<P> Humans have explored parts of Earth that match some conditions on Mars . Based on NASA rover data, temperatures on Mars (at low latitudes) are similar to those in Antarctica . The atmospheric pressure at the highest altitudes reached by manned balloon ascents (35 km (114,000 feet) in 1961, 38 km in 2012) is similar to that on the surface of Mars . </P> <P> Human survival on Mars would require complex life - support measures and living in artificial environments . </P> <P> Mars presents a hostile environment for human habitation . Different technologies have been developed to assist long - term space exploration and may be adapted for habitation on Mars . The existing record for the longest consecutive space flight is 438 days by cosmonaut Valeri Polyakov, and the most accrued time in space is 878 days by Gennady Padalka . The longest time spent outside the protection of the Earth's Van Allen radiation belt is about 12 days for the Apollo 17 moon landing . This is minor in comparison to the 1100 day journey planned by NASA as soon as the year 2028 . Scientists have also hypothesized that many different biological functions can be negatively affected by the environment of Mars colonies . Due to higher levels of radiation, there are a multitude of physical side - effects that must be mitigated . </P> <P> The difference in gravity will negatively affect human health by weakening bones and muscles . There is also risk of osteoporosis and cardiovascular problems . Current rotations on the International Space Station put astronauts in zero gravity for six months, a comparable length of time to a one - way trip to Mars . This gives researchers the ability to better understand the physical state that astronauts going to Mars will arrive in . Once on Mars, surface gravity is only 38% of that on Earth . Upon return to Earth, recovery from bone loss and atrophy is a long process and the effects of microgravity may never fully reverse . There are also severe radiation risks on Mars that can influence cognitive processes, deteriorate cardiovascular health, inhibit reproduction, and cause cancer . Additionally, in - utero development is very fragile and severely affected by radiation . Data from irradiated survivors of Hiroshima and Nagasaki provide insight into the "radiosensitivity in humans as a function of gestational age and dose for several CNS endpoints, including severe mental retardation, head circumference, intelligence test scores, and school performance". Close monitoring of the radiation received by reproductive colonists will be necessary to ensure the health of offspring . Additionally, a large focus of colonization development is on reducing the amount of radiation absorbed by astronauts . But early colonizing may be faced with these challenges and the harm could be seen for generations, as stated in academic articles: "the pioneers making the first journeys to Mars and its vicinity to explore and set up a base that eventually will lead to a continuously occupied colony, will face more hazards than those that follow". </P>

What are the requirements to live on mars