Radiation
Spending any prolonged amount of time in space, we’re talking months or years, runs an increased risk of developing a radiation-related sickness, such as cancer. Modern astronauts stay in the safe confines of Earth’s magnetosphere, while the Apollo astronauts spent just a few days at the Moon.
But on Mars, each Ares crew was spending up to a month on the surface in the movie. It’s likely that the habitat as depicted in the film might be a bit different on a real future Mars mission; it might be necessary to partly submerge it in the ground, providing natural protection from radiation.
“The reality is I think people will go underground, to protect against radiation from the Sun,” said Schmidt. “The structures will be on the surface, but machines will be used to protect them with Martian sand.”
And what about Watney, who spends more than a year on the surface, often with nothing more than his spacesuit for protection? Well, although the radiation levels on Mars are less than expected, it’s possible he would have considerably increased his risk of cancer, although he was unlikely to have experienced any immediate effects during his stay. We’ll call this one a tie.