Explainer · living on Mars
Not without heavy protection: Mars’s air pressure is 0.6% of Earth’s, the air is almost all carbon dioxide, and the median surface temperature is −65 °C (−85 °F). No one has been there yet. People would need sealed, shielded homes, and would have to make their own air, water and power from what Mars has.
Updated Sources (30)
Mars falls short on almost everything a body needs. Here is the planet next to Earth, using NASA’s numbers and the radiation NASA’s Curiosity rover measured on the ground.
| What you need | On Mars | On Earth | Source |
|---|---|---|---|
| Air pressure | 6.36 mbar0.6% of Earth’s; 4.0 to 8.7 mbar with the seasons | 1,014 mbar | [2][3] |
| Oxygen in the air | 0.16%95.1% is carbon dioxide | 20.95%78.08% is nitrogen | [2][3] |
| Temperature | −65 °C (−85 °F)median; from about 20 °C (68 °F) to −153 °C (−243 °F) | 15 °C (59 °F)average | [3][4] |
| Radiation dose | About 0.67 mSv a dayCuriosity, Gale Crater, 2012–2013 | About 6.2 mSv a yearaverage American, all sources | [6][9] |
| Gravity | 3.73 m/s²38% of Earth’s | 9.82 m/s² | [2][3] |
| Liquid water | None that lastsit vaporizes; water is frozen at the poles and underground | Lakes, rivers and seas | [17] |
| A message home | About 3 to 22 minutesone way, depending on where the planets are | Instant | [2] |
Mars and Earth values from NASA’s fact sheets; temperatures from NASA Science; radiation from Curiosity’s Radiation Assessment Detector and the US Nuclear Regulatory Commission (620 millirem). The message delay is our calculation: NASA’s closest and farthest Earth–Mars distances divided by the speed of light.[2][3][4][6][9]
Because almost nothing on Mars keeps a person alive without help. NASA’s Human Research Program sorts the dangers of a Mars mission into five hazards: space radiation, isolation and confinement, distance from Earth, gravity, and closed or hostile environments.[1] On the surface, that means:
About 0.67 millisieverts (mSv) a day on the surface, Curiosity measured: in about nine days, what the average American gets in a year.[6][9] Mars has no global magnetic field and only a thin atmosphere, so even on the ground people get little protection from solar particles and cosmic rays, NASA says.[10]
The trip there is worse than the stay. Inside its spacecraft on the way to Mars, Curiosity’s detector measured about 1.8 mSv a day. Its team estimated about 0.66 sievert for a round trip with today’s rockets, and about 1 sievert with a 500-day stay on the surface.[6] NASA’s own calculation, for 180 days each way and 500 days on Mars, also comes to about 1 sievert, split roughly evenly between the three legs.[5]
For scale, NASA’s current standard caps an astronaut’s whole-career dose at 600 mSv (0.6 sievert), though it is calculated a little differently.[8] The detector team said in 2013 that a dose of 1 sievert is linked to a 5% higher risk of fatal cancer.[7] NASA also lists damage to the central nervous system and changes in thinking, movement and behavior.[11]
Shielding helps. Hydrogen blocks these particles well, so NASA has studied water and plastics as shields; stored water could wall off a storm shelter inside a ship or habitat.[10]
Air, water, food, power and shelter, made on Mars wherever possible, because supplies from Earth would be rare. A crew on a round trip would get no resupply missions with fresh food, NASA says, so it is developing life-support systems that recycle air, water and food, and testing them on the space station.[15]
A sealed, pressurized home, either fixed in place or on wheels, with a robust water-recycling system, NASA says.[15] The closest thing so far is Mars Dune Alpha, a 3D-printed habitat of about 160 square meters (1,700 square feet) at NASA’s Johnson Space Center in Houston.[12][23]
NASA uses it for CHAPEA, a series of year-long Mars simulations with four volunteers each. The first crew lived inside from Jun 25, 2023 to Jul 6, 2024.[22] A second crew went in on Oct 19, 2025, for a 378-day stay set to end Oct 31, 2026. This crew’s year includes simulated “Marswalks” in spacesuits, robot operations, habitat repairs, exercise and growing crops, along with limited supplies, equipment failures and 22-minute delays on messages.[23]
SpaceX wants a city on Mars and China’s main rocket maker has sketched a Mars base, but no crewed Mars mission has a date yet.[24][26] SpaceX says a self-sufficient city would need more than 10 launches a day in the Launch windowA launch window is the stretch of time, about every 26 months, when Earth and Mars line up so a spacecraft can reach Mars using the least fuel.More in the glossary that open about every 26 months.[24] Elon Musk said in February 2026 that SpaceX would put a Moon city first and begin a Mars city “in about 5 to 7 years”.[25] NASA’s stated goal is to send astronauts “as early as the 2030s”.[15]
A self-sufficient city of a million people
“Establishing a self-sufficient city on Mars will require upwards of one million people and millions of tonnes of cargo to be delivered to the Red planet”
SpaceX · Mars & Beyond
The Moon first; a Mars city takes longer
“SpaceX has already shifted focus to building a self-growing city on the Moon, as we can potentially achieve that in less than 10 years, whereas Mars would take 20+ years”
Elon Musk on X, as quoted by SpacePolicyOnline · Musk Embraces the Moon
Crewed missions, then a Mars base
“starting with an orbital outpost, then landing on the planet's surface and finally constructing a Mars base”
Space.com, on a talk by Wang Xiaojun, president of the China Academy of Launch Vehicle Technology, at GLEX 2021 · China wants to build a sustainable human presence on Mars. Here's how.
The timelines are on when will humans land on Mars? and the details of SpaceX’s plan on SpaceX’s Mars plan.
It went bankrupt in 2019, years before its first planned landing. Mars One, a private venture that began in the Netherlands, planned to land people on Mars in 2023 and to build a reality TV series around a colony there. It put the cost at about $6 billion.[27] In 2013 it drew 202,586 applications for one-way trips. Delays pushed its target launch to 2031. In February 2019 NPR reported that a Swiss appeals court had upheld the bankruptcy of Mars One Ventures, the arm meant to raise money for the mission.[27]
Not with today’s technology, a NASA-sponsored study concluded in 2018. Terraforming means making a planet more like Earth. The usual idea is to free carbon dioxide locked in Mars’s ice and soil to thicken and warm the air. But stable liquid water would need carbon dioxide pressure close to Earth’s whole atmosphere, and the study found far too little within reach: vaporizing the polar caps would only double Mars’s air pressure, to about 1.2% of Earth’s. Gas seeping from inside the planet would take about 10 million years just to double the atmosphere.[28]
Some scientists want a fresh look. A 2025 paper in Nature Astronomy says new techniques could raise Mars’s average temperature by tens of degrees within a few decades. Its authors call for research first, to weigh the cost and risks against leaving Mars as a pristine wilderness.[29] They describe warming first, then engineered microbes slowly building up oxygen; Space.com, reporting on the paper, said full terraforming may take centuries, if not millennia.[29][30] These are proposals, not plans. SpaceX’s Mars page is blunter: Mars “is a little cold, but we can warm it up.”[24]
No. Mars’s air is 95.1% carbon dioxide and only 0.16% oxygen, and its pressure is 0.6% of Earth’s. Outside, you would need a pressurized spacesuit that supplies all your air.
No. No person has been to Mars. NASA’s goal is to send astronauts “as early as the 2030s”. The closest anyone has come is NASA’s year-long Mars simulation in a 3D-printed habitat in Houston.
Indoors, mostly. NASA’s simulated Mars crews live four to a habitat of about 160 square meters (1,700 square feet), go outside only in spacesuits, grow crops, fix their own equipment and wait 22 minutes for messages from “Earth”.
NASA is working on it, indoors. Astronauts have grown and eaten lettuce and kale on the space station. Martian soil holds perchlorate salts, and a NASA panel wants that tracked if crops are ever grown in it.
Nobody knows, and a NASA-sponsored study says it can’t be done with today’s technology. A 2025 paper says new techniques could warm Mars by tens of degrees within a few decades; Space.com, reporting on it, said full terraforming may take centuries, if not millennia.
Not soon. SpaceX says a self-sufficient city would take upwards of a million people. Elon Musk said in February 2026 that SpaceX would begin one in about 5 to 7 years, and that a self-growing Mars city would take 20+ years.
There’s no date. SpaceX says its first cargo flights to Mars start no earlier than 2028, and no crewed Mars mission is scheduled by anyone.