Definitely you don't become famous by doing something bad; that's a professional death sentence. You remember that whatever you do, someone will be watching, and you study all the time. It sounds terrible, but you get used to it. I'm 45, and I'm still at school, essentially.

The science behind Interstellar is interesting, because some of it is absolutely real astrophysics and orbital mechanics, some of it is theoretical physics, and some of it is completely Hollywood. When a science fiction movie is based on plausible science, it's really good.

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

When I saw the Earth from above, personally, as a spacecraft operator, it certainly reinforced and drove home the fact that there's one place where we can live right now. The seven billion of us are sharing a wonderful planet, and it's an absolute privilege to see it from above.

Most astronauts are very down-to-earth people. Many of us, three-quarters, have an engineering degree, and we have a very Cartesian, rational approach to things. You don't go and get swept off your feet. That's not your job and that's not why you're hired. So if you get so mesmerized that you forget to do what you're supposed to do, whether it's to open the cargo door of the space shuttle or configure something inside, then you should not be there as a professional operator.

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.

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.