I want to keep on the move, keep stimulated and challenged.

I think both the space shuttle program and the International Space Station program have not really lived up to their expectations.

The biggest benefit of Apollo was the inspiration it gave to a growing generation to get into science and aerospace.

I'm not in favor of just taking short-term isolated situations and depleting our resources to keep our climate just the way it is today.

Exploring Mars is a far different venture from Apollo expeditions to the moon; it necessitates leaving our home planet on lengthy missions with a constrained return capability.

We should go boldly where man has not gone before. Fly by the comets, visit asteroids, visit the moon of Mars. There's a monolith there. A very unusual structure on this potato shaped object that goes around Mars once in seven hours. When people find out about that they're going to say 'Who put that there? Who put that there?' The universe put it there. If you choose, God put it there.

Mars has been flown by, orbited, smacked into, radar examined, and rocketed onto, as well as bounced upon, rolled over, shoveled, drilled into, baked and even blasted. Still to come: Mars being stepped on.