The moon I see now is the same moon I saw before. Except that before, when I looked at it, it was in anticipation of what it would be like when I got there. That's behind me now.

I understand that Detroit was a pretty rough place to grow up in the '70s and '80s.

Just as Mars - a desert planet - gives us insights into global climate change on Earth, the promise awaits for bringing back to life portions of the Red Planet through the application of Earth Science to its similar chemistry, possibly reawakening its life-bearing potential.

NASA needs to focus on the things that are really important and that we do not know how to do. The agency is a pioneering force, and that is where its competitive advantage lies.

There are a lot of reasons for not doing something. And if humanity had come up with all the reasons for not doing something we wouldn't have spread across the Earth the way we have. There's a curiosity, and I would submit that that curiosity will put human beings on the surface of Mars.

Fear and worry are emotions that cloud the mind from being able to think clearly, to remember what the procedures are to deal with that emergency.

I don't think we're going to build a 50-person spacecraft or a 100-person spacecraft.