The much-hyped Ares 1-X was much ado about nothing.

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

Like actors and writers who are on and off again in terms of employment, I had a very unstructured life.

The decision to go to the moon is now appreciated and associated with President Kennedy's speech, but somebody else had told him it was a good idea. It turned out to be a good commitment, but it was a unique situation.

My first inclination is to be a bit skeptical about the claims that human-produced carbon dioxide is the direct contributor to global warming.

Absolutely the United States should lead in space, for the survival of the United States. It's inspiring for the next generation. If we lose leadership, then we'll be using Chinese capability to inspire Americans.

Space architectures capable of supporting a permanent human presence on Mars are extraordinarily complex, with many different interdependent systems.