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.

One of the biggest concerns about going out beyond lower Earth orbit is the radiation. We find that exercise seems to counteract a lot of the negative effects of space flight, like bone loss and muscle atrophy and cardiovascular systems issues. We exercise two hours a day on the station, which is a huge hit out of your day. It's great for staying in shape, but you know, it cuts into the productivity of the crew and if you look at how expensive it is to get a crew into space, if we can keep them healthy and have them exercise, but spend less time doing it, we can get more done.

Rockets have remained fundamentally unchanged, except for a few exceptions for the last almost 50 years. So, for there to be a fundamental shift in rocketry and getting into space, there almost has to be a breakthrough in propulsion. Either in how to bring the price down, or how to more efficiently get people up into space and the key barrier is the expense of a rocket.

The thing that you worry about your first flight or any flight is some kind of a problem coming up that is going to keep you from doing it. Whether it's being hit by a car, or getting in a bad accident, or coming down with some other medical disqualification. But once the boosters light, you're going.

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 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.

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.