On Monday, NASA officially opened an application window for the next generation of American astronauts it hopes to send to the International Space Station, lunar orbit and eventually to Mars. But to find the best candidates for dealing with the harsh levels of radiation in space and on the Red Planet, the agency may want to consider looking beyond the borders of the United States for applicants.
One of the biggest challenges in sending astronauts into deep space or setting up a base on Mars is dealing with the radiation from the cosmic rays that our sun and other stars send flying around the universe. Earth’s atmosphere and magnetic field deflect the worst of this radiation, but Mars has no substantial magnetic field, which has in turn allowed much of its atmosphere to be lost to space over the millennia.
Spacecraft can be equipped with radioactive shielding to some extent, and a base on Mars could also be constructed essentially underground, using several meters of Martian soil to provide radiation protection on par with Earth’s atmosphere (this is what Mars One hopes to do). But when it comes to roaming around the surface of Mars in a spacesuit or in a rover, there’s no real practical way for those astronauts to avoid some big doses of radiation in the process.