The next 15 years will see thousands of people leave the atmosphere on suborbital flights. My company's SS2 system might fly 100,000 people by 2024. If it is shown to be highly profitable, perhaps we will see 20,000 people traveling to orbit by 2035, and then thousands to the moon by 2050. If we make a courageous decision, like the program we kicked off for Apollo, we will see our grandchildren in outposts on other planets.

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.

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

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?

We didn't have practical model rockets in the '50s. The ones we made were very dangerous and the kids that played with them didn't have all their fingers, and sometimes were blind in one eye.

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.

Within 25 years, virtual reality meetings will be essentially transparent to being there in person. Once we can do this, the idea of climbing into an aircraft, and burning up huge quantities of fossil fuels to propel our bodies and briefcases full of papers, will seem absolutely backward.