We have the ability, at such high fidelity, to simulate the physical world through computers. But when the spiritual world or human behavior comes into play, we don't have a very good model for that at all.

Globalisation means many other countries are asserting themselves and trying to take over leadership. Please don't ask Americans to let others assume the leadership of human exploration. We can do wonderful science on the Moon, and wonderful commercial things. Then we can pack up and move on to Mars.

In Mars, we've been given a wonderful set of moons where we can send continuous numbers of people.

Exploration is wired into our brains. If we can see the horizon, we want to know what's beyond.

The big companies are the private industry. But they're faced with a short-term need to show a profit in short-term.

Ray Bradbury is one who is contributing to the understanding of the imagination and the curiosity of the human race.

I inherited depression from my mother's side of the family. Her father committed suicide. She committed suicide the year before I went to the moon.