And if we do get people to Mars, they will need to live underground for most (almost all) their time there. They will most likely die (and live) there. In the

And if we do get people to Mars, they will need to live underground for most (almost all) their time there. They will most likely die (and live) there. In the fictional Red Mars book by Kim Stanley Robinson, astronauts who had maxed out their radiation exposure often weren't allowed to continue missions.