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.

The most important thing about an astronaut is you have to take for a given a person's done pretty well in school, has the intelligence and all of that to learn new systems and new things. But after that, the most important thing I think is being able to get along with others. Flexibility and teamwork, those issues because as we fly longer and longer in space, those are really important factors, even on short shuttle missions, those are important factors, to put a crew together that can work together effectively as a team, that can get along.

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.

Because we didn't cooperate with China, we gave them motivation to develop their own capability. You know, they developed a very capable rocket system, very capable spacecraft. And if we don't cooperate with them in the future, they're going to develop more capable systems. If we're working together on a highly visible project, there is going to be much less, or there is going to be motivation for each country to not get into a conflict or any kind of tension in the military sense.

My mistakes made were learning how to work with different groups of people. I mean, I went to school at Berkeley, which is a pretty diverse group, but working in a professional setting, I hadn't really done that before and learning about office politics, learning about interactions between different people and I made a lot of mistakes there during my time as a young person. I was 19 or 20 at the time. So, I would say those were my biggest career mistakes, but fortunately they were made in the context of an engineering co-op program and not in a professional field.

One of my challenges was to try to photograph the Great Wall of China. And I did actually take some photos, but it was hard to discern the wall with the naked eye.

The Americans are still the leaders in human space flight. I feel we have a danger here of kind of stagnating. We're kind of resting on our laurels and there's a danger going forward if we don't take bold steps to really support human space flight in this country that we could fall behind. After the space shuttle is retired, we're going to have a big gap, five to seven years, at least where we're not going to have the ability to send our own astronauts into space, we'll have to buy rides on the Russian Soyuz, and so that will be a pretty big step down for us.