# What are the main hurdles to surviving on Mars until a return trip becomes possible?

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
• We need more delta-V. – ikrase Nov 25 '20 at 18:17
• fuel production would likely be working, or if you are being more cautious, complete before the crew left Earth. You still need to keep the fuel cold and replace any losses, but I doubt you'd land crew on Mars until you were sure you had return fuel. – Steve Linton Nov 26 '20 at 9:25
• There is an alternate route via Venus that only gives 1 one month stay time, bbut one spends longer in space – user20636 Nov 26 '20 at 12:26

• 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? – user Nov 3 '16 at 9:11