We didn't know the importance of home computers before the Internet. We had them mostly for fun, then the Internet came along and was enabled by all the PCs out there.

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.

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.

In the coming era of manned space exploration by the private sector, market forces will spur development and yield new, low-cost space technologies. If the history of private aviation is any guide, private development efforts will be safer, too.

I believe that research, that you can claim that you're doing research only if half of the people, and I'm talking about half of the experts, believe that the goal is impossible.

In 12 or 15 years, there will be routine, affordable space tourism not just in the U.S. but in a lot of countries.

No one knows how to make going to orbit orders of magnitude safer and orders of magnitude more affordable.