Flight out of the atmosphere is a simple thing to do and should have been available to the public twenty years ago. Ten years from now, we will have space tourism where you will be able to see the black sky and the curvature of the earth. It will be the most exciting roller coaster ride you can buy.

The photographs of space taken by our astronauts have been published all over the place. But the eye is a much more dynamic mechanism than any camera or pictures. It's a more exciting view in person than looking at the photographs. Of course, I personally am sick and tired of hearing people talk like that: I want to see it myself!

At various times over 20 years, I did preliminary designs for aircraft like the Stratolaunch. For that whole time I was encouraging us to do something that almost everyone else felt you could not do.

Virgin Galactic, which will be operating SpaceShipTwo, will be only one of several spacelines. The competitors for Virgin include the Russians, Bezos's Blue Origin, and possibly Rocketplane Kistler. And likely a couple of others who are smart enough not to tell people what they are doing!

We need affordable space travel to inspire our youth, to let them know that they can experience their dreams, can set significant goals and be in a position to lead all of us to future progress in exploration, discovery and fun. Thanks to the X Prize for the inspiration.

It's not good enough for us to have generations of kids that ... look forward to a better version of a cell phone with a video in it. They need to look forward to exploration.

By 1931, after a few years' experience of flying scheduled airlines, those planes were operating at roughly 600 times the safety of the space shuttle. I look at safety not in terms of fatalities per passenger-mile, but when you get in and close the door, what is the risk of dying on this flight?