You can't just ignore spacewalking suit; it partially defines the experience. So maybe the most difficult thing is becoming completely attuned to efficiently wearing a garment that is so inhibiting to motion, and making it look effortless, as if it's the most natural thing to be out there on a spacewalk.

Almost everything worthwhile carries with it some sort of risk, whether it's starting a new business, whether it's leaving home, whether it's getting married, or whether it's flying in space.

It’s not enough to shelve your own competitive streak. You have to try, consciously, to help others succeed.

When I stand on the edge of a cliff or right at the edge of a building or something, it's one of the few things that gives me kind of a deep, overwhelming, irrational fear where it affects my physiology.

Doing a space walk. It is one of the most rare human experiences. To leave your spaceship and go outside, so that you are alone in the universe with Earth distant and the universe around you. That is amazing.

Scientific literacy is one of the underpinnings of everything I do. It's why I work with schools. It's why I teach at university. I do a lot of outreach to try and improve general scientific literacy, but the core of all scientific literacy is just literacy.

I've had a chance to fly a lot of different airplanes, but it was nothing like the shuttle ride.