Tinkering is something we need to know how to do in order to keep something like the space station running. I am a tinkerer by nature.

The only two countries who will be able to launch people into space will be Russia and China. I've seen the Russian technology up close and I've had a chance to look at some of the Chinese technology. It's a very high level. They have good hardware and what China lacks is operational experience. But as they gain more experience, as they fly more missions, they'll catch up quickly. The U.S. does face the possibility of losing the lead in human space flight during this period of what we call the gap.

I was born in the United States, I'm proud to be an American, I'm an American first. But obviously, I'm a Chinese-American. And growing up, my family, my parents, and I think rightly so didn't put us in Chinatown, didn't put us with our other ethnic group, but put us in mainstream America. They're thinking was that will help us assimilate into the mainstream and be a part of it. And it did. It certainly gave me tolerance of other people, of other races, of other ethnicities and I think that's helped make me a better person.

I actually had four space flights altogether, three times on shuttles. My second flight was really unique for me because I was going back into space, first of all. The first one was like an appetizer at a nice dinner. You know, you want to go up and you want more. So, the second time I got into space, it was neat because I got to actually do two space walks.

As commander I was responsible for the overall success of the mission, and so I had to know at least a little bit about everything.

There is no one area of chemical engineering that specifically helped me in my career as an astronaut, it was more the general education in engineering. Also, it was a very difficult and rigorous course. So, it made me strong and resourceful.

Exercise is very important, first of all if you think about it, especially in a long flight like a six month space flight and on the ISS. If you didn't exercise and used the analogy on earth, it would be like laying in bed. So, just imagine laying in bed for several months, and even just trying to get up and walk, you probably wouldn't be able to. But if you got up and you exercised two hours a day, you'd probably be okay, and that's the same in space.