“If you’re an adrenaline junkie, I understand why you’d find that exciting. But I’m not, and I don’t.

To me, the only good reason to take a risk is that there’s a decent possibility of a reward that outweighs the hazard. Exploring the edge of the universe and pushing the boundaries of human knowledge and capability strike me as pretty significant rewards, so I accept the risks of being an astronaut, but with an abundance of caution: I want to understand them, manage them and reduce them as much as possible.

It’s almost comical that astronauts are stereotyped as daredevils and cowboys. As a rule, we’re highly methodical and detail-oriented. Our passion isn’t for thrills but for the grindstone, and pressing our noses to it. We have to: we’re responsible for equipment that has cost taxpayers many millions of dollars, and the best insurance policy we have on our lives is our own dedication to training. Studying, simulating, practicing until responses become automatic—astronauts don’t do all this only to fulfill NASA’s requirements. Training is something we do to reduce the odds that we’ll die.”