I have no doubt that humans will go to Mars. And I feel that America has led so many things in space - we have invested so much, and we have a lot to gain - that America could and should be the nation that should lead the settlement of Mars.

The life expectancy of people going to Mars may be decreased by the higher level of radiation that they receive.

Some things just can't be described. And stepping onto the moon was one of them.

There's a tremendously satisfying freedom associated with weightlessness. It's challenging in the absence of traction or leverage, and it requires thoughtful readjustment. I found the experience of weightlessness to be one of the most fun and enjoyable, challenging and rewarding, experiences of spaceflight. Returning to Earth brings with it a great sense of heaviness, and a need for careful movement. In some ways it's not too different from returning from a rocking ocean ship.

They didn’t tell me I was going into space until after they locked the shuttle doors and started counting down.

Retain the vision for space exploration. If we turn our backs on the vision again, we're going to have to live in a secondary position in human space flight for the rest of the century.

I am definitely not rich.