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.

Heavy lifting doesn't need to be heavy spending if we do the job right.

It's been one of the greatest challenges that ever came along in my life; it was one of the more difficult things to do.

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.

It's time to open the space frontier to citizen explorers.

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

Having walked on the Moon, I know something about what we need to explore, really explore, in space.