We were doing something called telemedicine, where we were using the ultrasound. One interesting application of this ultrasound is the possibility that you could possibly use it to measure critical bone areas during a long space mission and track if you're losing bone in these areas. On Earth, when they check you for bone loss, you get in this big machine. It's the size of a room and it's got a platform with an x-ray that scans your whole body and in critical areas and it takes a while and it just wouldn't be practical to have a machine like that in space.

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.

Even though I knew I was inside the space shuttle getting ready to go fly, something about it wasn't completely real up until we got the call at about one minute to go, to close and lock our visors and start our oxygen flow. People often ask me, "What did it feel like right at the moment of launch?" And they're surprised when I tell them actually what I felt was relief. It wasn't like being anxious or scared or anything. It was relief because this is something I had wanted to do my whole life and now that the boosters had lit, we were on our way to go do it and nothing was going to stop us.

The expense of getting into space is the rocket launch, the rocket itself. Rocket's right now, commercial rockets cost probably somewhere between $50, or $120, or $150 million per launch. And those are all expendable. That is, you've got to buy a new rocket for each launch. So, that really is the critical part. If there was some kind of really, a revolutionary breakthrough and the price of rockets fell by an order of magnitude, I mean, just imagine what that would do as far as getting access to more ordinary people.

I'm Chinese-American, of course, and so it's very interesting to see China actually launch their own astronauts, becoming the third nation, following the United States and Russia, to do so.

My advice for an aspiring astronaut is to really follow your passion. I mean, study something that interests you, but also qualifies you to apply. NASA recruits from a wide variety of backgrounds. I know people who have applied to be an astronaut who ask me, well should I do this or should I do that. And I said, you know, it doesn't matter. The basic requirements are you have to be in good health, and you have to have a good heart, I mean in a technical way, not to be a kind person, well that helps. Study something that you like and do well in it.

The space station mission was kind of the culmination of all of my experience of being a NASA Astronaut, so it had brought all of my previous experience into play. I had to learn the Russian language to a fluent level so that I could function as the co-pilot of the Soyuz Spacecraft that we flew up and back from the space station. And then the challenge of being the Commander of the whole expedition, a six and a-half month flight aboard the international space station. I felt the burden of the whole mission on my shoulders, which was fine, and fortunately everything did go well.