I think a Moon base is not necessary to get to Mars, but I think it will be helpful. It would give you a chance to develop and mature some systems; long duration, deep space stuff; and you're close enough to get some help, via radio from Earth.

The Moon was the most spectacularly beautiful desert you could ever imagine. Unspoilt. Untouched. It had a vibrancy about it and the contrast between it and the black sky was so vivid, it just made this impression of excitement and wonder.

Buzz Aldrin doesn't think we need to go back to the Moon - that we should go straight on to Mars. I'm more on the side that says we should go back to the Moon. I think there's a lot we can utilise the Moon for scientifically.

Two months after I got out of test pilot school, I saw an advert that said NASA was recruiting more astronauts. The best job you could have as a test pilot was being an astronaut, so I volunteered.

The only peace that can be made with a dictator is once that must be based on deterrence. For today, the dictator may be your friend, but tomorrow he will need you as an enemy.

I feel beautiful when I'm at peace with myself. When I'm serene, when I'm a good person, when I've been considerate of others.

I don't think journalists in World War II were objective about the Nazis, and I don't think they should have been.

Look, when AIs come up, they're not going to be like us. A self-aware, sentient AI is not going to be like a human.