# What are the main hurdles to surviving on mars until a return trip?

I watched a presentation on a manned mission to Mars and learned it would take two years until the Earth and Mars were properly aligned for the return mission from Mars. Are there any major technological hurdles to surviving on the planet and producing the fuel necessary for the return?

• If you wanted to make the return trip using ISRU you would need many many pirate ninjas to be able to generate the fuel necessary in the 2 year time frame. – Aron Nov 2 '16 at 3:43

• Mars has a surface gravity accelleration of approximately 3.7 m/s$^2$, which is about 38% of Earth's 9.8 m/s$^2$. Maybe that's what you were thinking of? – a CVn Nov 3 '16 at 9:11