Die from radiation, die of dehydration, die from asphyxiation, die from starvation, die from extraterrestrial snu snu causing you to run out of water and oxygen, die from having something put a hole in your ship ect. Die from having your suit punctured, die from going out to explore and getting lost and then running out of air, water or food. Get killed by any tremor type works that might live there, get killed by angry Martians, fall into a crater and die or get stuck. Die from having an asteroid or meteor land on you, die from a rock-slide, be buried under red sand, die from a sandstorm, die from any lethal bacteria you might come into contact with on an alien planet, die from the heat and or cold. Die from any other random things that could happen on a planet 9 months away from earth with no hope of rescue or supply's ever.