When I was a little kid, we only knew about our nine planets. Since then, we've downgraded Pluto but have discovered that other solar systems and stars are common. So life is probably quite prevalent.

I've been to the Titanic in a yellow submarine and the North Pole in a Russian nuclear ice breaker.

My expertise is the space program and what it should be in the future based on my experience of looking at the transitions that we've made between pre-Sputnik days and getting to the moon.

At the core of the risk-free society is a self-indulgent failure of nerve.

Unless we are able to commit to a permanent growing settlement [on Mars], then I don't think just going there with humans and coming back is worth doing. The expense of planning to come back is like the people who left Europe to come to America and then to turn around and go back to Europe, it really doesn't make any sense at all.

For the future, primarily, we must educate people in science, engineering, technology and math.

All the Chinese have to do is fly around the Moon and back, and they'll appear to have won the return to the Moon with humans. They could put one person on the surface of the Moon for one day and he'd be a national hero.