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.

One of the things, and the most exciting, actually definitely the most exciting thing is, having children. You know, I didn't have children before. I had been married only a year before my space station mission, so having three-year-olds is a whole new experience and that's the new adventure. It may sound funny because people have kids every day, but having your own kids, having my own kids, was as fundamentally, or maybe even more fundamentally life changing then even flying in space.

The training kicked in and we quickly went through our emergency procedures, I took manual control and I got the spacecraft under control and stopped about 50 meters from the space station. So, the net effect of the failure was that we were actually turning and speeding up towards the space station when we should have been slowing down, so it was quite a dangerous situation. But we got manual control, performed the first manual docking to the station at night. The training pays off. It was just automatic. We had our books out already, we went right to the right procedures and executed them.

The Russians right now require a customer coming in and spending about six months or so in Russia and they have to learn some Russian. They have to learn some critical words so they can, in an emergency, at least have minimum communication with the Russian commander of the Soyuz. They also have to learn systems and I think this just evolved that way. They just thought, what is the minimum set of things we think we can train someone to be more or less competent in our systems? And so that's what these guys go through. So, it's not just like buying a ticket and getting on an airliner.

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.

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.

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.