Many say exploration is part of our destiny, but it's actually our duty to future generations and their quest to ensure the survival of the human species.

I think we need to move to the moons of Mars and learn how to control robots that are on the surface. It's not the impatient way of getting there, but Mars has been there a long time.

You can tell I'm not too bashful about some of my feelings.

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.

There were about six years when there was not one American who went into space. We shouldn't do that again.

I inherited depression from my mother's side of the family.

Long-term, I see robotics prevailing on the moon. . . . The most important decision we'll have to make about space travel is whether to commit to a permanent human presence on Mars. Without it, we'll never be a true space-faring people.