I was always very interested in science, and I knew that for me, science was a better long-term career than tennis.

Astronauts will remain the explorers, the pioneers-the first to go back to moon and on to Mars. But I think it's really important to make space space available to as many people as we can. It's going to be a while before we can launch people for less than $20 million a ticket. But that day is coming.

The most important steps that I followed were studying math and science in school. I was always interested in physics and astronomy and chemistry and I continued to study those subjects through high school and college on into graduate school. That's what prepared me for being an astronaut; it actually gave me the qualifications to be selected to be an astronaut.

I slept just floating in the middle of the flight deck, the upper deck of the space shuttle.

Three Secrets to Success: Be willing to learn new things. Be able to assimilate new information quickly. Be able to get along with and work with other people.

I have a lot of common sense. I know what needs to be done and how to approach it. I have an ability to work with people on large enterprises.

It's easy to sleep floating around - it's very comfortable. But you have to be careful that you don't float into somebody or something!