The Navy's paid for you to go through school, and then they need doctors to go out and take care of people who are in various different parts of the world. I decided to pay back my time first as an undersea medical officer. I was stationed in Scotland.

If you're trying to get someone who's sick with a fever off of a submarine and it's cold and raining outside, the only way in and out of a submarine, generally, is through a fairly narrow hatch.

There are some very significant changes in the way the fluids are distributed in our body, the way our heart functions initially, and as well as our bone and muscle.

Whenever I do get to look out, it is glorious. Even the stars have a special brightness.

Some things are only capable of being done in space. Examples of that are looking at our Earth from that far away, and understanding the entire processes of storms and weather patterns, and oceans, and coastlines.

As a physician, I understand how important it is to collect data on people so we can understand what's happening with them. I will be in the position to help enable that knowledge.

Everyone that I've talked to who's been to space has thoroughly enjoyed the experience, and what you often hear them say is: It was great, but we just had to come home.