Once you've been first, it cannot be done again. Not by you, not by anyone else.

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

The pilgrims on the Mayflower landed at Plymouth Rock. To my knowledge, they didn't wait around for a return trip to Europe. You settle some place with a purpose. If you don't want to do that, stay home. You avoid an awful lot of risks by not venturing outward.

I think there would be no shortage of applicants to the government astronaut corps to be settlers on the planet Mars. And I think this would be very inspiring.

A space program that truly goes somewhere! With his deeds, not only words, President Obama has revitalized our struggling space program.

Sending a couple of guys to the Moon and bringing them back safely? That's a stunt! That's not historic.

Do we really need these big, gigantic, heavy rockets? What if we launch a rocket that's empty, and its sole purpose is to act as a source of fuel on the Moon? Who should build that? Well, I think the U.S. should build that.