Fuel. We have two options to to get back from Mars. Bring the fuel with us or harvest the fuel there. Bringing the fuel is unrealistic, "The bottom line of all

Fuel. We have two options to to get back from Mars. Bring the fuel with us or harvest the fuel there. Bringing the fuel is unrealistic, "The bottom line of all these calculations is that you can get about eight times as much stuff to Mars for the same amount of fuel if you send it one-way instead of trying to bring it back!"[1] So let's mine the fuel there. We've never done that. We don't know how long it takes. We have to bring all the equipment in one go, it might even increase the weight of the mission by 8x! The whole one-way thing is just the easiest. It's no guarantee you're stuck on Mars forever(future flights might be better equipped for return), and it's far simpler than making a guarantee that you won't get stuck on Mars forever. [1] http://www.polaris.iastate.edu/EveningStar/Unit7/unit7_sub2.htm http://www.polaris.iastate.edu/EveningStar/Unit7/unit7_sub2....