Mars is there, waiting to be reached.

The energy varies with the square of the velocity, so if you need five times the velocity, that's 25 times the energy.

At 10,000 feet, the 3 parachutes would come out, a little lower the pressure of the atmosphere outside was greater than inside, and we could smell the salt air and it was very encouraging to return to earth.

I think the people who experienced the Apollo missions came away from that experience wondering to themselves, 'When can we get a chance to experience spaceflight?' I've heard that many, many times: that people got into a new career field hoping that they would be able to experience spaceflight.

Any observations from the Moon or a sense of realising this or that about the greater meaning of things wasn't as influential for me as the experience of coming back and dealing with being a person who's been to the Moon.

To appropriately respond to an emergency requires a very clear mind, to cooly analyze what the observations are and how to fix it.

Unless we are able to commit to a permanent growing settlement [on Mars], then I don't think just going there with humans and coming back is worth doing. The expense of planning to come back is like the people who left Europe to come to America and then to turn around and go back to Europe, it really doesn't make any sense at all.