One day, people will be able to buy tickets to visit 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.

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.

I loved flying as much as I thought I would and continue to fly aircraft.

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.

I attended a big human space flight conference in Beijing and I was going as myself. And really, there weren't any NASA astronauts there, I was the only so-called American Astronaut there. We had astronauts from most of the other countries, certainly from Russia, from France, from Japan, several other countries, but it was a little bit odd because here we are at an international gathering of a lot of astronauts and I'm talking about somewhere upwards of 30 or so astronauts, and I'm the only American. And I wasn't even there in an official capacity.

If you think about the energy that a rocket engine has to put out and all the fuel and you're sitting on top of like a bomb. And on the Space Shuttle, that big orange tank is filled with liquid hydrogen and liquid oxygen, the white cell rocket boosters on the sides are filled with solid propellant. There's a lot of energy in all those chemicals there and you've got to control it in a way so it doesn't explode. So, there's a lot of plumbing, a lot of valving, a lot of control systems, and it's a very complicated thing. So, how do you bring the price of that down?