Achieving something that has never existed in manned spaceflight and that is high volume and public access.

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.

A NASA astronaut and a Russian cosmonaut can't be creative. He has to follow a predetermined detailed checklist written by an engineer and if he gets a little creative he'll never fly again.

I like to call the difference between research and development. Some people use that interchangeably. They'll say R&D. They're two totally different things.

I was shocked to find that there were actually climate scientists who wouldn't share the raw data, but would only share their conclusions in summary graphs that were used to prove their various theories about planet warming. In fact I began to smell something really bad, and the worse that smell got, the deeper I looked.

A NASA-funded study estimates that if the price of a ticket to space approached $100,000, close to a million people would buy one. That's a $100 billion industry. Microsoft cofounder Paul Allen gave me $20 million in startup funding to go after that market.

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.