Water is probably the major concern. Thinking about hiking/camping, with dehydrated food 3 calories per gram is fairly standard. 22 tons at 3 calories per gra

Water is probably the major concern. Thinking about hiking/camping, with dehydrated food 3 calories per gram is fairly standard. 22 tons at 3 calories per gram is about 7.3 million calories. That's 3000 days at 2500cal/d. But when you're hiking you can just source water along the way. You can't do that on a Mars journey. Can you do it on Mars? edit: in response to the recycling comment - of course! doh! then it should be easier, no?