When you're getting ready to launch into space, you're sitting on a big explosion waiting to happen.

So most astronauts getting ready to lift off are excited and very anxious and worried about that explosion - because if something goes wrong in the first seconds of launch, there's not very much you can do.

Even though NASA tries to simulate launch, and we practice in simulators, it's not the same - it's not even close to the same.

The pressure suit helps if something goes wrong during launch or re-entry - astronauts have a way to parachute off the shuttle. The suits protect you from loss of pressure in case of emergency.

The space shuttle is a better and safer rocket than it was before the Challenger accident.

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