I've discovered that half the people would love to go into space and there's no need to explain it to them. The other half can't understand and I couldn't explain it to them. If someone doesn't know why, I can't explain it.

So most astronauts are astronauts for a couple of years before they are assigned to a flight.

It's no secret that I've been reluctant to use my name for things.

My background is in physics, so I was the mission specialist, who is sort of like the flight engineer on an airplane.

The astronauts who came in with me in my astronaut class - my class had 29 men and 6 women - those men were all very used to working with women.

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.

Eventually private enterprise will be able to send people into orbit, but I suspect initially it's going to have to be with NASA's help. Whether it's going to be a consortium or one entity remains to be seen. I could be wrong. I could be one of the old fogies! Rocket science is tough, and rockets have a way of failing. It happens. A company has to be willing to bear the risk of its rocket failing. It's a very large capital investment.