Of course, you'll have to meet the physical and psychological demands. A space walk takes a lot of energy.

The United States, Russia, and China are the only three countries in the world that can launch astronauts into space. Mostly in the U.S. you see some companies trying to launch private commercial people into space, but nobody's done it yet. The only private vehicle that's made it into space so far is Spaceship 1 in 2004, and that was an effort that was funded by one of the Microsoft founders, and he spent about $20 million to develop this spacecraft to do a sub-orbital flight. And it's not the same as going into orbit, but it was a huge first step.

That was in 1994, July, 1994, and I can remember that like it was yesterday too because it was the culmination of a childhood dream to finally be laying on the launch pad inside a space shuttle and getting ready to be launched into space. The impression of going into a space shuttle is that it looks like a brand new simulator. We spend so many hours inside a simulator that everything is very familiar. Every switch, the seats, the way things work, but the vehicle, the actual spacecraft looks brand new because it hasn't been used nearly as much as the simulators.

When Russians were having troubles, the Space Shuttle supported the Space Station Mir bringing up much needed supplies and replacements, critical spares, really. That they were able to keep their space station going for much longer than they would have without us. So, I think that shows the value of international cooperation.

One day, people will be able to buy tickets to visit space.

The neatest thing about research and science is we don't necessarily know what's going to come down the pike. We think we know what we're working on. Oftentimes, discoveries are made when you're trying to discover something else. You end up accidentally discovering a different thing. So, one of those things might happen that enable us to have more efficient rockets.

My mistakes made were learning how to work with different groups of people. I mean, I went to school at Berkeley, which is a pretty diverse group, but working in a professional setting, I hadn't really done that before and learning about office politics, learning about interactions between different people and I made a lot of mistakes there during my time as a young person. I was 19 or 20 at the time. So, I would say those were my biggest career mistakes, but fortunately they were made in the context of an engineering co-op program and not in a professional field.