may not be possible at all on a Mars mission.", "compare": "The crew doctor must be surgeon, dentist, pharmacist and mental health nurse at once, with no ambulance.", "sources": [ "nasa_exmo" ] }, { "id": "F-25", "section": "1.4", "text": "Jean-Marc Salotti (Scientific Reports, 2020) worked out the smallest settlement that could survive on Mars by counting working hours, not genes: {sal} people, if they share the work well.", "compare": "Inside the era plan's First Town of {town_lo} to {town_hi} people (01-01 E-12): enough hands to farm, build, fix and care.", "sources": [ "salotti_2020" ] }, { "id": "F-26", "section": "1.4", "text": "The anthropologist Cameron Smith (Acta Astronautica, 2014) put the founding population needed to keep a people genetically healthy for five generations with no newcomers at roughly {sm_lo} to {sm_hi}. 'A few hundred' is far too few, he wrote.", "compare": "{smith_x} times the era plan's biggest City ({city_hi} people, 01-01 E-12). A settlement smaller than that relies on new arrivals to keep its gene pool healthy.", "sources": [ "smith_2014" ] }, { "id": "F-27", "section": "1.5", "text": "NASA has no age limit. Its astronaut candidates have been between {n_age_lo} and {n_age_hi} when chosen, {n_age_avg} on average.", "compare": "Add two years of training and a few years' wait: most astronauts first fly in their late 30s or 40s.", "sources": [ "nasa_faq" ] }, { "id": "F-28", "section": "1.5", "text": "John Glenn flew on the Space Shuttle in October 1998 at the age of {glenn}, partly to study how spaceflight resembles ageing. He is still the oldest person to orbit Earth.", "compare": "36 years after he first orbited Earth in 1962. Age alone did not stop him.", "sources": [ "nasa_glenn" ] }, { "id": "F-29", "section": "1.5", "text": "NASA's old career radiation limits (set in 1989) kept each astronaut's extra lifetime risk of dying of cancer under 3%, which made them depend on age and sex: about {r_w30} millisieverts for a 30-year-old woman but {r_m60} for a 60-year-old man. 'Radiation-related cancer risk is highest for younger age at exposure.'", "compare": "Under the old rule, a 60-year-old man could take {r_ratio} times the dose of a 30-year-old woman.", "sources": [ "space_radiation_limits", "mit_tr_2021" ] }, { "id": "F-30", "section": "1.5", "text": "See 01-02 F-18, which owns NASA's career limit: {r_lim} millisieverts. What matters for choosing crews stays here: unlike the old limits (F-29), it is 'universal for males and females' and the same at every age (NASA-STD-3001, Revision B, approved early 2022), set by the most sensitive case, a 35-year-old woman.", "compare": "About four six-month space station stays. A six-month stay gives {r_iss_lo} to {r_iss_hi} millisieverts.", "sources": [ "nasa_std_2022", "nasem_2021", "mit_tr_2021", "space_radiation_limits" ], "moved_to": "01-02 F-18" }, { "id": "F-31", "section": "1.5", "text": "The US National Academies (2021) estimated a Mars mission's dose at about {r_mars} millisieverts and concluded it is 'likely to exceed the exposure standard by up to {r_pct} percent'. Such a mission would need a waiver.", "compare": "The flights alone, about {rt_msv} millisieverts on today's rockets (01-01 F-31), are already {rt_pct}% of the career limit, before a single day on the surface.", "sources": [ "nasem_2021" ] }, { "id": "F-32", "section": "1.5", "text": "Valentina Tereshkova became the first woman in space on 16 June 1963. NASA picked its first six women astronauts in January 1978. By June 2020 women were still only {w_pct}% of everyone who had been to space.", "compare": "About 1 in 8. NASA's 2025 class was {n25_w} in {n25_s} (F-05); ESA's applicants were about 1 in 4 women (F-06).", "sources": [ "wiki_women_space" ] }, { "id": "F-33", "section": "1.6", "text": "Mars One, a Dutch company, said {mo_s0} people applied in 2013 for a one-way trip to settle Mars. In 2015 it admitted only {mo_s1} had finished an application. It cut those to {mo_s2}, then {mo_s3}, then the 'Mars 100'. Applicants paid a fee of ${mo_fee_lo} to ${mo_fee_hi}, set by their country's wealth.", "compare": "For every {mo_x} people it claimed, one had really applied.", "sources": [ "ibtimes_mo_2015", "npr_mo_2019" ] }, { "id": "F-34", "section": "1.6", "text": "Joseph Roche, an Irish astrophysicist in the Mars 100, said in 2015 that his only interview was a ten-minute Skype call, and that candidates' rankings rose with points earned by donating to Mars One or buying its merchandise.", "compare": "ESA's selection had six stages over about {esa_months} months (F-06). This took ten minutes and a shopping basket.", "sources": [ "ibtimes_mo_2015", "matter_roche_2015" ] }, { "id": "F-35", "section": "1.6", "text": "An MIT study (Do, de Weck and others, October 2014) found that if Mars One's greenhouses grew all the food, the oxygen they gave off would force air to be vented until the first settler suffocated in about {mo_days} days. It needed {mo_fh_mit} Falcon Heavy launches to start, not {mo_fh}, and spare parts would grow to {mo_spares}% of everything sent.", "compare": "About two months. Choosing people cannot fix a plan that does not keep them alive.", "sources": [ "mit_mo_2014" ] }, { "id": "F-36", "section": "1.6", "text": "Mars One planned to pay for its ${mo_cost} billion mission mainly through a reality television show. Its first landing slipped from 2023 to 2031, and in early 2019 its business was declared bankrupt in Basel, Switzerland, with debts of about €{mo_debt} million.", "compare": "Debts of about €{mo_debt} million against a promise of ${mo_cost} billion: the company never came close to the money it needed.", "sources": [ "npr_mo_2019" ] }, { "id": "F-37", "section": "1.7", "text": "Company claim: in 2016 Elon Musk said a trip to Mars using traditional methods would cost about ${mk_now} billion a person, and that SpaceX aimed to bring it down to about ${mk_tgt},000, about the median price of a US home, with {mk_ship_lo} to {mk_ship_hi} people a ship.", "compare": "A {mk_cut}-fold price cut: promised, not shown.", "sources": [ "nbc_musk_2016" ] }, { "id": "F-38", "section": "1.7", "text": "Company claim: in February 2019 Musk wrote that moving to Mars would 'one day cost less than $500k & maybe even below $100k', with the return ticket free, 'low enough that most people in advanced economies could sell their home on Earth & move to Mars'.", "compare": "At SpaceX's own published cargo price (01-01 F-19), $100,000 carries {kg_lo} kg to Mars and $500,000 carries {kg_hi} kg: about {food_hrs} hours' to {food_days} days' packaged food for one person (01-01 F-29). SpaceX lists no price for a person (01-01 F-21).", "sources": [ "cnbc_musk_2019" ] }, { "id": "F-39", "section": "1.7", "text": "Asked in September 2016 who should go first, Musk said: 'Are you prepared to die? If that's OK, then, you know, you're a candidate for going.' He said he would not recommend sending children on the early flights.", "compare": "The first settlers he described are volunteers for risk, not ticket buyers.", "sources": [ "space_musk_2016" ] } ], "eras": { "about": "Who goes in each era, how they are chosen and how long they stay. The era names come from 00-01 and the number of people from 01-01's era plan (E-12), both read live. The descriptions here are this file's assumptions (WG-01 to WG-12).", "rows": [ { "era": "robots", "who": "No one on Mars. Teams on Earth drive the robots, with a delay of minutes each way.", "chosen": "Engineers and robot operators, hired by the venture's partners.", "stay": "They never leave Earth. Many later apply for the First crew.", "refs": [ "WG-01" ] }, { "era": "crew", "who": "Specialists: career astronauts with long-duration flights, each holding two jobs, men and women, most in their 40s.", "chosen": "By the agencies and partners of the venture, as a team, after a long analogue stay.", "stay": "About one surface stay, home in the next return window (01-01 E-11).", "refs": [ "WG-02", "WG-03", "WG-04", "WG-05", "WG-06", "WG-07" ] }, { "era": "town", "who": "Rotating crews: more technicians and trades than scientists. Drillers, plant and power technicians, builders, mechanics, medics, cooks.", "chosen": "By employers, like staff for an Antarctic winter: medical and psychological screening, astronaut-style training.", "stay": "Most stay two return windows, so crews overlap and hand over in person; some one (WG-14). Everyone has a seat home.", "refs": [ "WG-08", "WG-10", "WG-14" ] }, { "era": "city", "who": "Settlers and their families, plus short-stay workers. Every kind of job a small town needs.", "chosen": "Employers, sponsors and personal applications, still screened medically and psychologically.", "stay": "Most stay for good; a few ships each window fly home (01-01 E-11).", "refs": [ "WG-09", "WG-11", "WG-12" ] } ] }, "skills_by_era": { "about": "Rough share of the people on Mars by kind of work, in percent (WG-13, low confidence). The Robots First era has no one on Mars.", "groups": [ { "id": "command", "name": "Command and piloting" }, { "id": "science", "name": "Science and growing food" }, { "id": "engineering", "name": "Engineering and trades" }, { "id": "medicine", "name": "Medicine" }, { "id": "services", "name": "Services, teaching, admin" }, { "id": "family", "name": "Children and family" } ], "crew": { "command": 15, "science": 30, "engineering": 35, "medicine": 20, "services": 0, "family": 0 }, "town": { "command": 5, "science": 20, "engineering": 55, "medicine": 8, "services": 12, "family": 0 }, "city": { "command": 2, "science": 8, "engineering": 45, "medicine": 5, "services": 25, "family": 15 } }, "first_crew_skills": { "about": "The skills every First crew must cover, each held by at least two people (WG-03).", "skills": [ "Command and piloting", "Reactor and power", "Fuel plant and life support", "Medicine", "Geology and drilling", "Biology and growing food" ], "per_person": 2, "cover": 2 }, "assumptions": [ { "id": "WG-01", "confidence": "Medium", "text": "Robots First: no one goes. The robots that land the reactors and fuel plant and build the first pad are driven from Earth by teams of operators and engineers. Many of the First crew are chosen from these teams, so they arrive already knowing the machines.", "why": "The order is decided: robots and cargo first (01-01 E-10). Driving machines from Earth is how every Mars rover has worked. Knowing the kit is the most useful skill a first crew can bring (F-22)." }, { "id": "WG-02", "confidence": "Medium", "text": "The First crew is chosen by the agencies and companies of the venture (01-01 E-05) from serving career astronauts who have already flown a long mission, plus a few specialists. Selection is years before launch, and every crew has a trained backup crew.", "why": "Every real agency picks from its own career corps and trains them for about two years before any flight (F-04, F-05, F-06, F-08). Nobody has been away as long as a Mars crew (F-13), so proven long-duration flyers are the safest pick. Backups are how every real crew is run." }, { "id": "WG-03", "confidence": "Medium", "text": "In the First crew every essential skill is held by at least two people, and every person holds at least two skills: command and piloting, reactor and power, fuel plant and life support, medicine (at least one emergency physician with aerospace training), geology and drilling, and biology and growing food.", "why": "Six skills held twice is twelve jobs: exactly two each for six people, the low end of the era plan's First crew (01-01 E-12). NASA sizes its crew by skill mix (F-22); a crew must split in two (F-23); the doctor must cover skills no single specialty teaches (F-24); CHAPEA's crew was a job list (F-17)." }, { "id": "WG-04", "confidence": "Medium", "text": "Crews are chosen as teams, not one by one. Final candidates live together in a long analogue (a winter at an Antarctic station or a year in a sealed habitat) and some who pass every test alone are not picked together. Mission control's own staff train with them.", "why": "NASA says crews must be 'chosen, trained, and supported' as teams (F-12). In Mars-500 most friction was with mission control, not within the crew (F-14), and people differed widely (F-14, F-15). Polar and habitat crews find monotony and a third-quarter slump, not danger, the hardest part (F-16, F-20)." }, { "id": "WG-05", "confidence": "Medium", "text": "The First crew is mostly aged 40 to 55 at launch. Older, experienced people with families already raised are preferred over the young.", "why": "Radiation risk is highest for the young (F-29), and the trip is over the career limit however old you are (F-31), so older crews carry less lifetime risk from the same dose. Astronauts are chosen at {n_age_avg} on average and then train and wait for years (F-27). Glenn flew at {glenn} (F-28); CHAPEA took people up to {ch_age_hi} (F-18)." }, { "id": "WG-06", "confidence": "Medium", "text": "Crews mix men and women in roughly equal numbers from the First crew on.", "why": "The single radiation limit (F-30) removed the rule that let women fly less. Recent classes are close to balanced ({n25_w} of {n25_s} women in NASA's 2025 class, F-05), though women have been only {w_pct}% of everyone who has flown (F-32)." }, { "id": "WG-07", "confidence": "Medium", "text": "Every First crew member knowingly accepts a dose above today's career limit and signs an informed-consent waiver. Past dose counts in selection: people who have already used much of their limit are not picked.", "why": "The flights alone are over NASA's career limit (F-31, 01-01 F-31), and the National Academies expect a Mars mission to need a waiver (F-31). Dose rules for people who live on Mars are 04-02-01 CR-13: nobody is asked to go over the career limit a second time, and anyone who chooses to signs a written consent." }, { "id": "WG-08", "confidence": "Medium", "text": "First Town: crews rotate, and most are technicians and trades rather than scientists: drillers, fuel plant and power technicians, builders, mechanics, electricians, medics and cooks. Employers choose them the way polar stations choose winter staff, with medical and psychological screening, then astronaut-style training.", "why": "A town's daily work is keeping power, water, air, fuel and machines running. Antarctic winter crews are screened medically and psychiatrically and trained as teams (F-19, F-20). Crews rotate every window and some stay for two (01-01 E-11)." }, { "id": "WG-09", "confidence": "Low", "text": "City: most people are settlers who choose to stay, many with families, alongside short-stay workers who fly home. They come through employers, sponsors and personal applications, and are still screened medically and psychologically before they fly.", "why": "In the City most people stay for good (01-01 E-11). Musk's vision is of ordinary people moving (F-38), but even he said the early flights are not for children (F-39). Its social side, who stays for life and when families and children come, is now 04-02-03 SG-01, SG-05 and SG-07.", "moves_to": "" }, { "id": "WG-10", "confidence": "High", "text": "No one is chosen for a one-way trip in the First crew or First Town eras. Everyone selected has a seat home in a returning ship; staying longer is agreed on Mars, not signed away on Earth.", "why": "The owner decided that the first crew flies home in the next window and that later crews rotate (01-01 E-11). Mars One's one-way offer (F-33) and plan that could not keep people alive (F-35) are the warning. How long First Town crews stay, and how they hand over, is WG-14." }, { "id": "WG-11", "confidence": "Low", "text": "See 04-02-02 MT-01, which now owns who pays for a trip: in the City most trips are still paid by an employer, a sponsor or the Settlement Authority as part of a work contract; few pay their own way.", "why": "Moved on 26 September 2026 so who pays is written once. Musk's ticket claims stay here (F-37, F-38): at SpaceX's own cargo price (01-01 F-19), $500,000 carries {kg_hi} kg, about {food_days} days' food (01-01 F-29).", "moved_to": "04-02-02 MT-01" }, { "id": "WG-12", "confidence": "Medium", "text": "The First Town can grow into a self-supporting workforce, but the City is not a closed gene pool: it keeps depending on new arrivals from Earth for generations.", "why": "The era plan's First Town, {town_lo} to {town_hi} people (01-01 E-12), brackets Salotti's minimum of {sal} (F-25). The City's {city_lo} to {city_hi} is well below the {sm_lo} to {sm_hi} Smith gives for a people with no newcomers (F-26)." }, { "id": "WG-13", "confidence": "Low", "text": "See 04-04-01 JB-02, which now owns the mix of work by era. The skills chart in section 1.4 keeps this page's first sketch: about a third scientists in the First crew, a fifth in the First Town, under a tenth in the City, where services and families appear.", "why": "Moved on 26 September 2026 so the mix of work is written once. The First crew exists to set up and explore (F-22, WG-03); a town mostly keeps its machines running (WG-08).", "moved_to": "04-04-01 JB-02" }, { "id": "WG-14", "confidence": "Medium", "text": "In the {era_town} a new crew lands every window and most people stay two return windows, about {two_win} days on Mars, so each crew overlaps the next for a whole surface stay and hands over in person. A one-window crew leaves about {gap} days before the next ships land, so it cannot hand over to them: one-window stays are for work that needs no handover, or that someone staying on covers. Seats home, {seats_lo} to {seats_hi} a window, cap how many can rotate.", "why": "Set by the planets: a crew waits about {stay} days on the surface for the trip home (01-01 F-33), and ships from Earth land about every {syn} days, the average Earth-Mars cycle worked out from 01-01's two years (planning rounds it to {window_mo} months). So a one-window crew is gone {gap} days ({syn} less {stay}) before the next one lands. Seats home are the {era_town}'s returning ships (01-01 E-12) times the people each carries (01-02 JN-04). Submarines' two crews hand over in person for the same reason: nobody takes over a live system cold." } ], "links": { "leans_on": [ { "ref": "00", "why": "Library rules: IDs, facts versus assumptions, counting years from the first crew landing (L-18)" }, { "ref": "00-01", "why": "Era names and their order (read live)" }, { "ref": "01-01 E-12", "why": "People in each era, from the era plan (read live)" }, { "ref": "01-01 E-10", "why": "Robots First come first, so no one goes in that era" }, { "ref": "01-01 E-11", "why": "The first crew flies home in the next window; later crews rotate; City settlers mostly stay" }, { "ref": "01-01 E-05", "why": "The venture is a mix of agencies and companies, who choose the crews" }, { "ref": "01-01 F-33", "why": "Time away for a Mars crew, against the longest spaceflight (read live)" }, { "ref": "01-01 F-31", "why": "Radiation dose of the round trip, against NASA's career limit (read live)" }, { "ref": "01-01 F-34", "why": "NASA's reference crew of six, for crew size (read live)" }, { "ref": "01-01 F-19", "why": "SpaceX's cargo price per tonne, to test ticket claims (read live)" }, { "ref": "01-01 F-21", "why": "SpaceX lists no price for a person" }, { "ref": "01-01 F-29", "why": "Packaged food eaten per person per day, for the ticket comparison (read live)" }, { "ref": "01-02 F-18", "why": "NASA's career radiation limit, for the dose chart and F-30 (read live)" }, { "ref": "01-02 F-23", "why": "Polyakov's record, the longest single spaceflight, for time away and F-13 (read live)" } ], "used_by": [ { "ref": "05-20", "why": "Mars games: Astronaut selection and the Mars-500 experiment, for Mars Quiz questions (worked_out)" }, { "ref": "03-14 Medical bay", "why": "The crew doctor's skills and how many medics each era has (WG-03, WG-08, F-24)" }, { "ref": "04-02-03 Staying for good", "why": "Reads F-25 and F-26: the smallest settlement and the genetic founding population (read live). SG-01 takes over WG-09's social side; cites WG-10 (no one-way trips before the City), WG-12 and F-39 (early flights are not for children)" }, { "ref": "04-02-02 Money and trade", "why": "Takes over WG-11 as MT-01 (who pays for a trip); cites WG-10 (a seat home for everyone) and F-37, F-38 (Musk's ticket claims)" }, { "ref": "01-02 The journey", "why": "Reads F-14 and F-15: Mars-500's crew, length and sleep problems, for 01-02 F-21 (read live)" }, { "ref": "01-05 The Earth-Mars link", "why": "Reads F-14: Mars-500's length, for 01-05 F-04 (read live)" }, { "ref": "02-06 The human body on Mars", "why": "Reads F-14 and F-15 (Mars-500, for 02-06 F-25 and its rehearsal chart) and F-16, F-17, F-19, F-20 (HI-SEAS, CHAPEA and Concordia: crews, days, floor area and the delay, for 02-06 F-26 to F-28, which now point here) (read live)" }, { "ref": "03-06 Habitats", "why": "Reads F-14: Mars-500's chamber volume, against living space per person (read live). Cites F-16: HI-SEAS crews found monotony hardest, for the viewing rooms" }, { "ref": "03-10 Greenhouses and food", "why": "Reads F-35: MIT's study of Mars One's greenhouse oxygen (read live)" }, { "ref": "03-12 Manufacturing", "why": "Reads F-35: Mars One's spare parts share (read live)" }, { "ref": "04-02-01 How the city is run", "why": "Reads F-14: Mars-500's conflicts with mission control and within the crew (read live). CR-13 extends WG-07's consent waiver to residents; cites WG-10 (everyone in the early eras has a seat home)" }, { "ref": "04-03-03 Language and culture", "why": "WG-02: the First crew comes from the partners' astronauts: their languages (LG-02); WG-09: City settlers from many countries: many home languages (LG-02); WG-10: no one-way trips in the early eras (F-31); WG-12: the City keeps getting newcomers, so speech does not drift far (LG-05)" }, { "ref": "04-04-01 Jobs", "why": "WG-13: the mix of work by era, taken over as JB-02; WG-03, the First crew's six skills (read live); WG-01, WG-08, WG-10" }, { "ref": "04-04-02 A day in the life", "why": "WG-05: ages that fit the First crew, for the residents" }, { "ref": "04-05-01 Characters", "why": "WG-03: six skills, each held by two people, two each: the First crew's grid (read live); WG-01: the robot operators on Earth become First crew: Ines; WG-05: First crew ages; WG-08: First Town trades; F-14: Mars-500's conflicts, for how stories show friction (read live); F-10: Harvard's intake, for comparing the Teacher in Space odds (read live)" }, { "ref": "04-02-04", "why": "Salotti's and Smith's populations (F-25, F-26), for the population lock (read live)" } ] }, "open_questions": [ "Medical standards for a Mars crew beyond radiation (bone, eyes, the heart after low gravity): for 02-06 The human body on Mars to set." ], "changes": [ "25 September 2026 (v1.0): Written. How astronauts are chosen today (NASA, ESA, JAXA, China), the odds, what Mars adds for the mind and the team, skills and crew size, age, sex and radiation, the Mars One warning and settlers' tickets, with 39 sourced facts and 13 assumptions (WG-01 to WG-13). People per era are read live from 01-01's era plan (E-12) and era names from 00-01.", "25 September 2026 (v1.1): Independent check. NASA's 2025 class corrected from 4 women and 6 men to 6 women and 4 men (NASA's own list of the ten). Concordia's time without flights corrected from about 4 months to about 9: planes can reach it only from November to February (Sandal and others, 2018); the 4 months is its darkness. F-24 now says what the NASA poster says: getting a patient back to Earth, not help from Earth, takes up to two weeks. Leans on 01-01 F-34 for NASA's crew of six, now listed. Application numbers for NASA 2017, 2021 and 2025, ESA 2021 to 2022, JAXA, Mercury, Mars One, Harvard and Oxford confirmed at their sources.", "26 September 2026 (v1.2): NASA's 600 mSv career limit (F-30) and Polyakov's record (F-13) are now read live from 01-02, which owns them (01-02 F-18, F-23); F-13 and F-30 are signposts with moved_to, and this file's own copies (numbers.radiation_msv.limit, numbers.days.polyakov) are removed. 01-02 added to quotes and leans_on. used_by lists 01-02, 01-05 and 02-06, which read Mars-500 (F-14, F-15).", "26 September 2026 (v1.3): HI-SEAS IV's crew and dome size are now numbers (numbers.hiseas), which F-16 fills in, so 02-06 can read them instead of keeping its own. 02-06 F-26 to F-28 now point to F-16, F-17, F-19 and F-20, which own CHAPEA, HI-SEAS and Concordia. used_by adds 03-06, 03-10 and 03-12, and the 02-06 line lists what it now reads.", "26 September 2026 (v1.4): Two open questions deleted as answered: lifetime dose rules for residents and a second pass of the career limit (04-02-01 CR-13), and when children first come (04-02-03 SG-05, SG-07). The medical-standards question now leaves only the 02-06 part; what care is on hand is answered by 03-14 MB-02 and MB-03. WG-07 cites 04-02-01 CR-13. WG-09 no longer moves: its social side is 04-02-03 SG-01, and the rest stays here for 04-05-01. used_by adds 04-02-01 and gives 04-02-03 what it reads.", "26 September 2026 (v1.5): WG-11 has moved: it is now a pointer to 04-02-02 MT-01, which owns who pays for a trip. used_by 04-02-02 says what it takes and cites.", "26 September 2026 (v1.6): WG-13 has moved to 04-04-01 JB-02 (the mix of work by era); this ID is now a pointer and the chart caption says so. Open questions deleted as answered: the named First crew (04-05-01 CH-02, CH-03) and the job list and shifts (04-04-01). used_by: back-links for 04-03-03, 04-04-01, 04-04-02, 04-05-01 (what each reads, from its leans_on).", "26 September 2026 (v1.7): used_by 04-05-01: the robot-team operator who joins the First crew is Ines (04-05-01 renamed her from Priya).", "26 September 2026 (v1.8): Beauty pass: a new opening picture, a crew walking out to the ship at dusk on Earth, labelled as art.", "26 September 2026 (v1.9): Final fix round: New WG-14: in the Early town most people stay two return windows (about 1,280 days) so crews overlap and hand over; a one-window crew leaves about 280 days before the next ships land; seats home cap rotation. All worked out live from 01-01 and 01-02. The era table's Early town row says so", "1 October 2026 (v1.10): used_by adds 04-02-04, the new pages on computing and on needing nothing from Earth.", "3 October 2026 (v1.11): Era names follow the owner's new names (00-01): Mars Today, Robots First, First Town, Many Cities; First Human Landing and The First Martian City, Arcadia, where an era is named as such." ], "sources": { "nasa_mercury7": { "name": "NASA History Office, 65 Years Ago: NASA Selects America's First Astronauts, April 2024", "url": "https://www.nasa.gov/history/65-years-ago-nasa-selects-americas-first-astronauts/" }, "nasa_requirements": { "name": "NASA, Astronaut Requirements (accessed September 2026)", "url": "https://www.nasa.gov/humans-in-space/astronauts/astronaut-requirements/" }, "nasa_record_2016": { "name": "NASA, Record Number of Americans Apply to #BeAnAstronaut at NASA, February 2016", "url": "https://www.nasa.gov/news-release/record-number-of-americans-apply-to-beanastronaut-at-nasa/" }, "npr_2017": { "name": "NPR, Meet NASA's New Astronaut Candidate Class Of 2017, 11 June 2017", "url": "https://www.npr.org/2017/06/11/532249940/meet-your-lucky-stars-nasa-announces-a-new-class-of-astronaut-candidates" }, "nasa_2021_grad": { "name": "NASA, NASA Opens Astronaut Applications as Newest Class Graduates, March 2024", "url": "https://www.nasa.gov/news-release/nasa-opens-astronaut-applications-as-newest-class-graduates/" }, "nasa_2025": { "name": "NASA, NASA Selects All-American 2025 Class of Astronaut Candidates, 22 September 2025", "url": "https://www.nasa.gov/news-release/nasa-selects-all-american-2025-class-of-astronaut-candidates/" }, "esa_2022": { "name": "ESA, ESA presents new generation of ESA astronauts, 23 November 2022", "url": "https://www.esa.int/Newsroom/Press_Releases/ESA_presents_new_generation_of_ESA_astronauts" }, "esa_timeline": { "name": "ESA, Timeline from applicant to astronaut, 2021", "url": 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human spaceflight (accessed September 2026)", "url": "https://www.nasa.gov/hrp/hazards/" }, "britannica_polyakov": { "name": "Encyclopaedia Britannica, Valery Vladimirovich Polyakov (accessed September 2026)", "url": "https://www.britannica.com/biography/Valery-Vladimirovich-Polyakov" }, "basner_plos_2014": { "name": "Basner and others, Psychological and Behavioral Changes during Confinement in a 520-Day Simulated Interplanetary Mission to Mars, PLOS ONE, 2014", "url": "https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0093298" }, "basner_pnas_2013": { "name": "Basner and others, Mars 520-d mission simulation reveals protracted crew hypokinesis and alterations of sleep duration and timing, PNAS, 2013", "url": "https://www.pnas.org/doi/abs/10.1073/pnas.1212646110" }, "phys_hiseas_2016": { "name": "Phys.org (AFP), Boredom was hardest part of yearlong dome isolation: NASA crew, August 2016", "url": "https://phys.org/news/2016-08-boredom-hardest-yearlong-dome-isolation.html" }, "nasa_chapea1": { "name": "NASA, CHAPEA Mission 1 (accessed September 2026)", "url": "https://www.nasa.gov/humans-in-space/chapea/chapea-mission-1/" }, "nasa_chapea1_crew": { "name": "NASA, NASA Selects Participants for One-Year Mars Analog Mission, April 2023", "url": "https://www.nasa.gov/missions/analog-field-testing/chapea/nasa-selects-participants-for-one-year-mars-analog-mission/" }, "space_chapea": { "name": "Space.com, NASA's 1st year-long mock Mars mission wraps up in Houston, July 2024", "url": "https://www.space.com/nasa-simulated-mars-mission-chapea-1-end" }, "nasa_chapea_call": { "name": "NASA, Martians Wanted: NASA Opens Call for Simulated Yearlong Mars Mission, February 2024", "url": "https://www.nasa.gov/news-release/martians-wanted-nasa-opens-call-for-simulated-yearlong-mars-mission/" }, "wiki_chapea": { "name": "Wikipedia, Crew Health and Performance Exploration Analog, 2026", "url": "https://en.wikipedia.org/wiki/Crew_Health_and_Performance_Exploration_Analog" }, "esa_concordia": { "name": "ESA, Concordia: Earth's most remote laboratory (Chronicles from Concordia), 2025", "url": "https://blogs.esa.int/concordia/concordia-earths-most-remote-laboratory/" }, "sandal_2018": { "name": "Sandal and others, Psychological Hibernation in Antarctica, Frontiers in Psychology, 2018", "url": "https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2018.02235/full" }, "mdrs_reports": { "name": "The Mars Society, Mars Desert Research Station (accessed September 2026)", "url": "https://reports.marssociety.org/" }, "wiki_mdrs": { "name": "Wikipedia, Mars Desert Research Station, 2026", "url": "https://en.wikipedia.org/wiki/Mars_Desert_Research_Station" }, "nasa_dra5_sp": { "name": "NASA, Human Exploration of Mars Design Reference Architecture 5.0, NASA SP-2009-566, 2009", "url": "https://www.nasa.gov/wp-content/uploads/2015/09/373665main_nasa-sp-2009-566.pdf" }, "wiki_mars_direct": { "name": "Wikipedia, Mars Direct (quoting Zubrin and Baker, 1990), 2026", "url": "https://en.wikipedia.org/wiki/Mars_Direct" }, "nasa_exmo": { "name": "NASA Technical Reports Server, Knowledge, skills and abilities for Exploration Crew Medical Officers (ExMO), poster, 2023", "url": "https://ntrs.nasa.gov/api/citations/20230007088/downloads/ExMO%20KSA%20Poster.pdf" }, "salotti_2020": { "name": "Jean-Marc Salotti, Minimum Number of Settlers for Survival on Another Planet, Scientific Reports, 2020", "url": "https://www.nature.com/articles/s41598-020-66740-0" }, "smith_2014": { "name": "Cameron M. Smith, Estimation of a genetically viable population for multigenerational interstellar voyaging, Acta Astronautica, 2014", "url": "https://www.sciencedirect.com/science/article/abs/pii/S0094576513004669" }, "nasa_faq": { "name": "NASA, Becoming an Astronaut: Frequently Asked Questions (accessed September 2026)", "url": "https://www.nasa.gov/humans-in-space/becoming-an-astronaut-frequently-asked-questions/" }, "nasa_glenn": { "name": "NASA History Office, 25 Years Ago: STS-95, John Glenn Returns to Space, October 2023", "url": "https://www.nasa.gov/history/25-years-ago-sts-95-john-glenn-returns-to-space" }, "space_radiation_limits": { "name": "Space.com, Why does NASA let male astronauts stay in space longer than females?, 2021", "url": "https://www.space.com/why-astronauts-radiation-levels" }, "mit_tr_2021": { "name": "MIT Technology Review, New NASA radiation rules could open up space missions to more women, 30 June 2021", "url": "https://www.technologyreview.com/2021/06/30/1027445/nasa-space-radiation-astronaut-missions-women/" }, "nasa_std_2022": { "name": "NASA Office of the Chief Health and Medical Officer, NASA-STD-3001 Volume 1 Rev B and Volume 2 Rev C newsletter, February 2022", "url": "https://www.nasa.gov/wp-content/uploads/2023/03/ochmo-standards-newsletter-february-2022.pdf" }, "nasem_2021": { "name": "National Academies of Sciences, Engineering, and Medicine, Space Radiation and Astronaut Health: Managing and Communicating Cancer Risks, chapter 3, 2021", "url": "https://nap.nationalacademies.org/read/26155/chapter/5" }, "wiki_women_space": { "name": "Wikipedia, Women in space, 2026", "url": "https://en.wikipedia.org/wiki/Women_in_space" }, "ibtimes_mo_2015": { "name": "International Business Times UK, Mars One admits it has only received 4,227 completed applications, not 200,000, 4 June 2015", "url": "https://www.ibtimes.co.uk/mars-one-admits-it-has-only-received-4227-completed-applications-not-200000-1504392" }, "matter_roche_2015": { "name": "Elmo Keep, Mars One Finalist Explains Exactly How It's Ripping Off Supporters, Matter (Medium), March 2015", "url": "https://medium.com/matter/mars-one-insider-quits-dangerously-flawed-project-2dfef95217d3" }, "mit_mo_2014": { "name": "MIT News, Mars One analysis (Do, de Weck and others), 14 October 2014", "url": "https://news.mit.edu/2014/technical-feasibility-mars-one-1014" }, "npr_mo_2019": { "name": "NPR, Mars One Fizzles Into Bankruptcy After Promising A New Life In Space, 12 February 2019", "url": "https://www.npr.org/2019/02/12/693945694/mars-one-fizzles-into-bankruptcy-after-promising-a-new-life-in-space" }, "nbc_musk_2016": { "name": "NBC News, Red means go: Elon Musk wants to colonize Mars, September 2016", "url": "https://www.nbcnews.com/mach/space/elon-musk-makes-his-case-colonizing-mars-n655641" }, "cnbc_musk_2019": { "name": "CNBC, Elon Musk: Moving to Mars will cost less than $500,000, 'maybe even below $100,000', 11 February 2019", "url": "https://www.cnbc.com/2019/02/11/elon-musk-how-much-it-will-cost-to-move-to-mars.html" }, "space_musk_2016": { "name": "Space.com, 1st Mars Colonists Should Be 'Prepared to Die,' Elon Musk Says, September 2016", "url": "https://www.space.com/34259-elon-musk-first-mars-colonists-prepared-die.html" } }, "sources_checked": "25 September 2026" }, "02-03": { "file": "02-03", "title": "Resource survey", "folder": "02", "facts_file": "02-03-resource-survey.json", "version": "2.25", "status": "Active", "last_updated": "9 October 2026", "about": "Facts file for 02-03 Resource survey. The page is built from this file, the library catalogue and the page template. Change a fact here, then run build.py. Words in curly brackets, like {ut_hi}, are filled in from the numbers in this file when the page is built, so each number is typed once. The 'sites' list is the shared site data that the map (02-04) and the website read.", "one_line": "What Mars offers a settlement: water, air, rock and shelter, where each one is, and why the ice and the caves are in different places.", "shelf_life": "Ice maps are refined every year or two (the SWIM team published new odds maps in 2026). The broad picture, ice-rich northern mid-latitudes and a dry equator, is stable. Exact depths at any one spot, site rankings and building-material test results are not. Re-check them by March 2027, or before relying on them. SpaceX's site choice (F-33, F-34) dates from 2021 and May 2025, before its February 2026 shift to the Moon first (01-01 F-24); re-check it when SpaceX publishes Mars plans.", "header": { "purpose": "Record what raw materials Mars has, in what form and where, so the map (02-04), the structures (03) and the cities (04) all draw from one inventory and one site list.", "why": "A settlement that imports everything is a camp, not a city. What can be made locally depends on what is in the ground and the air. This file also holds the most important fact for placing the city: where the shallow ice is.", "when": "Choosing or checking a site, deciding what is made locally and what is shipped, writing about mining, water, air-making, farming or building, or drawing the map's ice and cave layers.", "change": "Part One changes only with a citation; add new SWIM or radar results with their date. Part Two assumptions can be challenged one at a time. Edit this facts file, then run build.py.", "writing": "Every number is compared to something people know. Pictures first, short sentences, no walls of text." }, "comparisons": { "storey_m": 3.2, "person_m": 1.8, "gherkin_m": 180, "gherkin_floors": 41, "superior_km3": 12070, "pitch_length_m": [ 100, 110 ], "oven_c": 220, "walk_kmh": 5, "cubic_foot_l": 28.3, "us_pint_l": 0.473 }, "numbers": { "arcadia_km3": 10000, "utopia_thick_m": [ 80, 170 ], "utopia_cover_m": [ 1, 10 ], "utopia_lat": [ 39, 49 ], "utopia_ice_pct": [ 50, 85 ], "scarps": 8, "scarp_lat": [ 55, 58 ], "scarp_thick_m": 100, "scarp_cover_m": [ 1, 2 ], "ce_width_m": 150, "ce_depth_m": 21, "ce_lat": 35, "zhurong_depth_m": 80, "mff_thick_km": 3.7, "mff_cover_m": [ 300, 600 ], "mff_global_m": [ 1.5, 2.7 ], "swim_odds_pct": 64, "swim_gap_m": [ 1, 5 ], "morgan_gap_m": [ 5, 10 ], "soil_water_pct": 2, "leshin_pints": 2, "sam_c": 835, "npld_global_m": 1.5, "moxie_g": 122, "moxie_gph": 12, "moxie_purity_pct": 98, "moxie_runs": 16, "soil_pct": { "sio2": 46.5, "feo": 12.2, "fe2o3": 4.2, "al2o3": 10.5, "mgo": 8.9, "cao": 6.3, "so3": 4.9, "cl": 0.6 }, "sc_mpa": 50, "sc_sulphur_pct": 50, "tute_mpa": 3.66, "tute_flex_mpa": 5.95, "sulphur_melt_c": 120, "sublimation_x": 8000, "fibre_c": 1360, "insight_wh": [ 5000, 500 ], "kilopower_kw": 10, "kilopower_years": 10, "kilopower_units": 4, "krusty_hours": 28, "wind_regions": 13, "mole_target_m": 3, "earth_tube_m": [ 10, 30 ], "mars_tube_m": [ 40, 450 ], "tube_volume_x": 80, "sisters": 7, "sister_m": [ 100, 250 ], "sister_deep_m": 178, "mgc3": 1029, "mgc3_skylights": 349, "alba_segments": 300, "alba_km": 12000, "alba_lat": 40.5, "hebrus_caves": 8, "sun_limits_deg": [ 30, 40 ], "sx_elev_km": -2, "sx_slope_deg": 5, "menges_pct": 4, "menges_north_pct": 85, "hellas_glacier_m": [ 250, 450 ], "collapse_m": [ 40, 400 ], "swim_phases": 4, "ap9": { "lat": 40.02, "lon": -156.65, "elev_km": -3.9, "source": "golombek_2021", "note": "SpaceX site AP-9 (203.35°E in the source): the thickest radar ice of SpaceX's sites. No longer our pin; kept as the nearby ice alternative (R-02)." }, "drill_cm": 6.4 }, "sections": [ { "id": "3.1", "title": "Water" }, { "id": "3.2", "title": "Air" }, { "id": "3.3", "title": "The ground" }, { "id": "3.4", "title": "Energy" }, { "id": "3.5", "title": "Shelter" }, { "id": "3.6", "title": "Where it overlaps" } ], "facts": [ { "id": "F-01", "section": "3.1", "text": "There is shallow ground ice under roughly a third of the Martian surface (Colin Dundas, US Geological Survey, 2018).", "compare": "Roughly one step in three across Mars would be over buried ice.", "sources": [ "dundas_2018" ] }, { "id": "F-02", "section": "3.1", "text": "SWIM (Subsurface Water Ice Mapping) is a NASA-funded project led by the Planetary Science Institute, in four phases: a pilot study in Arcadia Planitia; SWIM 1.0 (2019), the northern mid-latitudes from 0 to 60°N; SWIM 2.0 (2020), the southern mid-latitudes and Tharsis; and SWIM4IMIM, detailed mapping of the southern edge of reachable ice for the planned International Mars Ice Mapper mission. It combines four kinds of orbital data: neutrons (hydrogen), heat behaviour, landforms and radar.", "compare": "Like four witnesses: a place scores highest when all four agree there is ice.", "sources": [ "swim_psi", "perry_2020" ] }, { "id": "F-03", "section": "3.1", "text": "Comparing 20 years of orbital data, SWIM's 2021 study (Morgan and others, Nature Astronomy) found signs of widespread ice under the Arcadia plains, purest close to the surface, and highlighted Arcadia and Deuteronilus Mensae. It also has a blind spot around {mg_gap_lo} to {mg_gap_hi} m deep.", "compare": "The blind spot is about {mg_gap_st_lo} to {mg_gap_st_hi} storeys down.", "sources": [ "morgan_2021" ] }, { "id": "F-04", "section": "3.1", "text": "In Arcadia Planitia, radar and terraced craters show a widespread layer of 'excess' ice (more ice than the gaps between grains could hold) that is tens of metres thick, about {arc_km3} km³ in volume (Bramson and others, 2015).", "compare": "Roughly Lake Superior's volume ({superior_km3} km³): the study gives only the order of magnitude.", "sources": [ "bramson_2015", "superior_wiki" ] }, { "id": "F-05", "section": "3.1", "text": "In Utopia Planitia, radar found a buried deposit {ut_lo} to {ut_hi} m thick, {uti_lo} to {uti_hi} percent water ice, under {utc_lo} to {utc_hi} m of soil, between {utl_lo} and {utl_hi}°N: roughly twice as thick as the ice measured in Arcadia. It covers more ground than New Mexico. Stuurman put it at around 1.2 times the volume of Lake Superior in water ice; JPL rounded this to about as much water as Lake Superior (2016).", "compare": "The thickest part is {ut_gherkin} percent of the Gherkin's height ({gherkin_m} m). The soil on top is at most about {utc_storeys} storeys deep.", "sources": [ "stuurman_2016", "planetary_2016", "gherkin_wiki" ] }, { "id": "F-06", "section": "3.1", "text": "{scarps} eroding cliffs at {sc_lat_lo} to {sc_lat_hi}° latitude, in both hemispheres, expose sheets of ice that can be more than {sc_thick} m thick, starting as little as {scc_lo} to {scc_hi} m below the surface (Dundas and others, Science, 2018).", "compare": "A wall of ice {sc_storeys} storeys tall, under soil about a person's height deep.", "sources": [ "dundas_2018", "dundas_2018_paper" ] }, { "id": "F-07", "section": "3.1", "text": "On 24 December 2021 a meteoroid hit Amazonis Planitia, leaving a crater {ce_w} m wide and {ce_d} m deep and throwing out boulder-sized chunks of ice. At about {ce_lat}°N it is the lowest-latitude impact to expose ice on Mars (Dundas and others, 2023).", "compare": "About {ce_pitch} football pitches across and {ce_storeys} storeys deep.", "sources": [ "jpl_ce_2022", "dundas_2023", "ifab_pitch" ] }, { "id": "F-08", "section": "3.1", "text": "China's Zhurong rover, in southern Utopia Planitia at about 25°N, used radar to look {zh_m} m down. It found layered sediment and no sign of liquid water; frozen salty water could not be ruled out (Li and others, Nature, 2022).", "compare": "{zh_m} m is about {zh_storeys} storeys down.", "sources": [ "zhurong_2022", "zhurong_gt_2022", "zhurong_wiki" ] }, { "id": "F-09", "section": "3.1", "text": "Near the equator, Mars Express radar suggests the Medusae Fossae Formation is ice-rich: layered deposits up to {mff_km} km thick under {mffc_lo} to {mffc_hi} m of dry material. Melted, the ice would cover Mars {mffg_lo} to {mffg_hi} m deep (Watters, 2024).", "compare": "The dry lid alone is {mff_gh_lo} to {mff_gh_hi} Gherkins stacked up: far too deep to mine with anything we know.", "sources": [ "watters_2024", "watters_2024_grl", "gherkin_wiki" ] }, { "id": "F-10", "section": "3.1", "text": "In 2026 the SWIM team (Sizemore, Courville and others, Planetary Science Journal) turned the maps into odds, such as a {odds} percent chance of finding ice at a given spot. Ice is most certain near the poles and absent near the equator. Today's data sees the top metre and radar sees below about 5 m, leaving a gap from {gap_lo} to {gap_hi} m.", "compare": "The layer a drill reaches first, up to about {gap_storeys} storeys down, is the one nobody can see yet.", "sources": [ "sizemore_2026" ] }, { "id": "F-11", "section": "3.1", "text": "Ordinary soil holds water too. Curiosity found about {soil_water} percent water by weight at Gale Crater, released by heating samples to {sam_c}°C. 'If you take a cubic foot of that soil you can basically get two pints of water out of it' (Laurie Leshin, 2013).", "compare": "About {soil_l} litre of water from a box of soil 30 cm on each side. Slow and energy-hungry, but it works anywhere, even at the equator.", "sources": [ "leshin_2013", "ming_2017" ] }, { "id": "F-12", "section": "3.1", "text": "The polar caps are Mars's biggest water stores. Separate ice layers buried about a mile under the north cap, the third-largest store, would alone make a global layer at least {npld_m} m deep (Nerozzi and Holt, 2019).", "compare": "Water up to the shoulders of a {person_m} m tall person, all over the planet.", "sources": [ "nerozzi_2019" ] }, { "id": "F-13", "section": "3.2", "text": "Curiosity measured Mars air as {co2} percent carbon dioxide, {n2} percent nitrogen, {ar} percent argon, {o2} percent oxygen and {co} percent carbon monoxide (quoted from 02-01 F-06, which owns the air mix).", "compare": "Nitrogen, the gas plants and soil need most, is only about 1 part in {n2_in} of already thin air.", "sources": [ "nasa_air_2019" ] }, { "id": "F-14", "section": "3.2", "text": "MOXIE, on the Perseverance rover, made {moxie_g} g of oxygen from Mars air over {moxie_runs} runs from 2021 to 2023, at up to {moxie_gph} g an hour and {moxie_pure} percent purity or better.", "compare": "About what a small dog breathes in 10 hours (NASA's comparison).", "sources": [ "moxie_2023" ] }, { "id": "F-15", "section": "3.2", "text": "The Sabatier reaction (1897) turns carbon dioxide and hydrogen into methane and water. NASA uses it on the Space Station. For Mars, hydrogen from mined water plus carbon dioxide from the air gives methane fuel, and splitting the water gives oxygen: the two things Starship burns.", "compare": "A gas cooker run backwards: a cooker burns methane with oxygen into carbon dioxide and water, and this turns carbon dioxide and water back into methane and oxygen.", "sources": [ "sabatier_wiki" ] }, { "id": "F-16", "section": "3.3", "text": "Average Martian soil (rover measurements, NASA JSC review): silica {sio2}%, iron oxides {fe_tot}%, aluminium oxide {al2o3}%, magnesium oxide {mgo}%, calcium oxide {cao}%, sulphur trioxide {so3}%, chlorine {cl}%, plus about {soil_water}% water. It is weathered basalt, the dark volcanic rock of Iceland and Hawaii.", "compare": "Nearly half is silica, the main ingredient of sand and glass; about a sixth is rust-coloured iron oxide.", "sources": [ "ming_2017" ] }, { "id": "F-17", "section": "3.3", "text": "The soil contains perchlorate salts, which are toxic to people: {pc_phx_lo} to {pc_phx_hi} percent by weight at the Phoenix site and up to about {pc_cur} percent in one Curiosity sample (quoted from 02-01 F-32, which owns them). They must be washed out of soil and water.", "compare": "About {pc_g_lo} to {pc_g_hi} g in every kilogram of Phoenix soil.", "sources": [ "hecht_2009" ] }, { "id": "F-18", "section": "3.3", "text": "Opportunity found the plains of Meridiani strewn with BB-sized spherules ('blueberries') of hematite, an iron oxide mineral that is mined as iron ore on Earth (NASA JPL, 2004).", "compare": "Iron is not scarce on Mars: the red colour is iron oxide.", "sources": [ "jpl_berries_2004" ] }, { "id": "F-19", "section": "3.3", "text": "Sulphur concrete: melted sulphur mixed with Mars soil simulant, about half and half, set into a concrete with a compressive strength above {sc_mpa} MPa, with no water, fast curing and full recyclability (Wan, Wendner and Cusatis, 2016).", "compare": "Needs no water at all: melt it, pour it, and melt it again to reuse.", "sources": [ "wan_2016" ] }, { "id": "F-20", "section": "3.3", "text": "Made at {s_melt}°C under carbon dioxide, like Mars air, a 2024 sulphur concrete reached only {tute_mpa} MPa in compression (at 60% sulphur) and {tute_flex} MPa in bending (Tute and Goulas, 2024).", "compare": "About {sc_ratio} times weaker than the 2016 figure: the result depends heavily on recipe and process.", "sources": [ "tute_2024" ] }, { "id": "F-21", "section": "3.3", "text": "Sulphur slowly turns to vapour in a vacuum, but at -60°C this is about {subl_x} times slower than at 20°C. Sulphur also shrinks as it cools and crystallises, which can crack the concrete (Shahsavari and others, 2022).", "compare": "{subl_x} times slower means a loss that takes one day at room temperature would take about {subl_yr} years in the Martian cold.", "sources": [ "shahsavari_2022" ] }, { "id": "F-22", "section": "3.3", "text": "Mars soil simulant pressed hard, with no oven and no binder, made bricks the team reported as stronger than steel-reinforced concrete; the iron oxide grains bind under pressure (Chow, Chen, Zhong and Qiao, UC San Diego, Scientific Reports, 2017).", "compare": "The press needed is about the force of a hammer blow on a small sample.", "sources": [ "chow_2017", "qiao_2017" ] }, { "id": "F-23", "section": "3.3", "text": "Chinese researchers melted Mars soil simulant at {fibre_c}°C and drew it into continuous fibres of controllable thickness (2024).", "compare": "About {fibre_oven} times a home oven's top heat ({oven_c}°C).", "sources": [ "fibre_2024" ] }, { "id": "F-24", "section": "3.4", "text": "InSight's solar panels made about {ins_hi} watt-hours a sol after landing in 2018 and about {ins_lo} by spring 2022, as dust built up (NASA JPL, 2022).", "compare": "Power fell by {ins_drop} percent: a tenth of what it started with.", "sources": [ "insight_power_2022" ] }, { "id": "F-25", "section": "3.4", "text": "NASA's Kilopower reactor is designed to make up to {kp_kw} kW of electricity for at least {kp_years} years; its uranium core is roughly the size of a paper towel roll. A ground test (KRUSTY) ran from November 2017 to March 2018, including a {kp_hours}-hour full-power run. NASA said {kp_units} units could power an outpost.", "compare": "NASA's comparison: one unit is enough for several average households.", "sources": [ "kilopower_2018" ] }, { "id": "F-26", "section": "3.4", "text": "Mars air is about {air_density} percent as dense as Earth's (worked out from 02-01's densities), so turbines need much larger blades. Even so, a 2023 NASA Ames model (Hartwick and others, Nature Astronomy) found wind could back up solar at night and in dust storms, and named {wind_regions} new windy regions.", "compare": "At the same wind speed a turbine on Mars catches only about {air_density}% of the power it would on Earth, so to match it the blades must sweep about {wind_area_x} times the area.", "sources": [ "hartwick_2023" ] }, { "id": "F-27", "section": "3.4", "text": "InSight's heat probe (the 'mole') was meant to dig at least {mole_m} m to measure heat from inside Mars. The soil clumped instead of flowing round the spike, which left it too little friction to hammer itself down, and the attempt ended on 9 January 2021 without a heat-flow measurement.", "compare": "We do not know whether usable heat lies near the surface: nobody has measured it.", "sources": [ "insight_mole_2021" ] }, { "id": "F-28", "section": "3.5", "text": "Lava tubes on Earth are usually {et_lo} to {et_hi} m across. From orbit, Martian collapse chains are {cc_lo} to {cc_hi} m wide, and the tubes beneath are estimated at up to about {mt_hi} m wide, and up to about {tube_x} times bigger than Earth's (Sauro and others, 2020).", "compare": "The widest would span about {tube_pitch} football pitches laid end to end.", "sources": [ "sauro_2020", "ifab_pitch" ] }, { "id": "F-29", "section": "3.5", "text": "Mars Odyssey found {ss_n} possible cave skylights, {ss_lo} to {ss_hi} m across, high on the Arsia Mons volcano (Cushing and others, 2007). One is at least {ss_deep} m deep. The team called them poor candidates for habitation because they are so high up.", "compare": "The deep one is almost as deep as the Gherkin is tall ({gherkin_m} m).", "sources": [ "cushing_2007", "arsia_wiki", "gherkin_wiki" ] }, { "id": "F-30", "section": "3.5", "text": "The Mars Global Cave Candidate Catalog lists {mgc3} possible cave entrances, {mgc3_sky} of them possible lava-tube skylights, spread across most of the Tharsis region; older volcanic regions have far fewer (Cushing, 2017).", "compare": "Roughly {mgc3_sky} of the {mgc3} are skylights: about one in {mgc3_in}.", "sources": [ "mgc3_2017" ] }, { "id": "F-31", "section": "3.5", "text": "On Alba Mons in northern Tharsis, more than {alba_seg} lava-tube segments have been mapped, about {alba_km} km in all, in a tube field at about {alba_lat}°N; the volcano's centre, our pin, is further north at {alba_pin}°N. Less than half show surface collapse, so many cavities may be intact (Crown, Scheidt and Berman, 2022).", "compare": "{alba_km} km is more than half way round Mars ({mars_circ} km).", "sources": [ "crown_2022", "alba_wiki", "mars_fact" ] }, { "id": "F-32", "section": "3.5", "text": "Not all caves are volcanic. A 2025 study found {hebrus_n} skylights in Hebrus Valles that may lead into caves dissolved by water, like limestone caves on Earth.", "compare": "{hebrus_n} skylights, against {mgc3} possible cave entrances in the global catalogue (F-30): a handful, but a different kind of cave, dissolved by water like the limestone caves of Cheddar Gorge.", "sources": [ "hebrus_2025" ] }, { "id": "F-33", "section": "3.6", "text": "SpaceX's landing-site work with NASA scientists (Golombek and others, 2021) required: latitude below {sx_lat}° for solar power and heat, elevation below {sx_elev} km, slopes under {sx_slope}°, and ice nearby. Its prime sites are in Arcadia Planitia (AP-1, AP-9), Erebus Montes (EM-16) and Phlegra Montes (PM-1). AP-1 appeared the safest site; AP-9 had the thickest radar ice; EM-16 the strongest shallow-ice signal.", "compare": "SpaceX's {sx_lat}° limit runs right through Arcadia: AP-1 ({lead_lat}°N, our pin) and EM-16 ({em16_lat}°N) sit just under it; AP-9, at {ap9_lat}°N, is a hair over (Golombek 2021).", "sources": [ "golombek_2021" ] }, { "id": "F-34", "section": "3.6", "text": "In May 2025 SpaceX presented Arcadia Planitia as the likely landing zone for its Mars city.", "compare": "AP-1, our pin in Arcadia, sits at {lead_lat}°N: about as far north on Mars as Madrid or New York on Earth.", "sources": [ "nsf_2025" ] }, { "id": "F-35", "section": "3.6", "text": "A 2026 study of natural landing pads (Menges and Cannon) surveyed northwestern Mars from 0 to 60°N and 180 to 360°E, an area that includes Arcadia and Acidalia. Only {mg_pct} percent of the ground qualified, {mg_north} percent of it north of 40°N. Favourable ground turned up in both Acidalia and Arcadia, particularly on the sediment-mantled plains of Acidalia Planitia. The study did not score ice.", "compare": "About one patch of ground in {mg_in}. Most of it lies just north of SpaceX's {sx_lat}° solar limit, so the first ship's natural pad is likely a little north of our city pin.", "sources": [ "menges_2026" ] }, { "id": "F-36", "section": "3.6", "text": "The Hellas basin floor lies about {hellas_km} km below Mars's average level, where the air reaches about {hellas_pa} Pa in winter (both quoted from 02-01 F-05 and F-50). Hellas is a known source of global dust storms, and radar shows buried glaciers {hg_lo} to {hg_hi} m thick in craters to its east.", "compare": "{hellas_km} km is about {hellas_gh} Gherkins stacked up, with about twice the average air pressure ({p_pa} Pa).", "sources": [ "hellas_wiki" ] }, { "id": "F-37", "section": "3.3", "text": "Mars is red because its dust is rusty. A 2025 study (Valantinas and others, Nature Communications) found the dust best matches ferrihydrite, an iron oxide that forms quickly in cool water, rather than hematite, which forms in dry conditions. That suggests Mars rusted mostly while it still had liquid water, early in its history; wind has since ground the rust fine and spread it over the whole planet.", "compare": "Like a bike left out in the rain: the rust comes from water, not from time alone.", "sources": [ "valantinas_2025" ] }, { "id": "F-38", "section": "3.3", "text": "In February 2013 Curiosity drilled {drill_cm} cm into a flat rock called John Klein, its first drill hole on Mars. The powder that came up was grey, not red: under its thin coat of rusty dust, Mars's rock is grey (NASA JPL, 2013).", "compare": "Red only skin-deep: a drill bit's depth down, the planet is grey.", "sources": [ "klein_2013" ] } ], "sites": { "about": "The shared site list. The map (02-04) and the website read it, so the pins and scores live in one place. Latitudes are planetocentric, north positive. Longitudes are east-positive, from -180 to 180; where a source gives 0 to 360°E, the pin note shows the source's own figure. 'elev_km' is the height above Mars's average level, given only where a source gives it (SpaceX's 2021 site study). Scores run 0 to 3 and are our judgement from the cited facts (assumption R-10); the sunlight score is not typed here but worked out from latitude when the page is built. 'order' is the pin number.", "scoring": { "ice": "3 thick ice mapped by radar; 2 ice likely; 1 uncertain; 0 none near the surface", "ground": "Landing ground: 3 low, flat plains; 2 plains with hills or rough patches; 1 rugged or high; 0 steep, high and thin-aired", "sun": "Worked out from latitude using numbers.sun_limits_deg: 3 within {sun_lo}° of the equator; 2 up to SpaceX's solar limit of {sun_hi}° (F-33); 1 further out. Our Arcadia pin (AP-1, 39.8°N) sits just inside the limit, so it scores 2", "tubes": "3 many mapped tubes or skylights; 1 a few candidates; 0 none known" }, "list": [ { "id": "arcadia", "order": 1, "name": "Arcadia Planitia", "role": "lead", "lat": 39.8, "lon": -157.9, "elev_km": -3.9, "pin_note": "SpaceX site AP-1, at 157.9°W (202.1°E in the source): SpaceX's safest Arcadia site, just inside its 40° solar limit. AP-9, a short way north-east, has the thickest radar ice (R-02).", "scores": { "ice": 3, "ground": 3, "tubes": 0 }, "ice": "Widespread excess ice tens of metres thick; SWIM's strongest region. AP-1 itself has a moderate SWIM ice score; nearby AP-9 has the thickest radar ice of SpaceX's sites.", "ground": "Smooth, low plains, well under SpaceX's height limit; SpaceX's safest Arcadia site.", "sunlight": "Just inside SpaceX's 40° solar limit, so it scores 2 for sun.", "lava_tubes": "None known.", "notes": "Our lead site (R-02), on SpaceX's AP-1 site. Named by SpaceX's 2021 site study and its May 2025 plan. Moved from AP-9 by the owner on 25 September 2026.", "facts": [ "F-03", "F-04", "F-33", "F-34" ], "sources": [ "bramson_2015", "morgan_2021", "golombek_2021", "nsf_2025" ] }, { "id": "erebus", "order": 2, "name": "Erebus Montes", "role": "candidate", "lat": 39.89, "lon": -167.97, "elev_km": -3.9, "pin_note": "SpaceX site EM-16, at 167.97°W (192.03°E in the source).", "scores": { "ice": 3, "ground": 2, "tubes": 0 }, "ice": "Strongest shallow-ice radar signal of SpaceX's sites.", "ground": "Low plains among small hills.", "sunlight": "Just under 40°N.", "lava_tubes": "None known.", "notes": "On the western edge of the Arcadia ice zone. The 2021 Christmas Eve crater (F-07) is in neighbouring Amazonis.", "facts": [ "F-33", "F-07" ], "sources": [ "golombek_2021" ] }, { "id": "phlegra", "order": 3, "name": "Phlegra Montes", "role": "candidate", "lat": 35.23, "lon": 163.95, "elev_km": -3.2, "pin_note": "SpaceX site PM-1.", "scores": { "ice": 2, "ground": 2, "tubes": 0 }, "ice": "Glacier landforms; ice likely but less mapped than Arcadia.", "ground": "Plains beside a mountain range.", "sunlight": "The sunniest of the icy candidates.", "lava_tubes": "None known.", "notes": "A SpaceX prime site. Not in the original 02-03; added in version 2.0.", "facts": [ "F-33" ], "sources": [ "golombek_2021", "phlegra_wiki" ] }, { "id": "utopia", "order": 4, "name": "Northern Utopia Planitia", "role": "candidate", "lat": 46.7, "lon": 117.5, "pin_note": "IAU centre of Utopia Planitia. The radar ice deposit lies in south-western Utopia, 39 to 49°N (Stuurman 2016).", "scores": { "ice": 3, "ground": 3, "tubes": 0 }, "ice": "A deposit 80 to 170 m thick under 1 to 10 m of soil: about a Lake Superior of water.", "ground": "Low, flat plains.", "sunlight": "Mostly north of 40°N: darker, colder winters, outside SpaceX's solar limit.", "lava_tubes": "None known.", "notes": "The thickest well-mapped mid-latitude ice. Zhurong, further south at 25°N, found no sign of water to 80 m (F-08).", "facts": [ "F-05", "F-08" ], "sources": [ "stuurman_2016", "utopia_wiki" ] }, { "id": "deuteronilus", "order": 5, "name": "Deuteronilus Mensae", "role": "candidate", "lat": 43.9, "lon": 22.6, "pin_note": "Centre of the region (40 to 48°N).", "scores": { "ice": 3, "ground": 1, "tubes": 0 }, "ice": "Debris-covered glaciers confirmed by radar; highlighted by SWIM.", "ground": "Flat-topped hills and cliffs: rugged, harder to land in.", "sunlight": "About 44°N.", "lava_tubes": "None known.", "notes": "Scenic glacier country.", "facts": [ "F-03" ], "sources": [ "morgan_2021", "deuteronilus_wiki" ] }, { "id": "acidalia", "order": 6, "name": "Acidalia Planitia", "role": "candidate", "lat": 49.76, "lon": -20.74, "pin_note": "IAU centre of the plain, at 20.74°W (339.26°E in the source).", "scores": { "ice": 1, "ground": 3, "tubes": 0 }, "ice": "Less certain: not singled out by SWIM's 2021 study, and the 2026 pad study did not score ice.", "ground": "Favourable natural landing ground, particularly on its sediment-mantled plains (2026 study).", "sunlight": "About 50°N: the darkest winters of the northern candidates.", "lava_tubes": "None known.", "notes": "Added in version 2.0 because of the 2026 landing-pad study (F-35). The fallback landing ground if Arcadia has no safe natural pad; not a city site (R-09).", "facts": [ "F-35" ], "sources": [ "menges_2026", "acidalia_wiki" ] }, { "id": "alba", "order": 7, "name": "Alba Mons (west flank)", "role": "tubes", "lat": 41.08, "lon": -110.71, "pin_note": "Volcano centre from the IAU Gazetteer of Planetary Nomenclature, at 110.71°W (249.29°E in the source). The mapped tubes are mostly on the western flank, further south (F-31).", "scores": { "ice": 1, "ground": 1, "tubes": 3 }, "ice": "Not mapped by us. At ice-band latitude but on high ground; unknown.", "ground": "Gentle slopes, but high: well above SpaceX's -2 km limit.", "sunlight": "Just outside SpaceX's 40° solar limit: the tube field (F-31) is a little north of it, and the volcano centre, our pin, further north still.", "lava_tubes": "More than 300 mapped segments, about 12,000 km in all.", "notes": "The one place where lava tubes reach the ice latitudes. Added in version 2.0; worth checking for ice before a tube outpost is placed (R-03).", "facts": [ "F-31" ], "sources": [ "crown_2022", "gazetteer_alba" ] }, { "id": "arsia", "order": 8, "name": "Arsia Mons lava tubes", "role": "tubes", "lat": -8.35, "lon": -120.1, "pin_note": "Volcano centre.", "scores": { "ice": 0, "ground": 0, "tubes": 3 }, "ice": "None near the surface.", "ground": "Wikipedia gives its peak as 11.7 km; a 1998 laser-altimeter profile puts the summit about 17.45 km above Mars's zero level (the two count from different bases). Steep flanks, very thin air.", "sunlight": "Near the equator: the best sun.", "lava_tubes": "Seven skylights 100 to 250 m across; Tharsis has the most cave candidates on Mars.", "notes": "Shelter without water. The skylights were rated poor for habitation because they are so high (F-29). One of two places considered for a later tube outpost (R-03).", "facts": [ "F-29", "F-30" ], "sources": [ "cushing_2007", "mgc3_2017", "arsia_wiki", "lpsc_1998" ] }, { "id": "elysium", "order": 9, "name": "Elysium Planitia", "role": "candidate", "lat": 4.5, "lon": 135.62, "pin_note": "InSight's landing site (4.5°N, 135.62°E, NASA).", "scores": { "ice": 0, "ground": 3, "tubes": 1 }, "ice": "Little or none near the surface.", "ground": "Flat plain; InSight landed here in 2018.", "sunlight": "Near the equator: the best sun.", "lava_tubes": "Young lava flows nearby; far fewer cave candidates than Tharsis.", "notes": "Warm by Mars standards and dry.", "facts": [ "F-27", "F-30" ], "sources": [ "elysium_wiki", "insight_nasa", "mgc3_2017" ] }, { "id": "hellas", "order": 10, "name": "Hellas Basin floor", "role": "candidate", "lat": -42.4, "lon": 70.5, "pin_note": "Basin centre.", "scores": { "ice": 2, "ground": 2, "tubes": 0 }, "ice": "Buried glaciers 250 to 450 m thick in craters to the east.", "ground": "The lowest ground on Mars, with the thickest air.", "sunlight": "About 42°S.", "lava_tubes": "None known.", "notes": "A source of global dust storms; harsh southern winters.", "facts": [ "F-36" ], "sources": [ "hellas_wiki" ] } ], "markers": [ { "id": "zhurong", "name": "Zhurong: no water seen to 80 m", "lat": 25.1, "lon": 109.9, "facts": [ "F-08" ], "sources": [ "zhurong_wiki" ] }, { "id": "christmas_eve", "name": "2021 crater: ice at about 35°N", "lat": 35, "lon": -170, "approx": true, "facts": [ "F-07" ], "sources": [ "dundas_2023" ] } ] }, "map_regions": { "about": "Rough shapes for the world strip on this page. They are sketches of where the cited facts point, not survey data. Boxes are [west lon, south lat, east lon, north lat], east-positive.", "ice_band": { "north": [ 35, 60 ], "south": [ -60, -35 ], "facts": [ "F-01", "F-07", "F-10" ] }, "ice_strong": [ { "name": "Arcadia", "box": [ -172, 36, -145, 50 ], "facts": [ "F-04" ] }, { "name": "Utopia", "box": [ 85, 39, 130, 49 ], "facts": [ "F-05" ] }, { "name": "Deuteronilus", "box": [ 15, 40, 35, 48 ], "facts": [ "F-03" ] } ], "deep_ice": [ { "name": "Medusae Fossae (deep)", "box": [ 140, -12, 180, 8 ], "facts": [ "F-09" ] }, { "name": "", "box": [ -180, -12, -135, 8 ], "facts": [ "F-09" ] } ], "tubes": [ { "name": "Tharsis volcanoes", "box": [ -135, -15, -100, 15 ], "facts": [ "F-29", "F-30" ] }, { "name": "Alba Mons", "box": [ -126, 33, -95, 49 ], "facts": [ "F-31" ] }, { "name": "Elysium Mons", "box": [ 140, 20, 152, 30 ], "facts": [ "F-30" ] } ] }, "resources": [ { "name": "Buried ice", "icon": "ice", "status": "Mapped from orbit", "where": "Northern mid-latitudes, poles", "tested": 2, "local": 3, "energy": 2, "note": "The resource that decides where the city goes. Depth of the top layer is the big unknown (F-10).", "facts": [ "F-04", "F-05", "F-06", "F-10" ] }, { "name": "Water from soil", "icon": "soil", "status": "Measured on Mars", "where": "Everywhere", "tested": 2, "local": 3, "energy": 3, "note": "About 2% by weight. Works anywhere, but needs a lot of heat and the water carries perchlorate.", "facts": [ "F-11", "F-17" ] }, { "name": "Oxygen from air", "icon": "air", "status": "Proven on Mars", "where": "Everywhere", "tested": 3, "local": 3, "energy": 3, "note": "MOXIE did it at desk scale. A settlement plant must be vastly larger.", "facts": [ "F-14" ] }, { "name": "Rocket fuel", "icon": "fuel", "status": "Proven on Earth", "where": "Wherever ice and air meet", "tested": 2, "local": 3, "energy": 3, "note": "Methane and oxygen from water plus air. The biggest power user (R-04).", "facts": [ "F-15" ] }, { "name": "Nitrogen", "icon": "air", "status": "Present, scarce", "where": "Everywhere, thinly", "tested": 1, "local": 1, "energy": 3, "note": "Only {n2}% of thin air. Recycled with care (R-07).", "facts": [ "F-13" ] }, { "name": "Iron", "icon": "rock", "status": "Measured on Mars", "where": "Everywhere; hematite at Meridiani", "tested": 1, "local": 3, "energy": 3, "note": "About a sixth of the soil is iron oxide. Smelting needs carbon and heavy power.", "facts": [ "F-16", "F-18" ] }, { "name": "Sulphur concrete", "icon": "brick", "status": "Lab tested", "where": "Sulphur is in all soil", "tested": 1, "local": 2, "energy": 2, "note": "No water needed, but results range widely (F-19, F-20) and the sulphur must first be freed from sulphate minerals.", "facts": [ "F-19", "F-20", "F-21" ] }, { "name": "Pressed bricks", "icon": "brick", "status": "Lab tested", "where": "Everywhere", "tested": 1, "local": 3, "energy": 1, "note": "Pressure alone, no oven. Small samples so far.", "facts": [ "F-22" ] }, { "name": "Rock fibre", "icon": "rock", "status": "Lab tested", "where": "Everywhere", "tested": 1, "local": 3, "energy": 3, "note": "Melted soil drawn into fibre, for rope, cloth and reinforcement.", "facts": [ "F-23" ] }, { "name": "Power", "icon": "power", "status": "Tested on Earth", "where": "Reactors anywhere; sun best near the equator", "tested": 2, "local": 1, "energy": 0, "note": "Solar fades with dust; reactor fuel comes from Earth. Energy limits everything else.", "facts": [ "F-24", "F-25", "F-26" ] }, { "name": "Natural shelter", "icon": "cave", "status": "Seen from orbit", "where": "Tharsis, Alba Mons, Elysium", "tested": 1, "local": 3, "energy": 1, "note": "Free rock roofs, but mostly far from the ice. Nobody has been inside one.", "facts": [ "F-28", "F-29", "F-31" ] } ], "assumptions": [ { "id": "R-01", "confidence": "High", "text": "Water is mined from buried ice in the northern mid-latitudes, and the settlement is built next to the ice, not the other way round. Ice is the first constraint on the map; everything else fits around it.", "why": "Water is needed in bulk for drinking and farming, and to make rocket fuel (F-15). Soil water works anywhere but is slow and dirty (F-11, F-17). Sitting on the ice is the only sensible choice.", "moves_to": "" }, { "id": "R-02", "confidence": "Medium", "text": "The primary city sits in the Arcadia Planitia ice zone, on SpaceX's AP-1 site ({lead_lat}°N, just inside SpaceX's {sx_lat}° solar limit), near SpaceX's other candidate sites. Thick ice close to the surface, low flat plains for landing, enough sun for solar to help, winters survivable.", "why": "SWIM's strongest region (F-03, F-04) and SpaceX's own 2025 choice (F-34). AP-1 is SpaceX's safest site and inside its solar limit (F-33); AP-9, about {d_ap9} km to the north-east, has the thickest radar ice and stays on record as the nearby ice alternative. Utopia has thicker ice but lies mostly north of 40°N; it is the next icy city site. The 2026 pad study (F-35) did not score ice; Acidalia is a fallback for landing ground only (R-09). 02-03 holds the lead candidate site; 04-01-01 FC-01 makes the pin the centre of the first crew's buried modules. Pin moved from AP-9 to AP-1 by the owner on 25 September 2026.", "moves_to": "" }, { "id": "R-03", "confidence": "Medium", "text": "Because there is no known lava tube at the ice, the city's shielding is made, not found: modules buried under about 3 m of soil (02-01 S-18) and later caverns dug into ice-free ground. A lava-tube settlement is a later outpost: 04-01-02 LT-01 places it at Arsia Mons, at the skylight Jeanne. Arsia Mons has the best-known skylights, though they were rated poor for habitation because they sit so high (F-29); Alba Mons reaches up to the ice latitudes (F-31) and stays the fallback.", "why": "Resolves the ice-versus-tubes tension without pretending it away (F-28 to F-31). Alba Mons is still to be checked for ice (open question): ice beside an open tube could make it beat Arsia. An outpost away from the ice would need its water brought in. Gives the world a contrasting outpost.", "moves_to": "" }, { "id": "R-04", "confidence": "High", "text": "The settlement makes its own oxygen from the air and its own rocket fuel from air plus mined water. The fuel plant is the largest industrial structure. In the early eras it is also the biggest single user of power; from the City on, the farms under lamps use several times more (03-10).", "why": "MOXIE proved the oxygen chemistry on Mars (F-14); the Sabatier reaction is used on the Space Station (F-15). How the plant works, its size and where it sits are in 03-04 (Fuel plant).", "moves_to": "" }, { "id": "R-05", "confidence": "Medium", "text": "Local building uses sulphur concrete and pressed or baked soil for bulk, rock fibre for reinforcement, and local iron later. Precision parts, electronics, seals and anything needing rare metals come from Earth until the settlement learns to make them, last of all (03-12 MF-09).", "why": "Each material has been made from simulant (F-19, F-22, F-23), but only in labs, and sulphur concrete results vary about {sc_ratio}-fold (F-20). Lowered from High in version 2.0. How local iron is made: 03-12 MF-03 (remelted ship hulls) and MF-04 (iron from soil, with hydrogen).", "moves_to": "" }, { "id": "R-06", "confidence": "High", "text": "See 03-03 G-01, which now owns the power plan.", "why": "The planetary facts the plan rests on stay here: dust cut InSight's power by {ins_drop} percent (F-24), a global dust storm can last for months (02-02 F-16), Kilopower was designed for Mars (F-25), and wind may help at night and in storms (F-26).", "moves_to": "", "moved_to": "03-03 G-01" }, { "id": "R-07", "confidence": "Medium", "text": "Nitrogen is the settlement's quiet obsession. It is the hardest essential to get and the easiest to lose. Farms are sealed, waste is recycled, and venting a nitrogen-rich room is treated like pouring away drinking water.", "why": "Only {n2} percent of thin air (F-13). It gives farming and life support a distinctive constraint.", "moves_to": "" }, { "id": "R-08", "confidence": "Low", "text": "Beyond iron, no metal mining is economic for export. There is no gold rush. The settlement's export to Earth, if any, is knowledge and story, not ore. The metals it needs for itself come from soil, ships and recycling (03-12 MF-08), and after the City from small local works (04-02-04 SF-16).", "why": "No evidence of rich near-surface deposits of rare metals, and launch costs make shipping ore absurd. Deliberately closes off a lazy plot line.", "moves_to": "" }, { "id": "R-09", "confidence": "Medium", "text": "The 2026 natural-landing-pad study does not move the city. Arcadia stays the lead and Utopia remains the next icy city site (R-02). Acidalia is an alternative for landing ground only: if a future study finds no safe natural pad in Arcadia for the first ship, Acidalia's plains are the fallback.", "why": "Menges and Cannon found favourable ground in both Acidalia and Arcadia, particularly on Acidalia's sediment-mantled plains, but did not score ice (F-35). Most of the qualifying ground ({mg_north}%) lies north of 40°N, just beyond SpaceX's solar limit, so the first ship's natural pad is likely a little north of the city pin. Acidalia is about {d_acidalia} km from our pin, too far to drive, and its ice is less certain, so it is not a city site.", "moves_to": "" }, { "id": "R-10", "confidence": "Low", "text": "The site scores in the comparison matrix (0 to 3 for ice, landing ground and lava tubes) are our judgement from the cited facts. The sunlight score is worked out from latitude.", "why": "No published study scores all these sites on the same scale. The scores make the trade-off visible; they are not measurements.", "moves_to": "" } ], "links": { "leans_on": [ { "ref": "01-01 F-24", "why": "SpaceX's February 2026 shift to the Moon first, for the shelf life of the site choice" }, { "ref": "02-01 S-18", "why": "Buried modules under about 3 m of soil for shielding" }, { "ref": "02-01 F-05, F-06, F-32, F-50", "why": "Air mix, perchlorate and Hellas, quoted live" }, { "ref": "02-01", "why": "Mars's radius and air density, for distances and wind" }, { "ref": "02-02 F-16", "why": "How long a global dust storm lasts, cited in R-06's planetary reason" }, { "ref": "02-05 SU-02, SU-03", "why": "Best estimates of the depth to the top and base of the ice at the pin, which the ice-depth open question now points to" }, { "ref": "02-07 SK-01", "why": "The sky colours, for the opening picture's sky (read live)" } ], "used_by": [ { "ref": "05-20", "why": "Mars games: Lava tubes, buried ice, the 2021 impact and MOXIE, for Mars Quiz questions (worked_out)" }, { "ref": "05-19", "why": "The pin's latitude, for how high Phobos climbs over the playable city (05-19 PA-13)" }, { "ref": "05-13 Mars Atlas", "why": "The city pin at AP-1, where the atlas draws Arcadia City, and the buried ice under Arcadia and the depth of the cave skylight Jeanne for the home page's fact cards (read live)" }, { "ref": "04-01-03", "why": "Water in ordinary soil, and the AP-1 pin for the distance to the science town (read live)" }, { "ref": "05-10", "why": "MOXIE's oxygen, for a pin in the viewer (read live)" }, { "ref": "02-01", "why": "Reads soil make-up, soil water, the Leshin pints, ice-cliff and lava-tube sizes and the site list live" }, { "ref": "02-02", "why": "Reads the sun limits, site list and map regions live" }, { "ref": "02-04", "why": "Reads the site list, pins, heights, sun limits, map regions and numbers live; M-01 and M-02 point to R-02, R-03 and R-09" }, { "ref": "03-01", "why": "Reads Arcadia's ice volume, Utopia's ice thickness and cover, soil water and the Kilopower figures; cites R-01, R-03 and R-04" }, { "ref": "03-02", "why": "Reads menges_pct and menges_north_pct, and cites F-35 and R-02 for natural landing ground; its open questions watch sulphur concrete as a pad surface" }, { "ref": "04-01-01 The first city", "why": "Reads R-02: the pin at AP-1, the map's origin, and AP-9 nearby (read live)" }, { "ref": "03-03 Power", "why": "Reads R-02, R-06, F-24, F-25: The lead site's latitude, for day length and the solar trade (read live); The old power plan, which this file took over (G-01); InSight's dusty panels (read live); Kilopower's power, life and test (read live)" }, { "ref": "03-04 Fuel plant", "why": "Reads F-14, F-15, R-04: MOXIE's results (read live); The Sabatier reaction and its use for Mars fuel; The settlement makes its own fuel; the plant is its largest industrial structure" }, { "ref": "03-05 Vehicles and port", "why": "Reads R-02: The city pin at AP-1 and nearby sites, for range rings (read live)" }, { "ref": "02-05 The site up close", "why": "Reads R-02 (the pin: AP-1's position and height), the site list, AP-9, SpaceX's slope and solar limits, the Arcadia ice box and SWIM's blind spot (F-10) (read live)" }, { "ref": "02-07 The Mars sky", "why": "Reads R-02: the site's latitude, for every sky position (read live)" }, { "ref": "03-07 Airlocks, suitports and dust", "why": "Reads F-24: InSight's power lost to dust (read live)" }, { "ref": "03-09 Life support", "why": "Reads F-14: MOXIE's results (read live)" }, { "ref": "03-10 Greenhouses and food", "why": "Cites R-07 (nitrogen is precious, so farms are sealed) and F-23 (fibres drawn from melted soil stand-in)" }, { "ref": "03-11 Construction and materials", "why": "Reads F-16, F-19, F-20, F-27: soil make-up, sulphur concrete's strength and making, and InSight's mole depth (read live). Cites F-21, F-22 and R-05 (local building)" }, { "ref": "03-12 Manufacturing", "why": "Reads F-16: soil make-up (read live). Cites F-18 (hematite), F-23 (rock fibre), R-05 (local iron later: MF-03, MF-04) and R-08 (no metal mining beyond iron)" }, { "ref": "04-01-02 The lava-tube outpost", "why": "Reads F-25 to F-33: lava-tube sizes, skylights, the cave catalogue, Alba's tubes, Kilopower and the landing limits (read live). LT-01 chooses between R-03's Alba and Arsia" }, { "ref": "03-13 Local communications", "why": "Reads R-02: the pin's latitude and longitude, for the town's clock (read live)" }, { "ref": "03-15 Waste and recycling", "why": "Cites R-07: nitrogen is the scarcest essential" }, { "ref": "05-02 The Olympus race", "why": "Reads R-02: the city pin at AP-1, for the distance and bearing to the start (read live)" }, { "ref": "04-02-02 Money and trade", "why": "Reads the AP-1 pin (R-02), for the distance to Jezero (read live)" }, { "ref": "04-03-01", "why": "The calendar and festivals: the pin's latitude and longitude (R-02), for daylight and the town's sol (read live)" }, { "ref": "04-04-02 A day in the life", "why": "R-02: the pin's latitude, for sunrise and sunset (read live)" }, { "ref": "05-03 Guided tours", "why": "The city pin at AP-1 (R-02) and the Jeanne skylight's depth (F-29) (read live)" }, { "ref": "05-05 The Q&A guide", "why": "SpaceX's AP-1 site (F-33), cited in 'Is this city real?'" }, { "ref": "05-06 Free roam", "why": "The city pin at AP-1 (R-02): the site's latitude for day lengths and the start of every distance (read live)" }, { "ref": "05-07 First-time onboarding", "why": "The AP-1 pin (R-02) where the fall ends (read live)" }, { "ref": "05-08 The journey experience", "why": "The city pin at AP-1 (R-02), for where the ride lands and when dawn comes (read live)" }, { "ref": "05-09 Sign-ups and business", "why": "The city pin at AP-1 (R-02), printed on the boarding pass, read live" }, { "ref": "00-04 Glossary and units", "why": "R-02: the pin AP-1: latitude, longitude and height (read live)" }, { "ref": "00-05 Writing and visual standard", "why": "R-02: AP-1's latitude, for a before-and-after example (read live)" }, { "ref": "02-08", "why": "The AP-1 pin (R-02), for the distance from Jezero (read live)" }, { "ref": "05-11", "why": "The site list's positions and facts, through the gazetteer in 02-04, for the globe's labels and cards (read live)" }, { "ref": "05-12", "why": "City experience reads this source live through the generated library bundle." }, { "ref": "04-02-04", "why": "R-08 closes off metal mining for export, not the metals Mars needs (SF-16)" }, { "ref": "04-01-04 The cities of Mars", "why": "The site list: every later town stands on one of its pins, for the reason the survey gives (read live)" }, { "ref": "05-17 Living on Mars", "why": "Arcadia City's pin (the lead site), where the explainer's Checked stamp is dated" } ] }, "open_questions": [ "02-04 and 04: Alba Mons' tube field (F-31) is at about {alba_lat}°N. Is there shallow ice on its western flank? If so it may beat Arsia for the tube outpost (R-03, 02-04 M-02).", "Water per return ship: see 03-04 Fuel plant (no figure here, folder 02 may not lean on 03).", "Sulphur concrete: no plume tests of sulphur concrete found yet (as 03-02 notes).", "Depth to the ice at our pin: 02-05 now gives best estimates for the top of the ice (SU-02) and the base of the ice-rich layer (SU-03), both Low confidence, and holds the follow-up. The 1 to 5 m gap (F-10) is exactly where a drill starts, so the first ground radar or drill at the site settles it. Watch for new high-frequency radar results." ], "changes": [ "25 September 2026 (before v2.2): Rebuilt as twin files (this facts file plus the page), with a world strip, site matrix, ice cross-section and resource cards. Version 1.0 was 16 September 2026.", "25 September 2026 (before v2.2): Corrected: the '170 m thick, under at most 20 m' ice was Utopia's figure, not Arcadia's. Arcadia's ice is tens of metres thick (F-04); Utopia's is 80 to 170 m under 1 to 10 m of soil (F-05).", "25 September 2026 (before v2.2): Corrected: fresh-crater ice at 35°N was in Amazonis, not Arcadia (F-07).", "25 September 2026 (before v2.2): Corrected: Zhurong found no sign of liquid water to 80 m; it did not rule out ice (F-08).", "25 September 2026 (before v2.2): Corrected: air is 2.6% nitrogen and 1.9% argon (Curiosity), not 2.7% and 1.6%.", "25 September 2026 (before v2.2): Corrected: perchlorate is 0.4 to 0.6% at Phoenix and up to about 1% at Curiosity (now quoted from 02-01), not 0.5 to 1% everywhere; soil sulphur is about 5% measured as sulphur trioxide.", "25 September 2026 (before v2.2): Corrected: Martian lava tubes are estimated at up to about 450 m wide, about 80 times Earth's by volume.", "25 September 2026 (before v2.2): Corrected: InSight did not rule out geothermal heat; its heat probe never dug deep enough to measure it (F-27).", "25 September 2026 (before v2.2): Corrected: Kilopower's core is about the size of a paper towel roll (F-25), not a wheelie bin; NASA compares one unit to several households.", "25 September 2026 (before v2.2): Corrected: the ice and the lava tubes are in different latitude bands, not on opposite sides of the planet. Alba Mons has tubes at ice latitudes (F-31).", "25 September 2026 (before v2.2): Removed unsourced claims: $100 million per tonne of imported water, 'sets in minutes', 'stronger than steel for its weight', solar 100 to 150 W per square metre, dust losses of 1 to 2% a sol, -140°C polar cold, and Honeybee's RedWater target as a reason for R-02 (not checked).", "25 September 2026 (before v2.2): Updated: wind is now a possible storm backup (F-26), not 'not worth the mass'.", "25 September 2026 (before v2.2): Moved the 600 to 700 t water-per-ship figure to an open question for 03-01.", "25 September 2026 (before v2.2): Added 2021 to 2026 results: SpaceX's site study, its 2025 Arcadia choice, the Christmas Eve crater, deep equatorial ice, SWIM's 2026 odds, the 2026 landing-pad study, Alba Mons tubes and water-carved caves.", "25 September 2026 (before v2.2): Added three sites (Phlegra Montes, Acidalia Planitia, Alba Mons) and Arcadia's pin now sits on SpaceX's AP-9 site. Site data is now one shared list for 02-04 and the website.", "25 September 2026 (before v2.2): Lowered R-05 from High to Medium. Added R-09 (Acidalia does not move the city) and R-10 (scores are judgement). Updated R-02, R-03 and R-06.", "25 September 2026 (version 2.1): Clarified: Utopia's deposit is about 1.2 Lake Superiors of water ice (Stuurman, Planetary Society 2016), about one Lake Superior of water (JPL 2016). Added 'roughly twice as thick as Arcadia's'.", "25 September 2026 (2.1): Added SWIM's fourth phase, SWIM4IMIM (F-02).", "25 September 2026 (2.1): Air mix, perchlorate, Hellas depth and pressure, Mars's radius and air density are now read live from 02-01, which owns them; air density corrected to 1.3%.", "25 September 2026 (2.1): Corrected lava-tube widths: collapse chains 40 to 400 m, tubes up to about 450 m (F-28).", "25 September 2026 (2.1): Updated pins: Alba Mons to the IAU Gazetteer centre, Elysium to InSight's 135.6°E; widened the Medusae Fossae deep-ice box; Utopia pin note says where the deposit lies.", "25 September 2026 (2.1): Updated R-02 and R-03 wording (the tube settlement is an outpost); removed citations of higher-numbered files from facts and assumptions; stale open questions deleted.", "25 September 2026 (2.1): Updated F-12, F-26, F-30 and several comparisons; fixed the clipped zoom figure and made diagram labels at least 11 px on phones.", "25 September 2026 (before v2.2): 25 September 2026: folder 05 renamed 'Visiting Mars' (decided 25 September 2026); links updated.", "25 September 2026 (v2.2): Added numbers.sun_limits_deg (30 and 40°, Golombek 2021: latitude 'must be <40°'), replacing sx_lat_max. The sun score now uses 40°, not 41°; the '+1 degree' fudge is gone, so the Arcadia pin (AP-9, 40.02°N) and Alba Mons score 1 for sun, honestly.", "25 September 2026 (v2.2): Corrected F-33's comparison: AP-1 and EM-16 sit just under 40°N; AP-9, our pin, is a hair over.", "25 September 2026 (v2.2): Updated pins to the source values: Arcadia 40.02°N, 156.65°W; Erebus 39.89°N, 167.97°W; Phlegra 35.23°N, 163.95°E; Acidalia 49.76°N, 20.74°W; Elysium 135.62°E. Pin notes give the source's 0 to 360° figure; sites.about states the coordinate system. Added elev_km for AP-9, EM-16 (-3.9 km) and PM-1 (-3.2 km) from Golombek 2021.", "25 September 2026 (v2.2): Updated R-02 (about 40°N, AP-9 right at SpaceX's limit), R-09 (Acidalia is a fallback for landing ground only; Utopia is the next icy city site) and F-35 (wording now matches Menges and Cannon: favourable ground in both Acidalia and Arcadia, particularly Acidalia; most of it north of 40°N).", "25 September 2026 (v2.2): Corrected: Alba Mons is one story. The tube field (F-31) is at about 40.5°N; the pin is the volcano centre at 41.1°N; site cards no longer say 'about 40°N'.", "25 September 2026 (v2.2): Updated R-03: where the tube outpost goes is undecided between Alba Mons and Arsia Mons, whose skylights were rated poor for habitation (F-29).", "25 September 2026 (v2.2): Added numbers.leshin_pints (Leshin 2013); the page works out 'about 0.9 litre' from it.", "25 September 2026 (v2.2): R-06 is now the one owner of the power plan (02-01 S-23 and 02-02 W-02 point to it), cites 02-02 F-16 for storm length and moves to a 03 power file when one exists. R-04 points to a future 03 fuel-plant file and to 03-01 F-19 and F-20.", "25 September 2026 (v2.2): Added to the shelf life: SpaceX's site choice predates its February 2026 Moon-first shift (01-01 F-24).", "25 September 2026 (v2.2): Removed three stale open questions (02-04's old Arcadia figures, 03-01 F-01, 03-01's 'nearly pure' ice) and replaced the water-per-ship note with a pointer to 03-01.", "25 September 2026 (v2.2): Corrected link reasons: R-01 now cites F-15 only for fuel; 03-02 reads only menges_pct and F-35; added 02-01 and 02-02, which read this file. Distances are now rounded to the nearest 10 km, as on the map (02-04). Page title now 'Resource survey', matching the catalogue.", "25 September 2026 (v2.2): R-04 no longer cites 03-01 (folder 02 may not lean on 03, L-03). F-36 says Hellas air is about twice the average, matching 02-04. R-02 says 04.01 Cities. The 03-02 link reason lists everything 03-02 reads.", "25 September 2026 (v2.3): the owner moved the city pin from AP-9 to AP-1 (39.8°N, 157.9°W, 3.9 km below average level; Golombek 2021: SpaceX's safest site, inside its 40° solar limit). AP-9 is kept in numbers.ap9 as the nearby thick-ice alternative. Arcadia now scores 2 for sun. F-33, R-02 and the site card updated; the owner question is closed.", "25 September 2026 (v2.4): R-06 is now a signpost: the power plan moved to 03-03 G-01, the new power file. Its planetary reasons (F-24 to F-26) stay here.", "25 September 2026 (v2.5): links made two-way for the new files 03-03 Power, 03-04 Fuel plant and 03-05 Vehicles and port (and older one-sided links), each reason taken from the other file's own link.", "25 September 2026 (v2.5): R-04 points to 03-04 for the fuel plant; the open question on power is answered by 03-03 Power and removed; link reasons updated now that S-23 and W-02 point straight to 03-03.", "25 September 2026 (v2.6): water per return ship now signposts 03-04 (the fuel plant owns it); link reason for 02-02 F-16 updated.", "26 September 2026 (v2.7): The open question on the depth to the ice at the pin now points to 02-05 SU-02 (top of the ice) and SU-03 (base of the ice-rich layer): best estimates, Low confidence, so it is kept, not deleted; 02-05 holds the follow-up. 02-05 added to leans_on. used_by lists 02-05 and 02-07, which read the pin (R-02) and the site list.", "26 September 2026 (v2.8): R-04 no longer calls the fuel plant the biggest user of power in every era: from the City on the farms under lamps use several times more (03-10). F-22's brick paper is credited to its first author, Brian Chow (Chow, Chen, Zhong and Qiao, Scientific Reports 2017), with the paper added as a source. F-27 gives NASA JPL's reason the mole failed: the clumping soil gave it too little friction to dig; the JPL source link was checked and works. R-05 points to 03-12 MF-03 and MF-04 for local iron. used_by adds 03-07, 03-09, 03-10, 03-11 and 03-12.", "26 September 2026 (v2.9): R-03 now says 04-01-02 LT-01 places the lava-tube outpost at Jeanne on Arsia Mons, with Alba Mons the fallback; the Alba ice question stays open. R-02 now points to 04-01-01 FC-01 for the exact spot. used_by: the old 04.01 Cities line becomes 04-01-01; adds 04-01-02, 03-13, 03-15 and 05-02.", "26 September 2026 (v2.10): used_by adds 04-02-02 Money and trade, which reads the AP-1 pin live.", "26 September 2026 (v2.11): F-28 now matches Sauro 2020: Martian tubes up to about 80 times bigger than Earth's (it had said 'on average', 'by volume'). The Arsia site card gives both heights as 04-01-02 F-05 does (Wikipedia's 11.7 km peak; the 1998 laser-altimeter summit about 17.45 km above zero level), with that source added. F-33 already follows Golombek 2021 and gives no reason for the height limit, so it is unchanged. used_by: back-links for 04-03-01, 04-04-02 (what each reads, from its leans_on). Also back-links for 05-03, 05-05, 05-06, 05-07, 05-08, 05-09 (wave 6 pages, from their leans_on as written today).", "26 September 2026 (v2.12): Comparison lines for F-15, F-21, F-26, F-32 and F-34 (worked out from this file and 02-01 where a number is involved); the shelf life names a re-check date (March 2027), as the Research log (90-04) audit asked. Back-links for 00-04 and 00-05, which read the AP-1 pin (R-02) live.", "26 September 2026 (v2.13): Beauty pass: a new opening picture, a not-to-scale cut through soil, buried ice and rock with a drill, labelled as art.", "26 September 2026 (v2.14): Final fix round: used_by: the folder-level '05 Visiting Mars' line removed; the 05 pages that really read this file are listed one by one. The opening picture's sky colours are now read live from 02-07 SK-01 instead of typed; leans_on and quotes add 02-07", "28 September 2026 (v2.15): Now used by the new 02-08 Jezero Crater, which reads it live.", "28 September 2026 (v2.16): Used by the Jezero science town (04-01-03) and the Stand in Jezero viewer (05-10).", "29 September 2026 (v2.17): Used by the Mars Through Time globe (05-11), and every site now has a plain name and hook in 02-04's gazetteer (rule L-22). No facts changed.", "30 September 2026 (v2.18): Added the city experience to the files that read this source.", "1 October 2026 (v2.19): R-05 now says precision parts, electronics and seals come from Earth until the settlement learns to make them (03-12 MF-09), because the last era is a Mars that needs nothing from Earth (00-01). R-08 now closes off metal mining for export only: the metals Mars needs for itself are 03-12 MF-08 and, after the City, 04-02-04 SF-16. used_by adds 04-02-04.", "1 October 2026 (v2.20): Used by the Mars Atlas (05-13).", "3 October 2026 (v2.21): Now also used by 04-01-04 The cities of Mars, which places the towns of Many Cities and Self-sustaining Mars.", "4 October 2026 (v2.22): used_by: 05-13 now also reads the Arcadia ice volume and the skylight depth for the home page fact cards.", "4 October 2026 (v2.23): Added F-37 (Mars rusted while it was wet: ferrihydrite in the dust, Valantinas 2025) and F-38 (Curiosity's first drill powder is grey, 2013), with numbers.drill_cm, for the atlas's How Mars turned red story and its Mars Today card (05-13).", "9 October 2026 (v2.24): Used by 05-19 Playable Arcadia, which reads this file live.", "10 October 2026 (v2.25): Used by 05-17 Living on Mars: the explainer's blueprint stamp is dated with today's Mars date from the shared sky model." ], "sources": { "dundas_2018": { "name": "NASA JPL, Steep slopes on Mars reveal structure of buried ice, 2018", "url": "https://www.jpl.nasa.gov/news/steep-slopes-on-mars-reveal-structure-of-buried-ice/" }, "dundas_2018_paper": { "name": "Dundas and others, Exposed subsurface ice sheets in the Martian mid-latitudes, Science, 2018 (USGS record)", "url": "https://pubs.usgs.gov/publication/70195019" }, "swim_psi": { "name": "Planetary Science Institute, Subsurface Water Ice Mapping (SWIM) project site (accessed September 2026)", "url": "https://swim.psi.edu/" }, "perry_2020": { "name": "Perry and others, SWIM on Mars: overview and methods, LPSC 2020", "url": "https://www.hou.usra.edu/meetings/lpsc2020/pdf/2645.pdf" }, "morgan_2021": { "name": "Purdue University, Ice frozen under Mars surface offers major resource (Morgan and others, Nature Astronomy), 2021", "url": "https://www.purdue.edu/newsroom/releases/2021/Q1/ice-frozen-under-mars-surface-offers-major-resource-to-aid-future-settlements.html" }, "bramson_2015": { "name": "Bramson and others, Widespread excess ice in Arcadia Planitia, Mars, Geophysical Research Letters, 2015 (arXiv 1509.03210)", "url": "https://arxiv.org/abs/1509.03210" }, "stuurman_2016": { "name": "NASA JPL, Mars ice deposit holds as much water as Lake Superior (Stuurman and others), 2016", "url": "https://www.jpl.nasa.gov/news/mars-ice-deposit-holds-as-much-water-as-lake-superior/" }, "jpl_ce_2022": { "name": "NASA JPL, InSight lander detects stunning meteoroid impact on Mars, 2022", "url": "https://www.jpl.nasa.gov/news/nasas-insight-lander-detects-stunning-meteoroid-impact-on-mars/" }, "dundas_2023": { "name": "Dundas and others, A large new crater exposes the limits of water ice on Mars, Geophysical Research Letters, 2023", "url": "https://doaj.org/article/a8658c3c93fd400a89d163a2d12500d7" }, "zhurong_2022": { "name": "Li and others, Layered subsurface in Utopia Basin of Mars revealed by Zhurong rover radar, Nature, 2022", "url": "https://www.nature.com/articles/s41586-022-05147-5" }, "zhurong_gt_2022": { "name": "Global Times, Zhurong finds no evidence of liquid water down to 80 metres, 2022", "url": "https://www.globaltimes.cn/page/202209/1276243.shtml" }, "zhurong_wiki": { "name": "Wikipedia, Zhurong (rover): landing coordinates, 2026", "url": "https://en.wikipedia.org/wiki/Zhurong_(rover)" }, "watters_2024": { "name": "Smithsonian National Air and Space Museum, Evidence of an ice-rich layered deposit on Mars (Watters, Geophysical Research Letters), 2024", "url": "https://airandspace.si.edu/newsroom/press-releases/new-study-reveals-evidence-ice-rich-layered-deposit-mars" }, "sizemore_2026": { "name": "Planetary Science Institute, Laying odds on the potential for Martian water (Sizemore, Courville and others, Planetary Science Journal), 2026", "url": "https://www.psi.edu/blog/laying-odds-on-the-potential-for-martian-water/" }, "leshin_2013": { "name": "The Irish Times, Mars soil sample analysis reveals 2% of water by weight (Leshin and others, Science), 2013", "url": "https://www.irishtimes.com/news/science/mars-soil-sample-analysis-reveals-2-of-water-by-weight-1.1542315" }, "nerozzi_2019": { "name": "University of Texas Institute for Geophysics, Massive Martian ice discovery (Nerozzi and Holt), 2019", "url": "https://ig.utexas.edu/news/2019/massive-martian-ice-discovery-opens-a-window-into-red-planets-history/" }, "nasa_air_2019": { "name": "NASA, Curiosity serves scientists a new mystery: oxygen, 2019", "url": "https://www.nasa.gov/missions/with-mars-methane-mystery-unsolved-curiosity-serves-scientists-a-new-one-oxygen/" }, "moxie_2023": { "name": "NASA JPL, Oxygen-generating experiment MOXIE completes Mars mission, 2023", "url": "https://www.jpl.nasa.gov/news/nasas-oxygen-generating-experiment-moxie-completes-mars-mission/" }, "sabatier_wiki": { "name": "Wikipedia, Sabatier reaction, 2026", "url": "https://en.wikipedia.org/wiki/Sabatier_reaction" }, "ming_2017": { "name": "Ming and Morris (NASA Johnson Space Center), Chemical, mineralogical and physical properties of Martian dust and soil, 2017", "url": "https://ntrs.nasa.gov/api/citations/20170005414/downloads/20170005414.pdf" }, "hecht_2009": { "name": "Hecht and others, Detection of perchlorate and the soluble chemistry of Martian soil at the Phoenix lander site, Science, 2009", "url": "https://www.science.org/doi/10.1126/science.1172466" }, "jpl_berries_2004": { "name": "NASA JPL, Mineral in Mars 'berries' adds to water story, 2004", "url": "https://www.jpl.nasa.gov/news/mineral-in-mars-berries-adds-to-water-story/" }, "wan_2016": { "name": "Wan, Wendner and Cusatis, A novel material for in situ construction on Mars, 2016 (arXiv 1512.05461)", "url": "https://arxiv.org/abs/1512.05461" }, "tute_2024": { "name": "Tute and Goulas, Mechanical behaviour of sulphur-based Martian regolith concrete processed under CO2-rich conditions, Icarus, 2024", "url": "https://www.sciencedirect.com/science/article/pii/S0019103524001945" }, "shahsavari_2022": { "name": "Shahsavari and others (KU Leuven), Martian and lunar sulfur concrete properties considering sublimation, Construction and Building Materials, 2022", "url": "https://www.sciencedirect.com/science/article/abs/pii/S0950061822025703" }, "qiao_2017": { "name": "UC San Diego, A simple, no-bake recipe to make bricks from Martian soil (on Chow and others, Scientific Reports), 2017", "url": "https://jacobsschool.ucsd.edu/news/release/2197?id=2197" }, "fibre_2024": { "name": "Mars Daily, Scientists demonstrate producing fibre from simulated Martian soil (Chinese Academy of Sciences, iScience), 2024", "url": "https://www.marsdaily.com/reports/Chinese_Scientists_Demonstrate_Feasibility_of_Producing_Fiber_Materials_from_Simulated_Martian_Soil_999.html" }, "insight_power_2022": { "name": "NASA JPL, InSight's power generation: after landing and spring 2022, 2022", "url": "https://www.jpl.nasa.gov/images/pia25284-insights-power-generation-after-landing-and-spring-2022/" }, "kilopower_2018": { "name": "NASA, Demonstration proves nuclear fission system can provide space exploration power, 2018", "url": "https://www.nasa.gov/news-release/demonstration-proves-nuclear-fission-system-can-provide-space-exploration-power/" }, "hartwick_2023": { "name": "Eos, Wind could power future settlements on Mars (Hartwick and others, Nature Astronomy), 2023", "url": "https://eos.org/articles/wind-could-power-future-settlements-on-mars" }, "insight_mole_2021": { "name": "NASA JPL, InSight's 'mole' ends its journey on Mars, 2021", "url": "https://www.jpl.nasa.gov/news/nasa-insights-mole-ends-its-journey-on-mars/" }, "sauro_2020": { "name": "Sauro and others, Lava tubes on Earth, Moon and Mars: a review on their size and morphology, Earth-Science Reviews, 2020", "url": "https://cris.unibo.it/retrieve/handle/11585/769982/bf298592-3a07-4d19-8979-599f91ae8131/2020+Sauro+et+al+ESR+Lava+tubes.pdf" }, "cushing_2007": { "name": "NASA JPL, NASA orbiter finds possible cave skylights on Mars (Cushing and others), 2007", "url": "https://www.jpl.nasa.gov/news/nasa-orbiter-finds-possible-cave-skylights-on-mars/" }, "arsia_wiki": { "name": "Wikipedia, Arsia Mons, 2026", "url": "https://en.wikipedia.org/wiki/Arsia_Mons" }, "lpsc_1998": { "name": "Lunar and Planetary Science Conference 1998, abstract 1322, Characterization of major volcanic edifices on Mars (Mars Orbiter Laser Altimeter profiles)", "url": "https://www.lpi.usra.edu/meetings/LPSC98/pdf/1322.pdf" }, "mgc3_2017": { "name": "Cushing, Mars Global Cave Candidate Catalog, AbSciCon 2017", "url": "https://www.hou.usra.edu/meetings/abscicon2017/pdf/3708.pdf" }, "crown_2022": { "name": "Planetary Science Institute, Large concentration of lava tubes on Alba Mons (Crown, Scheidt and Berman, JGR Planets), 2022", "url": "https://www.psi.edu/blog/psi-scientists-analyze-large-concentration-of-lava-tubes-on-martian-volcano-alba-mons/" }, "alba_wiki": { "name": "Wikipedia, Alba Mons, 2026", "url": "https://en.wikipedia.org/wiki/Alba_Mons" }, "hebrus_2025": { "name": "Astrobiology.com, Water-driven potential karstic caves in Hebrus Valles, Mars (Astrophysical Journal Letters), 2025", "url": "https://astrobiology.com/2025/11/13/water-driven-accessible-potential-karstic-caves-in-hebrus-valles-mars-implications-for-subsurface-habitability/" }, "golombek_2021": { "name": "Golombek, Wooster and others, SpaceX Starship landing sites on Mars, LPSC 2021", "url": "https://www.hou.usra.edu/meetings/lpsc2021/pdf/2420.pdf" }, "nsf_2025": { "name": "NASASpaceFlight, The future of the Starship programme, Block 3 and Mars, 2025", "url": "https://www.nasaspaceflight.com/2025/05/future-starship-block-3-mars/" }, "menges_2026": { "name": "Menges and Cannon, Natural Landing Pads on the Moon and Mars, Acta Astronautica, 2026", "url": "https://www.sciencedirect.com/science/article/pii/S0094576526000536" }, "hellas_wiki": { "name": "Wikipedia, Hellas Planitia, 2026", "url": "https://en.wikipedia.org/wiki/Hellas_Planitia" }, "utopia_wiki": { "name": "Wikipedia, Utopia Planitia, 2026", "url": "https://en.wikipedia.org/wiki/Utopia_Planitia" }, "deuteronilus_wiki": { "name": "Wikipedia, Deuteronilus Mensae, 2026", "url": "https://en.wikipedia.org/wiki/Deuteronilus_Mensae" }, "acidalia_wiki": { "name": "Wikipedia, Acidalia Planitia, 2026", "url": "https://en.wikipedia.org/wiki/Acidalia_Planitia" }, "phlegra_wiki": { "name": "Wikipedia, Phlegra Montes, 2026", "url": "https://en.wikipedia.org/wiki/Phlegra_Montes" }, "elysium_wiki": { "name": "Wikipedia, Elysium Planitia (InSight landing site), 2026", "url": "https://en.wikipedia.org/wiki/Elysium_Planitia" }, "superior_wiki": { "name": "Wikipedia, Lake Superior, 2026", "url": "https://en.wikipedia.org/wiki/Lake_Superior" }, "gherkin_wiki": { "name": "Wikipedia, 30 St Mary Axe (the Gherkin), 2026", "url": "https://en.wikipedia.org/wiki/30_St_Mary_Axe" }, "mars_fact": { "name": "NASA NSSDC, Mars fact sheet (accessed September 2026)", "url": "https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html" }, "ifab_pitch": { "name": "IFAB, Laws of the Game 2025/26, Law 1: The field of play", "url": "https://www.theifab.com/laws/latest/the-field-of-play/" }, "planetary_2016": { "name": "The Planetary Society, Subsurface water ice in Utopia Planitia, Mars (Stuurman), 2016", "url": "https://www.planetary.org/articles/1122-subsurface-water-ice-in-utopia-planitia-mars" }, "watters_2024_grl": { "name": "Watters and others, Evidence of ice-rich layered deposits in the Medusae Fossae Formation of Mars, Geophysical Research Letters, 2024", "url": "https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023GL105490" }, "insight_nasa": { "name": "Wikipedia, InSight: lander coordinates 4.5024°N 135.6234°E (accessed September 2026)", "url": "https://en.wikipedia.org/wiki/InSight" }, "gazetteer_alba": { "name": "IAU/USGS Gazetteer of Planetary Nomenclature, Alba Mons (accessed September 2026)", "url": "https://planetarynames.wr.usgs.gov/Feature/14306" }, "chow_2017": { "name": "Chow, Chen, Zhong and Qiao, Direct formation of structural components using a martian soil simulant, Scientific Reports 7, 1151, 2017", "url": "https://www.nature.com/articles/s41598-017-01157-w" }, "valantinas_2025": { "name": "Valantinas and others, Detection of ferrihydrite in Martian red dust records ancient cold and wet conditions on Mars, Nature Communications, 25 February 2025 (Brown University news)", "url": "https://www.brown.edu/news/2025-02-25/why-mars-red" }, "klein_2013": { "name": "Space.com, Red Planet Mars not so red beneath the surface (Curiosity's first drill sample, John Klein, February 2013)", "url": "https://www.space.com/19932-mars-color-gray-curiosity-rover.html" } }, "sources_checked": "25 September 2026" }, "02-06": { "file": "02-06", "title": "The human body on Mars", "folder": "02", "facts_file": "02-06-the-human-body-on-mars.json", "version": "1.16", "status": "Active", "last_updated": "10 October 2026", "about": "Facts file for 02-06 The human body on Mars. The page is built from this file, the library catalogue and the page template. Change a fact here, then run build.py. Words in curly brackets, like {nasa_lim}, are filled in when the page is built, so each number is typed once. Numbers owned by other files (the surface dose, gravity, the air, perchlorate, dust size, the sol and the light delay from 02-01; the journey dose, trip lengths and the era plan from 01-01; era names from 00-01) are read live, never retyped here.", "one_line": "What radiation, {g_pct}% gravity, toxic dust, confinement and a {sol_min}-minute-longer day do to people, and the limits the world must respect.", "shelf_life": "Space medicine moves fast. NASA revises its health standard (NASA-STD-3001) every year or two and set its first Mars dust limit in July 2026. The second CHAPEA year-long Mars simulation ends on 31 October 2026, and the first partial-gravity animal results came out in March 2026. The Sun is past the peak of its 11-year cycle, which changes the dose. Re-check NASA-STD-3001, CHAPEA results and new partial-gravity studies by September 2027.", "header": { "purpose": "Say what Mars does to a human body and mind: radiation and solar storms, bone and muscle in {g_pct}% gravity, walking, the heart and eyes, dust and perchlorate, isolation, sleep on a {sol_h}-hour day, pregnancy and children, and medical care far from help. Then add up each era's radiation dose against the limits people use on Earth.", "why": "Every habitat, suit, shift pattern, rule and story in the world has to fit inside what a body can take. If this is vague, the buried town, the storm drills and the day-in-the-life scenes have nothing firm to stand on.", "when": "Writing a character's health, a storm, an injury or a birth; sizing shielding, exercise time or surface shifts; setting dose rules in 04; or checking whether a scene is medically believable.", "change": "Part One changes only with a citation. Part Two assumptions can be challenged one at a time. Edit this facts file, then run build.py.", "writing": "Every number is compared to something people know. Pictures first, short sentences, no walls of text." }, "comparisons": { "about": "Yardsticks used only to compare. Each one either has a source below or is marked as our own round figure.", "days_per_month": 30.44, "waking_h": 16, "waking_note": "our own round figure for the waking hours in a day", "sqft_m2": 0.092903, "ms_kmh": 3.6 }, "numbers": { "nasa_reid_pct": 3, "nasa_ref_age": 35, "nas_over_pct": 150, "hassler_transit_days": 180, "hassler_stay_days": 500, "hassler_total_sv": 1, "icrp_fatal_pct_per_sv": 5, "uk_public_msv": 1, "child_x": [ 2, 3 ], "aug1972_bfo_rem": 130, "aug1972_skin_rem": 600, "rem_per_sv": 100, "may2024_ugy": 8100, "may2024_xrays": 30, "esa_hip_pct_month": 1.5, "esa_hip_pct_6mo": 10, "elderly_pct_year": [ 1, 2 ], "gabel_n": 17, "gabel_not_recovered": 9, "gabel_long_pct": 3.9, "gabel_months": [ 4, 7 ], "mice_n": 24, "mice_days": 28, "mice_g": [ 0.33, 0.67 ], "apollo17_h": 75, "kram_ms": { "g1": 1.98, "g04": 1.39 }, "kram_g": 0.4, "kram_froude": 0.5, "kram_curve": [ [ 1.0, 1.98 ], [ 0.8, 1.84 ], [ 0.6, 1.65 ], [ 0.5, 1.55 ], [ 0.4, 1.39 ], [ 0.2, 1.18 ], [ 0.1, 0.97 ] ], "sans_pct": { "disc": 64, "globe": 26, "folds": 15, "hyperopia": 14 }, "jugular": { "n": 11, "stasis": 6, "clot": 1, "mean_days": 210 }, "twins_days": 340, "twins_gene_pct": 91.3, "moonwalkers": 12, "mars_dust_pel_mgm3": 0.1, "moon_dust_pel_mgm3": 0.4, "dust_peak_mgm3": 10, "dust_pel_um": 10, "dust_pel_days": 30, "who_pm25_ugm3": 15, "perchlorate_rfd_ug_kg": 0.7, "palinkas_pct": 60, "circadian_h": 24.18, "scheer_lux": 450, "phoenix_staff": 19, "phoenix_weeks": 11, "sleep_shuttle_h": 5.96, "rat_flights": [ 1983, 1994, 1995 ], "sj10_embryos": 6000, "sj10_hours": 96, "sperm_years": 6, "sperm_pups": 168, "rogozov_year": 1961, "rogozov_min": 105, "iss_years": 25, "buried_msv_year": 20, "surface_h_per_sol": { "crew": 3, "town": 2, "city": 1 }, "walk_run_ms": 1.39, "hiseas_floor_m2": [ 30.3, 39.4 ], "scheer_h": 24.65, "ramsar_msv_year": 260, "young_jump": { "cm": 42, "date": "21 April 1972" }, "look": { "from": "HB-12", "about": "How people move in Arcadia City, so every picture, film and game scene shows the same gait (00-05 ST-20). Built from F-17, HB-06, 02-01 S-01, S-02 and S-04, choosing the most beautiful reading they allow (00 L-19). Proportions pass within about a quarter.", "parts": { "walk": { "name": "The walk", "look": "Longer, slower strides than on Earth with a slight bounce, the body tipped a little forward, arms loose. Indoors people move with a skipping economy, and a brisk walk turns into a lope at an ordinary Earth strolling pace (F-17, 02-01 S-01)." }, "run": { "name": "The lope", "look": "Running is a string of long, low bounds, both feet off the ground for most of each stride, the leading leg reaching forward and the trailing leg folding back, knees bending to soak up each landing, like the Apollo crews on the Moon but heavier and quicker (02-01 S-01)." }, "jump": { "name": "The jump", "look": "The same push lifts a person about two and a half times as high as on Earth, and they hang in the air that much longer, so a hop up a step or onto a wall looks easy and slow (02-01 S-02)." }, "indoors": { "name": "Built for it", "look": "High ceilings, steep open stairs taken several steps at a bound, handrails, soft floors in play areas, hoops raised for Mars on the court (02-01 S-02, 05-19 PA-07). People train every day, and it shows: lean, strong, relaxed (02-01 S-04)." }, "outside": { "name": "Out on the plain", "look": "In suits (03-08) people bound in pairs, never alone, along graded paths, leaving long lines of deep boot prints; each landing raises a small puff of dust that falls slowly back (02-01 S-12)." } }, "people": "Settlers of every age and background, in everyday clothes indoors and suits outside, small in frame and busy with their own day, never posed or looking at the camera.", "light": "Golden hour or dusk: the long shadows of a bound show how high it rises. Indoors under a water roof the light ripples blue across the floor.", "eras": { "city": "Mostly suited workers bounding between the buried rows, and runners on the first dome's track.", "far": "Families and children leaping in the dome parks; bounding is simply how everyone moves." }, "never": [ "People moving stiffly as on Earth, or floating as if weightless", "A jump much higher than about two and a half times an Earth jump, or a slow-motion drift down", "Anyone outside without a suit, or outside alone (03-08 SS-05)", "A blue daytime sky, snow, rain or puddles outside", "People posed for the camera or staring at it" ], "shots": [ { "id": "track", "name": "The track under the water roof", "frame": "Inside a dome neighbourhood at golden hour: runners bounding round a park track, a person bounding up an outside stair to a roof terrace, and through the glass two suited people bounding along a path on the plain." }, { "id": "bound", "name": "Two in step on the plain", "frame": "Eye level on the plain, two suited people side by side in mid-bound along a trail of boot prints, low Sun behind." } ], "open": [] }, "aldrin_bootprint": { "date": "20 July 1969", "photo": "AS11-40-5878" } }, "sections": [ { "id": "1.1", "title": "Radiation: the dose budget" }, { "id": "1.2", "title": "Solar storms" }, { "id": "1.3", "title": "Bone and muscle in 0.38 g" }, { "id": "1.4", "title": "Walking and running" }, { "id": "1.5", "title": "Heart, blood and eyes" }, { "id": "1.6", "title": "Air, dust and perchlorate" }, { "id": "1.7", "title": "The mind: isolation and confinement" }, { "id": "1.8", "title": "Sleep and the sol" }, { "id": "1.9", "title": "Pregnancy and children" }, { "id": "1.10", "title": "When someone falls ill" } ], "facts": [ { "id": "F-01", "section": "1.1", "text": "See 01-02 F-18, which owns NASA's career limit: {nasa_lim} mSv of spaceflight radiation for a whole career, the same for everyone. How it was set stays here: the most vulnerable case, a woman of {ref_age}, has on average a {reid}% chance of dying of a cancer the radiation caused (NASA-STD-3001, Volume 1, Revision B, 2022).", "compare": "{nasa_lim} mSv is about {lim_bg} years of Earth's natural background, or {lim_sols} days standing on the open Mars surface (02-01 F-25).", "sources": [ "nasa_std_2022", "nasem_2021" ], "moved_to": "01-02 F-18" }, { "id": "F-02", "section": "1.1", "text": "Reviewing that limit in 2021, the US National Academies found that a mission to Mars is likely to exceed it by up to {nas_over}%. Any astronaut going over it would need a waiver from NASA before the mission.", "compare": "The round trip alone (01-01 F-31, F-33) comes to {trip_msv} mSv, {trip_pct}% of the career limit. One crossing is about {one_msv} mSv ({one_pct}%), spent before anyone steps outside.", "sources": [ "nasem_2021" ] }, { "id": "F-03", "section": "1.1", "text": "Curiosity's radiation team added it up for a classic mission: journeys of about {hs_transit} days each way, about {rt_sv} Sv (01-01 F-31), plus {hs_stay} days on the surface come to about {hs_total} Sv in all, if nobody is shielded on the ground.", "compare": "About {hs_xray} chest X-rays (02-01 F-29), and {hs_pct}% of NASA's career limit (01-02 F-18).", "sources": [ "swri_2013", "hassler_2014" ] }, { "id": "F-04", "section": "1.1", "text": "The International Commission on Radiological Protection works with a rounded figure of about {icrp}% extra risk of a fatal cancer for every sievert a person receives.", "compare": "For the {hs_total} Sv mission (F-03), about {mission_risk} extra fatal cancers in every 100 people, turning up years or decades later, mostly back on Earth.", "sources": [ "nrc_icrp103" ] }, { "id": "F-05", "section": "1.1", "text": "UK law limits a member of the public to {uk_public} mSv a year from man-made radiation, and a radiation worker to {uk_worker} mSv a year (the worker figure is the yardstick 02-01 uses).", "compare": "One day on the open Mars surface ({sol_rate} mSv, 02-01 F-25) uses {sol_pub_pct}% of a British member of the public's yearly allowance.", "sources": [ "irr17" ] }, { "id": "F-06", "section": "1.2", "text": "On 4 August 1972, between the Apollo 16 and 17 Moon landings, the Sun threw out a huge burst of particles. America's radiation protection council later worked out that a crew on the Moon's surface would have received about {a72_bfo} rem ({a72_bfo_sv} Sv) to the blood-forming organs and {a72_skin} rem ({a72_skin_sv} Sv) to the skin.", "compare": "{a72_bfo_sv} Sv from one storm: about {a72_x} times NASA's whole-career limit (01-02 F-18).", "sources": [ "alsj_wotm" ] }, { "id": "F-07", "section": "1.2", "text": "In the 'Halloween' solar storms of 2003, MARIE, the instrument on NASA's Mars Odyssey orbiter that was measuring the radiation a crew would meet on the way to Mars, stopped working properly on 28 October 2003. Controllers could not restore it.", "compare": "The instrument sent to measure the danger was knocked out by it.", "sources": [ "jpl_odyssey_2003" ] }, { "id": "F-08", "section": "1.2", "text": "On 20 May 2024 a large solar storm reached Mars. Curiosity's radiation detector measured {m24} micrograys. NASA's comparison: an astronaut standing beside the rover would have received about the dose of {m24_x} chest X-rays. Its lead scientist said cliffs or lava tubes would give extra shielding, and that in orbit or deep space the dose rate would be far higher.", "compare": "About {m24_days} days' worth of the ordinary dose near the top of the solar cycle ({gy_lo} mGy a day, 02-01 F-26), arriving at once. NASA's comparison works out at about {m24_per} mGy per X-ray, more than the {xray} mSv this library uses for one chest X-ray (02-01 F-29).", "sources": [ "jpl_storm_2024" ] }, { "id": "F-09", "section": "1.2", "text": "See 01-02 F-20, which owns NASA's Orion storm shelter: stowage bags of food, water and supplies packed round the crew, built within {or_h} hour of a warning, lived in for up to {or_stay} hours.", "compare": "Like building a fort of sandbags out of the larder, then sleeping in it for a day.", "sources": [ "nasa_orion_2016" ], "moved_to": "01-02 F-20" }, { "id": "F-10", "section": "1.3", "text": "See 01-02 F-12, which owns bone loss in weightlessness: weight-bearing bones lose on average {bone_lo}% to {bone_hi}% of their mineral density every month (NASA).", "compare": "Unchecked, the {cruise}-day trip to Mars (01-01 F-15) would cost about {cruise_lo} to {cruise_hi}% of the hip's bone before landing.", "sources": [ "nasa_body_2021" ], "moved_to": "01-02 F-12" }, { "id": "F-11", "section": "1.3", "text": "ESA says the top of the thigh bone at the hip loses {esa_m}% of its mass a month in space, about {esa_6}% over a six-month stay: roughly ten times the rate of osteoporosis. Older people on Earth lose {old_lo} to {old_hi}% a year.", "compare": "One month in orbit costs the hip about as much as {old_mo_lo} to {old_mo_hi} months of old age.", "sources": [ "esa_bone" ] }, { "id": "F-12", "section": "1.3", "text": "A 2022 study of {gb_n} space station astronauts back from {gb_m_lo} to {gb_m_hi} months in orbit found that {gb_not} of them had still not recovered their shin-bone density a year later. Those who flew longer than six months kept a {gb_long}% loss of bone strength. The authors compare the lasting loss to a decade or more of ageing on Earth.", "compare": "About half the group ({gb_not} of {gb_n}) still carried the loss a year on.", "sources": [ "gabel_2022" ] }, { "id": "F-13", "section": "1.3", "text": "See 01-02 F-14, which owns the space station's exercise: at least {ex_h} hours a day, to hold on to bone and muscle.", "compare": "About {ex_pct}% of waking hours, every day. 02-01 S-04 already assumes daily exercise on Mars.", "sources": [ "nasa_exercise_2023" ], "moved_to": "01-02 F-14" }, { "id": "F-14", "section": "1.3", "text": "In March 2026 a team led by the University of Rhode Island reported the first test of Mars-like gravity on mammals: {mice_n} mice spun for {mice_d} days in JAXA's centrifuge on the space station. At {g_lo} g, close to Mars, muscle wasting was reduced but not prevented. At {g_hi} g it was fully prevented.", "compare": "Mars pulls at {g_frac} g (02-01 F-01): on this first evidence it helps, but it is not enough on its own.", "sources": [ "mortreux_2026", "ut_mice_2026" ] }, { "id": "F-15", "section": "1.3", "text": "Nobody has lived long in partial gravity. The longest stay on another world was Apollo 17's {a17_h} hours on the Moon in December 1972.", "compare": "The first crew's {stay}-day stay (01-01 F-33) is about {stay_x} times as long.", "sources": [ "nasa_apollo17" ] }, { "id": "F-16", "section": "1.3", "text": "See 01-02 F-23 and F-35, which own Valeri Polyakov's record: {pol_d} days on the Mir station (January 1994 to March 1995), flown to learn how the body would cope with a trip to Mars, ending with a walk from the capsule.", "compare": "About {pol_pct}% of the first crew's whole {crew_trip}-day mission (01-01 F-33), all of it weightless.", "sources": [ "wiki_polyakov", "britannica_polyakov" ], "moved_to": "01-02 F-23" }, { "id": "F-17", "section": "1.4", "text": "In a 1997 experiment, a harness took away part of each person's weight. People switched from walking to running at {kr_1} m/s in full gravity but at only {kr_04} m/s at {kr_g} g, the setting nearest Mars. The authors found the switch came at slower and slower speeds as gravity fell, but at roughly the same Froude number (about {fr}), a ratio of speed, gravity and leg length that treats a walk as a body vaulting over a stiff leg like an upside-down pendulum.", "compare": "{kr_04_kmh} km/h is an ordinary Earth walking pace ({walk} km/h, 02-01): on Mars a normal stroll is already on the edge of a run.", "sources": [ "kram_1997" ] }, { "id": "F-18", "section": "1.5", "text": "NASA's 2023 clinical update on long-stay space station crews found swelling where the optic nerve enters the eye in {sans_disc}%, flattening of the back of the eyeball in {sans_globe}%, folds in the retina in {sans_folds}% and a shift towards long sight in {sans_hyp}%. The condition is called spaceflight associated neuro-ocular syndrome (SANS). Its cause is not fully known; body fluids shift towards the head in weightlessness (NASA).", "compare": "About {sans_10} in every 10 long-stay astronauts show the first sign.", "sources": [ "brunstetter_2022", "nasa_body_2021" ] }, { "id": "F-19", "section": "1.5", "text": "Ultrasound scans of {jv_n} space station crew members, who flew {jv_days} days on average, found blood standing still or flowing backwards in the left jugular vein of the neck in {jv_st} of them about 50 days into flight. One had a blood clot blocking the vein and was treated with blood-thinning drugs for the rest of the flight (2019).", "compare": "More than half of a crew, with a clot found only because researchers happened to look.", "sources": [ "marshall_goebel_2019" ] }, { "id": "F-20", "section": "1.5", "text": "In NASA's Twins Study (published 2019), astronaut Scott Kelly spent about {tw_d} days on the space station while his identical twin stayed on Earth. About {tw_pct}% of the genes whose activity changed in space went back to normal within six months of landing. His speed and accuracy on thinking tests dropped after landing and stayed lower for six months.", "compare": "Most of the body snaps back; not all of it does.", "sources": [ "nasa_twins_2019" ] }, { "id": "F-21", "section": "1.6", "text": "Apollo 17's Harrison Schmitt called it 'lunar hay fever'. All {moonwalkers} people who walked on the Moon reacted to the dust they carried back into the cabin: sneezing and blocked noses, in some cases lasting days. The dust smelt of burnt gunpowder.", "compare": "Like a bad pollen day, from dust on your own spacesuit.", "sources": [ "esa_dust_2018" ] }, { "id": "F-22", "section": "1.6", "text": "In July 2026 NASA set its first limit for Mars dust in the air of a habitat: {mpel} mg per cubic metre of particles under {pel_um} µm, averaged over 24 hours, for up to {pel_days} days, with a short peak of up to {peak} mg allowed at airlock entry. It is a third of its Moon dust limit ({moonpel} mg) because far less is known about real Mars dust.", "compare": "Mars airborne dust is about {dust_d} µm across (02-01 F-30), well inside the size this limit covers.", "sources": [ "nasa_mars_dust_2026", "nasa_dust_sp_2026" ] }, { "id": "F-23", "section": "1.6", "text": "The World Health Organization's 2021 guideline for fine particles (PM2.5), the smog-sized dust in city air, is {who} micrograms per cubic metre averaged over 24 hours.", "compare": "NASA's Mars dust limit (F-22) is about {pel_who} times that: a working limit for a month-long stay, not a guide to lifelong breathing.", "sources": [ "who_aqg_2021" ] }, { "id": "F-24", "section": "1.6", "text": "The US EPA's safe daily dose (its reference dose) for perchlorate is {rfd} micrograms per kilogram of body weight, set in 2005 to protect the thyroid's uptake of iodine. The most sensitive people are the unborn children of mothers short of iodine or thyroid hormone.", "compare": "For an {kg} kg adult that is {rfd_day} µg a day. A gram of soil at {pc_ref}% perchlorate (02-01 F-32) holds {pc_mg} mg: about {pc_days} days' worth.", "sources": [ "epa_iris_2005" ] }, { "id": "F-25", "section": "1.7", "text": "See 01-03 F-14 and F-15, which own Mars-500: {m5_crew} men sealed in a mock spaceship in Moscow for {m5_d} days (June 2010 to November 2011). They moved less and slept and rested more as the months passed. {m5_bad} of the {m5_crew} had sleep problems.", "compare": "{m5_d} days is {m5_pct}% of the first crew's whole mission (01-01 F-33).", "sources": [ "basner_2013" ], "moved_to": "01-03 F-14" }, { "id": "F-26", "section": "1.7", "text": "See 01-03 F-17, which owns NASA's first CHAPEA mission: {ch_crew} people for {ch_d} days (25 June 2023 to 6 July 2024) in a {ch_sqft} square foot 3D-printed Mars habitat in Houston. Added here: messages to Earth were delayed by up to {ch_delay} minutes for a round trip, and a second crew went in on 19 October 2025 and is due out on 31 October 2026.", "compare": "About {ch_m2} m² for four people: {ch_pp} m² each, {ch_x} times the HI-SEAS share (F-27). The real delay is {lt_lo} to {lt_hi} minutes each way (02-01 F-39).", "sources": [ "nasa_chapea_2024", "nasa_chapea2_2025" ], "moved_to": "01-03 F-17" }, { "id": "F-27", "section": "1.7", "text": "See 01-03 F-16, which owns HI-SEAS IV: {hs4_crew} people in a dome about {hs4_m} m across on the slopes of Mauna Loa, Hawaii, for a year (2015 to 2016). Added here: it was the longest NASA-funded space simulation at the time.", "compare": "{hs4_m2} m² of floor over two storeys for six people: about {hs4_pp} m² each.", "sources": [ "wiki_hiseas" ], "moved_to": "01-03 F-16" }, { "id": "F-28", "section": "1.7", "text": "See 01-03 F-19 and F-20, which own Concordia station and the 2018 study of {cc_n} people followed through winters of about {cc_m} months, with its midwinter flatness the researchers called 'psychological hibernation'. Added here: an earlier American study found that low mood, trouble adapting and poor sleep made up {pal}% of all diagnoses in Antarctica.", "compare": "Less a breakdown than a slow dimming, strongest in the long middle of the stay.", "sources": [ "sandal_2018" ], "moved_to": "01-03 F-20" }, { "id": "F-29", "section": "1.8", "text": "Without daylight to reset it, the human body clock runs on a cycle of about {circ} hours (1999). In a 2007 experiment, people were kept in step with a {sch_h}-hour Mars day by moderately bright light, about {lux} lux, in the second half of each waking day.", "compare": "A sol is {sol_over} minutes longer than the body's own cycle; an Earth day is {earth_under} minutes shorter. Each needs a daily nudge from light, the sol a bigger one.", "sources": [ "czeisler_1999", "scheer_2007" ] }, { "id": "F-30", "section": "1.8", "text": "During NASA's Phoenix Mars Lander mission in 2008, {ph_n} scientists and engineers lived on Mars time for more than {ph_w} weeks, starting work about 40 minutes later each Earth day. With training and blue-light boxes at their desks, most kept in step (2012).", "compare": "A shift that starts {sol_min} minutes later every day has gone right round the clock in about {lap_d} days.", "sources": [ "barger_2012" ] }, { "id": "F-31", "section": "1.8", "text": "See 01-02 F-11, which owns the ten-year study of astronaut sleep (2014): about {sl_iss} hours a night on the space station against {sl_sched} scheduled. The Space Shuttle figure stays here: {sl_sh} hours a night.", "compare": "About {sl_short} hours a night short: a full night's sleep lost every {sl_every} nights.", "sources": [ "barger_2014" ], "moved_to": "01-02 F-11" }, { "id": "F-32", "section": "1.9", "text": "No human has conceived or been pregnant in space. Pregnant rats flew in {rat1} ({rat_c}), {rat2} and {rat3} (Space Shuttle) and gave birth to healthy young after landing. No study has yet looked at pregnancy or growth in Moon or Mars gravity (2026 review).", "compare": "Everything known comes from a few rat litters and a few days of weightlessness.", "sources": [ "frontiers_repro_2026" ] }, { "id": "F-33", "section": "1.9", "text": "In April 2016 China's SJ-10 satellite carried more than {sj_n} early mouse embryos; some grew to the blastocyst stage within {sj_h} hours, the first mammal embryos to develop in space. In 2021 Japanese researchers reported {sp_pups} healthy mouse pups from freeze-dried sperm kept on the space station for nearly {sp_y} years.", "compare": "The first days of life and stored sperm seem to cope. Everything between conception and a grown adult is untested.", "sources": [ "cas_sj10_2016", "phys_sperm_2021" ] }, { "id": "F-34", "section": "1.9", "text": "The World Health Organization says children may be {ch_lo} or {ch_hi} times more sensitive to radiation than adults, and children under 10 are particularly susceptible.", "compare": "A child's year in the buried City ({city_yr} mSv, HB-02, HB-03) would weigh like {child_lo} to {child_hi} mSv on an adult.", "sources": [ "who_paed_2016" ] }, { "id": "F-35", "section": "1.10", "text": "In {rog_y}, the only doctor at the Soviet Antarctic station Novolazarevskaya, Leonid Rogozov, removed his own appendix under local anaesthetic, working partly by touch and with a mirror held by a helper. The operation took {rog_h}. He was back at work within two weeks.", "compare": "When help is months away, the patient may have to be the surgeon.", "sources": [ "rogozov_2009" ] }, { "id": "F-36", "section": "1.10", "text": "In January 2026 NASA brought its Crew-11 home about a month early because one astronaut had a serious but stable medical condition: the first medical evacuation in more than {iss_y} years of people living on the space station.", "compare": "From the station, home is hours away. From Mars it is a return window (every {window} months) plus a {cruise}-day trip (01-01 F-15).", "sources": [ "npr_crew11_2026" ] }, { "id": "F-37", "section": "1.1", "text": "Some people on Earth live with far more natural radiation than average. In the highest background areas of Ramsar, Iran, the dose from the ground and the radon in homes reaches up to {ramsar} mSv a year, and families have lived there for generations.", "compare": "About as much in a year as {ramsar_days} days on the open surface of Mars (02-01 F-25).", "sources": [ "ghiassi_2002" ] }, { "id": "F-38", "section": "1.4", "text": "On {yj_date}, during Apollo 16, John Young jumped about {yj_cm} cm off the Moon while saluting the flag, in his full suit and backpack. Charlie Duke photographed him in mid-air (NASA photo AS16-113-18339).", "compare": "About knee height, wearing everything he needed to stay alive.", "sources": [ "commons_as16_jump" ] }, { "id": "F-39", "section": "1.4", "text": "On {bp_date}, about an hour into the first moonwalk, Buzz Aldrin stepped into fresh lunar dust and photographed his own bootprint (NASA photo {bp_photo}) as part of a study of how the ground packs under a boot.", "compare": "The most famous footprint in history was taken as a soil test.", "sources": [ "commons_as11_bootprint" ] } ], "assumptions": [ { "id": "HB-01", "confidence": "Medium", "text": "The world measures every dose against NASA's {nasa_lim} mSv career limit (01-02 F-18). The first crew is expected to go over it on the round trip alone, whatever it does on the ground, and flies with its eyes open: a written, informed acceptance of the risk, like the waiver the National Academies describe (F-02).", "why": "The sum is arithmetic: the two crossings (01-01 F-31, F-33) come to {trip_msv} mSv, {trip_pct}% of the limit; one crossing is about {one_msv} mSv. No shielding on the ground can undo that. Medium, not High, because the rules residents live by are 04-02-01 CR-13, which extends this rule to them: nobody is asked to go over the limit a second time without written consent.", "moves_to": "" }, { "id": "HB-02", "confidence": "Low", "text": "Inside the buried town, under {cover} m of soil (03-06 HA-01), we plan with a dose of at most {buried} mSv a year: the UK worker limit (F-05). The real figure may well be lower. The dome neighbourhoods' water roofs are sized to give the same (03-10 GF-17).", "why": "About {sh_lo} to {sh_hi} m of soil brings the dose below {sh_target} mSv a year (02-01 F-28), and the dose keeps falling with depth. Ice-rich soil, like our site's, shields better than dry rock (Röstel et al. 2020 found about 0.9 m of water-rich soil enough for 100 mSv, against about 1.7 m of dry rock). No source checked gives the dose at {cover} m, so this is a planning ceiling, not a measurement (open question).", "sources": [ "rostel_2020" ], "moves_to": "" }, { "id": "HB-03", "confidence": "Medium", "text": "Time spent on the open surface, averaged over every sol: about {h_crew} hours for the first crew, {h_town} for the First Town and {h_city} for a City resident. Surface workers spend more, most City people far less. A suit or a rover cabin is counted as no shield at all.", "why": "The first crew builds, drills and explores by hand; later, robots do more and most jobs are below ground (02-01 S-18, S-20). Counting suits as no shield is cautious: they stop little of the cosmic rays that make up most of the dose (02-01 F-24). Who spends these hours, and when, is 04-04-01 JB-09, which takes over the jobs side; the averages stay here.", "moves_to": "" }, { "id": "HB-04", "confidence": "Medium", "text": "Solar storm rule: space-weather warnings give minutes to an hour. Anyone outside heads for the town, a buried shelter or a shielded rover, and should be under cover within about an hour, as Orion's crews must be (01-02 F-20). Inside the buried town, a storm changes nothing but the mood.", "why": "The Mars air already takes the edge off storms: the May 2024 storm gave about {m24_days} days' dose in one go (F-08), not a deadly one. The rare giant like August 1972 (F-06) is what the rule is for. The drill, with its distances, is 04-04-03 SE-08; the rule stays here.", "moves_to": "" }, { "id": "HB-05", "confidence": "Medium", "text": "Mars gravity slows bone and muscle loss but does not stop it (F-14). Everyone trains every sol, as 02-01 S-04 already assumes. New arrivals, after about seven months weightless (01-01 E-07), are unsteady and weak for their first weeks, work light duties and are watched for fainting.", "why": "Weightless bone loss (01-02 F-12; F-11 here) and slow, incomplete recovery (F-12) are measured. The only partial-gravity evidence is mice at {g_lo} g (F-14) and three days on the Moon (F-15). Polyakov walked after {pol_d} days (01-02 F-23), so arrivals can stand, but not work hard at once. The first days after landing (rest, medical checks and light indoor work) are 01-02 JN-09's; this assumption covers the weeks after.", "moves_to": "" }, { "id": "HB-06", "confidence": "Medium", "text": "The engine animates walking up to about {walk_run} m/s and switches to a loping run above it, with long, slow, bounding strides (02-01 S-01).", "why": "Measured in simulated gravity at {kr_g} g, the nearest setting to Mars's {g_frac} g (F-17). At {g_frac} g the switch would be very slightly slower still.", "moves_to": "" }, { "id": "HB-07", "confidence": "Medium", "text": "Indoor air is kept well under NASA's Mars dust limit (F-22), and no perchlorate reaches food or water above the EPA's safe daily dose (F-24). Dust in the living space is treated as a breach, as 02-01 S-13 says. Coughs and itchy eyes after surface work are common, as they were on the Moon (F-21).", "why": "NASA's limit is set cautiously for a month-long stay; residents breathe the air for years, so the settlement aims lower. Keeping the dust out is 03-07's job; cleaning water of perchlorate is 03-01's.", "moves_to": "" }, { "id": "HB-08", "confidence": "Medium", "text": "The worst mental strain is not panic but a slow flattening in the long middle of a stay: less movement, more sleep, withdrawal (01-03 F-14, F-15; F-28 here). The first crew's hardest stretch is expected in the third quarter of its {crew_trip}-day mission, about days {q3_lo} to {q3_hi} of its stay on Mars.", "why": "Seen in Mars-500 (01-03 F-14, F-15) and in Antarctic winters (F-28). This is the body's side of 02-01 S-20 (living enclosed), which owns the design answers.", "moves_to": "" }, { "id": "HB-09", "confidence": "High", "text": "Everyone's body clock is held to the sol by lighting (02-01 S-08, S-25). The people who suffer are those tied to Earth's clock: staff who talk to Earth in Earth hours, and anyone on night shifts.", "why": "Scheer's 2007 experiment and the Phoenix team show people can live on a {sol_hd}-hour day with light cues (F-29, F-30). Astronauts already sleep badly (01-02 F-11), so the settlement cannot afford more drift.", "moves_to": "" }, { "id": "HB-10", "confidence": "Low", "text": "See 04-02-03 SG-04 and SG-05, which now own when the first pregnancies come: none planned before the City, then a few volunteers with full consent. The body facts stay here: nobody knows whether a pregnancy can run safely to term in {g_frac} g, or how a child grows there (F-32, F-33), and children count as {ch_lo} to {ch_hi} times as sensitive to radiation in any dose budget (F-34).", "why": "Moved in version 1.4 so the decision is written once. No evidence either way on the body side.", "moves_to": "", "moved_to": "04-02-03 SG-04, SG-05" }, { "id": "HB-11", "confidence": "High", "text": "There is no evacuation. Anyone who falls ill on Mars is treated on Mars, by the people there, with what is there: the earliest way home is the next return window plus a months-long flight. Every crew has to be able to operate.", "why": "Even the space station, hours from Earth, has needed an early return (F-36). Antarctica shows what happens when help cannot come (F-35). The medical bay itself is 03-14, which builds its care on this rule (MB-01).", "moves_to": "" }, { "id": "HB-12", "confidence": "Medium", "text": "How people move is fixed in numbers.look: the bouncing walk, the long low lope, the slow high jump, a city built for it (high ceilings, steep stairs, daily training) and suited pairs bounding on the plain. Every picture, film and game scene of people moving is made from it and checked against it.", "why": "00-05 ST-20 (owner, 10 October 2026). Built from F-17, HB-06 and 02-01 S-01, S-02, S-04 and S-12, choosing the most beautiful reading they allow (00 L-19).", "moves_to": "" } ], "world_spec": { "about": "The numbers the engine (00-02) could read to animate people. The format belongs to the engine; the numbers belong to this file. Each names the fact or assumption it comes from.", "walk_run_ms": { "value": 1.39, "unit": "m/s", "from": "HB-06", "path": "numbers.walk_run_ms" }, "buried_msv_year": { "value": 20, "unit": "mSv a year", "from": "HB-02", "path": "numbers.buried_msv_year" } }, "links": { "leans_on": [ { "ref": "00-01", "why": "Era names, read live" }, { "ref": "01-01 F-31", "why": "Dose on the journey, 1.8 mSv a day (read live)" }, { "ref": "01-01 F-33", "why": "About 500 days on the surface and 900 days away, for the first crew's dose (read live)" }, { "ref": "01-01 F-15", "why": "The 26-month window and 200-day cruise (read live)" }, { "ref": "01-01 E-07", "why": "About seven months weightless on the way out" }, { "ref": "01-01 E-12", "why": "People in each era, for the dose table (read live)" }, { "ref": "02-01 F-25", "why": "Surface dose, 0.64 mSv a day (read live)" }, { "ref": "02-01 F-26", "why": "Absorbed dose over the solar cycle (read live)" }, { "ref": "02-01 F-28", "why": "Soil depth for 100 mSv a year (read live)" }, { "ref": "02-01 F-01", "why": "Mars and Earth gravity (read live)" }, { "ref": "02-01 F-07", "why": "The Armstrong limit and surface pressure (read live)" }, { "ref": "02-01 F-17", "why": "The length of the sol (read live)" }, { "ref": "02-01 F-29", "why": "Everyday doses and the UK worker limit (read live)" }, { "ref": "02-01 F-30", "why": "Dust grain size (read live)" }, { "ref": "02-01 F-32", "why": "Perchlorate in the soil (read live)" }, { "ref": "02-01 F-39", "why": "The light delay to Earth (read live)" }, { "ref": "02-01 S-18", "why": "The buried town. Its depth is 03-06 HA-01's, read from 02-01's sanctioned copy (numbers.copies_of_03_06.cover_m)" }, { "ref": "02-01 S-04", "why": "Daily exercise of 1.5 to 2 hours" }, { "ref": "02-01 F-08", "why": "About 14 seconds of consciousness in near-vacuum (read live)" }, { "ref": "02-01 F-27", "why": "A 2017 solar storm doubled the dose within hours" }, { "ref": "02-01 F-31", "why": "Dust grains are charged and cling" }, { "ref": "02-01 S-01", "why": "The loping walk in 38% gravity" }, { "ref": "02-01 S-03", "why": "Heavy kit light to lift but hard to stop, for injuries" }, { "ref": "02-01 S-08", "why": "Lighting on the sol cycle, for sleep" }, { "ref": "02-01 S-13", "why": "Dust in living space is a breach" }, { "ref": "02-01 S-20", "why": "Living enclosed, the design answers to confinement" }, { "ref": "02-01 S-25", "why": "Everyone lives on the sol" }, { "ref": "01-02", "why": "Read live: NASA's career limit (F-18), bone loss in weightlessness (F-12), station exercise (F-14), the Orion storm shelter (F-20), sleep in orbit (F-11) and Polyakov's record (F-23, F-35); cited: the first days after landing (JN-09)" }, { "ref": "01-03", "why": "Reads F-14 and F-15 (Mars-500's crew, length and sleep problems, for F-25 and the rehearsal chart) and F-16, F-17, F-19, F-20 (HI-SEAS, CHAPEA and Concordia: crews, days, floor area and the delay each way, which F-26 to F-28 now point to) (read live)" }, { "ref": "02-07 SK-01", "why": "The sky colours, for the opening picture's sky (read live)" } ], "used_by": [ { "ref": "05-20", "why": "Mars games: Moon dust, bone loss and living on Mars time, for Mars Quiz questions (worked_out)" }, { "ref": "04-01-03", "why": "Surface hours, for sleeping in a landed ship (JT-05)" }, { "ref": "03-06 Habitats", "why": "Reads HB-02 (the dose ceiling inside the buried town) and F-29 (light keeps the body clock on the sol) live. Cites HB-03 (viewing-room visits count as surface hours) and HB-04. HB-02 stays here; 03-06 quotes it" }, { "ref": "03-07 Airlocks, suitports and dust", "why": "Reads F-21, F-22, F-24, HB-03: lunar hay fever, NASA's Mars dust limit and the airlock entry peak, perchlorate's safe dose, and hours outside per era (read live). Keeping dust out (HB-07) is its job" }, { "ref": "03-14 Medical bay", "why": "Reads F-19, F-28, F-35 and F-36 (the jugular clot, Antarctic diagnoses, Rogozov and Crew-11) live; cites HB-01, HB-08, HB-10 and HB-11 (no evacuation)" }, { "ref": "04-02-01 How the city is run", "why": "Reads the town's dose ceiling (HB-02) and surface hours per sol (HB-03) live; CR-13 extends HB-01's dose rule to residents" }, { "ref": "00-02", "why": "The engine: walking and running speed (HB-06)" }, { "ref": "02-07 The Mars sky", "why": "Reads F-08: the 20 May 2024 storm dose and NASA's chest X-ray comparison, for 02-07 F-27 (read live)" }, { "ref": "03-08 Spacesuits", "why": "Reads HB-03: time outside per sol in each era, with suits counted as no shield (read live). Cites HB-04 (the solar storm rule), HB-05 (new arrivals are weak) and HB-06 (walking and loping speeds)" }, { "ref": "03-09 Life support", "why": "Cites F-22 (NASA's Mars dust limit for habitat air) and HB-07 (indoor air kept under it)" }, { "ref": "03-10 Greenhouses and food", "why": "Cites F-24: the safe daily dose of perchlorate" }, { "ref": "03-11 Construction and materials", "why": "Cites HB-03: hours outside add dose, so robots do the heavy digging" }, { "ref": "04-02-03 Staying for good", "why": "Reads F-32, F-33, F-34, HB-02 and HB-03 (read live); cites F-02 and HB-01. HB-10's pregnancy decision moved there as SG-04 and SG-05" }, { "ref": "03-13 Local communications", "why": "Reads F-30: the Phoenix team lived on Mars time (read live). Cites HB-09: people tied to Earth's clock suffer, so the town keeps its own" }, { "ref": "04-03-01", "why": "The calendar and festivals: people can live by the sol with light cues (F-29, F-30, HB-09)" }, { "ref": "04-03-02 Food and home life", "why": "F-29: bright light at set times holds the body clock to the sol (read live); HB-09: everyone's body clock is held to the sol; HB-10: children are more sensitive to radiation" }, { "ref": "04-03-03 Language and culture", "why": "F-17: the walk-run switch at 0.4 g (read live); HB-06: the loping run (LG-10)" }, { "ref": "04-04-01 Jobs", "why": "HB-03: hours outside per sol by era (read live), whose jobs side is taken over as JB-09; HB-09, night shifts; F-30, Phoenix on Mars time" }, { "ref": "04-04-02 A day in the life", "why": "F-29: the body clock and the light that holds it to a Mars day (read live); F-30: the Phoenix team on Mars time (read live); HB-03: average hours outside per sol by era (read live); HB-09: people tied to Earth's clock suffer: why nobody works Earth hours" }, { "ref": "04-04-03 Safety and emergencies", "why": "HB-04: the solar storm rule: under cover within an hour (SE-08 adds the drill)" }, { "ref": "04-05-02 Arrival day", "why": "HB-05: new arrivals weak and unsteady for weeks, light duties; F-17: walking and running speeds in low gravity (read live)" }, { "ref": "05-06 Free roam", "why": "The walk-to-run speed (F-17, HB-06) (read live)" }, { "ref": "00-04 Glossary and units", "why": "HB-02: the planning dose inside the buried town, and rem per sievert (read live)" }, { "ref": "05-19", "why": "Playable Arcadia: the yearly dose in the buried rows, for the radiation meter" }, { "ref": "05-17", "why": "The Living on Mars explainer page's radiation picture: the dose in the buried rows; its Walking and running stop: where a walk becomes a run (F-17, HB-06), John Young's Moon jump (F-38) and the look book (HB-12)" } ] }, "open_questions": [ "The dose inside the buried town under {cover} m of ice-rich soil (HB-02; the depth is 03-06 HA-01): no source checked gives it. Röstel et al. 2020 (JGR Planets) modelled down to 10 m; its figure data should answer it. For 03-06 Habitats and 02-01's matching open question.", "How big a Carrington-scale (1859) solar particle event would be on the Mars surface: no measured case; published estimates are for open space, and 04-04-03 Safety and emergencies found no source either. Watch for a Mars-surface estimate.", "Whether {g_frac} g prevents the eye changes of SANS (F-18) or the neck-vein clots (F-19): no data. Watch NASA's human research programme.", "How much of the bone lost on the way out comes back on Mars, and how fast: no human data in partial gravity (F-12, F-14, F-15)." ], "changes": [ "25 September 2026 (v1.0): Written. What Mars does to the body and mind, with 36 sourced facts and 11 assumptions (HB-01 to HB-11): radiation and the dose budget by era, solar storms, bone and muscle, walking, heart and eyes, dust and perchlorate, isolation, sleep, pregnancy and children, and medical care. Surface dose, gravity, air, dust, perchlorate and the sol are read live from 02-01; the journey dose, trip lengths and the era plan from 01-01.", "25 September 2026 (v1.1): Independent check against the sources. HB-01, F-02, the at-a-glance tile and the 1.1 heading now say the round trip (720 mSv, 120%) passes the limit, not 'the journey': one crossing is about 360 mSv, 60%, so the budget is not spent before landing. F-01, F-05 and the era table count days, not sols, because 02-01 F-25 is a daily dose. F-13 no longer retypes 02-01 S-04's hours. F-17 follows Kram and others' own wording on the Froude number. Two labels in the dose chart and the storm timeline no longer overlap.", "26 September 2026 (v1.2): Facts 01-02 and 01-03 own are now read live, not copied: F-01 (career limit, 01-02 F-18), F-09 (Orion shelter, 01-02 F-20), F-10 (bone loss, 01-02 F-12), F-13 (station exercise, 01-02 F-14), F-16 (Polyakov, 01-02 F-23, F-35), F-31 (station sleep, 01-02 F-11) and F-25 (Mars-500, 01-03 F-14, F-15) are signposts with moved_to; each keeps only its own detail (how the limit was set, the Shuttle sleep figure). Their numbers are removed from this file and the template reads them from 01-02 and 01-03 (added to quotes and leans_on). Internal citations (F-03, F-06, HB-01, HB-04, HB-05, HB-08, HB-09) now name the owners. F-08: the 30 chest X-rays are labelled NASA's comparison, and the compare says it implies about 0.27 mGy per X-ray, against the 0.1 mSv this library uses (02-01 F-29). HB-05 cites 01-02 JN-09 for the first days after landing. used_by lists 02-07, which reads F-08.", "26 September 2026 (v1.3): The burial depth is now 03-06 HA-01's: HB-02 cites it and reads the number through 02-01's sanctioned copy; HB-02 no longer moves to 03-06, because 03-06 quotes its dose ceiling rather than taking it over. F-26, F-27 and F-28 repeated CHAPEA, HI-SEAS and Concordia facts that 01-03 owns: each now points to 01-03 (F-17, F-16, F-19 and F-20) and keeps only what is added here (the delay and the second CHAPEA crew, the floor area, the Antarctic diagnoses). Their numbers (crews, days, floor area, the delay, Concordia's people and months) are read live from 01-03, and this file's copies are removed. used_by adds 03-08 to 03-11 and names what 03-06 and 03-07 read.", "26 September 2026 (v1.4): HB-10 is now a pointer to 04-02-03 SG-04 and SG-05, which own when the first pregnancies come; the body facts stay here. HB-01 no longer moves: residents' dose rules are 04-02-01 CR-13, which extends it. Two open questions deleted as answered: pregnancy and birth (04-02-03 SG-04, SG-05; the body question stays open there), and what the medical bay must do (03-14 MB-02, MB-03). used_by: the old 04.02 line becomes 04-02-01; adds 04-02-03 and 03-13; the 03-14 line says what it reads. Two captions now point to 04-02-01 CR-13 (lifetime doses) and 04-02-03 SG-04, SG-05 (first pregnancies).", "26 September 2026 (v1.5): The old 04.04 placeholder in used_by is split by subject: 04-04-01 Jobs (HB-03), 04-04-02 A day in the life (HB-09) and 04-04-03 Safety and emergencies (HB-04).", "26 September 2026 (v1.6): HB-03 no longer moves: its jobs side is 04-04-01 JB-09 (cited), the averages stay here. HB-04 no longer moves: it stays the rule and cites the drill in 04-04-03 SE-08. The Carrington question notes 04-04-03 found no source either. used_by: back-links for 04-03-01, 04-03-02, 04-03-03, 04-04-01, 04-04-02, 04-04-03, 04-05-02 (what each reads, from its leans_on). Also back-links for 05-06 (wave 6 pages, from their leans_on as written today).", "26 September 2026 (v1.7): Back-link for 00-04, which reads the planning dose (HB-02) live.", "26 September 2026 (v1.8): Beauty pass: a new opening picture, a suited person on a rise at dusk, labelled as art.", "26 September 2026 (v1.9): Final fix round: HB-11: moves_to cleared: it stays here as the body-side rule, and 03-14 MB-01 builds the medical bay on it. The dose by era table's City row now adds up: journey plus ten years on Mars equals the total, with the yearly dose in the note. The opening picture's sky colours are now read live from 02-07 SK-01 instead of typed; leans_on and quotes add 02-07", "28 September 2026 (v1.10): Used by the Jezero science town (04-01-03).", "3 October 2026 (v1.11): Era names follow the owner's new names (00-01): Mars Today, Robots First, First Town, Many Cities; First Human Landing and The First Martian City, Arcadia, where an era is named as such.", "9 October 2026 (v1.12): 05-19 (Playable Arcadia) now quotes this file, for the radiation meter's buried dose; used_by updated.", "10 October 2026 (v1.13): Now used by 05-17 Living on Mars, for its explainer page.", "10 October 2026 (v1.14): Added F-37: Ramsar, Iran, where natural background reaches up to 260 mSv a year (Ghiassi-nejad and others, 2002), as a yardstick for Mars doses; used by 05-19's radiation meter.", "10 October 2026 (v1.15): Added F-38 (John Young's jump salute on the Moon, about 42 cm, Apollo 16) and HB-12 with numbers.look, the look book for how people move, for 05-17's Walking and running on Mars stop.", "10 October 2026 (v1.16): Added F-39 (Buzz Aldrin's bootprint photo, taken as a soil test on 20 July 1969) for 05-17's Walking and running on Mars Mission check, so it no longer repeats the Sports stop's jump salute." ], "sources": { "nasa_std_2022": { "name": "NASA Office of the Chief Health and Medical Officer, OCHMO Standards Newsletter: NASA-STD-3001 Volume 1 Rev B (600 mSv career limit), February 2022", "url": "https://www.nasa.gov/wp-content/uploads/2023/03/ochmo-standards-newsletter-february-2022.pdf" }, "nasem_2021": { "name": "National Academies of Sciences, Engineering, and Medicine, Space Radiation and Astronaut Health: Managing and Communicating Cancer Risks, chapter 3, 2021", "url": "https://www.nationalacademies.org/read/26155/chapter/5" }, "swri_2013": { "name": "Southwest Research Institute, SwRI scientists publish first radiation measurements from the surface of Mars, 9 December 2013", "url": "https://www.swri.org/newsroom/press-releases/swri-scientists-publish-first-radiation-measurements-the-surface-of-mars" }, "hassler_2014": { "name": "Hassler et al., Mars' surface radiation environment measured with the Mars Science Laboratory's Curiosity rover, Science 343, 2014", "url": "https://www.science.org/doi/10.1126/science.1244797" }, "nrc_icrp103": { "name": "US Nuclear Regulatory Commission, Synopsis of ICRP Publication 103 (the 2007 recommendations), 2008", "url": "https://www.nrc.gov/docs/ML0833/ML083360609.pdf" }, "irr17": { "name": "UK Ionising Radiations Regulations 2017, Schedule 3 (dose limits)", "url": "https://www.legislation.gov.uk/uksi/2017/1075/schedule/3" }, "alsj_wotm": { "name": "NASA Apollo Lunar Surface Journal, Working on the Moon: Radiation, quoting NCRP Report No. 98 (1989) (accessed September 2026)", "url": "https://www.nasa.gov/wp-content/uploads/static/history/alsj/WOTM/WOTM-Radiation.html" }, "jpl_odyssey_2003": { "name": "NASA JPL, Mars Odyssey mission status (MARIE), 26 November 2003", "url": "https://www.jpl.nasa.gov/news/mars-odyssey-mission-status/" }, "jpl_storm_2024": { "name": "NASA JPL, NASA watches Mars light up during epic solar storm, 10 June 2024", "url": "https://www.jpl.nasa.gov/news/nasa-watches-mars-light-up-during-epic-solar-storm/" }, "nasa_orion_2016": { "name": "NASA, Scientists and engineers evaluate Orion radiation protection plan, 22 September 2016", "url": "https://www.nasa.gov/missions/artemis/orion/scientists-and-engineers-evaluate-orion-radiation-protection-plan/" }, "nasa_body_2021": { "name": "NASA, The human body in space, 2 February 2021 (updated 2026)", "url": "https://www.nasa.gov/humans-in-space/the-human-body-in-space/" }, "esa_bone": { "name": "ESA, Preventing bone loss in space (accessed September 2026)", "url": "https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/International_Space_Station_Benefits_for_Humanity/Preventing_Bone_Loss_in_Space" }, "gabel_2022": { "name": 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mission details (accessed September 2026)", "url": "https://www.nasa.gov/missions/apollo/apollo-17-mission-details/" }, "wiki_polyakov": { "name": "Wikipedia, Valeri Polyakov, 2026", "url": "https://en.wikipedia.org/wiki/Valeri_Polyakov" }, "britannica_polyakov": { "name": "Encyclopaedia Britannica, Valery Vladimirovich Polyakov, 2026", "url": "https://www.britannica.com/biography/Valery-Vladimirovich-Polyakov" }, "kram_1997": { "name": "Kram, Domingo and Ferris, Effect of reduced gravity on the preferred walk-run transition speed, Journal of Experimental Biology 200, 1997", "url": "https://pubmed.ncbi.nlm.nih.gov/9076966/" }, "brunstetter_2022": { "name": "Brunstetter et al. 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Rogozov and N. Bermel, Auto-appendectomy in the Antarctic: case report, BMJ 339, 2009", "url": "https://sofia.medicalistes.fr/spip/IMG/pdf/Rogozov_V_Bermel_N_Auto-appendectomy_in_the_Antarctic_case_report.pdf" }, "npr_crew11_2026": { "name": "NPR, After a medical evacuation from space, NASA's Crew-11 returns to Earth a month early, 15 January 2026", "url": "https://www.npr.org/2026/01/15/nx-s1-5677647/nasa-spacex-crew-11-splashdown-return" }, "rostel_2020": { "name": "Röstel, Guo et al., Subsurface radiation environment of Mars and its implication for shielding protection of future habitats, JGR Planets 125, 2020", "url": "https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JE006246" }, "commons_as16_jump": { "name": "Wikimedia Commons, John W. Young on the Moon: NASA photo AS16-113-18339 by Charles M. Duke Jr., 21 April 1972, its description (jumping about 42 cm) and licence (public domain), checked 10 October 2026", "url": "https://commons.wikimedia.org/wiki/File:John_W._Young_on_the_Moon.jpg" }, "ghiassi_2002": { "name": "Ghiassi-nejad and others, Very high background radiation areas of Ramsar, Iran: preliminary biological studies, Health Physics 82(1), 2002", "url": "https://pubmed.ncbi.nlm.nih.gov/11769138/" }, "commons_as11_bootprint": { "name": "Wikimedia Commons, Apollo 11 bootprint (NASA photo AS11-40-5878), file description, checked 2026", "url": "https://commons.wikimedia.org/wiki/File:Apollo_11_bootprint.jpg" } }, "sources_checked": "25 September 2026" }, "02-09": { "file": "02-09", "title": "Life on Ancient Mars", "folder": "02", "facts_file": "02-09-life-on-ancient-mars.json", "version": "1.6", "status": "Active", "last_updated": "3 October 2026", "about": "Facts file for 02-09 Life on Ancient Mars: what has really been found, where life could have lived, and the eight kinds of life our world shows. The world's position (rule L-23): no life has been confirmed, so we show the most stunning serious reading, that ancient Mars was home to microbes, labelled Our world. Each lifeform's confidence says how likely it is if Mars had life at all, not the odds that it did. Built from two deep research reports (thinking/active/ancient-life) and checked against their original papers.", "one_line": "No life has been found on Mars yet. If it was there, these are the eight places and ways it most likely lived, and why it never grew bigger than a speck.", "shelf_life": "This subject moves every few months. Re-check Cheyava Falls, Curiosity's organic molecules, the methane puzzle, Rosalind Franklin's launch and Tianwen-3's dates by April 2027.", "header": { "purpose": "Own every fact and assumption about possible life on ancient Mars, so the website's First Martians story (05-14) and any later scene never contradict the science.", "why": "Life on Mars is the most exciting and most misreported subject the project touches. Headlines say life was found; it was not. One honest file lets the website paint a living ancient Mars while the evidence, its limits and its sources stay one tap away.", "when": "Before any picture, caption, tour or game shows ancient Martian life; before writing what a microbe looked like, where it lived or when; and whenever a new rover or orbiter result about life comes out.", "change": "Facts change only with a citation. The eight lifeforms are assumptions: challenge one by its ID (for example 02-09 AL-07) with a source. Their pictures and visitor words live in 05-14.", "writing": "Plain words, every number compared to something people know, no claim of life presented as found. Microbes are never given feelings, faces or legs." }, "comparisons": { "about": "Everyday sizes this page compares with. Everest and a human hair are owned by 02-01, a football pitch by 02-08, read live through worked_out.", "egypt_million_km2": { "value": 1.01, "source": "wiki_egypt" }, "people_bn": { "value": 8.2, "source": "un_wpp_2024" }, "milky_way_stars_bn": { "value": [ 100, 400 ], "source": "wiki_milky_way" } }, "numbers": { "cells": { "um": [ 0.5, 5 ], "about": "Most bacteria on Earth are about 0.5 to 5 micrometres long (F-20)." }, "cheyava": { "spot_mm": 1, "about": "NASA describes the pale spots as millimetre-size (F-02)." }, "deep": { "water_km": [ 11.5, 20 ], "about": "Depth range of liquid water suggested by InSight's seismic data (F-10)." }, "home_plate": { "width_m": 90, "lat": -14.6, "lon": 175.5 }, "eridania": { "age_bn": 3.7, "area_million_km2": 1.1, "lat": -30, "lon": 178, "position_note": "No single published centre: the position is the approximate middle of the basin, at the head of Ma'adim Vallis, and is drawn as approximate.", "volume_km3": 562000 }, "nili": { "lat": 22.57, "lon": 76.8, "length_km": 667 }, "iron_lake": { "cells_per_ml": [ 1000, 10000000 ] }, "missions": { "rf_launch": "late 2028", "rf_drill_m": 2, "tw3_launch_year": 2028, "tw3_return_year": 2031, "tw3_sample_g": 500, "sapphire_date": "21 July 2024", "sapphire_cm": 6.2, "sapphire_no": "25th" }, "earth": { "oldest_life_bn": 3.43, "oxygen_bn": [ 2.4, 2.3 ], "animals_myr": 575 }, "lifeforms": { "about": "The eight kinds of life our world shows, in story order. 'act' is the part of the story they belong to (05-14), 'when_bn' when they are shown (billion years ago; 0 means they may still be alive), 'if_life' how likely each is if Mars had life at all (from report A in thinking/active/ancient-life, checked against the papers), 'place' the gazetteer entry it is shown at (02-04; none where it lived in many places), 'facts' the evidence it stands on and 'assumption' the line that puts it in our world.", "list": [ { "id": "vents", "name": "Seabed Bacteria", "what": "Trillions of tiny living cells, like bacteria, coating the hot rock chimneys on the floor of a deep sea, living on chemicals in the hot water instead of sunlight", "act": "spark", "where": "Eridania basin", "when_bn": [ 3.7 ], "if_life": "Medium-high", "facts": [ "F-13" ], "assumption": "AL-05", "place": "eridania" }, { "id": "springs", "name": "Hot Spring Bacteria", "what": "Tiny living cells growing in long, bright ribbons in the warm springs on land, laying down glassy silica as the water cools", "act": "spark", "where": "Home Plate, Gusev Crater", "when_bn": [ 3.6 ], "if_life": "Medium-high", "facts": [ "F-12" ], "assumption": "AL-06", "place": "home_plate" }, { "id": "domes", "name": "Lake Shore Bacteria", "what": "A living carpet of tiny cells along the lake shore that traps mud and grows up through it, building low domes of stone layer by layer (stromatolites)", "act": "bloom", "where": "Jezero's shore", "when_bn": [ 3.6 ], "if_life": "Medium-high", "facts": [ "F-11", "F-17" ], "assumption": "AL-07", "place": "jezero" }, { "id": "rust", "name": "Rust Bacteria", "what": "Tiny cells floating in the sunlit lake that use sunlight and dissolved iron, and give off rust instead of oxygen", "act": "bloom", "where": "Sunlit water of Jezero's lake", "when_bn": [ 3.6 ], "if_life": "Medium", "facts": [ "F-18" ], "assumption": "AL-08", "place": "jezero" }, { "id": "mud", "name": "Lake Mud Bacteria", "what": "Tiny cells in the airless lake mud that breathe iron and sulphur instead of oxygen, break down the dead, and leave pale spots ringed in black", "act": "bloom", "where": "Neretva Vallis, Jezero", "when_bn": [ 3.6 ], "if_life": "High", "facts": [ "F-02" ], "assumption": "AL-09", "place": "jezero" }, { "id": "salt", "name": "Salt Pool Bacteria", "what": "Salt-loving cells that live in the last salty pools, then seal themselves inside the salt crystals as the pools dry", "act": "hold", "where": "Salt basins of the southern highlands", "when_bn": [ 3.3 ], "if_life": "Medium", "facts": [ "F-14", "F-15" ], "assumption": "AL-10", "place": null }, { "id": "stones", "name": "Rock-Dwelling Bacteria", "what": "Tiny cells living a few millimetres inside pale stones, where the rock shields them from cold, dryness and harsh light", "act": "hold", "where": "Bare rock across the drying planet", "when_bn": [ 3.2 ], "if_life": "Medium", "facts": [ "F-16" ], "assumption": "AL-11", "place": null }, { "id": "deep", "name": "Deep Underground Bacteria", "what": "Tiny cells living kilometres underground in wet cracks, eating hydrogen made where rock meets water, and the only ones that could be alive today", "act": "hold", "where": "Deep crust, for example under Nili Fossae", "when_bn": [ 3.6, 0 ], "if_life": "High", "facts": [ "F-08", "F-09", "F-10", "F-19" ], "assumption": "AL-12", "place": "nili_fossae" } ] }, "spans": { "about": "How long each of the eight lived, in billion years ago, for drawing them side by side on one time scale (AL-13). The lake's three (lake shore bacteria, rust bacteria, lake mud bacteria) use the lake's own dates in 02-08, and the salt pool bacteria end when the water is gone (02-04), so those are not typed here.", "vents_bn": [ 3.8, 3.6 ], "springs_bn": [ 3.7, 3.4 ], "salt_from_bn": 3.5, "stones_bn": [ 3.3, 3.0 ], "deep_from_bn": 3.7 }, "earth_life": { "about": "Counts and dates from life on Earth today, which this page compares the eight with (section 1.4).", "vent_cells_per_g": 10000000000.0, "vent_tubes_bn": 3.77, "lost_city_storeys": 18, "sediment_cells_per_cm3": [ 100000000.0, 1000000000.0 ], "brine_cells_per_ml": 27800000.0, "land_life_bn": 3.48, "stromatolite_reign_bn": 3, "salt_crystal_myr": 250, "mine_km": 2.8, "underground_share_pct": 70, "deep_carbon_x_humans": [ 245, 385 ], "kidd_creek_km": 3, "kidd_creek_water_bn": 2 } }, "worked_out": { "spot_mm": "02-09:numbers.cheyava.spot_mm", "deep_lo": "02-09:numbers.deep.water_km.0", "deep_hi": "02-09:numbers.deep.water_km.1", "ev_lo": { "ratio": [ "02-09:numbers.deep.water_km.0", "02-01:comparisons.everest_km.value" ], "dp": 1 }, "ev_hi": { "ratio": [ "02-09:numbers.deep.water_km.1", "02-01:comparisons.everest_km.value" ], "dp": 1 }, "hp_m": "02-09:numbers.home_plate.width_m", "pitch_m": "02-08:comparisons.pitch_m", "er_age": "02-09:numbers.eridania.age_bn", "er_area": "02-09:numbers.eridania.area_million_km2", "egypt": "02-09:comparisons.egypt_million_km2.value", "cell_lo": "02-09:numbers.cells.um.0", "cell_hi": "02-09:numbers.cells.um.1", "hair_um": "02-01:comparisons.hair_um.value", "hair_x": { "ratio": [ "02-01:comparisons.hair_um.value", "02-09:numbers.cells.um.0" ], "round": 10 }, "rf_launch": "02-09:numbers.missions.rf_launch", "rf_drill_m": "02-09:numbers.missions.rf_drill_m", "tw3_launch_year": "02-09:numbers.missions.tw3_launch_year", "tw3_return_year": "02-09:numbers.missions.tw3_return_year", "tw3_g": "02-09:numbers.missions.tw3_sample_g", "ml_lo": "02-09:numbers.iron_lake.cells_per_ml.0", "ml_hi": "02-09:numbers.iron_lake.cells_per_ml.1", "nili_km": "02-09:numbers.nili.length_km", "oldest_life": "02-09:numbers.earth.oldest_life_bn", "ox_hi": "02-09:numbers.earth.oxygen_bn.0", "ox_lo": "02-09:numbers.earth.oxygen_bn.1", "animals_myr": "02-09:numbers.earth.animals_myr", "lake_age": "02-08:numbers.lake.age_bn", "dry_by": "02-04:numbers.drying.dry_by_bn", "wet_myr": { "minus": [ "02-04:numbers.shoreline.age_bn", "02-04:numbers.drying.dry_by_bn" ], "times": 1000, "round": 10 }, "animal_wait_bn": { "minus": [ "02-09:numbers.earth.oldest_life_bn", { "of": "02-09:numbers.earth.animals_myr", "times": 0.001 } ], "dp": 1 }, "vents_a": "02-09:numbers.spans.vents_bn.0", "vents_b": "02-09:numbers.spans.vents_bn.1", "springs_a": "02-09:numbers.spans.springs_bn.0", "springs_b": "02-09:numbers.spans.springs_bn.1", "salt_a": "02-09:numbers.spans.salt_from_bn", "stones_a": "02-09:numbers.spans.stones_bn.0", "stones_b": "02-09:numbers.spans.stones_bn.1", "deep_a": "02-09:numbers.spans.deep_from_bn", "tubes_bn": "02-09:numbers.earth_life.vent_tubes_bn", "lc_storeys": "02-09:numbers.earth_life.lost_city_storeys", "vent_g_bn": { "of": "02-09:numbers.earth_life.vent_cells_per_g", "times": 1e-09, "dp": 0 }, "people_bn": "02-09:comparisons.people_bn.value", "land_bn": "02-09:numbers.earth_life.land_life_bn", "reign_bn": "02-09:numbers.earth_life.stromatolite_reign_bn", "mud_lo": { "of": "02-09:numbers.earth_life.sediment_cells_per_cm3.0", "dp": 0 }, "mud_hi": { "of": "02-09:numbers.earth_life.sediment_cells_per_cm3.1", "dp": 0 }, "brine_m": { "of": "02-09:numbers.earth_life.brine_cells_per_ml", "times": 1e-06, "dp": 0 }, "salt_litre_bn": { "of": "02-09:numbers.earth_life.brine_cells_per_ml", "times": 1e-06, "dp": 0 }, "salt_x": { "ratio": [ { "of": "02-09:numbers.earth_life.brine_cells_per_ml", "times": 1000 }, { "of": "02-09:comparisons.people_bn.value", "times": 1000000000.0 } ], "dp": 1 }, "salt_myr": "02-09:numbers.earth_life.salt_crystal_myr", "mine_km": "02-09:numbers.earth_life.mine_km", "under_pct": "02-09:numbers.earth_life.underground_share_pct", "dc_lo": "02-09:numbers.earth_life.deep_carbon_x_humans.0", "dc_hi": "02-09:numbers.earth_life.deep_carbon_x_humans.1", "kc_km": "02-09:numbers.earth_life.kidd_creek_km", "kc_bn": "02-09:numbers.earth_life.kidd_creek_water_bn", "er_vol": "02-09:numbers.eridania.volume_km3", "er_depth_m": { "ratio": [ "02-09:numbers.eridania.volume_km3", { "of": "02-09:numbers.eridania.area_million_km2", "times": 1000000.0 } ], "times": 1000, "round": 10 }, "sapphire_date": "02-09:numbers.missions.sapphire_date", "sapphire_cm": "02-09:numbers.missions.sapphire_cm", "sapphire_no": "02-09:numbers.missions.sapphire_no" }, "sections": [ { "id": "1.1", "title": "Has life ever been found?" }, { "id": "1.2", "title": "Where it could have lived" }, { "id": "1.3", "title": "Why no fish or forests" }, { "id": "1.4", "title": "Life like this on Earth" } ], "facts": [ { "id": "F-01", "section": "1.1", "text": "No life, living or fossil, has been confirmed on Mars. The strongest leads so far are chemical, and every one of them can also be made without life.", "compare": "Exciting clues, not a discovery.", "sources": [ "hurowitz_2025", "nasa_alkanes_2026" ] }, { "id": "F-02", "section": "1.1", "text": "Perseverance's Cheyava Falls rock, from the river valley that fed Jezero's lake, holds organic carbon and pale spots ringed by iron phosphate and iron sulphide minerals. On Earth, microbes that breathe iron and sulphate often leave this mix, but chemistry without life can make it too.", "compare": "Each spot is about {spot_mm} mm across, the size of a grain of sand.", "sources": [ "hurowitz_2025", "jpl_pia26368" ] }, { "id": "F-03", "section": "1.1", "text": "Curiosity found decane, undecane and dodecane in a mudstone in Gale Crater: the largest organic molecules yet found on Mars. They may be pieces of fatty acids, which on Earth are mostly made by life, but can also form without it.", "compare": "Chains of 10 to 12 carbon atoms: the kind of chain cell membranes are built from.", "sources": [ "freissinet_2025" ] }, { "id": "F-04", "section": "1.1", "text": "In February 2026 a NASA-led study found that the non-living sources it tested could not fully explain how much of those molecules there was, so life is a reasonable explanation to test. The authors say it is not proof.", "sources": [ "nasa_alkanes_2026" ] }, { "id": "F-05", "section": "1.1", "text": "Curiosity measures traces of methane at Gale Crater that rise and fall with the seasons, but ESA's Trace Gas Orbiter finds almost none higher in the air. Nobody has explained the gap, and methane can also come from rock and water alone.", "sources": [ "esa_methane_2021" ] }, { "id": "F-06", "section": "1.1", "text": "ESA's Rosalind Franklin rover is due to launch in {rf_launch} to Oxia Planum, with a drill that reaches {rf_drill_m} m below the surface, where old chemistry is shielded from radiation. Searching for signs of past and present life is its main goal.", "compare": "{rf_drill_m} m is about the height of a door.", "sources": [ "esa_rfm", "esa_rover_drill" ] }, { "id": "F-07", "section": "1.1", "text": "China's Tianwen-3 aims to launch in {tw3_launch_year} and bring about {tw3_g} g of Mars back to Earth around {tw3_return_year}, with searching for signs of life as its main goal.", "compare": "About half a 1 kg bag of sugar.", "sources": [ "tianwen3_2025" ] }, { "id": "F-08", "section": "1.2", "text": "A 2022 study modelled microbes that eat hydrogen and breathe carbon dioxide, giving off methane, in the porous, salty ground of early Mars. They could have thrived there, and by eating the air's hydrogen they could have cooled the whole planet and pushed themselves deeper.", "sources": [ "sauterey_2022" ] }, { "id": "F-09", "section": "1.2", "text": "Radioactive elements in Martian rock slowly split groundwater apart. A 2021 study worked out that this alone could feed microbes that breathe sulphate, wherever liquid water remains underground.", "compare": "Rock making food, with no sunlight at all.", "sources": [ "tarnas_2021" ] }, { "id": "F-10", "section": "1.2", "text": "Shaking measured by NASA's InSight lander fits liquid water in cracked rock {deep_lo} to {deep_hi} km down. That is a reading of the rock, not a sign of life.", "compare": "{ev_lo} to {ev_hi} times the height of Everest, straight down.", "sources": [ "wright_2024" ] }, { "id": "F-11", "section": "1.2", "text": "Carbonate rocks ring the inside of Jezero's rim. A 2020 study suggested they formed at the lake's shore, and Perseverance's close look in 2026 fits shallow shoreline water. No stromatolite has been confirmed there.", "sources": [ "horgan_2020", "jones_2026" ] }, { "id": "F-12", "section": "1.2", "text": "Spirit found opal-like silica at Home Plate in Gusev Crater, with knobbly, finger-like shapes very like silica built where microbes live in hot springs at El Tatio in Chile. The same shapes can form without life.", "compare": "Home Plate is about {hp_m} m across, a little shorter than a football pitch ({pitch_m} m).", "sources": [ "ruff_farmer_2016", "wiki_home_plate" ] }, { "id": "F-13", "section": "1.2", "text": "Deposits in the Eridania basin, about {er_age} billion years old, look like the work of hot water venting through the floor of a deep sea. The sea held more water than all of Mars's other lakes put together.", "compare": "The sea covered about {er_area} million km², roughly the area of Egypt ({egypt} million km²).", "sources": [ "michalski_2017", "sciencedaily_eridania_2017", "wiki_eridania" ] }, { "id": "F-14", "section": "1.2", "text": "Orbiters have found chloride salt deposits across the southern highlands, many in small, low basins: the floors of the last salty pools as the water dried up.", "sources": [ "osterloo_2008" ] }, { "id": "F-15", "section": "1.2", "text": "In Chile's Atacama, one of the driest places on Earth, microbes live inside salt crusts, drawing water out of the air.", "sources": [ "davila_2010" ] }, { "id": "F-16", "section": "1.2", "text": "In Antarctica's dry valleys, microbes live a few millimetres inside sandstone, where the rock shields them from cold, wind and harsh light. Crack the stone open and they show as a thin coloured band.", "sources": [ "friedmann_1982" ] }, { "id": "F-17", "section": "1.2", "text": "Wrinkled and rolled textures in rocks Curiosity photographed in Gale Crater look like those that microbial mats leave on Earth. Ordinary sediment can make the same shapes, so they are not counted as fossils.", "sources": [ "noffke_2015" ] }, { "id": "F-18", "section": "1.2", "text": "A 2021 study, not yet peer reviewed, modelled microbes that use sunlight and dissolved iron in Gale Crater's ancient lake and found they could have reached {ml_lo} to {ml_hi} cells in every millilitre of water, limited by nitrogen.", "compare": "A millilitre is a fifth of a teaspoon.", "sources": [ "iron_preprint_2021" ] }, { "id": "F-19", "section": "1.2", "text": "Nili Fossae, a set of troughs {nili_km} km long, exposes rock that reacts with water to make hydrogen: food for microbes that eat it.", "sources": [ "nisson_2026", "wiki_nili" ] }, { "id": "F-20", "section": "1.2", "text": "Most bacteria are {cell_lo} to {cell_hi} micrometres long.", "compare": "About {hair_x} of the smallest would fit across a human hair ({hair_um} micrometres).", "sources": [ "wiki_bacteria" ] }, { "id": "F-21", "section": "1.3", "text": "Earth's oldest widely accepted signs of life are stromatolites about {oldest_life} billion years old, in Western Australia.", "sources": [ "allwood_2006" ] }, { "id": "F-22", "section": "1.3", "text": "Earth's air only filled with oxygen about {ox_hi} to {ox_lo} billion years ago, more than a billion years after life began.", "sources": [ "lyons_2021" ] }, { "id": "F-23", "section": "1.3", "text": "The first large animals appear about {animals_myr} million years ago: about {animal_wait_bn} billion years after Earth's oldest life.", "sources": [ "wiki_ediacaran" ] }, { "id": "F-24", "section": "1.4", "text": "Deep-sea vents are one of the two leading ideas for where life on Earth began. The other is warm springs on land.", "sources": [ "martin_2008", "damer_2020" ] }, { "id": "F-25", "section": "1.4", "text": "Tiny tubes left by sea-floor vents in Quebec, at least {tubes_bn} billion years old, may be Earth's oldest signs of life. Not everyone agrees they are.", "compare": "About the same age as the Eridania vents on Mars ({er_age} billion years).", "sources": [ "dodd_2017" ] }, { "id": "F-26", "section": "1.4", "text": "In 1977 the submersible Alvin found vents swarming with life on the Galapagos Rift sea floor, where no sunlight reaches. Until then, scientists thought all life ultimately depended on the Sun.", "sources": [ "whoi_1977" ] }, { "id": "F-27", "section": "1.4", "text": "Lost City, a vent field in the Atlantic found in December 2000, has chimneys up to {lc_storeys} storeys tall. Its microbes live on hydrogen and methane made when rock reacts with seawater, the kind of rock found at Nili Fossae on Mars.", "sources": [ "uw_2005" ] }, { "id": "F-28", "section": "1.4", "text": "The outer crust of living vent chimneys holds up to about {vent_g_bn} billion cells in every gram.", "compare": "A crumb weighing one gram holds more living cells than there are people on Earth ({people_bn} billion).", "sources": [ "chevaldonne_1997" ] }, { "id": "F-29", "section": "1.4", "text": "In 1966 Thomas Brock's team found the microbe Thermus aquaticus in a Yellowstone hot spring. Its heat-proof enzyme made PCR possible (Nobel Prize, 1993), the method behind COVID-19 tests.", "sources": [ "wyohistory_brock" ] }, { "id": "F-30", "section": "1.4", "text": "Earth's oldest signs of life on land are in hot-spring deposits {land_bn} billion years old, in the Pilbara of Western Australia. Mars has hot-spring deposits of a similar age.", "sources": [ "djokic_2017" ] }, { "id": "F-31", "section": "1.4", "text": "Shark Bay in Western Australia has the most diverse and abundant living stromatolites in the world. Domes like them were the main life in Earth's seas for over {reign_bn} billion years.", "sources": [ "unesco_shark_bay" ] }, { "id": "F-32", "section": "1.4", "text": "Most of the world's iron ore is in banded iron formations: layers of rust laid down in ancient seas, with the help of microbes. Microbes that use sunlight and dissolved iron could have laid them down.", "sources": [ "csiro_bif_2024", "kappler_2005" ] }, { "id": "F-33", "section": "1.4", "text": "The top layer of mud on the Baltic Sea floor holds {mud_lo} to {mud_hi} cells in every cubic centimetre.", "compare": "Up to a billion in a cube of mud one centimetre across.", "sources": [ "iodp_347" ] }, { "id": "F-34", "section": "1.4", "text": "In 1987 scientists found huge numbers of microbes breathing iron instead of oxygen in the mud of Maryland's rivers. Their relatives can make electricity: microbes digesting a teaspoon of sugar can light a Christmas tree bulb.", "sources": [ "csm_lovley_2003" ] }, { "id": "F-35", "section": "1.4", "text": "Brine in salt pans holds up to about {brine_m} million cells in every millilitre.", "compare": "A one-litre bottle holds about {salt_litre_bn} billion, {salt_x} times the people on Earth.", "sources": [ "anton_2000" ] }, { "id": "F-36", "section": "1.4", "text": "Lake Hillier in Western Australia is bubble-gum pink because of pigment-rich microbes living in its salty water.", "sources": [ "sierra_2022" ] }, { "id": "F-37", "section": "1.4", "text": "In 2000, scientists reported waking bacteria sealed inside {salt_myr}-million-year-old salt crystals in New Mexico. Others think the bacteria are younger contamination, and the claim is still argued about.", "sources": [ "vreeland_2000" ] }, { "id": "F-38", "section": "1.4", "text": "{mine_km} km down in a South African gold mine lives a microbe that is the only species in its world, fed by natural radioactivity splitting water.", "sources": [ "nasa_audaxviator_2008" ] }, { "id": "F-39", "section": "1.4", "text": "About {under_pct}% of Earth's bacteria and archaea live underground. Together, deep life holds {dc_lo} to {dc_hi} times as much carbon as every person on Earth, in a home almost twice the volume of the oceans.", "sources": [ "dco_2018" ] }, { "id": "F-40", "section": "1.4", "text": "Water nearly {kc_km} km down in Canada's Kidd Creek mine is about {kc_bn} billion years old, and shows signs of microbes that breathe sulphur.", "sources": [ "earthdate_kidd_creek" ] }, { "id": "F-41", "section": "1.2", "text": "The Eridania sea held at least {er_vol} km³ of water. Spread over its {er_area} million km², that is about {er_depth_m} m deep on average, and deeper in its middle.", "sources": [ "wiki_eridania", "michalski_2017" ] }, { "id": "F-42", "section": "1.1", "text": "On {sapphire_date} Perseverance drilled a core {sapphire_cm} cm long from Cheyava Falls, its {sapphire_no} sample, named Sapphire Canyon. The rover still carries it, sealed in a tube, among the samples it is collecting for a future mission to bring back to Earth.", "sources": [ "nasa_rock_samples" ] } ], "assumptions": [ { "id": "AL-01", "confidence": "Low", "text": "Ancient Mars was alive: microbes lived in its seas, lakes, springs and rocks.", "why": "No life has been confirmed (F-01), but the leads are real (F-02 to F-04) and the water lasted (02-08 F-03). Under L-23 we show the most stunning serious reading, labelled Our world, and say plainly that it is unconfirmed.", "moves_to": "" }, { "id": "AL-02", "confidence": "High", "text": "All of it stayed microscopic. It shows only through what it built and stained: films, mats, low domes, crusts, strands and colour. No animals, fish, plants, seaweed or coral.", "why": "On Earth, large animals came about {animal_wait_bn} billion years after the first life (F-21 to F-23) and needed oxygen-rich air. In our world Mars's surface stayed wet for about {wet_myr} million years (02-04 M-05). Making a creature small does not fix this.", "moves_to": "" }, { "id": "AL-03", "confidence": "Low", "text": "The eight are one family of life that kept adapting as Mars dried: born at the vents, spreading through the lakes, then retreating into salt, stone and the deep.", "why": "One beginning is the simplest reading, and it makes the story one lineage visitors can follow. Nothing yet says Mars had one origin of life, or any.", "moves_to": "05-14" }, { "id": "AL-04", "confidence": "Low", "text": "The colours of the life are chosen, not known: amber, rust, ochre, deep violet and maroon, and never leafy green. Pictures may show the shore mats green where a picture is already approved.", "why": "No Martian pigment is known. Green reads as Earth's plants and oxygen-making bacteria; the leads on Mars point to life that made no oxygen. Colour is Art (L-19), so pictures may choose, but the library records the choice.", "moves_to": "90-02" }, { "id": "AL-05", "confidence": "Medium", "text": "Seabed bacteria lived on the floor of the Eridania sea, on chemicals from hot water rising through it.", "why": "Hot water venting through a sea floor is one of the richest places for chemical energy (F-13), and is one of the two leading ideas for where life began on Earth. No sign of life has been found there.", "moves_to": "" }, { "id": "AL-06", "confidence": "Medium", "text": "Hot spring bacteria lived in the warm springs at Home Plate: mats in the pools and long strands waving in the outflow.", "why": "The silica looks like hot-spring silica built where microbes live (F-12). Strands need steady flowing water, the least certain part.", "moves_to": "" }, { "id": "AL-07", "confidence": "Medium", "text": "Lake shore bacteria lined Jezero's shore: mats that trapped mud and built fields of low, layered domes.", "why": "The shore carbonates are where such mats would live and be kept (F-11). Kept low and dome-shaped, never branching like coral.", "moves_to": "" }, { "id": "AL-08", "confidence": "Medium", "text": "Rust bacteria lived in the sunlit water, using sunlight and dissolved iron, and the rust they made drifted down like snow.", "why": "Early Mars had sunlight and iron-rich water with little oxygen (F-18). Sunlight can also rust dissolved iron without life, so the haze is shown faint.", "moves_to": "" }, { "id": "AL-09", "confidence": "High", "text": "Lake mud bacteria lived in the lake mud, breathing iron and sulphate, and left the leopard spots Perseverance found.", "why": "This is the one lifeform tied to a real rock (F-02). High is for how well it fits if Mars had life; whether the spots are life is still open.", "moves_to": "" }, { "id": "AL-10", "confidence": "Medium", "text": "Salt pool bacteria held on in the last salty pools, then inside the salt crusts as the pools dried.", "why": "The salt basins are real (F-14) and salt-crust life is real on Earth (F-15). Very salty water can also be too salty for life.", "moves_to": "" }, { "id": "AL-11", "confidence": "Medium", "text": "As the surface dried, life retreated a few millimetres inside pale stones.", "why": "Earth's driest, coldest deserts have exactly this (F-16). It still needs the odd drop of water, so it fades as Mars dries completely.", "moves_to": "" }, { "id": "AL-12", "confidence": "Medium", "text": "Deep underground bacteria lived kilometres down, eating hydrogen, from the wet era onwards, and some may still be alive today.", "why": "The deep crust is the best-supported home for life on Mars, then and now (F-08 to F-10, F-19). Whether anything lives there today is unknown; the methane puzzle (F-05) has not settled it.", "moves_to": "" }, { "id": "AL-13", "confidence": "Low", "text": "How long each kind of life lived: the seabed bacteria about {vents_a} to {vents_b} billion years ago, the hot spring bacteria {springs_a} to {springs_b}, the lake's three while the lake was full, the salt pool bacteria from {salt_a} billion years ago until the water was gone, the rock-dwelling bacteria {stones_a} to {stones_b}, and the deep underground bacteria from {deep_a} billion years ago to today.", "why": "Only a few of these dates are measured: the Eridania deposits (F-13), Jezero's lake (02-08) and the drying (02-04). The rest are chosen to follow the story's order (AL-03), so a visitor can compare the eight on one time scale. They are a picture, not a finding.", "moves_to": "" }, { "id": "AL-14", "confidence": "Low", "text": "Seabed bacteria are the one ancestor of the other seven. That life may also have begun in warm springs is told as an open question, not as a second family.", "why": "Vents and springs are the two leading ideas for life's start on Earth (F-24). One ancestor keeps the story simple, matches AL-03, and the rival idea still starts conversations (owner, 3 October 2026).", "moves_to": "" }, { "id": "AL-15", "confidence": "Low", "text": "Rust bacteria and the lake mud bacteria share one lake and one loop of iron: the rust made in the sunlit water is breathed in the mud below.", "why": "A study of Gale Crater's lake found life there could be sustained by iron going round this way (F-18), and the Cheyava Falls spots point to microbes that breathe iron (F-02).", "moves_to": "" }, { "id": "AL-16", "confidence": "Low", "text": "A little of Mars's rust was made by life.", "why": "Almost all of Mars's rust is explained without life, but a small share made by microbes like the rust bacteria is not ruled out. Plausible, not proven (owner, 3 October 2026).", "moves_to": "" }, { "id": "AL-17", "confidence": "Low", "text": "The methane that comes and goes at Gale Crater is made by the deep underground bacteria.", "why": "Nobody has explained it (F-05); methane can come from life or from rock and water. Plausible, not proven.", "moves_to": "" }, { "id": "AL-18", "confidence": "Low", "text": "Life on ancient Mars is as crowded as the busiest places for microbes on Earth today, so each of the eight numbers trillions upon trillions.", "why": "The counts are measured on Earth (F-28, F-33, F-35) and modelled for an ancient Martian lake (F-18). The owner asked that we never undersell (3 October 2026).", "moves_to": "" } ], "links": { "leans_on": [ { "ref": "02-01", "why": "Everest's height and a human hair's width, for the size comparisons (read live)" }, { "ref": "02-04 M-05", "why": "How long the surface stayed wet in our world, and the ocean's age (read live)" }, { "ref": "02-08 F-03", "why": "When Jezero's lake was full (read live)" }, { "ref": "02-08 F-14", "why": "When Cheyava Falls was found and announced" }, { "ref": "02-04", "why": "The gazetteer's places each lifeform is shown at" } ], "used_by": [ { "ref": "05-20", "why": "Mars games: The Eridania sea, for Mars Quiz questions (worked_out)" }, { "ref": "05-13", "why": "How many lifeforms there are, for the home page atlas key in Ancient Mars (read live)" }, { "ref": "05-14", "why": "Every lifeform, fact and caveat in The First Martians story (read live)" }, { "ref": "02-04", "why": "Gazetteer entries for Home Plate, Eridania and Nili Fossae" } ] }, "open_questions": [ "Home Plate's age is not pinned down. Our world shows its springs at the timeline's start; a dated source would settle it.", "Eridania's deposits are about 3.7 billion years old, just before the timeline starts (3.6). 05-14 tells the vents as a prologue; decide whether the timeline should start earlier instead.", "Should the salt basins get one named place? There are many small basins, not one." ], "changes": [ "3 October 2026 (v1.0): First written, from two deep research reports (thinking/active/ancient-life) checked against their papers. Five errors in report B were left out.", "3 October 2026 (v1.1): Added AL-13 and numbers.spans: how long each of the eight lived, so the home page can compare them on one time scale (asked by the owner).", "3 October 2026 (v1.2): Asked by the owner: the eight have new names (the Embers, Ribbons, Architects, Rustmakers, Spotmakers, Sleepers, Hidden and Survivors) and plain descriptions. Added section 1.4, life like this on Earth today (F-24 to F-40), with counts and comparisons, and AL-14 to AL-18: one ancestor, the iron loop, Mars's rust, the methane, and how many.", "3 October 2026 (v1.3): Added F-41: the Eridania sea's volume and its average depth, worked out from volume and area, for the cutaway of where the eight live.", "3 October 2026 (v1.4): Asked by the owner: names that say what each one is, Seabed Bacteria, Hot Spring Bacteria, Lake Shore Bacteria, Rust Bacteria, Lake Mud Bacteria, Salt Pool Bacteria, Rock-Dwelling Bacteria and Deep Underground Bacteria, and the three ages Life in Hot Water, Life in the Lake and Life Goes Underground.", "3 October 2026 (v1.5): used_by: 05-13 now reads the lifeform count for the home page atlas key.", "3 October 2026 (v1.6): F-42 Perseverance's sealed core of Cheyava Falls (Sapphire Canyon, sample 25), for the field guide's The search is on (05-14)." ], "sources": { "hurowitz_2025": { "name": "Hurowitz and others, Redox-driven mineral and organic associations in Jezero Crater, Mars, Nature, 2025", "url": "https://www.nature.com/articles/s41586-025-09413-0" }, "jpl_pia26368": { "name": "NASA/JPL-Caltech/MSSS, PIA26368: Perseverance finds a rock with leopard spots, 2024", "url": "https://www.jpl.nasa.gov/images/pia26368-perseverance-finds-a-rock-with-leopard-spots/" }, "freissinet_2025": { "name": "Freissinet and others, Long-chain alkanes preserved in a Martian mudstone, PNAS, 2025", "url": "https://www.pnas.org/doi/10.1073/pnas.2420580122" }, "nasa_alkanes_2026": { "name": "NASA, Non-biologic processes don't fully explain Mars organics, 2026", "url": "https://science.nasa.gov/blogs/science-news/2026/02/06/nasa-study-non-biologic-processes-dont-fully-explain-mars-organics" }, "esa_methane_2021": { "name": "ESA, ExoMars orbiter continues hunt for key signs of life on Mars, 2021", "url": "https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Exploration/ExoMars/ExoMars_orbiter_continues_hunt_for_key_signs_of_life_on_Mars" }, "esa_rfm": { "name": "ESA, ExoMars Rosalind Franklin mission, 2026", "url": "https://explorationscience.esa.int/project/exomars-rosalind-franklin-rfm/" }, "esa_rover_drill": { "name": "ESA, The ExoMars rover, 2026", "url": "https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Exploration/ExoMars/ExoMars_rover" }, "tianwen3_2025": { "name": "In search of signs of life on Mars with China's sample return mission Tianwen-3, 2025", "url": "https://www.researchgate.net/publication/392834250_In_search_of_signs_of_life_on_Mars_with_China%27s_sample_return_mission_Tianwen-3" }, "sauterey_2022": { "name": "Sauterey and others, Early Mars habitability and global cooling by H2-based methanogens, Nature Astronomy, 2022", "url": "https://www.nature.com/articles/s41550-022-01786-w" }, "tarnas_2021": { "name": "Tarnas and others, Earth-like habitable environments in the subsurface of Mars, Astrobiology, 2021", "url": "https://pubmed.ncbi.nlm.nih.gov/33885329/" }, "wright_2024": { "name": "Wright, Manga and Panning, Liquid water in the Martian mid-crust, PNAS, 2024 (reported by The Guardian)", "url": "https://www.theguardian.com/science/article/2024/aug/12/new-hope-of-finding-life-on-mars-after-indication-of-water-scientists-say" }, "horgan_2020": { "name": "Horgan and others, The mineral diversity of Jezero crater: evidence for possible lacustrine carbonates on Mars, Icarus, 2020", "url": "https://www.sciencedirect.com/science/article/pii/S0019103518306067" }, "jones_2026": { "name": "Jones and others, Stratigraphy of carbonate-bearing rocks at the margin of Jezero Crater, JGR Planets, 2026", "url": "https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025JE009111" }, "ruff_farmer_2016": { "name": "Ruff and Farmer, Silica deposits on Mars with features resembling hot spring biosignatures at El Tatio in Chile, Nature Communications, 2016", "url": "https://www.nature.com/articles/ncomms13554" }, "wiki_home_plate": { "name": "Wikipedia, Home Plate (Mars), 2026", "url": "https://en.wikipedia.org/wiki/Home_Plate_(Mars)" }, "michalski_2017": { "name": "Michalski and others, Ancient hydrothermal seafloor deposits in Eridania basin on Mars, Nature Communications, 2017", "url": "https://www.nature.com/articles/ncomms15978" }, "sciencedaily_eridania_2017": { "name": "ScienceDaily (NASA JPL), Mars study yields clues to possible cradle of life, 2017", "url": "https://www.sciencedaily.com/releases/2017/10/171006154947.htm" }, "wiki_eridania": { "name": "Wikipedia, Eridania Lake, 2026", "url": "https://en.wikipedia.org/wiki/Eridania_Lake" }, "wiki_egypt": { "name": "Wikipedia, Egypt (area), 2026", "url": "https://en.wikipedia.org/wiki/Egypt" }, "osterloo_2008": { "name": "Osterloo and others, Chloride-bearing materials in the southern highlands of Mars, Science, 2008", "url": "https://www.science.org/doi/10.1126/science.1150690" }, "davila_2010": { "name": "Davila and others, Hygroscopic salts and the potential for life on Mars, Astrobiology, 2010", "url": "https://digital.csic.es/bitstream/10261/44460/1/15_Astrobiology_8264561.pdf" }, "friedmann_1982": { "name": "Friedmann, Endolithic microorganisms in the Antarctic cold desert, Science, 1982", "url": "https://pubmed.ncbi.nlm.nih.gov/17771821/" }, "noffke_2015": { "name": "Noffke, Ancient sedimentary structures in the Gillespie Lake Member, Mars, Astrobiology, 2015", "url": "https://www.liebertpub.com/doi/pdf/10.1089/ast.2014.1218" }, "iron_preprint_2021": { "name": "Microbial habitability of early Mars lacustrine environments sustained by iron redox cycling, bioRxiv preprint, 2021", "url": "https://www.biorxiv.org/content/10.1101/2021.09.07.459191v1" }, "nisson_2026": { "name": "Nisson and others, Thermodynamic constraints on H2 production and methane generation during Martian serpentinization, JGR Planets, 2026", "url": "https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2025JE009395" }, "wiki_nili": { "name": "Wikipedia, Nili Fossae, 2026", "url": "https://en.wikipedia.org/wiki/Nili_Fossae" }, "wiki_bacteria": { "name": "Wikipedia, Bacteria (size), 2026", "url": "https://en.wikipedia.org/wiki/Bacteria" }, "allwood_2006": { "name": "Allwood and others, Stromatolite reef from the Early Archaean era of Australia, Nature, 2006", "url": "https://www.nature.com/articles/nature04764" }, "lyons_2021": { "name": "Lyons and others, review of the rise of oxygen on Earth, 2021", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC8403206/" }, "wiki_ediacaran": { "name": "Wikipedia, Ediacaran biota, 2026", "url": "https://en.wikipedia.org/wiki/Ediacaran_biota" }, "martin_2008": { "name": "Martin and others, Hydrothermal vents and the origin of life, Nature Reviews Microbiology, 2008", "url": "https://www.nature.com/articles/nrmicro1991" }, "damer_2020": { "name": "Damer and Deamer, The hot spring hypothesis for an origin of life, Astrobiology, 2020", "url": "https://www.liebertpub.com/doi/10.1089/ast.2019.2045" }, "dodd_2017": { "name": "Dodd and others, Evidence for early life in Earth's oldest hydrothermal vent precipitates, Nature, 2017 (NASA Astrobiology summary)", "url": "https://astrobiology.nasa.gov/news/oldest-evidence-for-early-life-on-earth-dated-to-at-least-377-billion-years/" }, "whoi_1977": { "name": "Woods Hole Oceanographic Institution, 1977: astounding discoveries", "url": "https://www.whoi.edu/feature/history-hydrothermal-vents/discovery/1977.html" }, "uw_2005": { "name": "University of Washington, Life in Lost City, 2005 (on Kelley and others, Science, 2005)", "url": "https://washington.edu/news/2005/03/10/life-in-lost-city" }, "chevaldonne_1997": { "name": "Chevaldonne and Godfroy, Enumeration of microorganisms from deep-sea hydrothermal chimney samples, FEMS Microbiology Letters, 1997", "url": "https://academic.oup.com/femsle/article/146/2/211/489502" }, "wyohistory_brock": { "name": "WyoHistory, The Yellowstone microbe that changed the world, 2021", "url": "https://www.wyohistory.org/encyclopedia/yellowstone-microbe-changed-world" }, "djokic_2017": { "name": "Djokic and others, Earliest signs of life on land preserved in ca. 3.5 Ga hot spring deposits, Nature Communications, 2017 (UNSW summary)", "url": "https://unsw.edu.au/newsroom/news/2017/05/oldest-evidence-of-life-on-land-found-in-3-48-billion-year-old-a" }, "unesco_shark_bay": { "name": "UNESCO World Heritage, Shark Bay, Western Australia", "url": "https://whc.unesco.org/en/list/578" }, "csiro_bif_2024": { "name": "CSIRO, Banded iron formations, 2024", "url": "https://www.csiro.au/en/news/all/articles/2024/march/banded-iron-formations" }, "kappler_2005": { "name": "Kappler and others, Deposition of banded iron formations by anoxygenic phototrophic Fe(II)-oxidizing bacteria, Geology, 2005", "url": "https://authors.library.caltech.edu/records/24csj-ef922" }, "iodp_347": { "name": "IODP Expedition 347, Baltic Sea Paleoenvironment, Proceedings, 2015", "url": "https://publications.iodp.org/proceedings/347/101/101_f7.htm" }, "csm_lovley_2003": { "name": "Christian Science Monitor, Breathing rust, and new life into bug science, 2003", "url": "https://www.csmonitor.com/2003/1016/p16s01-sten.html" }, "anton_2000": { "name": "Anton and others, Extremely halophilic bacteria in crystallizer ponds from solar salterns, Applied and Environmental Microbiology, 2000", "url": "https://journals.asm.org/doi/10.1128/aem.66.7.3052-3057.2000" }, "sierra_2022": { "name": "Sierra and others, Microbiome and metagenomic analysis of Lake Hillier, Environmental Microbiome, 2022", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC9768965" }, "vreeland_2000": { "name": "American Scientist, Rock of Ages (on Vreeland and others, Nature, 2000)", "url": "https://www.americanscientist.org/node/480" }, "nasa_audaxviator_2008": { "name": "NASA Astrobiology, Life without the Sun, 2008 (on Chivian and others, Science, 2008)", "url": "https://astrobiology.nasa.gov/news/life-without-the-sun/" }, "dco_2018": { "name": "Deep Carbon Observatory, Life in deep Earth totals 15 to 23 billion tons of carbon, 2018 (Phys.org)", "url": "https://phys.org/news/2018-12-life-deep-earth-totals-billion.html" }, "earthdate_kidd_creek": { "name": "EarthDate, The world's oldest water (Sherwood Lollar and others, 2016)", "url": "https://www.earthdate.org/episodes/worlds-oldest-water" }, "un_wpp_2024": { "name": "United Nations, World Population Prospects 2024", "url": "https://population.un.org/wpp/" }, "wiki_milky_way": { "name": "Wikipedia, Milky Way", "url": "https://en.wikipedia.org/wiki/Milky_Way" }, "nasa_rock_samples": { "name": "NASA Science, Mars 2020 Perseverance: Mars rock samples (sample 25, Sapphire Canyon), 2024", "url": "https://science.nasa.gov/mission/mars-2020-perseverance/mars-rock-samples" } }, "sources_checked": "3 October 2026" }, "03-05": { "file": "03-05", "title": "Vehicles and port", "folder": "03", "facts_file": "03-05-vehicles-and-port.json", "version": "1.22", "status": "Active", "last_updated": "23 October 2026", "about": "Facts file for 03-05 Vehicles and port. The page is built from this file, the library catalogue and the page template. Change a fact here, then run build.py. Words in curly brackets, like {bay_m3}, are filled in when the page is built, from the numbers in this file or from numbers quoted live from other files, so each number is typed once.", "one_line": "A landed Starship is a {ship_storeys}-storey tower that cannot move. This is how its cargo gets down, where the tower ends up, and what drives around it.", "shelf_life": "Moon rovers, cargo landers and SpaceX's Mars plans are changing fast: NASA picked two crewed Moon rovers in May 2026 and SpaceX has not shown how a Mars Starship unloads. Re-check the Lunar Terrain Vehicle, the pressurised rover and any SpaceX unloading design by March 2027, or before relying on them. Rover records on Mars change whenever Perseverance drives.", "header": { "purpose": "Describe, as universal kit, how cargo leaves a ship, where landed ships stand and what happens to the ones that never fly again, how far apart pads and parked ships sit, and the rovers, robots, roads and cranes that serve the port.", "why": "Every tonne that reaches Mars arrives at the port, about 40 metres off the ground (our guess, V-03), inside a ship that cannot drive. No file said how it gets down, where the ship goes next, or what the town drives. 03-02 left those questions open.", "when": "Laying out a port or a road in a city file, drawing vehicles in the 3D world, writing arrival day, a rover trip or a salvage job, or checking how far a crew can safely drive.", "change": "Part One changes only with a citation. Part Two assumptions can be challenged one at a time. Edit this facts file, then run build.py.", "writing": "Every number is compared to something people know. Pictures first, short sentences, no walls of text." }, "comparisons": { "about": "Yardsticks used only to compare. Each has a source below, or is marked as our own round figure. Person height and walking pace are read from 02-01; storey height from 03-02.", "container_m3": { "value": 33.1, "source": "wiki_container", "note": "Inside volume of a standard 20-foot shipping container." }, "card_mm": { "value": 0.76, "source": "wiki_iso7810", "note": "A bank card's thickness (ISO/IEC 7810)." }, "car_m": { "value": [ 4.5, 1.5 ], "note": "Our own round figure for a family car, length and height, used only in the line-up drawing." }, "mile_km": 1.609, "ft_m": 0.3048, "lb_kg": 0.4536, "inch_cm": 2.54, "ft3_m3": 0.0283168 }, "sections": [ { "id": "5.1", "title": "Getting cargo off a ship" }, { "id": "5.2", "title": "Where landed ships stand" }, { "id": "5.3", "title": "How far apart" }, { "id": "5.4", "title": "Rovers" }, { "id": "5.5", "title": "Wheels, dust and getting stuck" }, { "id": "5.6", "title": "Robots and remote driving" }, { "id": "5.7", "title": "Roads, fuel and charging" } ], "facts": [ { "id": "F-01", "section": "5.1", "text": "SpaceX's 2020 Starship users guide gives an {bay_d} m wide payload space, extendable to {bay_h} m tall, behind a clamshell door that opens to release cargo and closes again for the trip home. SpaceX says Starship was designed from the start to carry more than 100 tonnes to Mars and the Moon. It has not published how cargo reaches the ground on Mars.", "compare": "At most about {bay_m3} m³, a cylinder that size: the room inside about {containers} twenty-foot shipping containers.", "sources": [ "spacex_ug_2020", "wiki_container" ] }, { "id": "F-02", "section": "5.1", "text": "On the Moon, Starship HLS will use an elevator to carry crew and cargo between its living area near the top and the surface. In November 2023 NASA astronauts in spacesuits tried a mockup with a full-size basket and working controls at SpaceX in Hawthorne, California. NASA says HLS, at about {hls_h} m, is about the same height as a {hls_storeys}-storey building.", "compare": "The ride down starts near the top of that building.", "sources": [ "nasa_elevator_2023", "nasa_hls_2024" ] }, { "id": "F-03", "section": "5.1", "text": "In November 2024 NASA said it intends a Starship cargo lander to deliver Japan's pressurised Moon rover, no earlier than its {rover_fy} budget year. NASA's large cargo landers are to carry about {cl_lo} to {cl_hi} tonnes.", "compare": "{cl_lo} to {cl_hi} t is {cl_pct_lo} to {cl_pct_hi} percent of the {cargo_t} t this library lands per Mars cargo ship (01-01 E-09).", "sources": [ "nasa_cargo_2024" ] }, { "id": "F-04", "section": "5.1", "text": "NASA Langley's Lunar Surface Manipulation System is a folding crane built to unload landers, sized to lift {lsms_t} tonne at the tip on the Moon with a {lsms_reach} m reach, standing {lsms_shoulder} m at the shoulder. The first test-bed weighed about {lsms_kg} kg, about {lsms_bed_pct} percent of that load; NASA estimates a flight version with composite parts at under {lsms_pct} percent. In a 2008 field test in Washington State it unloaded payloads in under {lsms_min} minutes each. A heavy-lift version was studied for {lsmsh_t}-tonne Moon payloads.", "compare": "Mars gravity is {g_ratio} times the Moon's, so a crane rated for {lsms_t} t on the Moon lifts only about {lsms_mars_kg} kg on Mars.", "sources": [ "doggett_2008", "jefferies_2010", "nssdc_moon" ] }, { "id": "F-05", "section": "5.1", "text": "The Apollo rover travelled folded flat against the side of the lunar module. Astronauts lowered and unfolded it with a system of pulleys and braked reels, using ropes and cloth tapes.", "compare": "A car delivered like a folding chair, let down on a rope.", "sources": [ "nssdc_lrv" ] }, { "id": "F-06", "section": "5.2", "text": "On Earth, NASA moves whole rockets on its crawler-transporter: about {ct_mlb} million pounds, able to carry {ct_carry_mlb} million pounds, at {ct_mph_lo} mph loaded and {ct_mph_hi} mph empty. It takes a rocket {ct_miles} miles to pad 39B, burning a gallon of fuel every 32 feet. It first moved under its own power in {ct_year}.", "compare": "About {ct_t} tonnes creeping at {ct_kmh} km/h, a third of walking pace: the trip to the pad takes about {ct_hours} hours.", "sources": [ "nasa_crawler" ] }, { "id": "F-07", "section": "5.2", "text": "At Starbase, SpaceX moves launch-mount sections and other ground hardware between sites on self-propelled modular transporters (SPMTs). A retired booster, Booster 12, was moved to the site's 'rocket garden' on 28 October 2024, where it will likely stay as a showpiece.", "compare": "Even on Earth a finished Starship never drives itself anywhere.", "sources": [ "nsf_2024" ] }, { "id": "F-08", "section": "5.2", "text": "Turning a spent rocket into a home was planned before. In {wet_year} Wernher von Braun proposed fitting out an empty rocket stage in orbit as a laboratory (the 'wet workshop'). It proved so hard that on {dry_date} NASA chose to fit out Skylab's Saturn stage on the ground instead, and the wet workshop never flew. The finished workshop was {sky_l} ft long and {sky_w} ft wide.", "compare": "Skylab's {sky_m3} m³ of working space is about {sky_pct} percent of a Starship's cargo space (F-01).", "sources": [ "nasa_skylab_hist" ] }, { "id": "F-09", "section": "5.3", "text": "Apollo 12 landed about {surveyor_m} m from Surveyor 3, and grains struck the old probe at {hit_lo} to {hit_hi} km per second (03-02 F-05). Although Surveyor sat in a crater, {surv_below} m below the lander, it was sandblasted and pitted. Citing this, NASA in 2011 asked future landers to keep {heritage_km} km from Apollo landing sites, and {impact_km} km from old impact sites.", "compare": "{heritage_km} km is about {heritage_x} times the Surveyor distance: a {heritage_walk}-minute walk.", "sources": [ "nasa_heritage_2011" ] }, { "id": "F-10", "section": "5.3", "text": "A 2022 NASA policy study says stones {otps_cm_lo} to {otps_cm_hi} cm across, thrown by landing jets at the Apollo sites, could have flown up to {otps_km} km. Quoting Wittal and others (2020), it says a {otps_t}-tonne lander near a base 1 km² in size could expect up to {otps_n} hits per landing at 1 km away, a {otps_p5} percent chance of a hit at 5 km and {otps_p10} percent at 10 km.", "compare": "Moving a base from 1 km to 10 km away turns several hits every landing into roughly one hit in ten landings.", "sources": [ "nasa_otps_2022" ] }, { "id": "F-11", "section": "5.3", "text": "Metzger and colleagues (2019) estimated that an Apollo lunar module landing threw out about {lm_ej} t of soil in all, and a {m_lander} t lander carrying {m_payload} t of cargo about {m_ej} t. The outpost layout they assessed kept the landing zone {m_km} km from homes and power, and {m_below} m lower down.", "compare": "The bigger lander throws about {ej_x} times as much soil as Apollo's.", "sources": [ "metzger_2019" ] }, { "id": "F-12", "section": "5.3", "text": "When NASA planned the Saturn launch pads in the early 1960s, it reckoned that protecting rockets on neighbouring pads from each other's blast and noise might take a safety zone of nearly {moonport_km} km.", "compare": "About an hour's walk between neighbouring pads.", "sources": [ "moonport" ] }, { "id": "F-13", "section": "5.4", "text": "The Apollo Lunar Roving Vehicle weighed {lrv_kg} kg, carried {lrv_pay} kg and was {lrv_len} m long. On Apollo 17 it covered {a17_km} km in {a17_h} hours of driving, never more than {a17_range} km from the lander. NASA gives its top speed as {lrv_top} km/h. The rover programme (four rovers) cost {lrv_cost} million dollars against a {lrv_cost0} million contract.", "compare": "Apollo 17 averaged about {a17_kmh} km/h, {a17_x} times walking pace. It weighed about as much as {lrv_people} people.", "sources": [ "nssdc_lrv", "nasa_rover_brief_2023" ] }, { "id": "F-14", "section": "5.4", "text": "NASA's Lunar Terrain Vehicle is an open rover that astronauts drive in spacesuits and that can also drive itself. In April 2024 NASA gave three companies contracts to design one. On {ltv_date} it chose two: Astrolab's CLV-1, about {clv_lb} lb and over {clv_mph} mph, and Lunar Outpost's Pegasus, driven by hand, by itself or by remote at over {peg_mph} mph, working for up to a year.", "compare": "Pegasus at {peg_kmh} km/h is a brisk bike ride; CLV-1 weighs about {clv_x} times the Apollo rover.", "sources": [ "nasa_ltv_2026", "wiki_ltv" ] }, { "id": "F-15", "section": "5.4", "text": "Toyota and JAXA's 2019 concept for a pressurised Moon rover, now nicknamed Lunar Cruiser, is {lc_l} m long, {lc_w} m wide and {lc_h} m tall, with {lc_m3} m³ of living space for {lc_crew} people ({lc_crew_max} in an emergency), a {lc_range} km driving range and fuel-cell power. Japan agreed with NASA in April 2024 to provide a pressurised rover; NASA will deliver it.", "compare": "{lc_range} km is about a quarter of the way round the Earth; the whole rover is about the size of two microbuses (Toyota).", "sources": [ "toyota_2019", "jaxa_2024", "nasa_cargo_2024" ] }, { "id": "F-16", "section": "5.4", "text": "NASA's Space Exploration Vehicle, a pressurised rover prototype first tested in {sev_year}, has {sev_wheels} wheels that swivel all the way round, drives at about {sev_kmh} km/h in any direction, climbs {sev_slope}° slopes and houses {sev_crew} astronauts for up to {sev_days} days in shirtsleeves. Suitports on its back let a crew get out in about {sev_min} minutes. It has driven {sev_km} km over rough lava.", "compare": "About the size of a pickup truck, and about {sev_x} times walking pace.", "sources": [ "nasa_sev" ] }, { "id": "F-17", "section": "5.4", "text": "NASA's reference Mars plan (DRA 5.0, 2009) gives the crew two small pressurised rovers (crew of two, {dra_km} km before resupply, one to two weeks out) and two open rovers like Apollo's. It puts a suited astronaut's walking range at roughly {dra_walk} km in all, on one charge of the backpack.", "compare": "{dra_walk} km there and back means about {walk_out} km out: a {walk_out_h}-hour walk home on Earth.", "sources": [ "dra5_sp" ] }, { "id": "F-18", "section": "5.4", "text": "Zubrin and colleagues' Mars Direct plan (1991) gives the crew a pressurised rover with an engine burning methane and oxygen made on Mars. {zb_t} t of that propellant would drive about {zb_km} km, on trips up to {zb_r} km from base at about {zb_day} km a day.", "compare": "About {zb_kg_km} kg of propellant per kilometre. {zb_km} km is more than half way round the Earth.", "sources": [ "zubrin_1991" ] }, { "id": "F-19", "section": "5.5", "text": "On Apollo 17 a hammer caught the rover's rear fender and tore off its extension, so the wheels sprayed dust over the crew and gear. The astronauts rebuilt it from maps, duct tape and clamps. Rover fenders were damaged on all three missions that carried one.", "compare": "A broken mudguard, fixed with a road map and tape, with no garage anywhere.", "sources": [ "nasa_rover_brief_2023" ] }, { "id": "F-20", "section": "5.5", "text": "A 2005 NASA review of Apollo sorted moon dust trouble into nine kinds: blocked vision, false readings, coating, lost grip, clogged mechanisms, wear, overheating, failed seals, and breathing it in. Simple fixes worked for grip but not for clogging, wear or heat. Ground tests always underestimated how bad it would be.", "compare": "Like beach sand that finds its way into every zip, camera and seal however careful you are, only finer, and with nothing to wash it off.", "sources": [ "gaier_2005" ] }, { "id": "F-21", "section": "5.5", "text": "Curiosity's aluminium wheels are {cw_cm} cm across with a skin only {cw_mm} mm thick. Holes appeared by sol {cw_hole} and a large rip by sol {cw_rip} (November 2013), torn by sharp rocks cemented into the ground. Drivers now plan routes from orbital images, drive shorter hops and sometimes drive backwards.", "compare": "The skin is about as thick as a bank card ({card_mm} mm).", "sources": [ "planetary_wheels_2014", "wiki_iso7810" ] }, { "id": "F-22", "section": "5.5", "text": "In April 2009 Spirit's wheels broke through a crust at a place called Troy and churned into soft sand. Its last {sp_drives} backward drives, in early 2010, moved it just {sp_in} inches. It never drove free, and its last message came on {sp_last}.", "compare": "{sp_cm} cm in about a month of trying: a hidden soft patch ended a rover.", "sources": [ "jpl_spirit_2010" ] }, { "id": "F-23", "section": "5.5", "text": "Opportunity finished the first Mars marathon, {op_km} km, on {op_date}, about {op_y} years and {op_m} months after landing. In July 2014 it had passed the old off-world record, {lk_km} km, set by the Soviet Lunokhod 2 on the Moon in {lk_year} in under five months.", "compare": "About {op_m_day} m a day on average: a short stroll, spread over eleven years.", "sources": [ "nasa_opp_2015", "jpl_opp_2014" ] }, { "id": "F-24", "section": "5.6", "text": "Lunokhod 2 was driven from Crimea by a crew of six: a commander, a navigator, a driver, an engineer, a radio operator and one in reserve, steering by joystick from a mast camera's pictures.", "compare": "Six people to drive one car-sized rover, because every move had to be seen, judged and sent.", "sources": [ "robinson_2014" ] }, { "id": "F-25", "section": "5.6", "text": "Mars is too far for a joystick. Drivers plan a route, send it, and the rover drives it the next sol. Perseverance's self-driving system maps the ground and steers round hazards itself, at up to about {pv_mh} m an hour against Curiosity's {cu_mh}. Its record is {pv_day} m in one sol, and {pv_auto} m with no human checking the route.", "compare": "About {pv_x} times slower than walking. The delay is {lt_min} to {lt_max} minutes each way (02-01 F-39).", "sources": [ "jpl_autonav_2021", "verma_2023" ] }, { "id": "F-26", "section": "5.6", "text": "On {an_date}, astronaut Luca Parmitano, aboard the International Space Station, drove a rover in the Netherlands and picked up rocks with its arm, feeling the forces it felt (ESA's Analog-1). The lag averaged about {an_s} seconds, with spikes to {an_max} seconds.", "compare": "Mars's one-way delay is {an_x_lo} to {an_x_hi} times Analog-1's average lag.", "sources": [ "dlr_2019" ] }, { "id": "F-27", "section": "5.6", "text": "Tesla's humanoid robot Optimus was presented in 2021 as {op_h} m tall, {op_kg} kg and able to carry {op_carry} kg: company figures. In May 2025 Musk said the first Mars ships would carry Optimus robots (01-01 F-23) and that it would be 'an epic picture' to see one walking on Mars. None has flown to Mars.", "compare": "A claimed load of {op_pct} percent of its own mass. On Mars {op_carry} kg would weigh what {op_mars} kg weighs on Earth.", "sources": [ "wiki_optimus", "space_2025" ] }, { "id": "F-28", "section": "5.7", "text": "The South Pole Traverse drags fuel about {spot_mi} miles overland from McMurdo to the South Pole: tractors pull sheets of plastic, each carrying two {spot_gal}-gallon fuel bladders, climbing over {spot_ft} feet. A round trip takes about {spot_days} days, and each trip saves about {spot_fl} flights by LC-130 cargo planes.", "compare": "About {spot_kmday} km a day, round trip: spread over 24 hours that is {spot_kmh} km/h, slower than walking.", "sources": [ "spot" ] }, { "id": "F-29", "section": "5.7", "text": "The Apollo rover ran on two {lrv_v}-volt silver-zinc batteries of {lrv_ah} amp-hours that could not be recharged. Lunar Cruiser is designed around fuel cells (F-15), and NASA's new Pegasus rover is to work for up to a year (F-14).", "compare": "About {lrv_kwh} kWh in all, used once. {lrv_kwh_compare}", "sources": [ "nssdc_lrv", "toyota_2019", "nasa_ltv_2026" ] }, { "id": "F-30", "text": "Apollo 15 saw the first use of the Lunar Roving Vehicle. Dave Scott photographed Jim Irwin beside it on {a15_date}, and over the mission the two drove it {a15_km} km.", "section": "5.4", "compare": "{a15_km} km is about {a15_walk} hours of walking, the first drive people ever took on another world.", "sources": [ "wiki_apollo15", "commons_a15_lrv" ] }, { "id": "F-31", "text": "Skylab, launched on {sky_launch}, was built from a spare Saturn V third stage fitted out on the ground (F-08). Its three crews lived aboard for {sky_days} days in all.", "section": "5.2", "compare": "{sky_days} days, nearly half a year, in a home made from a rocket.", "sources": [ "wiki_skylab" ] }, { "id": "F-32", "section": "5.2", "text": "On 7 March 2004 the rover Spirit photographed a streak across the Martian night sky, likely the first image of a meteor seen from another world. Meteors burn in Mars's thin air as they do in Earth's, so a ship coming in from orbit glows too.", "compare": "A shooting star you could watch from a Mars porch, as you can from an Earth garden.", "sources": [ "astronomy_meteors_2020" ] }, { "id": "F-33", "section": "5.2", "text": "When the air around a rocket nozzle is at a lower pressure than the exhaust leaving it, the flow is underexpanded and keeps expanding outward after it leaves the nozzle. Mars's air is thin, so a ship's plume spreads wide.", "compare": "Like the cone of a garden hose turned to spray, opening out the moment it leaves the nozzle.", "sources": [ "aerospaceweb_nozzle" ] }, { "id": "F-34", "section": "5.2", "text": "When SpaceX first loaded an orbital Starship with propellant, on 23 January 2023, the stainless-steel ship went frosty white from the supercold propellant inside.", "compare": "The same white bloom as a cold can of drink on a warm day, on a ship as tall as a 16-storey building.", "sources": [ "space_starship_wdr_2023" ] }, { "id": "F-35", "section": "5.7", "text": "NASA's Phoenix lander carried a telltale: a lightweight tube hung on a mast about two metres above the ground, photographed more than 7,500 times as the wind bent it. It showed mid-summer winds of about 15 to 20 km/h and gusts near 60 km/h.", "compare": "Mid-summer's 15 to 20 km/h is a gentle breeze on Earth; in Mars's thin air it barely pushes at all.", "sources": [ "ut_telltale_2009" ] }, { "id": "F-36", "section": "5.1", "text": "Astronauts back from about six months on the International Space Station show balance problems, muscle weakness and a heart and blood system used to weightlessness; NASA's Field Test found tasks needing a steady stance the hardest.", "compare": "Like stepping off a boat after a long voyage, when the ground seems to sway.", "sources": [ "nasa_field_test_2015" ] } ], "assumptions": [ { "id": "V-01", "confidence": "High", "text": "A landed Starship cannot move itself. It stands where it lands until it takes off again or is taken apart.", "why": "It has no wheels, and even on Earth finished stages are carried by crawlers and transporters (F-06, F-07). Landing is the only time it chooses its spot.", "moves_to": "" }, { "id": "V-02", "confidence": "Medium", "text": "Cargo comes down two ways. Crates and people ride a lift like HLS's elevator (F-02) from the cargo door to the gravel apron. Heavy, bulky items such as reactors and rovers are lowered by a folding crane of the Langley type, carried on the early ships near the door and later replaced by a crane on the apron.", "why": "SpaceX has shown a lift for the Moon but no Mars unloading method (F-01). Folding cranes are tested and light (F-04). Mars gravity is {g_ratio} times the Moon's, so Mars cranes must be sized for Mars loads, not borrowed from Moon designs.", "moves_to": "" }, { "id": "V-03", "confidence": "Low", "text": "Emptying one cargo ship of about {cargo_t} t takes about {un_lo} to {un_hi} sols once it is safe to approach, and the ship is safe after {safe_lo} to {safe_hi} sols. Haulers carrying {hl_lo} to {hl_hi} t a load make {trips_lo} to {trips_hi} runs to the town.", "why": "Our figures: {lift_lo} to {lift_hi} lifts a sol averaging {lt_lo} to {lt_hi} t each. The crane test managed a load in under {lsms_min} minutes (F-04), but on Mars each load must be unstrapped, checked, lowered about {door_m} m, driven clear and dusted, in daylight. The cargo mass is 01-01 E-09; the town distance is 03-02 P-01. Replace when anyone publishes a real unloading plan.", "moves_to": "" }, { "id": "V-04", "confidence": "Low", "text": "The port has two zones: landing pads (03-02) and a ship yard. Before a ship mover exists (V-05), a ship that will not fly again lands on its own patch of good natural ground in a landing field beside the pads, and is unloaded and stays there for good; pads are kept for ships that will fly home. From the First Town on, every ship lands on a pad. A ship that is staying is carried to the yard as soon as it is safe to approach ({safe_lo} to {safe_hi} sols, V-03) and unloaded there, so its pad is free again within about that many sols. A ship that will fly home is unloaded on its pad and waits there for the return window.", "why": "Answers 03-02's open question on where landed ships stand. Moving staying ships before unloading keeps 03-02 P-02's pad counts and pad turnaround (a pad free again every {pad_days} days) working. Before the mover, the only choice is to land where the ship will stay (V-01). The first ship already lands on natural ground (03-02 F-14).", "moves_to": "" }, { "id": "V-05", "confidence": "Low", "text": "From the First Town on, a ship mover (a slow, many-wheeled crawler) drives under an emptied ship, lifts it by its legs and carries it upright to the yard at the crawler's loaded pace of about {ct_kmh} km/h. An empty ship of about {sh_dry} t weighs on Mars what {sh_dry_earth} t weighs on Earth.", "why": "The crawler carries far heavier loads on Earth (F-06), and SpaceX already moves launch hardware on transporters (F-07). The mover is landed as cargo in the First Town, when the number of staying ships would otherwise fill the landing field (01-01 E-12). Its own mass and design are unknown, hence Low. Empty mass is 03-02's Version 2 figure (03-02 P-07).", "moves_to": "" }, { "id": "V-06", "confidence": "Low", "text": "Pads stand {sp_lo} to {sp_hi} km apart, centre to centre, in an arc round the tank farm, beyond the nearest pad (04-01-01 FC-02 puts every pad the same distance from the tanks), and the ship yard and landing field stand to one side, at least {yg_lo} km from the nearest pad. The fuel plant and its tank farm stand beyond the pads, on the far side from the town, {pl_lo} to {pl_hi} km from the nearest pad (03-04). Every landing is treated as a stone-throwing event for anything within {stone_km} km: the stone zone, which is why the least gap between pads is the same.", "why": "Answers 03-02's open question on pad spacing. Apollo 12 pitted Surveyor 3 at {surveyor_m} m (F-09); NASA expects several hits per landing on a base 1 km away from a lander {otps_x} times lighter than a loaded Starship (F-10, 03-02 P-07); NASA keeps landers {heritage_km} km from Apollo sites (F-09). Mars air slows dust but not stones, and berms (03-02 P-02) catch some. A ship standing next door is the most exposed thing, so we take 1 km as the least and 2 km as the aim. The fuel plant and its tanks stand further off, because stones from Apollo landings flew up to {otps_km} km (F-10). Replace when a Mars plume study sizes it.", "moves_to": "" }, { "id": "V-07", "confidence": "Medium", "text": "Ships that will never fly again are stripped, not wasted. Cargo comes out first, then fittings, wiring, tanks and engines kept as spares, then hull steel as building stock. Early hulls serve as unpressurised sheds and landmarks, not homes. By the end of the City era about {hulks_city} ships stand in the yard and landing field, holding about {steel_city} t of steel if none were cut up.", "why": "Follows the reuse-everything culture (01-01 E-06) and the first ship's site (03-02 P-06, now 04-01-01 FC-10, First Landing). Skylab shows refitting a rocket as a home is harder than it looks (F-08). Counts come from ships minus returning ships per window in each era (01-01 E-12). Steel uses 03-02's Version 2 empty mass (03-02 P-07). {steel_city} t is {eiffel_x} times the iron frame of the Eiffel Tower.", "moves_to": "" }, { "id": "V-08", "confidence": "Low", "text": "The fleet grows by era: {fleet_line}. Beyond walking range of home, crewed vehicles always go out in pairs, so one can rescue the other; within it, an open rover may go alone with two people aboard (V-09).", "why": "Pairs copy NASA's reference Mars plan, which lands two of each rover (F-17). Types copy tested or chosen designs (F-13 to F-16). Counts are our scaling with ships and people per era (01-01 E-12). Construction diggers and loaders are not counted here: they are 03-11 CM-05.", "moves_to": "" }, { "id": "V-09", "confidence": "Medium", "text": "How far crews may drive: an open rover alone goes no further than a suited walk home, about {walk_out} km. A pair of open rovers may go further, with one able to carry both crews home. Pressurised rovers go out in pairs up to about {pr_r} km. From the City era, methane-and-oxygen rovers go up to {zb_r} km. On graded roads rovers drive at up to {road_kmh} km/h; off road, walking pace.", "why": "The walk-home rule is Apollo's (F-13) with DRA 5.0's walking range (F-17). {pr_r} km is half of DRA 5.0's {dra_km} km before resupply. The long range is Mars Direct's (F-18), fuelled by the plant (03-04). The road speed sits between the Space Exploration Vehicle's {sev_kmh} km/h and the Apollo rover's {lrv_top} km/h top speed (F-13, F-16).", "moves_to": "" }, { "id": "V-10", "confidence": "Medium", "text": "Before any crew arrives, robots on Mars are given tasks from Earth once a sol and carry them out on their own, like today's rovers. Once people land, robots and the crane are driven live from inside the town, with a delay of about {town_lo} to {town_hi} seconds. Humanoid robots are treated as a SpaceX and Tesla plan, not a fact.", "why": "A {lt_min} to {lt_max} minute delay each way (02-01 F-39) rules out joysticks from Earth (F-25); Lunokhod needed a crew of six even at the Moon (F-24); a lag under a second already allowed fine work in Analog-1 (F-26). The town's delay is our guess for radio relays and computers across a few kilometres. Optimus figures are company claims (F-27).", "moves_to": "" }, { "id": "V-11", "confidence": "Medium", "text": "Graded, rolled gravel roads, about {road_w} m wide, join the pads, the yard, the fuel plant and the town, beside the buried power and data line (03-02 P-01). Near the port, vehicles keep to roads. Roads are swept after landings and checked for sharp stones.", "why": "Mars rovers have been torn by sharp rocks (F-21) and trapped by hidden soft sand (F-22); a known, graded track avoids both. 03-02 P-01 already calls for a graded road. The width fits the widest vehicle, Lunar Cruiser (F-15), passing another. How the roads are built (graded native soil rolled and compacted, with made gravel near the port, because AP-1 has few rocks) is 03-11 CM-08.", "moves_to": "" }, { "id": "V-12", "confidence": "Medium", "text": "Battery rovers and robots charge from the town grid (03-03 G-01) in covered bays that double as dust locks. Long-range pressurised rovers run on fuel cells or engines fed with methane and oxygen from the fuel plant (03-04). In a storm warning every vehicle is brought in within the few days of notice (02-02 W-03).", "why": "Electric drive is the Moon and test-rig standard (F-29, F-16). Mars makes methane and oxygen anyway (F-18; 03-04), and Lunar Cruiser already uses fuel cells (F-15). Dust in seals and mechanisms is the top Apollo lesson (F-20), and dust clings to everything (02-01 S-13).", "moves_to": "" }, { "id": "V-13", "text": "Moved to 03-04 C-07, which owns how propellant reaches a returning ship (read live: {transfer_word}).", "why": "One owner for propellant transfer, so this file no longer keeps a second guess at a different confidence.", "moves_to": "", "moved_to": "03-04 C-07" }, { "id": "V-14", "confidence": "Low", "text": "Arrival day for vehicles: every rover and robot is parked behind a berm or in its bay, cameras watching. After touchdown nobody drives near until the ship is declared safe (V-03). Robots go first, then the crane crew, then the haulers. Outside, the landing is heard only faintly: in Mars air a shout carries only about {carry_m} m (02-01).", "why": "Built on the keep-out distances (V-06, 03-02 P-01) and landing day as an event (03-02 P-04). Sound is thin because the air is thin (02-01). Pure story beyond that. The day itself, for the people landing and the town meeting them, is 04-05-02 Arrival day, which reads this assumption for its vehicles.", "moves_to": "" }, { "id": "V-15", "confidence": "Medium", "text": "Wheels, seals and joints are the port's consumables. Every vehicle is cleaned at the bay door, wheels are swapped on a schedule, and a workshop near the yard reuses parts from stripped ships.", "why": "Dust defeated Apollo's seals and mechanisms (F-20) and tore Curiosity's wheels (F-21). Stripped ships are the nearest store of spares (V-07). Wheel life on Mars is unknown for heavy vehicles.", "moves_to": "" }, { "id": "V-16", "confidence": "Medium", "text": "Arcadia's working rovers come in three designs (numbers.rover_designs): the two-seat Trail rover for short trips in suits, the Long-range rover, a pressurised cabin the size of Toyota's Lunar Cruiser (numbers.lunar_cruiser), and the Hauler that carries one container. Each has a fixed size, wheel count and look, and every picture, film and 3D scene of the city draws them the same way.", "why": "Owner, 10 October 2026: the rover should look real and stunning, and its design should live in the library so the whole world stays consistent. The open rover follows Apollo's (wire-mesh wheels, two seats), the pressurised rover Toyota's and JAXA's Lunar Cruiser, both scaled for Mars.", "moves_to": "" }, { "id": "V-17", "confidence": "Medium", "text": "The port has a control tower about 20 m tall between the town and the pads, with a glass cab facing the pads. How the port looks is fixed in numbers.look: the landed ship, the crew lift, the folding crane, the haulers, the rovers, the roads, the charging bays, the tower and the cargo yard. Every picture and 3D scene of the port is made from it.", "why": "00-05 ST-20 (owner, 10 October 2026). People need to see the pads for the last checks before a landing even when the ships fly themselves; a tower is the most beautiful answer and contradicts nothing." }, { "id": "V-18", "confidence": "Medium", "text": "A landing at the port plays out the same way every time. The ship's entry glows across the sky like a slow meteor (F-32), its boom arrives as a double thump, it falls belly-first, flips and lands on a burn whose plume spreads wide in the thin air (F-33). Once it stands, crews unload it, fuel it for home and new arrivals walk to the hospital for their welcome check-up, steady on their feet only after a few days (F-36; 03-14). While it is fuelled, carbon dioxide from the air freezes on the cold steel (03-04 freezes it out the same way), so a white frost line climbs the hull with each tank (F-34). A telltale like Phoenix's (F-35) hangs by the tower so the crews can see the wind.", "why": "Owner, 23 October 2026: make the port's landings an event, truer to the physics and full of life. Each step follows a real precedent; the timings are our estimate." } ], "world_spec": { "about": "The numbers the engine's 'Place the kit' step reads to lay out a port and its vehicles. The format belongs to the engine (00-02); the numbers belong to this file. Pad sizes and the town distance belong to 03-02. Each entry names the assumption it comes from.", "pad_spacing_km": { "value": [ 1, 2 ], "from": "V-06", "path": "numbers.pad_spacing_km" }, "stone_zone_km": { "value": 1, "from": "V-06", "path": "numbers.stone_zone_km" }, "yard_gap_km": { "value": [ 1, 2 ], "from": "V-06", "path": "numbers.yard_gap_km" }, "yard_ship_spacing_m": { "value": 50, "from": "V-04", "path": "numbers.yard_ship_spacing_m" }, "road_width_m": { "value": 12, "from": "V-11", "path": "numbers.road_width_m" }, "road_speed_kmh": { "value": 15, "from": "V-09", "path": "numbers.road_speed_kmh" }, "open_rover_radius_km": { "value": 10, "from": "V-09", "note": "Half of DRA 5.0's walking range (numbers.dra5.walk_km); the template checks they agree." }, "pressurised_rover_radius_km": { "value": 50, "from": "V-09", "note": "Half of DRA 5.0's range before resupply (numbers.dra5.range_km); the template checks they agree." }, "ship_mover_speed_kmh": { "value": 1.6, "from": "V-05", "note": "The crawler's loaded speed (numbers.crawler.mph[0]) in km/h, rounded; the template checks they agree." } }, "links": { "leans_on": [ { "ref": "01-01 E-09", "why": "About 100 t landed per cargo ship, to unload (read live)" }, { "ref": "01-01 E-12", "why": "Ships, people and returning ships per era, for the port by era and the yard (read live)" }, { "ref": "01-01 E-06", "why": "Reuse everything: ships that stay are stripped" }, { "ref": "01-01 E-10", "why": "Robots First land before any crew" }, { "ref": "01-01 F-23", "why": "SpaceX's plan to send Optimus robots on the first Mars ships" }, { "ref": "01-01 F-15", "why": "The 26-month launch window, for windows per era (read live)" }, { "ref": "01-01", "why": "Starship height and the Eiffel Tower yardstick (read live)" }, { "ref": "00-01", "why": "Era names (read live)" }, { "ref": "02-01 F-01", "why": "Mars and Earth gravity, for crane loads and weights (read live)" }, { "ref": "02-01 F-39", "why": "The 3 to 22 minute signal delay, for remote driving (read live)" }, { "ref": "02-01 S-13", "why": "Dust clings to vehicles and works into seals" }, { "ref": "02-01", "why": "Mars radius, person height, walking pace and how far a voice carries (read live)" }, { "ref": "02-02 W-03", "why": "Days of storm warning to bring vehicles in" }, { "ref": "02-03 R-02", "why": "The city pin at AP-1 and nearby sites, for range rings (read live)" }, { "ref": "03-02 P-01", "why": "The nearest pad 3 to 5 km from the habitat, and its graded road (read live)" }, { "ref": "03-02 P-02", "why": "Pads per era and the pad turnaround (read live)" }, { "ref": "03-02 P-06", "why": "The first ship's site, stripped for parts" }, { "ref": "03-02 P-07", "why": "Version 2 empty mass, for the ship mover and the yard's steel (read live)" }, { "ref": "03-02 F-05", "why": "Apollo 12 and Surveyor 3 at 155 m, and how fast the grains hit it (read live)" }, { "ref": "03-02 F-14", "why": "The first ship lands on natural ground" }, { "ref": "03-03 G-01", "why": "The power plan: the grid that charges battery vehicles, the reactor unit size, and where the two reactor fields sit (G-03, F-24) (read live)" }, { "ref": "03-04 C-07", "why": "Propellant reaches the pads by pipeline, and the plant's distance from the pads (read live)" }, { "ref": "02-05 SU-06", "why": "The dust-carrying wind at the pin, which settles which way the port lies from the town (03-02 P-01 uses it; 04-01-01 FC-01 sets the bearing)" }, { "ref": "03-11 CM-05, CM-08", "why": "How roads are made (CM-08), cited in V-11, and the construction diggers beside the port fleet (CM-05), cited in V-08" }, { "ref": "03-12 MF-03", "why": "Remelting stripped hulls into steel, which took over the open question on hull steel" }, { "ref": "02-07 SK-01", "why": "The sky colours, for the opening scene's sky (read live)" } ], "used_by": [ { "ref": "05-20", "why": "Mars games: Opportunity's marathon, for Mars Quiz questions (worked_out)" }, { "ref": "03-02", "why": "Where landed ships stand (V-04) and pad-to-pad spacing (V-06)" }, { "ref": "04-01-01 The first city", "why": "Reads V-06 live: pad spacing, yard gap, yard ship spacing, road speed; places the landing field, the ship yard and the mover's park (FC-10)" }, { "ref": "00-02 The engine", "why": "Lays out the port and vehicles from the world spec" }, { "ref": "03-03 Power", "why": "Reads V-06: landing jets throw stones about 2 km, so the plant reactor field keeps at least 2 km from the pads (G-03)" }, { "ref": "03-04 Fuel plant", "why": "Reads V-06 and F-10: the plant and tank farm sit at least 2 km beyond the pads, clear of thrown stones (C-07)" }, { "ref": "03-07 Airlocks, suitports and dust", "why": "Reads F-16 (suitports on NASA's rover prototype, about 10 minutes to get out) and V-08 (pressurised rovers per era, for docking ports) live. Cites F-20 and V-12 (vehicle bays that double as dust locks)" }, { "ref": "03-08 Spacesuits", "why": "Reads F-17: walking range on one backpack charge (read live). Cites F-16 and V-09 (how far people go on foot or in an open rover)" }, { "ref": "03-11 Construction and materials", "why": "Reads V-11 (road width) and V-03 (hauler loads) live. Cites V-10 (robots driven from inside the town). Builds the roads (CM-08); its diggers sit beside the port fleet (CM-05)" }, { "ref": "03-12 Manufacturing", "why": "Cites V-07 and V-15: ships that never fly again are stripped for spares and steel, near the ship yard (MF-03)" }, { "ref": "03-13 Local communications", "why": "Reads V-10: robots driven live from the town with a short delay (read live); cites V-06 (the antenna field keeps away from the port) and V-09 (crewed rovers in pairs)" }, { "ref": "03-14 Medical bay", "why": "Reads V-09: road speed, for ambulance times (read live)" }, { "ref": "03-15 Waste and recycling", "why": "Cites V-07: ships that never fly again are stripped for metal" }, { "ref": "04-01-02 The lava-tube outpost", "why": "Reads V-09 and F-18: rover ranges and Mars Direct's rover pace, against the Starship hop (read live)" }, { "ref": "04-04-01 Jobs", "why": "Drivers, crane operators and ship strippers; F-24, Lunokhod's crew; V-10, robots tasked from Earth" }, { "ref": "04-04-02 A day in the life", "why": "V-09: road speed, for drive times (read live)" }, { "ref": "04-04-03 Safety and emergencies", "why": "V-06: the stone zone round a landing (read live); V-09: road speed and how far crews may drive (read live)" }, { "ref": "04-05-02 Arrival day", "why": "V-03: sols before a ship is safe, and the ship's height (read live); V-09: road speed (read live); V-11 the graded road, V-14 nobody near until safe" }, { "ref": "05-04 Missions", "why": "Road speed, the open-rover limit and pairs (V-09), robots worked once a sol (V-10), Spirit and Apollo 17's fender (F-19, F-22, F-25, read live)" }, { "ref": "05-06 Free roam", "why": "Road speed and how far rovers go (V-09), the stone-throwing zone at landings (V-06), the Apollo rover (F-13), Perseverance's driving (F-25) and the Apollo heritage distance (F-09) (read live)" }, { "ref": "05-08 The journey experience", "why": "Sols before a landed ship is safe (V-03, V-14), for the hand-off (read live)" }, { "ref": "05-12", "why": "City experience reads this source live through the generated library bundle." }, { "ref": "05-17", "why": "Living on Mars's list of the twenty parts a city needs (ships, the port and vehicles), and its racing buggies, which run on methane and oxygen like V-09's rovers" }, { "ref": "05-19", "why": "Playable Arcadia: road width and speed, and the rovers' sizes (V-09, V-11)" } ] }, "open_questions": [ "SpaceX has not shown how a Mars Starship unloads. Replace V-02 and V-03 when it does.", "No study yet gives plume debris distances for a Starship-sized landing on Mars. Replace V-06's 1 to 2 km when one does.", "The ship mover (V-05) needs a design and a landed mass. Neither 03-11 (construction machines, CM-05) nor 03-12 (manufacturing) takes it on, so it stays with this file until SpaceX or NASA shows how landed ships are moved.", "Battery or methane-and-oxygen for long-range rovers (V-12): revisit once 03-03's storage plan and 03-04's spare output are settled.", "A rover trip and the salvage job as later missions for 05-04 Missions: not yet written there (arrival day is 04-05-02).", "04-05-02 AR-03 proposes an airtight lift cab that mates with a crew ship's hatch, rides down its side and docks nose to nose with a pressurised rover, so newcomers from the First Town on never suit up on arrival day. Not decided: its size, mass and when it lands would belong here, beside V-02 and V-03." ], "changes": [ "25 September 2026 (v1.0): Written. 29 sourced facts on unloading, moving and reusing ships, landing debris distances, rovers, wheels and dust, remote driving, and supply convoys; 15 assumptions (V-01 to V-15); a world spec for the engine; the port drawn by era from 01-01's era plan and 03-02's pads.", "25 September 2026 (v1.0): Answers two open questions from 03-02: where landed ships stand (V-01, V-04, V-05) and pad-to-pad spacing (V-06). Cargo cranes and rovers, also asked for in 03-02, are V-02 and V-08.", "25 September 2026 (v1.1): review fixes. F-22: Spirit's last 10 backward drives (not 13) moved it 13 inches. F-04: the test-bed crane weighed about 309 kg; under 3% is NASA's estimate for a composite flight version; under 5 minutes each was for unloading; shoulder height now a number (3.8 m). F-02 uses NASA's own 15-storey comparison. F-07: only launch-mount parts and hardware are cited as riding SPMTs. F-08: the wet workshop never flew; source name corrected. F-10 now says it quotes Wittal and others (2020) and drops its grit speed, which 03-02 F-05 owns (F-09 quotes it). F-13: the cost is for the programme of four rovers. F-15, F-26, F-29 comparisons reworded.", "25 September 2026 (v1.1): one site plan with 03-02, 03-03 and 03-04: nearest pad 3 to 5 km from town, further pads in an arc, yard or landing field to one side, fuel plant and tank farm beyond the pads at 03-04's distance (read live), plant reactors beside the plant, town reactors on the far side of town. The port drawing is redrawn for every era; the Robots and cargo era has no town. V-04: staying ships go to the yard once safe and are unloaded there, freeing the pad; returning ships wait for the return window, not for fuel. V-05, V-06, V-07, V-09, V-10, V-12, V-14 reworded. V-13 is now a pointer to 03-04 C-07; tanker sizes and transfer notes removed.", "25 September 2026 (v1.2): used_by lists 03-03 and 03-04, which now read V-06 and F-10 for their distances from the pads.", "26 September 2026 (v1.3): The open question on which way the port lies now points to 02-05 SU-06 (the dust-carrying wind at the pin), which 03-02 P-01 uses to put the port downwind of the town; the exact bearing and road routes stay with 04.01 Cities. 02-05 added to leans_on. This page shows no horizon or visibility figure, so nothing is read from 02-05 SU-09.", "26 September 2026 (v1.4): V-11 cites 03-11 CM-08 for how roads are built; V-08 notes construction diggers are 03-11 CM-05. The open question on how much of a stripped hull is reusable steel moved to 03-12, which plans remelting (MF-03) and now holds the question. The ship-mover question stays here: neither 03-11 nor 03-12 takes it on. leans_on adds 03-11 and 03-12; used_by adds 03-07, 03-08, 03-11 and 03-12.", "26 September 2026 (v1.5): Answered by 04-01-01 The first city. Deleted the open question on which way the port lies: FC-01 and FC-02 put it south-east of the pin, bearing 135°. The ship-mover question keeps only the design and mass: where the mover runs and parks is FC-10. V-06 says the pads stand on an arc round the tank farm (FC-02); V-07 notes the first ship's site is now 04-01-01 FC-10. numbers.town_delay_s notes that 03-13 LC-12 uses it. The port layout (5.x) now matches the master map: pads on a 3 km arc round the tanks, built in the master map's order, and the town field's first unit shown in the Robots and cargo era; its caption no longer says the direction waits for 04.01. used_by: 04.01 Cities becomes 04-01-01; adds 03-13, 03-14, 03-15 and 04-01-02. The leans_on line for 02-05 SU-06 no longer mentions the deleted open question.", "26 September 2026 (v1.6): The old 04.04 placeholder is now 04-04-01 Jobs (used_by and the open question).", "26 September 2026 (v1.7): Open questions: the jobs pointer trimmed (answered by 04-04-01); new question on 04-05-02 AR-03's proposed airtight lift cab (not decided). The 05 Visiting Mars used_by line names 04-05-02 for arrival day. used_by: back-links for 04-04-01, 04-04-02, 04-04-03, 04-05-02 (what each reads, from its leans_on). Also back-links for 05-04, 05-06, 05-08 (wave 6 pages, from their leans_on as written today).", "26 September 2026 (v1.8): V-08 and V-09 reconciled: pairs beyond walking range of home; within it an open rover may go alone with two people aboard. New number: the stone zone round a landing (V-06, also in the world spec), which 04-04-03 reads and 05-06 can read; the least pad gap must equal it (checked when the page is built).", "26 September 2026 (v1.9): F-20 has a comparison line; the shelf life names a re-check date (March 2027), as the Research log (90-04) audit asked.", "26 September 2026 (v1.10): Beauty pass: an opening scene at the top of At a glance: unloading day at the port at dusk, to scale; the links list no longer overflows on phones. No fact or number changed.", "26 September 2026 (v1.11): Final fix round: V-14: moves_to cleared; the rest of arrival day now lives in 04-05-02 Arrival day, which cites V-14 for its vehicles. used_by: the folder-level '05 Visiting Mars' line removed; the 05 pages that really read this file are listed one by one; the open question on 05 now points to 05-04 Missions as a later mission. The opening scene's sky colours are now read live from 02-07 SK-01 instead of typed; leans_on and quotes add 02-07", "30 September 2026 (v1.12): Added the city experience to the files that read this source.", "3 October 2026 (v1.13): Era names follow the owner's new names (00-01): Mars Today, Robots First, First Town, Many Cities; First Human Landing and The First Martian City, Arcadia, where an era is named as such.", "4 October 2026 (v1.14): Used by 05-17 Living on Mars, the home page's cards on how each part of a Mars city works in each era.", "4 October 2026 (v1.15): 05-17 Living on Mars now shows six cards; this part stays in its list of the twenty parts a city needs, so the link's reason is updated.", "4 October 2026 (v1.16): 05-17 Living on Mars's dune buggy racing (LV-07) follows V-09's methane and oxygen rovers; the link's reason says so.", "9 October 2026 (v1.17): 05-19 (Playable Arcadia) now quotes this file: roads and rovers; used_by updated.", "10 October 2026 (v1.18): Added V-16 and numbers.rover_designs: the three rover designs (Trail rover, Long-range rover, Hauler) with sizes, wheels and look, so every scene draws them the same (owner).", "10 October 2026 (v1.19): rover_designs sizes now match the 3D models (owner: keep the design and the picture the same): Trail rover 3.6 m wide over its wheels and 2.3 m to the top of its dish mast, Long-range rover 3.2 by 2.9 m, Hauler 4.3 by 3.9 m.", "10 October 2026 (v1.20): The port's look book (numbers.look, V-17): the control tower and the cargo yard (00-05 ST-20).", "10 October 2026 (v1.21): The look book now covers the landed ship, the crew lift, the folding crane, the hauler, the rovers, the roads and the charging bays, with Unloading day and The road home shots (numbers.look, V-17); worked_out reads the ship's height, width, storeys and cargo from 01-01; F-30 (Apollo 15's rover) and F-31 (Skylab) added, for the explainer's ships and rovers stops (05-17).", "23 October 2026 (v1.22): A landing as an event (V-18), with five new facts: Spirit's meteor (F-32), the spreading plume in thin air (F-33), Starship's frost on fuelling (F-34), Phoenix's telltale (F-35) and astronauts' balance after a long flight (F-36)." ], "sources": { "spacex_ug_2020": { "name": "SpaceX, Starship Users Guide, Revision 1.0, March 2020", "url": "https://www.spacex.com/media/starship_users_guide_v1.pdf" }, "nasa_elevator_2023": { "name": "NASA, NASA astronauts test SpaceX elevator concept for Artemis lunar lander, 21 December 2023", "url": "https://www.nasa.gov/image-article/nasa-astronauts-test-spacex-elevator-concept-for-artemis-lunar-lander" }, "nasa_hls_2024": { "name": "NASA, NASA, SpaceX illustrate key moments of Artemis lunar lander mission, 20 November 2024", "url": "https://www.nasa.gov/humans-in-space/nasa-spacex-illustrate-key-moments-of-artemis-lunar-lander-mission/" }, "nasa_cargo_2024": { "name": "NASA, NASA plans to assign missions for two future Artemis cargo landers, 19 November 2024", "url": "https://www.nasa.gov/news-release/nasa-plans-to-assign-missions-for-two-future-artemis-cargo-landers/" }, "doggett_2008": { "name": "Doggett, King, Jones, Dorsey and Mikulas (NASA Langley), Design and field test of a mass-efficient crane for lunar payload handling (the Lunar Surface Manipulation System), 2008", "url": "https://ntrs.nasa.gov/api/citations/20080040185/downloads/20080040185.pdf" }, "jefferies_2010": { "name": "Jefferies, Doggett and others (NASA Langley), Lunar lander offloading operations using a heavy-lift Lunar Surface Manipulation System, 2010", "url": "https://ntrs.nasa.gov/api/citations/20100033143/downloads/20100033143.pdf" }, "nssdc_moon": { "name": "NASA NSSDC, Moon Fact Sheet (surface gravity), accessed September 2026", "url": "https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html" }, "nssdc_lrv": { "name": "NASA NSSDC, The Apollo Lunar Roving Vehicle, accessed September 2026", "url": "https://nssdc.gsfc.nasa.gov/planetary/lunar/apollo_lrv.html" }, "nasa_rover_brief_2023": { "name": "NASA Office of the Chief Health and Medical Officer, NASA-STD-3001 Technical Brief: Extraterrestrial Surface Transport Vehicles (Rovers), Rev A, 2023", "url": "https://www.nasa.gov/wp-content/uploads/2023/12/ochmo-tb-023-extraterrestrial-surface-transport-vehicles-rovers.pdf" }, "nasa_crawler": { "name": "NASA Kennedy Space Center, Crawler-Transporters fact sheet, 2021", "url": "https://www.nasa.gov/wp-content/uploads/2021/04/combined_crawler-transporters_fact_sheet_final.pdf" }, "nsf_2024": { "name": "NASASpaceFlight.com, Starship preparations as rollouts begin ahead of full stack testing, November 2024", "url": "https://www.nasaspaceflight.com/2024/11/starship-roundup-11-11-24/" }, "nasa_skylab_hist": { "name": "Elder, chapter 9 in Mack (ed.), From Engineering Science to Big Science, NASA SP-4219, 1998", "url": "https://www.nasa.gov/history/SP-4219/Chapter9.html" }, "nasa_heritage_2011": { "name": "NASA, Recommendations to space-faring entities: how to protect and preserve the historic and scientific value of U.S. government lunar artifacts, 20 July 2011", "url": "https://www.nasa.gov/wp-content/uploads/2017/10/617743main_nasa-usg_lunar_historic_sites_reva-508.pdf" }, "nasa_otps_2022": { "name": "NASA Office of Technology, Policy and Strategy, Lunar Landing and Operations Policy Analysis, 2022", "url": "https://www.nasa.gov/wp-content/uploads/2023/05/nasa-otps-lunar-landing-and-operations-policy-analysis-final-report-2.pdf" }, "metzger_2019": { "name": "Metzger and others, Lander plume effects at an outpost on the Moon, NASA SSERVI Exploration Science Forum, 2019", "url": "https://www.lpi.usra.edu/exploration/publications/MetzgerEtAl_SSERVI%20ESF2019_LanderPlumeEjecta.pdf" }, "moonport": { "name": "Benson and Faherty, Moonport: A History of Apollo Launch Facilities and Operations, NASA SP-4204, 1978, chapter 4", "url": "https://www.american-spacecraft.org/documents/sp-4204/chapter-4.html" }, "nasa_ltv_2026": { "name": "NASA, NASA provides update on Moon base rovers, landers, missions, 26 May 2026", "url": "https://www.nasa.gov/news-release/nasa-provides-update-on-moon-base-rovers-landers-missions/" }, "wiki_ltv": { "name": "Wikipedia, Lunar Terrain Vehicle (April 2024 feasibility awards), 2026", "url": "https://en.wikipedia.org/wiki/Lunar_Terrain_Vehicle" }, "toyota_2019": { "name": "Design World, JAXA and Toyota cooperate on a manned, pressurized Moon rover concept (Toyota and JAXA figures), March 2019", "url": "https://www.designworldonline.com/jaxa-and-toyota-cooperate-on-a-manned-pressurized-moon-rover-concept/" }, "jaxa_2024": { "name": "JAXA, NASA and Japanese Government sign the implementing arrangement concerning lunar surface exploration using the pressurized rover, April 2024", "url": "https://www.exploration.jaxa.jp/e/news/detail/005552.html" }, "nasa_sev": { "name": "NASA, Multi-Mission Space Exploration Vehicle (tests from 2008), accessed September 2026", "url": "https://www.nasa.gov/exploration/technology/space_exploration_vehicle/index.html" }, "dra5_sp": { "name": "Drake (ed.), Human Exploration of Mars Design Reference Architecture 5.0, NASA SP-2009-566, 2009", "url": "https://www.nasa.gov/wp-content/uploads/2015/09/373665main_nasa-sp-2009-566.pdf" }, "zubrin_1991": { "name": "Zubrin, Baker and Gwynne, Mars Direct: a simple, robust and cost effective architecture for the Space Exploration Initiative, AIAA-91-0328, 1991", "url": "https://marspapers.org/paper/Zubrin_1991.pdf" }, "gaier_2005": { "name": "Gaier (NASA Glenn), The effects of lunar dust on EVA systems during the Apollo missions, NASA TM-2005-213610, 2005", "url": "https://ntrs.nasa.gov/citations/20050160460" }, "planetary_wheels_2014": { "name": "Lakdawalla, Curiosity wheel damage: the problem and solutions, The Planetary Society, 2014", "url": "https://www.planetary.org/articles/08190630-curiosity-wheel-damage" }, "jpl_spirit_2010": { "name": "NASA JPL, NASA trapped Mars rover finds evidence of subsurface water, 2010", "url": "https://www.jpl.nasa.gov/news/nasa-trapped-mars-rover-finds-evidence-of-subsurface-water/" }, "nasa_opp_2015": { "name": "NASA, NASA's Opportunity Mars rover finishes marathon, clocks in at just over 11 years, 2015", "url": "https://www.nasa.gov/news-release/nasas-opportunity-mars-rover-finishes-marathon-clocks-in-at-just-over-11-years" }, "jpl_opp_2014": { "name": "NASA JPL, NASA long-lived Mars Opportunity rover sets off-world driving record, 2014", "url": "https://www.jpl.nasa.gov/news/nasa-long-lived-mars-opportunity-rover-sets-off-world-driving-record/" }, "robinson_2014": { "name": "Robinson, Trundling across the Moon, The Planetary Society, 2014", "url": "https://www.planetary.org/articles/0527-trundling-across-the-moon" }, "jpl_autonav_2021": { "name": "NASA JPL, NASA's self-driving Perseverance Mars rover 'takes the wheel', 2021", "url": "https://www.jpl.nasa.gov/news/nasas-self-driving-perseverance-mars-rover-takes-the-wheel/" }, "verma_2023": { "name": "Verma and others (JPL), Science Robotics, 2023, as reported by SciTechDaily, 2023", "url": "https://scitechdaily.com/autonavs-triumph-on-mars-perseverance-rovers-record-speed-on-the-martian-terrain/" }, "dlr_2019": { "name": "DLR, An astronaut controls a rover on Earth (ESA Analog-1), 25 November 2019", "url": "https://www.dlr.de/en/latest/news/2019/04/20191125_astronaut-controls-rover-on-earth" }, "wiki_optimus": { "name": "Wikipedia, Optimus (robot): Tesla AI Day 2021 figures, 2026", "url": "https://en.wikipedia.org/wiki/Optimus_(robot)" }, "space_2025": { "name": "Space.com, Elon Musk says SpaceX will launch its biggest Starship yet by year's end, but Mars in 2026 is '50/50', 30 May 2025", "url": "https://www.space.com/space-exploration/private-spaceflight/elon-musk-says-spacex-will-launch-its-biggest-starship-yet-this-year-but-mars-in-2026-is-50-50" }, "spot": { "name": "South Pole ASMA Management Group, Station logistics (South Pole Traverse), accessed September 2026", "url": "https://www.southpole.aq/activities/station-logistics.html" }, "wiki_container": { "name": "Wikipedia, Intermodal container (ISO 668 sizes), 2026", "url": "https://en.wikipedia.org/wiki/Intermodal_container" }, "wiki_iso7810": { "name": "Wikipedia, ISO/IEC 7810 (card thickness), 2026", "url": "https://en.wikipedia.org/wiki/ISO/IEC_7810" }, "wiki_apollo15": { "name": "Wikipedia, Apollo 15, 2026", "url": "https://en.wikipedia.org/wiki/Apollo_15" }, "commons_a15_lrv": { "name": "Wikimedia Commons, Apollo 15 Lunar Rover and Irwin.jpg (NASA/David Scott, 31 July 1971, public domain)", "url": "https://commons.wikimedia.org/wiki/File:Apollo_15_Lunar_Rover_and_Irwin.jpg" }, "wiki_skylab": { "name": "Wikipedia, Skylab, 2026", "url": "https://en.wikipedia.org/wiki/Skylab" }, "astronomy_meteors_2020": { "name": "Astronomy, Is it possible to see meteors on Mars?, April 2020", "url": "https://astronomy.com/science/is-it-possible-to-see-meteors-on-mars" }, "aerospaceweb_nozzle": { "name": "Aerospaceweb, Nozzle overexpansion and underexpansion", "url": "https://aerospaceweb.org/question/propulsion/q0220.shtml" }, "space_starship_wdr_2023": { "name": "Space.com, SpaceX's 1st orbital Starship looks supercool in these fueling test photos, 24 January 2023", "url": "https://www.space.com/spacex-first-orbital-starship-fueling-test-photos" }, "ut_telltale_2009": { "name": "Universe Today, Phoenix's telltale tells all about winds on Mars, September 2009 (results presented at EPSC 2009)", "url": "https://www.universetoday.com/articles/phoenixs-telltale-tells-all-about-winds-on-mars" }, "nasa_field_test_2015": { "name": "NASA, Walk the line: NASA studies physical performance after spaceflight, 29 September 2015", "url": "https://www.nasa.gov/humans-in-space/walk-the-line-nasa-studies-physical-performance-after-spaceflight" } }, "sources_checked": "25 September 2026", "numbers": { "bay_d_m": 8, "bay_h_m": 22, "hls_h_m": 50, "cargo_lander_t": [ 12, 15 ], "pr_rover_fy": 2032, "moon_g_ms2": 1.62, "lsms": { "tip_t": 1, "reach_m": 7.5, "mass_pct": 3, "cycle_min": 5, "heavy_t": 12, "shoulder_m": 3.8, "testbed_kg": 309 }, "crawler": { "mlb": 6.65, "carry_mlb": 18, "mph": [ 1, 2 ], "miles": 4.2, "first_year": 1965 }, "skylab": { "idea_year": 1959, "dry_date": "18 July 1969", "ft": [ 41, 22 ], "ft3": 10426, "launch": "14 May 1973", "days": 171 }, "surveyor_below_m": 4.3, "heritage_km": 2.0, "impact_site_km": 0.5, "otps": { "stone_cm": [ 1, 10 ], "stone_km": 1.5, "lander_t": 10, "hits_1km": 8, "pct_5km": 37, "pct_10km": 10 }, "metzger": { "lm_ejecta_t": 2.6, "lander_t": 40, "payload_t": 9, "ejecta_t": 470, "outpost_km": 2.2, "outpost_below_m": 290 }, "moonport_km": 5, "lrv": { "kg": 210, "payload_kg": 490, "length_m": 3.1, "height_m": 1.14, "top_kmh": 18, "a17_km": 35.9, "a17_drive_min": 266, "a17_range_km": 7.6, "cost_musd": [ 19, 38 ], "volts": 36, "amp_hours": 121, "batteries": 2 }, "ltv": { "date": "26 May 2026", "clv_lb": 2000, "clv_mph": 6, "peg_mph": 9 }, "lunar_cruiser": { "length_m": 6.0, "width_m": 5.2, "height_m": 3.8, "living_m3": 13, "crew": [ 2, 4 ], "range_km": 10000 }, "sev": { "year": 2008, "wheels": 12, "kmh": 10, "slope_deg": 40, "crew": 2, "days": 14, "suitport_min": 10, "lava_km": 140 }, "dra5": { "range_km": 100, "walk_km": 20 }, "zubrin": { "prop_t": 11, "km": 22000, "radius_km": 500, "km_per_day": 100 }, "curiosity": { "wheel_cm": 50, "skin_mm": 0.75, "hole_sol": 411, "rip_sol": 463 }, "spirit": { "drives": 10, "inches": 13, "last": "22 March 2010" }, "opportunity": { "km": 42.195, "date": "24 March 2015", "years": 11, "months": 2, "lunokhod_km": 39, "lunokhod_year": 1973 }, "perseverance": { "m_per_h": 120, "curiosity_m_per_h": 20, "sol_record_m": 347.7, "unchecked_m": 699.9 }, "analog1": { "date": "25 November 2019", "delay_s": 0.8, "max_s": 3 }, "optimus": { "height_m": 1.73, "kg": 57, "carry_kg": 20 }, "spot": { "miles": 1030, "days": 52, "climb_ft": 9300, "bladder_gal": 3000, "flights": 33 }, "unload": { "from": "V-03", "safe_sols": [ 1, 2 ], "lifts_per_sol": [ 10, 20 ], "lift_t": [ 1, 2 ], "door_m": 40, "hauler_t": [ 5, 10 ], "note": "Our guesses. door_m is roughly how far cargo is lowered: the cargo space sits in the upper part of a 52 m ship." }, "pad_spacing_km": [ 1, 2 ], "stone_zone_km": 1, "yard_gap_km": [ 1, 2 ], "yard_ship_spacing_m": 50, "road_width_m": 12, "road_speed_kmh": 15, "fleet_by_era": { "from": "V-08", "note": "Counts at the end of each era, our scaling. Each entry is [low, high].", "robots": { "open": [ 2, 4 ], "pressurised": [ 0, 0 ], "crane": [ 1, 2 ], "hauler": [ 1, 2 ], "mover": [ 0, 0 ] }, "crew": { "open": [ 2, 4 ], "pressurised": [ 0, 2 ], "crane": [ 1, 2 ], "hauler": [ 2, 3 ], "mover": [ 0, 0 ] }, "town": { "open": [ 4, 8 ], "pressurised": [ 2, 4 ], "crane": [ 2, 3 ], "hauler": [ 4, 8 ], "mover": [ 1, 1 ] }, "city": { "open": [ 20, 40 ], "pressurised": [ 6, 12 ], "crane": [ 4, 8 ], "hauler": [ 10, 20 ], "mover": [ 1, 2 ] } }, "hls_storeys": { "value": 15, "source": "nasa_hls_2024", "note": "NASA's own comparison: 'about the same height as a 15-story building'." }, "town_delay_s": { "value": [ 0.1, 0.5 ], "from": "V-10", "note": "Our guess: radio relays and computers across a few kilometres. 03-13 LC-12 uses it for driving robots live over the town's network." }, "rover_designs": { "from": "V-16", "note": "How Arcadia's three working rovers look and measure, so every picture, film and 3D scene draws the same machines. Sizes are our design and match the 3D models: width over the wheels, height to the top of the mast or roof. The pressurised rover is as long as lunar_cruiser. Speeds on roads are V-09's.", "open": { "name": "Trail rover", "role": "Two people in suits, short trips within walking range of home (V-09)", "length_m": 4.4, "width_m": 3.6, "height_m": 2.3, "wheels": 4, "wheel_d_m": 1.1, "crew": 2, "look": "Low and wide, like a desert racing buggy crossed with Apollo's rover: four open wire-mesh wheels with titanium tread strips, long-travel suspension arms, a sculpted white composite body on a brushed titanium frame, a slim roll cage, two bucket seats shaped for suit backpacks, a gold-foil dish antenna on a mast, a light bar, a rear tray with a tool rack and a spare oxygen bottle, coral accent stripes.", "wheel_note": "Wire-mesh wheels as Apollo's rover used (81.8 cm across, Wikipedia: Lunar Roving Vehicle, 2026), scaled up for a heavier rover on Mars.", "model": "play/models/rover-trail.glb" }, "pressurised": { "name": "Long-range rover", "role": "Up to four people in shirt-sleeves for days at a time, always in pairs (V-08, V-09)", "size": "numbers.lunar_cruiser", "length_note": "As long as the Lunar Cruiser; narrower and lower than it, our design.", "width_m": 3.2, "height_m": 2.9, "wheels": 6, "wheel_d_m": 1.4, "crew": 4, "look": "A smooth rounded white cabin with a big wraparound tinted windscreen, six large tread wheels on independent suspension, a solar array on the roof, two round suitports on the side, slim light bars, small radiator fins, a brushed titanium chassis and a coral band down each side.", "model": "play/models/rover-cruiser.glb" }, "hauler": { "name": "Hauler", "role": "Carries one standard container between the port, the yards and the town", "length_m": 10, "width_m": 4.3, "height_m": 3.9, "wheels": 8, "wheel_d_m": 1.4, "crew": "driven from the town, a pod for one aboard", "look": "A compact rounded white driver pod with tinted windows at the front of a long titanium-grey deck on eight tread wheels, one weathered container strapped on, light bars and coral accent stripes.", "model": "play/models/rover-hauler.glb" } }, "look": { "from": "V-17", "about": "How the port's ships, lift, crane, haulers, control tower, yard, rovers and roads look (00-05 ST-20). The tower is our design: no file sizes it. Rover sizes are rover_designs; the ship is 01-01's, drawn as the rocket pages draw it. First Landing's own look is 04-01-01's.", "parts": { "tower": { "name": "The control tower", "look": "A slim printed tower about 20 m tall between the town and the pads, its shaft printed from soil with fine layer lines and a stair core, topped by a wide glass cab that leans outward towards the pads, a white roof ring, antenna masts, a radar dish and a red beacon. Inside the cab warm screens glow. A low printed building at its foot houses the crew who run the pads." }, "yard": { "name": "The cargo yard", "look": "Stacked cargo containers in several colours under a yellow gantry crane, a cargo rover waiting." }, "ship": { "name": "A landed ship", "look": "Starship as the rocket pages draw it (rockets/ar/starship.glb, 05-19 PA-18): the upper stage alone, about 52 m tall and 9 m wide, brushed stainless steel with black hexagonal heat-shield tiles down its windward side, two small forward flaps near the nose and two larger aft flaps, standing on six short landing legs splayed from the skirt, each with a wide round footpad; six engines in its base (three small sea-level engines in the middle, three wide-bell vacuum engines round them). The cargo door is a clamshell high on the hull, near the top of the steel body." }, "lift": { "name": "The crew lift", "look": "An open white basket with a waist-high rail and a coral stripe, riding twin cables from a small boom beside the cargo door down the ship's flank to the gravel apron (F-02, V-02)." }, "crane": { "name": "The folding crane", "look": "A slim white jointed arm of the Langley type (F-04) folded out at the cargo door, lowering a big white crate on cables; later a heavier crane on tracks on the apron (V-02)." }, "hauler": { "name": "The hauler", "look": "rover_designs.hauler: a rounded white driver pod at the front of a long titanium-grey deck on eight tread wheels, one weathered container strapped on, about 10 m long." }, "rovers": { "name": "The rovers", "look": "rover_designs: the low two-seat Trail rover with wire-mesh wheels and a gold dish antenna, the smooth white Long-range rover with its wraparound windscreen and suitports, and the Hauler. White composite, brushed titanium, coral stripes, dust thickest low down." }, "roads": { "name": "The roads", "look": "Graded, rolled gravel about 12 m wide (V-11), a shade paler than the plain, with twin wheel ruts, lit marker posts every few hundred metres and the buried power line's small yellow markers beside it." }, "bays": { "name": "The charging bays", "look": "Low printed sheds of rust-coloured soil with round roll-up doors, a coral stripe and a lit sign, where rovers charge out of the dust (V-12)." } }, "palette": { "shaft": "#B98F72", "cab_glass": "#2A333C", "roof": "#F2F0EC", "beacon": "#FF4B3A", "crane": "#E8B23A", "steel": "#C9CCD0", "tile": "#1E1E22", "rover_white": "#F4F2EE", "coral": "#E0825E" }, "weathering": "Everything outside wears the plain: red dust banked against its foot and settled on every upward face, paler wind streaks running down from edges and bolt heads, thin dark panel seams, and scuffs where boots, hands and wheels touch. Dust is finer and lighter on what is cleaned often (hatches, grilles), heavy on what is not (radiators' feet, tank legs).", "light": "By day the cab mirrors the sky; at dusk and night it glows warm from inside and the beacon blinks.", "never": [ "An airport tower from Earth with flags and windsocks", "Anyone outside without a suit, or working outside alone (03-08 SS-05)", "A blue daytime sky, snow, rain or puddles", "Brass, copper or old-fashioned gauges and lamps", "Clean, showroom-new surfaces outside: everything outside wears dust", "A ship with four legs, or with fins like an old rocket", "Rovers with car doors, rubber tyres or headlights like a road car", "A paved tarmac road with painted lines", "Anyone climbing a ship's side, or walking under a load on the crane" ], "shots": [ { "id": "watch", "name": "The ship comes in", "frame": "From the tower's foot looking up past the lit cab to a ship descending on its flame towards the pad." }, { "id": "unloading", "name": "Unloading day", "frame": "Low and three-quarter on at golden hour, a ship tall on its pad, the crew lift halfway down its flank with two people in it, the folding crane at the cargo door lowering a white crate, a hauler waiting on the apron with its container, two crew guiding it, the tower small behind." }, { "id": "road", "name": "The road home", "frame": "Low beside a graded road at golden hour, the three rovers in a line towards the camera (Trail rover leading, Long-range rover, Hauler with its container), dust trailing, marker posts leading back to the town's domes and a ship on its pad on the horizon." } ], "open": [], "eras": { "city": "A working port: a ship on its pad with the lift down and the crane lowering crates, haulers queueing on the road, rovers in pairs, First Landing visible to the south (04-01-01 FC-10).", "far": "A busy port: ships landing and lifting off every window, a ship yard of stripped hulls in neat rows (V-07), long-range rovers on roads that run to the horizon." } }, "apollo15": { "date": "31 July 1971", "km": 27.9 } }, "worked_out": { "ship_h": "01-01:rockets#starship.upper_stage_height_m", "ship_w": "01-01:rockets#starship.width_m", "ship_storeys": { "ratio": [ "01-01:rockets#starship.upper_stage_height_m", "01-01:comparisons.storey_m" ], "dp": 0 }, "cargo_t": "01-01:rockets#starship.payload_mars_t" } } }, "calendar": { "first_crew_year": 2036, "era_years": { "robots": [ 2032, 2036 ], "crew": [ 2036, 2038 ], "town": [ 2038, 2056 ], "city": [ 2056, 2066 ], "cities": [ 2066, 2096 ] } }, "worked_out": { "grav_pct": "38", "sol_hm": "24 h 40 min", "drift_min": "40", "mars_year": "687", "year_months": "23", "mars_tilt": "25", "earth_tilt": "23", "air_pct": "0.6", "phoenix_snow": "4", "phobos_km": "26", "deimos_km": "12.5", "phobos_fall": "2", "break_lo": "30", "break_hi": "50", "sun_pct": "43", "earth_photo": "160", "oly_ev": "2.4", "oly_scarp": "8", "valles_km": "3,870", "carry_m": "8", "carry_e": "65", "snd_hi": "250", "snd_lo": "240", "snd_e": "343", "conscious": "14", "co2": "95.1", "o2": "0.16", "dd_km": "20", "dd_w": "70", "dd_ev": "2.3", "sparks": "55", "dry_ice": "-125", "atm_swing": "30", "feet_c": "24", "head_c": "0", "lt_min": "3", "lt_max": "22", "mean_c": "-59", "mars_80kg": "30", "sol_h": "24.66", "mars_bdays": "21", "earth_year": "365", "earth_pa": "101,325", "mars_pa": "636", "earth_o2": "20.95", "everest_km": "8.849", "moon_km": "3,474.8", "moon_phobos": "134", "sun_w": "66", "oly_km": "21.3", "ldn_ny": "5,570", "hellas_km": "7.2", "earth_water": "70.8", "xrays": "6", "global_every": "3", "ss_h": "124", "window_mo": "26", "trip_mo": "7", "m4_h": "10", "perse_min": "11", "opp_x": "60", "cover_m": "3", "q_0202_sparks_0": "55", "q_0207_phobos_eclipse_s": "40", "q_0203_earth_tube_m_1": "30", "q_0203_mars_tube_m_1": "450", "q_0204_canyon_noctis_km": "1,263", "q_0204_canyon_ophir_km": "317", "q_0203_numbers_ce_width_m": "150", "q_0209_eridania_area_million_km2": "1.1", "q_0209_eridania_age_bn": "3.7", "q_0305_opportunity_km": "42.195", "q_0102_perse_entry_kmh": "19,500", "q_0102_perse_peak_c": "1,300", "q_0102_perse_rover_kg": "1,025", "q_0103_y2017_selected": "12", "q_0103_days_mars500": "520", "q_0103_mars500_control_conflicts": "41", "q_0102_body_taller_m": "1.8", "q_0206_numbers_esa_hip_pct_month": "1.5", "q_0206_numbers_moonwalkers": "12", "q_0102_mind_flash_min": "2.9", "q_0203_numbers_moxie_g": "122", "q_0203_numbers_moxie_runs": "16", "q_0102_mind_polyakov_days": "437", "q_0207_clouds_amec_km": "1,800", "q_0207_clouds_amec_kmh": "600", "q_0203_earth_tube_m_0": "10", "q_0203_npld_global_m": "1.5", "q_0305_opportunity_years": "11", "q_0206_phoenix_weeks": "11", "ff_taller_cm": "5", "ff_twilight_h": "2", "ff_jump_x": "2.6", "ff_cloud_km": "60", "ff_dich_lo": "1", "ff_dich_hi": "3", "qz_tower_m": "96" }, "worked_quoted": { "02-04": { "ocean_m": "3,760", "shore_spread": "560", "ocean_age": "3.6", "area_pct": "18", "depth_m": "580", "vol_mkm3": "15", "head_vol": "14", "earth_ocean_km": "3.68", "ocean_depth_km": "0.58", "hellas_km": "5.8", "ap1_sea_m": "140", "dry_by": "3.2", "jz_age": "3.6", "noc_km": "1,263", "ius_km": "938", "melas_km": "547", "candor_km": "773", "ophir_km": "317", "slide_ms": "100", "slide_run_km": "120", "slide_kmh": "360", "ldn_mad": "1,260", "ldn_ber": "930", "ldn_edi": "530", "ldn_par": "340", "st_hel_rock": "370", "st_hel_age": "4", "st_hel_par_x": "1.1", "st_uto": "3,300", "st_uto_x": "1.4", "st_arg_rock": "200", "st_arg_age": "3.9", "st_arg_w": "1,800", "st_oly_hz": "3", "st_oly_air": "11", "st_stripe": "1,930", "st_stripe_x": "1.3", "st_air_swing": "30" }, "02-09": { "spot_mm": "1", "deep_lo": "11.5", "deep_hi": "20", "ev_lo": "1.3", "ev_hi": "2.3", "hp_m": "90", "pitch_m": "105", "er_age": "3.7", "er_area": "1.1", "egypt": "1.01", "cell_lo": "0.5", "cell_hi": "5", "hair_um": "70", "hair_x": "140", "rf_launch": "late 2028", "rf_drill_m": "2", "tw3_launch_year": "2028", "tw3_return_year": "2031", "tw3_g": "500", "ml_lo": "1,000", "ml_hi": "10,000,000", "nili_km": "667", "oldest_life": "3.43", "ox_hi": "2.4", "ox_lo": "2.3", "animals_myr": "575", "lake_age": "3.6", "dry_by": "3.2", "wet_myr": "400", "animal_wait_bn": "2.9", "vents_a": "3.8", "vents_b": "3.6", "springs_a": "3.7", "springs_b": "3.4", "salt_a": "3.5", "stones_a": "3.3", "stones_b": "3", "deep_a": "3.7", "tubes_bn": "3.77", "lc_storeys": "18", "vent_g_bn": "10", "people_bn": "8.2", "land_bn": "3.48", "reign_bn": "3", "mud_lo": "100,000,000", "mud_hi": "1,000,000,000", "brine_m": "28", "salt_litre_bn": "28", "salt_x": "3.4", "salt_myr": "250", "mine_km": "2.8", "under_pct": "70", "dc_lo": "245", "dc_hi": "385", "kc_km": "3", "kc_bn": "2", "er_vol": "562,000", "er_depth_m": "510", "sapphire_date": "21 July 2024", "sapphire_cm": "6.2", "sapphire_no": "25th" }, "03-05": { "ship_h": "52", "ship_w": "9", "ship_storeys": "16", "cargo_t": "100" } }, "timeline": { "start_bn": 3.6, "ancient_ends_bn": 3.2, "eras": [ { "id": "ancient", "name": "Ancient Mars", "short": "Ancient Mars", "plain": "Mars about 3.6 billion years ago, when a northern ocean may have filled the lowlands and rivers ran into lakes such as Jezero's. Water the rocks record is Real; debated water, such as the ocean, is shown in its most stunning serious form as Our world (00 L-23).", "when": "About 3.6 billion years ago", "when_short": "3.6 bn years ago", "from": { "bn": 3.6 }, "to": { "bn": 3.2 }, "colour": "#7A6034", "colour_dark": "#D2B27A" }, { "id": "today", "name": "Mars Today", "short": "Today", "plain": "Mars as it is now. Nobody at our site; real rovers and landers work far away at their own sites (02-04).", "when": "Today", "when_short": "Today", "from": { "now": true }, "to": { "now": true }, "colour": "#5A606A", "colour_dark": "#B8BEC6" }, { "id": "robots", "name": "Robots First", "short": "Robots First", "plain": "Uncrewed ships and robots. The first ship lands on natural ground, robots build the first pad, and the reactors and fuel plant start work (01-01 E-10).", "when": "2032 to 2036", "when_short": "2032 to 2036", "from": { "year": 2032 }, "to": { "year": 2036 }, "colour": "#6F737A", "colour_dark": "#A3A8AE" }, { "id": "crew", "name": "First Human Landing", "short": "Humans Land", "plain": "The first crew lands in 2036 on the robot-built pad beside a working fuel plant, lives in the first habitat and flies home in the next return window (01-01 E-11).", "when": "2036 to 2038", "when_short": "2036 to 2038", "from": { "year": 2036 }, "to": { "year": 2038 }, "colour": "#2A5FA8", "colour_dark": "#7FA8E0" }, { "id": "town", "name": "First Town", "short": "First Town", "plain": "The first crew's base grown into a small town. Crews rotate every window and some stay for two.", "when": "2038 to 2056", "when_short": "2038 to 2056", "from": { "year": 2038 }, "to": { "year": 2056 }, "colour": "#2D7A71", "colour_dark": "#6CC3B5" }, { "id": "city", "name": "The First Martian City, Arcadia", "short": "Arcadia", "plain": "The city we show. Most people stay for good.", "when": "2056 to 2066", "when_short": "2056 to 2066", "from": { "year": 2056 }, "to": { "year": 2066 }, "colour": "#B4502B", "colour_dark": "#E88A62" }, { "id": "cities", "name": "Many Cities", "short": "Many Cities", "plain": "The City grown into a world of towns and cities, each built for its own reason. Factories learn to make what the ships used to bring (machines, medicines, power kit and, last of all, computer chips), so the list of things only Earth can send gets shorter every window (04-02-04).", "when": "2066 to 2096", "when_short": "2066 to 2096", "from": { "year": 2066 }, "to": { "year": 2096 }, "colour": "#8E3B63", "colour_dark": "#E59ABD" }, { "id": "far", "name": "Self-sustaining Mars", "short": "Self-sustaining", "plain": "Mars needs nothing from Earth. If every ship stopped coming, the cities would carry on and keep growing (04-02-04). People, ideas and trade still cross by choice. Works further ahead, such as the roofed crater city, are our best estimate, labelled as assumptions.", "when": "After 2096", "when_short": "After 2096", "from": { "year": 2096 }, "to": null, "colour": "#3E3A7A", "colour_dark": "#A7A2E8" } ] }, "places": [ { "id": "olympus", "name": "Olympus Mons", "plain_name": "Tallest mountain", "category": "mountain", "category_name": "Mountain", "label": "real", "hook": "2.4 times the height of Everest", "headline": "The tallest volcano in the Solar System", "big": "2.4×", "big_sub": "the height of Everest", "detail": "It rises 21.3 km above Mars's average ground level and is about 600 km wide, with a base about the size of Italy. The slopes are so gentle that a walker would barely notice the climb.", "earth": "Its base would cover Italy, yet its slopes are so gentle that a walker would barely notice the climb.", "story": "Stand on the summit and you can't tell you're on a mountain: the slopes roll on past a horizon just 3 km away, and the air is only 11% as thick as at Mars's average ground.", "compare": { "kind": "heights", "unit": "km", "items": [ [ "Everest", 8.849, "earth" ], [ "Olympus Mons", 21.3, "mars" ] ] }, "facts": [ "02-01 F-48", "02-04 F-08", "02-04 F-28" ], "lat": 18.65, "lon": -133.8, "label_at_is_art": false, "where": "02-04:places.list#olympus", "to_find": "", "eras": {} }, { "id": "tharsis", "name": "Tharsis", "plain_name": "Volcano country", "category": "region", "category_name": "Region", "label": "real", "hook": "About as wide as London to New York", "headline": "A bulge of giant volcanoes", "big": "5,000 km", "big_sub": "across, and up to 7 km high", "detail": "A huge volcanic rise topped by three giant volcanoes in a row, with Olympus Mons on its edge. It is about as wide as London to New York (5,570 km).", "earth": "It stretches 23% of the way round Mars: on Earth, about as far as London to New York (5,570 km).", "story": "So heavy it tipped the planet: its weight slid the whole surface of Mars round and moved the poles. On Earth, the same shift would put Paris inside the Arctic Circle.", "compare": { "kind": "lengths", "unit": "km", "items": [ [ "London to New York", 5570.254753353933, "earth" ], [ "Tharsis", 5000, "mars" ] ] }, "facts": [ "02-04 F-07", "02-04 F-29" ], "lat": 0, "lon": -100, "label_at_is_art": false, "where": "02-04:labels.list#Tharsis", "to_find": "", "eras": {} }, { "id": "ascraeus", "name": "Ascraeus Mons", "plain_name": "Tharsis volcano, north", "category": "mountain", "category_name": "Mountain", "label": "real", "hook": "One of three giant volcanoes in a row, 456 km wide", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-07" ], "lat": 11.92, "lon": -104.08, "label_at_is_art": false, "where": "02-04:places.list#ascraeus", "to_find": "", "eras": {} }, { "id": "pavonis", "name": "Pavonis Mons", "plain_name": "Tharsis volcano, middle", "category": "mountain", "category_name": "Mountain", "label": "real", "hook": "A pit about 90 m deep may be a cave skylight", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-01 F-52" ], "lat": 1.48, "lon": -112.96, "label_at_is_art": false, "where": "02-04:places.list#pavonis", "to_find": "", "eras": {} }, { "id": "arsia", "name": "Arsia Mons lava tubes", "plain_name": "Volcano with cave skylights", "category": "cave", "category_name": "Caves", "label": "real", "hook": "7 possible skylights, 100 to 250 m across", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-03 F-29" ], "lat": -8.35, "lon": -120.1, "label_at_is_art": false, "where": "02-03:sites.list#arsia", "to_find": "", "eras": {} }, { "id": "alba", "name": "Alba Mons (west flank)", "plain_name": "Lava-tube volcano", "category": "cave", "category_name": "Caves", "label": "real", "hook": "More than 300 mapped lava-tube segments", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-03 F-31" ], "lat": 41.08, "lon": -110.71, "label_at_is_art": false, "where": "02-03:sites.list#alba", "to_find": "", "eras": {} }, { "id": "elysium_mons", "name": "Elysium Mons", "plain_name": "Elysium's big volcano", "category": "mountain", "category_name": "Mountain", "label": "real", "hook": "Peak of Mars's second volcano region, 401 km wide", "headline": "The peak of Mars's second volcano region", "big": "401 km", "big_sub": "wide at its base", "detail": "", "earth": "Its base alone is about 75% of the way from London to Edinburgh.", "story": "Mars still shakes here. The long cracks beside this volcano are where NASA's InSight lander traced its first big marsquakes.", "compare": null, "facts": [ "02-04 F-04", "02-04 F-31" ], "lat": 25.02, "lon": 147.21, "label_at_is_art": false, "where": "02-04:places.list#elysium_mons", "to_find": "", "eras": {} }, { "id": "valles", "name": "Valles Marineris", "plain_name": "Grand Canyon of Mars", "category": "canyon", "category_name": "Canyon", "label": "real", "hook": "Everest would fit inside, with 450 m to spare", "headline": "The biggest canyon in the Solar System", "big": "5×", "big_sub": "as deep as the Grand Canyon", "detail": "About 3,870 km long, up to 600 km wide and up to 9.3 km deep. Laid across the USA it would stretch from California to New York, about 9 times the Grand Canyon's length.", "earth": "Laid across the USA it would reach from California to New York, 9 times the Grand Canyon's length.", "story": "No river carved it. The ground tore apart as the giant volcanoes next door swelled, the way Africa's Great Rift Valley is opening on Earth.", "compare": { "kind": "canyon", "unit": "km", "items": [ [ "Valles Marineris", 9.3, "mars" ], [ "Grand Canyon", 1.83, "earth" ], [ "Everest", 8.849, "earth" ] ] }, "facts": [ "02-01 F-51", "02-04 F-09", "02-04 F-30" ], "lat": -13.74, "lon": -59.2, "label_at_is_art": false, "where": "02-04:places.list#valles", "to_find": "", "eras": {} }, { "id": "hellas", "name": "Hellas Planitia", "plain_name": "Deepest crater", "category": "crater", "category_name": "Crater or basin", "label": "real", "hook": "7.2 km deep, the lowest ground on Mars", "headline": "The deepest basin on Mars", "big": "7.2 km", "big_sub": "below average ground level", "detail": "A crater 2,300 km across, blasted out by a giant impact: 1.6 times the distance from London to Rome. Its floor is 1.9 times as deep as Earth's oceans are on average, and the air down there is about 1.9 times as thick as the Mars average.", "earth": "About 4 times as deep as the Grand Canyon, and 1.6 times as wide as London to Rome.", "story": "A single rock 370 km wide punched this hole 4 billion years ago. The rock alone was wider than London to Paris.", "compare": { "kind": "depths", "unit": "km", "items": [ [ "Earth's oceans, average", 3.682, "earth" ], [ "Hellas floor", 7.152, "mars" ] ] }, "facts": [ "02-01 F-50", "02-03 F-36", "02-04 F-10", "02-04 F-25" ], "lat": -42.4, "lon": 70.5, "label_at_is_art": false, "where": "02-03:sites.list#hellas", "to_find": "", "eras": { "ancient": { "plain_name": "Hellas lake", "label": "world", "hook": "An ice-capped lake, 5.8 km down", "headline": "A frozen lake in the deepest crater", "big": "5.8 km", "big_sub": "below Mars's average ground level, at the water's edge", "detail": "A sheet of ice caps a lake at the bottom of the planet's deepest crater. Its shoreline is still written in the landforms around the basin today.", "facts": [ "02-04 F-15" ] } } }, { "id": "argyre", "name": "Argyre Planitia", "plain_name": "Giant impact crater", "category": "crater", "category_name": "Crater or basin", "label": "real", "hook": "Its floor alone is 893 km across", "headline": "One of the great impact basins of the south", "big": "893 km", "big_sub": "across its floor", "detail": "", "earth": "Its floor alone is 1.7 times as wide as London to Edinburgh (530 km).", "story": "A rock 200 km wide carved this basin 3.9 billion years ago. Later it filled with water, which spilled out north through a long channel.", "compare": null, "facts": [ "02-04 F-04", "02-04 F-27" ], "lat": -49.84, "lon": -43.31, "label_at_is_art": false, "where": "02-04:places.list#argyre", "to_find": "", "eras": {} }, { "id": "isidis", "name": "Isidis Planitia", "plain_name": "Impact basin by Jezero", "category": "crater", "category_name": "Crater or basin", "label": "real", "hook": "Perseverance landed on its western edge", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-05" ], "lat": 13.94, "lon": 88.38, "label_at_is_art": false, "where": "02-04:places.list#isidis", "to_find": "", "eras": {} }, { "id": "jezero", "name": "Jezero Crater", "plain_name": "Old lake bed", "category": "crater", "category_name": "Crater or basin", "label": "real", "hook": "A lake filled it 3.6 billion years ago", "headline": "An old lake bed, explored by a rover", "big": "3.6 billion", "big_sub": "years since a lake filled it", "detail": "A river once filled this 45 km crater with a lake 35 km across, 1.9 times the length of Windermere, and up to 30 m deep. NASA's Perseverance rover landed here on 18 February 2021 to search its old river delta.", "earth": "", "story": "", "compare": { "kind": "lengths", "unit": "km", "items": [ [ "Windermere", 18, "earth" ], [ "Jezero's lake", 35, "sea" ] ] }, "facts": [ "02-08 F-01", "02-08 F-02", "02-08 F-03", "02-08 F-04" ], "lat": 18.38, "lon": 77.58, "label_at_is_art": false, "where": "02-08:numbers.jezero", "to_find": "", "eras": { "ancient": { "plain_name": "Jezero lake", "hook": "A river-fed lake, 3.6 billion years ago", "headline": "A lake with a river delta", "big": "35 km", "big_sub": "across, and up to 30 m deep", "detail": "A river poured through a gap in the crater's western rim and built a delta into a lake 35 km across. The rocks Perseverance is exploring today were laid down here." } } }, { "id": "christmas_eve", "name": "2021 impact crater", "plain_name": "Crater that dug up ice", "category": "crater", "category_name": "Crater or basin", "label": "real", "hook": "A fresh 150 m crater threw out ice at about 35°N", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-03 F-07" ], "lat": 35, "lon": -170, "label_at_is_art": false, "where": "02-03:sites.markers#christmas_eve", "to_find": "", "eras": {} }, { "id": "lowlands", "name": "The northern plains", "plain_name": "Northern lowlands", "category": "region", "category_name": "Region", "label": "real", "hook": "A third of Mars, sunk up to 3 km below the rest", "headline": "Mars is split in two", "big": "1 to 3 km", "big_sub": "lower than the southern highlands", "detail": "The northern lowlands cover about a third of the planet. The step down from the south runs right round Mars and is up to 34% of Everest's height. Go back in time and this low ground fills with an ocean.", "earth": "", "story": "", "compare": { "kind": "heights", "unit": "km", "items": [ [ "Everest", 8.849, "earth" ], [ "The great step", 3, "mars" ] ] }, "facts": [ "02-04 F-06" ], "lat": 58, "lon": 150, "label_at_is_art": true, "where": "02-04:facts#F-06", "to_find": "", "eras": { "ancient": { "plain_name": "Northern ocean", "label": "world", "hook": "18% of Mars under water", "headline": "An ocean across the north", "big": "18%", "big_sub": "of Mars under water", "detail": "An ocean covers the northern plains, about 580 m deep on average, its shore wrapping right round the planet. Billions of years from now, the first city will stand on its floor.", "facts": [ "02-04 F-13", "02-04 F-14", "02-04 F-16" ], "compare": { "kind": "depths", "unit": "km", "items": [ [ "Earth's oceans, average", 3.682, "earth" ], [ "This ocean, average", 0.58, "sea" ] ] } } } }, { "id": "highlands", "name": "The southern highlands", "plain_name": "Southern highlands", "category": "region", "category_name": "Region", "label": "real", "hook": "1 to 3 km higher than the north", "headline": "The old, cratered south", "big": "1 to 3 km", "big_sub": "higher than the northern plains", "detail": "", "earth": "The step up from north to south is up to 34% of the height of Everest.", "story": "The rock here still holds a lost magnetic field, frozen in stripes up to 1,930 km long, 1.3 times London to Rome. The north has almost none.", "compare": null, "facts": [ "02-04 F-06", "02-04 F-33" ], "lat": -30, "lon": -10, "label_at_is_art": true, "where": "02-04:facts#F-06", "to_find": "", "eras": {} }, { "id": "boreum", "name": "Planum Boreum", "plain_name": "North ice cap", "category": "ice", "category_name": "Ice", "label": "real", "hook": "1.9 times London to Edinburgh across", "headline": "The north ice cap", "big": "1.6 million km³", "big_sub": "of ice, mostly water", "detail": "About 1,000 km across in summer: 1.9 times the distance from London to Edinburgh.", "earth": "About 1.9 times as wide as London to Edinburgh.", "story": "Wind spinning off the pole carves the ice into a giant swirl, and its layers stack up like tree rings: a diary of Mars's weather over millions of years.", "compare": { "kind": "lengths", "unit": "km", "items": [ [ "London to Edinburgh", 533.7028900689734, "earth" ], [ "North ice cap", 1000, "mars" ] ] }, "facts": [ "02-04 F-11", "02-04 F-34" ], "lat": 87.32, "lon": 54.96, "label_at_is_art": false, "where": "02-04:places.list#boreum", "to_find": "", "eras": {} }, { "id": "australe", "name": "Planum Australe", "plain_name": "South ice cap", "category": "ice", "category_name": "Ice", "label": "real", "hook": "Water ice under 8 m of dry ice", "headline": "The south ice cap", "big": "8 m", "big_sub": "of dry ice on top", "detail": "Water ice about 350 km across and 3 km thick, under a permanent layer of frozen carbon dioxide: the same stuff as the dry ice used for stage smoke.", "earth": "Its top layer of dry ice alone is about 2.5 storeys of a building deep.", "story": "Each winter so much air freezes onto the poles that the whole sky of Mars thins by about 30%. In spring it bursts out of this ice in geysers that scratch spiders into it.", "compare": null, "facts": [ "02-04 F-11", "02-04 F-35" ], "lat": -83.35, "lon": 157.7, "label_at_is_art": false, "where": "02-04:places.list#australe", "to_find": "", "eras": {} }, { "id": "deuteronilus", "name": "Deuteronilus Mensae", "plain_name": "Glacier country", "category": "ice", "category_name": "Ice", "label": "real", "hook": "Glaciers hidden under rock, confirmed by radar", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-03 F-03" ], "lat": 43.9, "lon": 22.6, "label_at_is_art": false, "where": "02-03:sites.list#deuteronilus", "to_find": "", "eras": {} }, { "id": "utopia", "name": "Utopia Planitia", "plain_name": "Buried ice sheet", "category": "plain", "category_name": "Plain", "label": "real", "hook": "About a Lake Superior of water, under the soil", "headline": "A hidden ice sheet", "big": "80 to 170 m", "big_sub": "thick, under 1 to 10 m of soil", "detail": "Radar found a buried layer that is 50 to 85% water ice and covers more ground than New Mexico. It holds about as much water as Lake Superior. China's Zhurong rover landed nearby in 2021.", "earth": "It holds about as much water as Lake Superior, and covers more ground than New Mexico.", "story": "The biggest impact crater on Mars hides under this plain: 3,300 km across, 1.4 times as wide as Hellas, filled in and smoothed flat.", "compare": null, "facts": [ "02-03 F-05", "02-04 F-26" ], "lat": 46.7, "lon": 117.5, "label_at_is_art": false, "where": "02-03:sites.list#utopia", "to_find": "", "eras": {} }, { "id": "arcadia", "name": "AP-1, Arcadia Planitia", "plain_name": "Arcadia City", "category": "site", "category_name": "Landing site", "label": "world", "hook": "Where the first city on Mars will rise", "headline": "Where Arcadia City will stand", "big": "10,000 km³", "big_sub": "of buried ice across Arcadia", "detail": "Low, flat ground that SpaceX has scouted for its first landings, 3.9 km below Mars's average ground level. Under it lies a sheet of ice tens of metres thick: water for drinking, breathing and rocket fuel, right under the city's feet. Across Arcadia it adds up to roughly a Lake Superior.", "earth": "", "story": "", "compare": null, "facts": [ "02-03 R-02", "02-03 F-04" ], "lat": 39.8, "lon": -157.9, "label_at_is_art": false, "where": "02-03:sites.list#arcadia", "to_find": "", "eras": { "ancient": { "hook": "Sea floor, 140 m under the waves", "detail": "The ground where Arcadia City will one day stand lies here on the sea floor, about 140 m under the waves.", "facts": [ "02-04 F-13", "02-03 R-02" ] } } }, { "id": "erebus", "name": "Erebus Montes", "plain_name": "SpaceX candidate site EM-16", "category": "site", "category_name": "Landing site", "label": "real", "hook": "The strongest shallow-ice radar signal of SpaceX's sites", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-03 F-33" ], "lat": 39.89, "lon": -167.97, "label_at_is_art": false, "where": "02-03:sites.list#erebus", "to_find": "", "eras": {} }, { "id": "phlegra", "name": "Phlegra Montes", "plain_name": "SpaceX candidate site PM-1", "category": "site", "category_name": "Landing site", "label": "real", "hook": "The sunniest of the icy candidates", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-03 F-33" ], "lat": 35.23, "lon": 163.95, "label_at_is_art": false, "where": "02-03:sites.list#phlegra", "to_find": "", "eras": {} }, { "id": "acidalia", "name": "Acidalia Planitia", "plain_name": "Northern landing plain", "category": "plain", "category_name": "Plain", "label": "real", "hook": "Smooth ground that suits a natural landing", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-03 F-35" ], "lat": 49.76, "lon": -20.74, "label_at_is_art": false, "where": "02-03:sites.list#acidalia", "to_find": "", "eras": {} }, { "id": "elysium", "name": "Elysium Planitia", "plain_name": "InSight's plain", "category": "plain", "category_name": "Plain", "label": "real", "hook": "Flat, dry and warm by Mars standards", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-03 F-27" ], "lat": 4.5, "lon": 135.62, "label_at_is_art": false, "where": "02-03:sites.list#elysium", "to_find": "", "eras": {} }, { "id": "amazonis", "name": "Amazonis Planitia", "plain_name": "Smooth northern plain", "category": "plain", "category_name": "Plain", "label": "real", "hook": "A 2021 impact here threw out buried ice", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-03 F-07" ], "lat": 25.75, "lon": -162.91, "label_at_is_art": false, "where": "02-04:labels.list#Amazonis Planitia", "to_find": "", "eras": {} }, { "id": "chryse", "name": "Chryse Planitia", "plain_name": "The first landing plain", "category": "plain", "category_name": "Plain", "label": "real", "hook": "Viking 1 and Pathfinder both landed here", "headline": "Where the first robots set down", "big": "1976", "big_sub": "Viking 1 lands here", "detail": "", "earth": "Viking 1 touched down here seven years to the day after Apollo 11 landed on the Moon. Pathfinder followed in 1997.", "story": "The great flood channels of Mars all end here. Water from the southern highlands and the Grand Canyon of Mars poured down into this low plain.", "compare": null, "facts": [ "02-04 F-05", "02-04 F-18", "02-04 F-32" ], "lat": 28.43, "lon": -40.31, "label_at_is_art": false, "where": "02-04:labels.list#Chryse Planitia", "to_find": "", "eras": {} }, { "id": "meridiani", "name": "Meridiani Planum", "plain_name": "Opportunity's plain", "category": "plain", "category_name": "Plain", "label": "real", "hook": "Opportunity landed here in 2004", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-05" ], "lat": -0.04, "lon": -3.14, "label_at_is_art": false, "where": "02-04:labels.list#Meridiani Planum", "to_find": "", "eras": {} }, { "id": "syrtis", "name": "Syrtis Major", "plain_name": "Syrtis Major", "category": "region", "category_name": "Region", "label": "real", "hook": "", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-04" ], "lat": 9.2, "lon": 67.1, "label_at_is_art": false, "where": "02-04:labels.list#Syrtis Major", "to_find": "A sourced, relatable fact about Syrtis Major.", "eras": {} }, { "id": "hesperia", "name": "Hesperia Planum", "plain_name": "Hesperia Planum", "category": "plain", "category_name": "Plain", "label": "real", "hook": "", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-04" ], "lat": -21.42, "lon": 109.89, "label_at_is_art": false, "where": "02-04:labels.list#Hesperia Planum", "to_find": "A sourced, relatable fact about Hesperia Planum.", "eras": {} }, { "id": "lunae", "name": "Lunae Planum", "plain_name": "Lunae Planum", "category": "plain", "category_name": "Plain", "label": "real", "hook": "", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-04" ], "lat": 10.79, "lon": -65.51, "label_at_is_art": false, "where": "02-04:labels.list#Lunae Planum", "to_find": "A sourced, relatable fact about Lunae Planum.", "eras": {} }, { "id": "daedalia", "name": "Daedalia Planum", "plain_name": "Daedalia Planum", "category": "plain", "category_name": "Plain", "label": "real", "hook": "", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-04" ], "lat": -18.35, "lon": -125.95, "label_at_is_art": false, "where": "02-04:labels.list#Daedalia Planum", "to_find": "A sourced, relatable fact about Daedalia Planum.", "eras": {} }, { "id": "malea", "name": "Malea Planum", "plain_name": "Malea Planum", "category": "plain", "category_name": "Plain", "label": "real", "hook": "", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-04" ], "lat": -65.82, "lon": 62.94, "label_at_is_art": false, "where": "02-04:labels.list#Malea Planum", "to_find": "A sourced, relatable fact about Malea Planum.", "eras": {} }, { "id": "mars3", "name": "Mars 3", "plain_name": "Mars 3 lander", "category": "robot", "category_name": "Robot", "label": "real", "hook": "Landed 1971: the first to send data from the surface", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-05" ], "lat": -45, "lon": -158, "label_at_is_art": false, "where": "02-04:places.list#mars3", "to_find": "", "eras": {} }, { "id": "viking1", "name": "Viking 1", "plain_name": "Viking 1 lander", "category": "robot", "category_name": "Robot", "label": "real", "hook": "Landed 1976 on Chryse Planitia", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-05" ], "lat": 22.27, "lon": -47.95, "label_at_is_art": false, "where": "02-04:places.list#viking1", "to_find": "", "eras": {} }, { "id": "viking2", "name": "Viking 2", "plain_name": "Viking 2 lander", "category": "robot", "category_name": "Robot", "label": "real", "hook": "Landed 1976 on Utopia Planitia", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-05" ], "lat": 48.27, "lon": 134.28, "label_at_is_art": false, "where": "02-04:places.list#viking2", "to_find": "", "eras": {} }, { "id": "pathfinder", "name": "Mars Pathfinder", "plain_name": "Pathfinder and Sojourner", "category": "robot", "category_name": "Robot", "label": "real", "hook": "Landed 1997 with the small Sojourner rover", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-05" ], "lat": 19.1, "lon": -33.25, "label_at_is_art": false, "where": "02-04:places.list#pathfinder", "to_find": "", "eras": {} }, { "id": "spirit", "name": "Spirit", "plain_name": "Spirit rover", "category": "robot", "category_name": "Robot", "label": "real", "hook": "Landed 2004 in Gusev Crater", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-05" ], "lat": -14.57, "lon": 175.48, "label_at_is_art": false, "where": "02-04:places.list#spirit", "to_find": "", "eras": {} }, { "id": "opportunity", "name": "Opportunity", "plain_name": "Opportunity rover", "category": "robot", "category_name": "Robot", "label": "real", "hook": "Landed 2004 on Meridiani Planum", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-05" ], "lat": -1.95, "lon": -5.53, "label_at_is_art": false, "where": "02-04:places.list#opportunity", "to_find": "", "eras": {} }, { "id": "phoenix", "name": "Phoenix", "plain_name": "Phoenix lander", "category": "robot", "category_name": "Robot", "label": "real", "hook": "Landed 2008 on the far northern plains", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-05" ], "lat": 68.22, "lon": -125.75, "label_at_is_art": false, "where": "02-04:places.list#phoenix", "to_find": "", "eras": {} }, { "id": "curiosity", "name": "Gale Crater", "plain_name": "Curiosity rover", "category": "robot", "category_name": "Robot", "label": "real", "hook": "Here since 2012, in Gale Crater", "headline": "Curiosity's home", "big": "2012", "big_sub": "the year Curiosity landed", "detail": "NASA's Curiosity rover landed in Gale Crater in 2012. In April 2015 it photographed a Martian sunset, when the sky round the Sun turns blue: the reverse of Earth.", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-05", "02-01 F-16" ], "lat": -4.59, "lon": 137.44, "label_at_is_art": false, "where": "02-04:places.list#curiosity", "to_find": "", "eras": {} }, { "id": "insight", "name": "InSight", "plain_name": "InSight lander", "category": "robot", "category_name": "Robot", "label": "real", "hook": "Landed 2018 on Elysium Planitia", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-05" ], "lat": 4.5, "lon": 135.62, "label_at_is_art": false, "where": "02-04:places.list#insight", "to_find": "", "eras": {} }, { "id": "perseverance", "name": "Perseverance", "plain_name": "Perseverance rover", "category": "robot", "category_name": "Robot", "label": "real", "hook": "Landed 2021 in Jezero Crater", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-05" ], "lat": 18.44, "lon": 77.45, "label_at_is_art": false, "where": "02-04:places.list#perseverance", "to_find": "", "eras": {} }, { "id": "zhurong", "name": "Zhurong", "plain_name": "Zhurong rover", "category": "robot", "category_name": "Robot", "label": "real", "hook": "China's first Mars rover, landed 2021", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-05" ], "lat": 25.07, "lon": 109.93, "label_at_is_art": false, "where": "02-04:places.list#zhurong", "to_find": "", "eras": {} }, { "id": "phobos", "name": "Phobos", "plain_name": "Phobos", "category": "moon", "category_name": "Moon", "label": "real", "hook": "A moon the size of a city, circling 3.2 times a Mars day", "headline": "A moon the size of a city", "big": "26 km", "big_sub": "long, 1.2 times the length of Manhattan", "detail": "A lumpy rock that skims only 6,000 km above the ground, racing round 3.2 times a Mars day. Because it outruns the planet's spin, it rises in the west and sets in the east, crossing the sky about twice a day.", "earth": "", "story": "", "compare": { "kind": "lengths", "unit": "km", "items": [ [ "Manhattan", 21.6, "earth" ], [ "Phobos", 26, "mars" ] ] }, "facts": [ "02-01 F-42", "02-07 F-07" ], "lat": null, "lon": null, "label_at_is_art": false, "where": "02-01:numbers.moons", "to_find": "", "eras": {} }, { "id": "deimos", "name": "Deimos", "plain_name": "Deimos", "category": "moon", "category_name": "Moon", "label": "real", "hook": "From the ground it looks like a bright star", "headline": "The small, far moon", "big": "12.5 km", "big_sub": "across", "detail": "Mars's outer moon circles 23,459 km from the planet's centre, once every 30 h 18 min. From the surface it shines like a star, as bright as Venus seen from Earth.", "earth": "", "story": "", "compare": null, "facts": [ "02-01 F-44", "02-07 F-13" ], "lat": null, "lon": null, "label_at_is_art": false, "where": "02-01:numbers.moons", "to_find": "", "eras": {} }, { "id": "home_plate", "name": "Home Plate", "plain_name": "Hot-spring stone", "category": "region", "category_name": "Region", "label": "real", "hook": "Silica like a hot spring's, 90 m across", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-09 F-12" ], "lat": -14.6, "lon": 175.5, "label_at_is_art": false, "where": "02-09:numbers.home_plate", "to_find": "", "eras": {} }, { "id": "eridania", "name": "Eridania basin", "plain_name": "Lost southern sea", "category": "region", "category_name": "Region", "label": "real", "hook": "Once held more water than all Mars's other lakes", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-09 F-13" ], "lat": -30, "lon": 178, "label_at_is_art": false, "where": "02-09:numbers.eridania", "to_find": "", "eras": {} }, { "id": "nili_fossae", "name": "Nili Fossae", "plain_name": "Hydrogen troughs", "category": "region", "category_name": "Region", "label": "real", "hook": "Troughs 667 km long, where rock makes hydrogen", "headline": "", "big": "", "big_sub": "", "detail": "", "earth": "", "story": "", "compare": null, "facts": [ "02-09 F-19" ], "lat": 22.57, "lon": 76.8, "label_at_is_art": false, "where": "02-09:numbers.nili", "to_find": "", "eras": {} }, { "id": "noctis", "name": "Noctis Labyrinthus", "plain_name": "Labyrinth of Night", "category": "canyon", "category_name": "Canyon", "label": "real", "hook": "A maze of canyons 1,263 km across, about London to Madrid", "headline": "Where the Grand Canyon of Mars begins", "big": "", "big_sub": "", "detail": "The ground here cracked and sank as magma drained away beneath the great volcanoes, leaving a maze of steep-walled canyons and tall mesas.", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-19" ], "lat": -7, "lon": -102.2, "label_at_is_art": false, "where": "02-04:places.list#noctis", "to_find": "", "eras": {} }, { "id": "ius", "name": "Ius Chasma", "plain_name": "The Long Canyon", "category": "canyon", "category_name": "Canyon", "label": "real", "hook": "938 km of canyon, about London to Berlin", "headline": "The first great trench of the Grand Canyon of Mars", "big": "", "big_sub": "", "detail": "A single canyon about 938 km long, with side canyons carved where water seeped out at the foot of the walls.", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-20" ], "lat": -7, "lon": -85.8, "label_at_is_art": false, "where": "02-04:places.list#ius", "to_find": "", "eras": {} }, { "id": "geryon", "name": "Geryon Montes", "plain_name": "The Ridge Down the Middle", "category": "canyon", "category_name": "Canyon", "label": "real", "hook": "A mountain ridge of ancient bedrock splits the canyon in two", "headline": "Two canyons for the price of one", "big": "", "big_sub": "", "detail": "The ridge is the planet's old bedrock, left standing as the ground on either side dropped away.", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-20" ], "lat": -8.15, "lon": -80, "label_at_is_art": false, "where": "02-04:places.list#geryon", "to_find": "", "eras": {} }, { "id": "labes", "name": "Ius Labes", "plain_name": "The Giant Landslides", "category": "canyon", "category_name": "Canyon", "label": "real", "hook": "Whole canyon walls collapsed here, racing across the floor at over 360 km/h", "headline": "Walls that fell", "big": "", "big_sub": "", "detail": "Landslides in this canyon ran up to 120 km across the floor.", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-20", "02-04 F-22" ], "lat": -8.6, "lon": -77.6, "label_at_is_art": false, "where": "02-04:places.list#labes", "to_find": "", "eras": {} }, { "id": "melas", "name": "Melas Chasma", "plain_name": "The Widest Stretch", "category": "canyon", "category_name": "Canyon", "label": "real", "hook": "The canyon's widest part, 547 km long: about London to Edinburgh", "headline": "The heart of the Grand Canyon of Mars", "big": "", "big_sub": "", "detail": "The widest part of the whole canyon system, with landslides piled up where it meets the canyons on either side.", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-21" ], "lat": -10.4, "lon": -72.7, "label_at_is_art": false, "where": "02-04:places.list#melas", "to_find": "", "eras": {} }, { "id": "candor", "name": "Candor Chasma", "plain_name": "The Layered Mountains", "category": "canyon", "category_name": "Canyon", "label": "real", "hook": "Mountains of rock laid down layer on layer, holding minerals that form in water", "headline": "A canyon full of mountains", "big": "", "big_sub": "", "detail": "Its walls and mesas are stacked like the pages of a book, each layer a chapter of Mars's past.", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-23" ], "lat": -6.6, "lon": -70.9, "label_at_is_art": false, "where": "02-04:places.list#candor", "to_find": "", "eras": {} }, { "id": "ophir", "name": "Ophir Chasma", "plain_name": "The Canyon of Gold", "category": "canyon", "category_name": "Canyon", "label": "real", "hook": "Named after King Solomon's land of gold, and 317 km long", "headline": "The end of the run", "big": "", "big_sub": "", "detail": "Ophir's walls show bands of dark volcanic rock and pale, layered deposits.", "earth": "", "story": "", "compare": null, "facts": [ "02-04 F-24" ], "lat": -4, "lon": -72.5, "label_at_is_art": false, "where": "02-04:places.list#ophir", "to_find": "", "eras": {} } ], "files": { "00": { "title": "How this library is organised", "path": "00 Engine room/00-how-this-library-is-organised.html" }, "00-01": { "title": "Project map", "path": "00 Engine room/00-01-project-map.html" }, "00-02": { "title": "The engine", "path": "00 Engine room/00-02-the-engine.html" }, "00-03": { "title": "Library contents", "path": "00 Engine room/00-03-library-contents.html" }, "00-04": { "title": "Glossary and units", "path": "00 Engine room/00-04-glossary-and-units.html" }, "00-05": { "title": "Writing and visual standard", "path": "00 Engine room/00-05-writing-and-visual-standard.html" }, "01-01": { "title": "Getting to Mars", "path": "01 Earth/01-01-getting-to-mars.html" }, "01-02": { "title": "The journey", "path": "01 Earth/01-02-the-journey.html" }, "01-03": { "title": "Who goes", "path": "01 Earth/01-03-who-goes.html" }, "01-04": { "title": "Law, money and governance on Earth", "path": "01 Earth/01-04-law-money-and-governance.html" }, "01-05": { "title": "The Earth-Mars link", "path": "01 Earth/01-05-the-earth-mars-link.html" }, "01-06": { "title": "Rocket engines", "path": "01 Earth/01-06-rocket-engines.html" }, "01-07": { "title": "Ways to space today", "path": "01 Earth/01-07-ways-to-space-today.html" }, "01-08": { "title": "Inside the rockets", "path": "01 Earth/01-08-inside-the-rockets.html" }, "01-09": { "title": "How the rockets fly", "path": "01 Earth/01-09-how-the-rockets-fly.html" }, "01-10": { "title": "Who got us here", "path": "01 Earth/01-10-who-got-us-here.html" }, "02-01": { "title": "Physical constraints", "path": "02 Mars the planet/02-01-physical-constraints.html" }, "02-02": { "title": "Weather", "path": "02 Mars the planet/02-02-weather.html" }, "02-03": { "title": "Resource survey", "path": "02 Mars the planet/02-03-resource-survey.html" }, "02-04": { "title": "Interactive map", "path": "02 Mars the planet/02-04-mars-map.html" }, "02-05": { "title": "The site up close", "path": "02 Mars the planet/02-05-the-site-up-close.html" }, "02-06": { "title": "The human body on Mars", "path": "02 Mars the planet/02-06-the-human-body-on-mars.html" }, "02-07": { "title": "The Mars sky", "path": "02 Mars the planet/02-07-the-mars-sky.html" }, "02-08": { "title": "Jezero Crater", "path": "02 Mars the planet/02-08-jezero-crater.html" }, "02-09": { "title": "Life on Ancient Mars", "path": "02 Mars the planet/02-09-life-on-ancient-mars.html" }, "03-01": { "title": "Water extraction", "path": "03 Structures/03-01-water-extraction.html" }, "03-02": { "title": "Landing pads", "path": "03 Structures/03-02-landing-pads.html" }, "03-03": { "title": "Power", "path": "03 Structures/03-03-power.html" }, "03-04": { "title": "Fuel plant", "path": "03 Structures/03-04-fuel-plant.html" }, "03-05": { "title": "Vehicles and port", "path": "03 Structures/03-05-vehicles-and-port.html" }, "03-06": { "title": "Habitats", "path": "03 Structures/03-06-habitats.html" }, "03-07": { "title": "Airlocks, suitports and dust", "path": "03 Structures/03-07-airlocks-suitports-and-dust.html" }, "03-08": { "title": "Spacesuits", "path": "03 Structures/03-08-spacesuits.html" }, "03-09": { "title": "Life support", "path": "03 Structures/03-09-life-support.html" }, "03-10": { "title": "Greenhouses and food", "path": "03 Structures/03-10-greenhouses-and-food.html" }, "03-11": { "title": "Construction and materials", "path": "03 Structures/03-11-construction-and-materials.html" }, "03-12": { "title": "Manufacturing", "path": "03 Structures/03-12-manufacturing.html" }, "03-13": { "title": "Local communications", "path": "03 Structures/03-13-local-communications.html" }, "03-14": { "title": "Medical bay", "path": "03 Structures/03-14-medical-bay.html" }, "03-15": { "title": "Waste and recycling", "path": "03 Structures/03-15-waste-and-recycling.html" }, "03-16": { "title": "Computing and AI", "path": "03 Structures/03-16-computing-and-ai.html" }, "04-01-01": { "title": "The first city", "path": "04 Settled world/04-01-01-the-first-city.html" }, "04-01-02": { "title": "The lava-tube outpost", "path": "04 Settled world/04-01-02-the-lava-tube-outpost.html" }, "04-01-03": { "title": "The Jezero science town", "path": "04 Settled world/04-01-03-the-jezero-science-town.html" }, "04-01-04": { "title": "The cities of Mars", "path": "04 Settled world/04-01-04-the-cities-of-mars.html" }, "04-02-01": { "title": "How the city is run", "path": "04 Settled world/04-02-01-how-the-city-is-run.html" }, "04-02-02": { "title": "Money and trade", "path": "04 Settled world/04-02-02-money-and-trade.html" }, "04-02-03": { "title": "Staying for good", "path": "04 Settled world/04-02-03-staying-for-good.html" }, "04-02-04": { "title": "Needing nothing from Earth", "path": "04 Settled world/04-02-04-needing-nothing-from-earth.html" }, "04-03-01": { "title": "The calendar and festivals", "path": "04 Settled world/04-03-01-the-calendar-and-festivals.html" }, "04-03-02": { "title": "Food and home life", "path": "04 Settled world/04-03-02-food-and-home-life.html" }, "04-03-03": { "title": "Language and culture", "path": "04 Settled world/04-03-03-language-and-culture.html" }, "04-04-01": { "title": "Jobs", "path": "04 Settled world/04-04-01-jobs.html" }, "04-04-02": { "title": "A day in the life", "path": "04 Settled world/04-04-02-a-day-in-the-life.html" }, "04-04-03": { "title": "Safety and emergencies", "path": "04 Settled world/04-04-03-safety-and-emergencies.html" }, "04-05-01": { "title": "Characters", "path": "04 Settled world/04-05-01-characters.html" }, "04-05-02": { "title": "Arrival day", "path": "04 Settled world/04-05-02-arrival-day.html" }, "05-02": { "title": "The Olympus race", "path": "05 Visiting Mars/05-02-the-olympus-race.html" }, "05-03": { "title": "Guided tours", "path": "05 Visiting Mars/05-03-guided-tours.html" }, "05-04": { "title": "Missions", "path": "05 Visiting Mars/05-04-missions.html" }, "05-05": { "title": "The Q&A guide", "path": "05 Visiting Mars/05-05-the-qa-guide.html" }, "05-06": { "title": "Free roam", "path": "05 Visiting Mars/05-06-free-roam.html" }, "05-07": { "title": "First-time onboarding", "path": "05 Visiting Mars/05-07-first-time-onboarding.html" }, "05-08": { "title": "The journey experience", "path": "05 Visiting Mars/05-08-the-journey-experience.html" }, "05-09": { "title": "Sign-ups and business", "path": "05 Visiting Mars/05-09-sign-ups-and-business.html" }, "05-10": { "title": "Stand in Jezero", "path": "05 Visiting Mars/05-10-stand-in-jezero.html" }, "05-11": { "title": "Mars Through Time", "path": "05 Visiting Mars/05-11-mars-through-time.html" }, "90-01": { "title": "Asset register", "path": "90 Making-of/90-01-asset-register.html" }, "90-02": { "title": "Prompt library", "path": "90 Making-of/90-02-prompt-library.html" }, "90-03": { "title": "Building the ground", "path": "90 Making-of/90-03-building-the-ground.html" }, "90-04": { "title": "Research log", "path": "90 Making-of/90-04-research-log.html" }, "90-05": { "title": "3D model sources and licences", "path": "90 Making-of/90-05-3d-model-sources.html" }, "05-12": { "title": "A Living City", "path": "05 Visiting Mars/05-12-a-living-city.html" }, "05-13": { "title": "Mars Atlas", "path": "05 Visiting Mars/05-13-mars-atlas.html" }, "05-14": { "title": "Early Life on Mars", "path": "05 Visiting Mars/05-14-the-first-martians.html" }, "05-15": { "title": "Engine lab", "path": "05 Visiting Mars/05-15-engine-lab.html" }, "05-16": { "title": "Rocket pages", "path": "05 Visiting Mars/05-16-rocket-pages.html" }, "05-17": { "title": "Living on Mars", "path": "05 Visiting Mars/05-17-living-on-mars.html" }, "05-18": { "title": "Mars Atmosphere", "path": "05 Visiting Mars/05-18-mars-atmosphere.html" }, "05-19": { "title": "Playable Arcadia", "path": "05 Visiting Mars/05-19-playable-arcadia.html" }, "05-20": { "title": "Mars games", "path": "05 Visiting Mars/05-20-mars-games.html" } }, "built_from": "05 Visiting Mars/05-20-mars-games.json" }