You're always under the microscope, you don't know which mission you're going to get. It's a surprise.

I always call myself a space construction worker. We were only the second mission ever to go to the space station. There was nothing on board. We brought the first three tons of equipment, including some of the Imax camera stuff. We literally switched the light on to the station and walked in. It was an assembly mission.

You're less apprehensive when you know what to expect. Also, the first flight is very important in this performance-driven culture I work in; it establishes your reputation. If you don't do well, it's probably your last flight.

The opportunities to become an astronaut in Canada were far and few.

I really believe that, in 500 years, we will still remember the International Space Station, because it will have been the first time, really and truly, that nations put a lot of money, brains, resources, and effort together to build something peacefully, and to work together for the sole and unique purpose of furthering our knowledge and bringing it back to Earth for our mutual good.

I'm 45, and I'm still at school, essentially. Even after being assigned to the mission, I had to write a number of exams, with people commenting on my performance.

Some people will always be volunteers to explore, and it is, in my mind, a privilege.