Of course, you'll have to meet the physical and psychological demands. A space walk takes a lot of energy.

Coming down under a parachute is quite different as well. You hit the ground pretty hard, but all the systems work very well to keep it from hurting, so it doesn't even hurt when you hit. It was a great experience to be able to do both.

You saw Britain back in the early days of sailing ships. They were the sea power, the controlled the seas and they had colonies all over the world and then you can look at history and watch the way that their empire kind of crumbled. I certainly don't want that to happen to the United States in space technology.

I had done everything I could do as an astronaut, and we have a long line of inexperienced astronauts waiting for their first missions, and so my role really should be to step aside and help them prepare for their missions, rather than to try to get another mission.

I would say keep supporting space flight, keep telling the public and the politicians why it's important to advance science and explore the galaxy. I encourage the Japanese to keep doing what they're doing.

I hope that China will continue with space exploration. It would be logical to have international co-operation. I hope that it will come about and that I can be involved in it.

Space is very unforgiving business

When Russians were having troubles, the Space Shuttle supported the Space Station Mir bringing up much needed supplies and replacements, critical spares, really. That they were able to keep their space station going for much longer than they would have without us. So, I think that shows the value of international cooperation.

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.

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.

I think it's good to have competition. Now we have a third country that can launch astronauts, so it's good for all of us. It makes us a little bit more competitive and wanting to be the leader.