I remember getting advice like, "Oh, do what interests you. Don't worry about tomorrow, live for today," kind of thing. And to a degree, you've got to do that, you've got to follow your passions. You've got to follow your dreams, but you also have to have a plan. You can't just say I'm going to do what interests me today and I'm not going to worry about tomorrow, that doesn't work. And anyone who's tried that I think quickly finds that out. Think about what turns you on, what do you dream about? But along with that, make a plan and work hard to make it happen.

Because we didn't cooperate with China, we gave them motivation to develop their own capability. You know, they developed a very capable rocket system, very capable spacecraft. And if we don't cooperate with them in the future, they're going to develop more capable systems. If we're working together on a highly visible project, there is going to be much less, or there is going to be motivation for each country to not get into a conflict or any kind of tension in the military sense.

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.

Richard Branson is probably the most visible of the private commercial space guys, and what is venture, Virgin Galactic is about is sub orbital flight. That is, you'll see a spacecraft that looks more or less like an airplane and it will fly into space, but only spend about 15 minutes. It'll go up in a parabolic arc and then fall back down, and so the customers on that flight will only get about five minutes of weightlessness. They'll get to glimpse the horizon of the Earth, take a look at it before just before they start coming back down into the atmosphere.

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.

The Russians have been flying long duration crews since the early '70's. And in the early days, they've ended at least two missions early because of conflicts within the crew. So, they learned early on the importance of studying this and making sure you put the right crew together. Since we began our work together on the International Space station with the Russians in the early 2000's, NASA has started to learn the importance of this kind of work. And so, I think it's important work and we are not fully onboard and recognize it as important.

One of my challenges was to try to photograph the Great Wall of China. And I did actually take some photos, but it was hard to discern the wall with the naked eye.