Small samples in the centrifuge will spin at varying rates to create synthetic gravity, like the gravity of Mars or the gravity of the moon, and measure how the specimens respond within the centrifuge.

After assembly complete, when we have a larger crew on orbit, a more complex vehicle, more laboratories and more robot arms, maybe we'll have room for specialists. But right now we don't.

My dad served in two wars has been flying airplanes for 60 years now. He was certainly quite an inspiration.

If I wasn't doing this kind of exploration, I'd like to be doing some other kind of exploration. It might be more risky, or less risky, but, in the business of exploration, risk is part of the territory.

We're going to be focusing our science on things that will take us farther and longer into space. For many of those experiments, the crew members are human guinea pigs, which is fine; that's part of my job. I don't mind being a human guinea pig.

The Space Shuttle will stop directly below the Space Station and Sergei and I will be looking out two different windows looking straight down at the Space Shuttle.

Every day, we get a little bit closer to the kind of expertise and the kind of experience we're going to need to go there. I'd love to be the guy walking on Mars.