It took me a long time to get selected as an astronaut. In fact, I applied for 20 years before I was selected.

There weren't any astronauts until I was about 10. Yuri Gagarin went into space right around my 10th birthday.

I never made a career decision based solely on my desire to be an astronaut. I attended the Naval Academy because I wanted to be a Navy pilot. I majored in math because math had always come pretty easily to me and I liked it.

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.

Even with only two people on board, where maintenance is a large piece of our working day, we still have time to do scientific research. We have to be ready to support those Shuttle visits in a lot of different ways.

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.

In the 19th Century people were looking for the Northwest Passage. Ships were lost and brave people were killed, but that doesn't mean we never went back to that part of the world again, and I consider it the same in space exploration.