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.

Getting into a space suit and going outside, to me, getting your peripheral vision involved and looking at the Earth was a whole different experience than looking through the window. And it's kind of the same on earth. If you're driving in a car and you see like a beautiful sunset or landscape, it looks so much better if you stop and get out and kind of take it all in and that's kind of what it's like doing a spacewalk.

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.

The ultrasound that has application not only in space for a long mission or for a mission to the Moon or Mars, but also in remote areas on the Earth. Not even just - I'm not even talking about expeditions like to the Antarctic, but just a remote area, a small town somewhere. The local doctor is not going to know everything, and so if that person can link in with a diagnostic ultrasound to the hospital in New York City through the internet, then they can do a very quick diagnosis of something that's wrong with someone that's in this remote area.

That was in 1994, July, 1994, and I can remember that like it was yesterday too because it was the culmination of a childhood dream to finally be laying on the launch pad inside a space shuttle and getting ready to be launched into space. The impression of going into a space shuttle is that it looks like a brand new simulator. We spend so many hours inside a simulator that everything is very familiar. Every switch, the seats, the way things work, but the vehicle, the actual spacecraft looks brand new because it hasn't been used nearly as much as the simulators.

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.

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.