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.

I want to know: How does a space suit on Mars work? Show me how it is pressurized, and how it is cooled. What's the glove design? None of that stuff can be bought off the rack. It does not exist. You can't just go to SpaceMart and buy those things.

In any new situation, whether it involves an elevator or a rocket ship, you will almost certainly be viewed in one of three ways. As a minus one: actively harmful, someone who creates problems. Or as a zero: your impact is neutral and doesn't tip the balance one way or the other. Or you'll be seen as a plus one: someone who actively adds value. Everyone wants to be a plus one, of course. But proclaiming your plus-oneness at the outset almost guarantees you'll be perceived as a minus one, regardless of the skills you bring to the table or how you actually perform.

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.

To me, it's not about being anywhere, but being able to change my perceptions and experience something new.

Our three big emergencies are fire, loss of pressurization or contaminated atmosphere. Any of those things in a spaceship are very deadly and time critical. Everybody's trained, but I'm the commander of the ship, and it's up to me to decide.

From space, the Bahamas is the most beautiful place on Earth.