Rockets have remained fundamentally unchanged, except for a few exceptions for the last almost 50 years. So, for there to be a fundamental shift in rocketry and getting into space, there almost has to be a breakthrough in propulsion. Either in how to bring the price down, or how to more efficiently get people up into space and the key barrier is the expense of a rocket.

On the mission I brought a flag from China, I brought the stone sculpture from Hong Kong, and I brought a scroll from Taiwan. And what I wanted to do is, because as I was going up and I am this Chinese-American, I wanted to represent Chinese people from the major population centers around the world where there are a lot of Chinese people. And so, I wanted to bring something from each of those places and so it really wasn't a political thing and I hope people saw it that way. I was born here, I was raised in the U.S., and I'm an American first, but also very proud of my heritage.

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.

Two years ago, China tested an anti-satellite weapon that actually caused quite a bit of controversy and one of the controversies is that by blowing up a satellite, you are creating more space debris which is a hazard to satellites and spacecraft in lower Earth orbit and if they had been a partner, you'd have to do an experiment, and if they had been a partner in the international space station, would they have really done that test? They would have really thought twice about creating that tension between the countries and potentially endangering a project that they were a part of.

It was in the back of my mind, even while I was going to school, but it wasn't until I was at university studying engineering that I thought, well what do I really want to do? And I kind of came back to that and I said, well the degrees I'm trying to get are going to qualify me to apply. And so, that's what I did after I finished my, or after I was getting my doctorates. That's when I first applied to NASA.

In 2006, I became the fist American to be allowed to go visit their astronaut center in China in Beijing. I think that it makes sense for the U.S. to work with China in the future and I hope to see, if the political atmosphere between the United States and China allow for us to do more cooperation together, especially in the area of human space flight. I think in the same way that it's help improve the relations between the U.S. and Russia; it would help to improve the relations between the U.S. and China.

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.