What Would Happen to Our Bodies on a Trip to Mars?

November 20, 2015 | Elizabeth Knowles

NASA astronaut Scott Kelly
Photo credit: NASA Johnson

And how is NASA working to solve these problems?

Astronauts traveling to Mars will be embarking on a three-year journey, with no shortcuts or vacation time. Their bodies will be exposed to whatever space has to offer. NASA doesn’t want to be unprepared, which is one of the reasons why astronauts are spending longer and longer chunks of time living aboard the International Space Station.


When astronauts travel to Mars they will experience three different gravitational fields. While traveling, they will be weightless, and once they reach Mars and live on the surface of the planet, gravity will be about one third of what we experience here on Earth. Once they return home, their bodies will have to acclimate once again to Earth’s gravity.

Transitioning between gravitational fields can cause spatial disorientation, trouble with hand-eye coordination, and motion sickness, as well as make it more difficult to balance and move around. When your body is weightless, your muscles don’t have to work to support you and they get much weaker. Your bones also lose minerals and density which is why astronauts exercise regularly, but it isn’t enough to overcome the loss of endurance and cardiovascular deconditioning they experience. Another problem with low gravity is that fluids inside your body float upwards, putting pressure on your eyes and causing vision problems.

Some of the solutions that NASA has come up with are: having astronauts wear compression cuffs on their thighs to help keep blood in their lower extremities, proper nutrition including vitamin D to replace what astronauts would get naturally from sunlight, and lots and lots of exercise.


Astronauts are carefully chosen and trained, but groups of people confined to small spaces will inevitably develop behavioral issues. Typical problems include sleeping disorders, changes in mood, stress, depression, and fatigue. Since resupply missions are rare, a lack of fresh food can contribute to diminished psychological and physiological well being.

To combat these effects, astronauts aboard the International Space Station (ISS) will install new lighting that will align their circadian rhythms and improve sleep, alertness and performance. Journaling can also decrease stress and give researchers insight into what is going on in an astronaut's mind.

Planning for self-sufficiency is also key because astronauts have to be prepared for all types of medical emergencies that might happen while they are away from Earth. Astronauts get medical training before they leave home so that they can deal with many types of emergencies.

Hostile Environment

Astronauts are more susceptible to allergies and illnesses while in space because of the closed nature of their spacecraft. However, the most dangerous element comes from outside: radiation. Earth’s atmosphere and magnetic field protect us from most radiation, but in space it can damage astronauts’ central nervous systems and cause radiation sickness.

NASA closely monitors the air quality in the space station and the same will probably be true for a journey to Mars. As for radiation, NASA can equip the vessel with protective shielding, but it isn’t effective against all types of radiation.

US astronaut Scott Kelly is currently attempting to set the record for the longest time an American has ever spent in space. Scott Kelly’s identical twin will undergo the same tests on Earth as his brother will in space in order to act as a control group. If Kelly succeeds, he will beat the previous seven-month record by three months. However, he will not break Russian cosmonaut Valeri Polyakov’s record from 1995 -— 437 days in space. When Polyakov returned to Earth, the first thing he told a fellow cosmonaut was: “We can fly to Mars.” Hopefully NASA is just as optimistic!

You might also like: What Would You Do if You Were Stranded on Mars?

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