Breakthroughs are what define our species. They come about because we are threatened.

Usually the wacky people have the breakthroughs. The 'smart' people don't.

To allow public access to orbit, we would need breakthroughs that would lower the cost by a lot more than an order of magnitude and increase safety by a factor of 100 as compared to every launch system used since the first manned space flight. I think airborne launch will be a significant part of the safety solution.

There was a wonderful little short four-year time period when marvelous things happened. It started in 1908, when the Wright brothers flew in Paris, and everybody said, 'Ooh, hey, I can do that.' There's only a few people that have flown in early 1908. In four years, 39 countries had hundreds of airplanes, thousands of pilots.

When there's ever a breakthrough, a true breakthrough, you can go back and find a time period when the consensus was 'well, that's nonsense!' so what that means is that a true creative researcher has to have confidence in nonsense.

Space travel is the only technology that is more dangerous and more expensive now than it was in its first year. Fifty years after Yuri Gagarin, the space shuttle ended up being more dangerous and more expensive to fly than those first throwaway rockets, even though large portions of it were reusable. It's absurd.