Instead of planning the retirement of the Space Shuttle program, America should be preparing the shuttles for their next step in space: evolving, not shutting them down and laying off thousands of people.

I expected the unexpected and went [on the Moon] with an open mind. I think the visual scene was described by my words on first landing - "magnificent desolation." Magnificent for the achievement of being there, and desolate for the eons of lifelessness.

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.

Returning to the Moon with NASA astronauts is not the best usage of our resources. Because OUR resources should be directed to outward, beyond-the-moon, to establishing habitation and laboratories on the surface of Mars that can be built, assembled, from the close-by moons of Mars.

I do celebrity ski races all over the world.

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

As someone who flew two space capsules and twice landed in the ocean, I can attest from personal experience how much logistics work is needed to get you home.