It so happened that my goals kind of matched my career progression toward becoming an astronaut.

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

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.

We would like to carry out 100 percent, or maybe more, of our scientific program; I would like to devote some of my spare time toward extra scientific work.

Since the Columbia accident, the Russian space agency, or the Russian space program, has been literally carrying the load bringing us all the supplies we need on the Progress vehicle, smaller amounts on the Soyuz vehicles.

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.

Researchers can measure what kind of angles your legs take up during the day when they're just trailing around behind you in weightless conditions, and what kind of impacts you feel during your exercise. They're going to compare that with what we do on the ground.