Andy Weir said this quote

When I was up there, stranded by myself, did I think I was going to die? Yes. Absolutely, and that’s what you need to know going in because it’s going to happen to you. This is space. It does not cooperate. At some point everything is going to go south on you. Everything is going to go south and you’re going to say 'This is it. This is how I end.' Now you can either accept that or you can get to work. That’s all it is. You just begin. You do the math, you solve one problem. Then you solve the next one, and then the next and if you solve enough problems you get to come home.