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.

Science is not about consensus, and consensus is not science.

The criticism is, once I get something flying, I lose interest in it.

I have a hunch the most important reason we're going to space is not known now.

When you have a transportation system that the price of propellant is essentially negligible something is very wrong. If you look at any other transportation system, a car, a motorcycle, a train, an oil tanker, an airliner, you name it; about a quarter to a third of the operating cost is buying the propellant.

I spent about seven years during the Vietnam War flight-testing airplanes for the Air Force. And then I went in and I had a lot of fun building airplanes that people could build in their garages. And some 3,000 of those are flying. Of course, one of them is around-the-world Voyager.

NASA works for the White House. There are many at NASA that wish they were building a modern replacement for the Shuttle. However, they had marching orders to instead work on other things, some of which should have no place in a research organization.