Anything from making a mistake on an experiment that would ruin some scientist on earth's experiment - career, potentially - to doing something wrong with the satellite that a country was depending on for its communications, to making some mistake that could actually cost you and the crew either a mission or your lives. So there is a lot of pressure that's put on every astronaut to just make sure that he or she understands exactly what to do, exactly when to do it, and is trained and prepared to carry it out.

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

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

There's a huge amount of pressure on every astronaut, because when you get right down to it, the experiments that are conducted on a space flight, or the satellites that are carried up, the work that's to be done, is important and expensive work, and you are up there for a week or two on a Space Shuttle flight. The country has invested a lot of money in you and your training, and the Space Shuttle and everything that's in it, and you have to do things correctly. You can't make a mistake during that week or two that you're in space.

The food isn't too bad. It's very different from the food that the astronauts ate in the very early days of the space program.

One thing I probably share with everyone else in the astronaut office is composure.

My parents must have done a great job. Anytime I wanted to pursue something that they weren't familiar with, that was not part of their lifestyle, they let me go ahead and do it.