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

I didn't really decide that I wanted to be an astronaut for sure until the end of college.

I never went into physics or the astronaut corps to become a role model. But after my first flight, it became clear to me that I was one. And I began to understand the importance of that to people. Young girls need to see role models in whatever careers they may choose, just so they can picture themselves doing those jobs someday. You can't be what you can't see.

But even in elementary school and junior high, I was very interested in space and in the space program.

The rockets light! The shuttle leaps off the launch pad in a cloud of steam and a trail of fire.

Science is fun. Science is curiosity. We all have natural curiosity. Science is a process of investigating. It's posing questions and coming up with a method. It's delving in.

The view of earth is absolutely spectacular, and the feeling of looking back and seeing your planet as a planet is just an amazing feeling. It's a totally different perspective, and it makes you appreciate, actually, how fragile our existence is.