It's our destiny to explore. It's our destiny to be a space-faring nation.

Mom was always doing something for somebody. She came from a Czech background, one that made her a devout Catholic and gave her a strong belief in the family.

When you head on out to the Moon, in very short order, and you get a chance to look back at the Earth, that horizon slowly curves around in upon himself, and all of sudden you're looking at something that is very strange, but yet is very, very familiar, because you're beginning to see the Earth evolve.

Am I willing to go to Mars? Yes, but I'm not willing to spend nine months getting there, then wait 18 more months until the planets align to come home.

I know the stars are my home. I learned about them, needed them for survival in terms of navigation. I know where I am when I look up at the sky. I know where I am when I look up at the Moon; it's not just some abstract romantic idea, it's something very real to me. See, I've expanded my home.

Curiosity is the essence of human existence. 'Who are we? Where are we? Where do we come from? Where are we going?' I don't know. I don't have any answers to those questions. I don't know what's over there around the corner. But I want to find out.

Some astronauts describe the routine flushing of urine into space, where the freezing temperatures turn the droplets into a cloud of bright, drifting crystals, as being among the most amazing sights they saw on an entire voyage.