The one thing we can't really train for is weightlessness, real weightlessness. It's a ton of fun. It's pure Newtonian physics. You push in one direction, you go in the opposite direction with an equal force.

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

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 one thing we can't really train for is weightlessness, real weightlessness. It's a ton of fun. It's pure Newtonian physics. You push in one direction, you go in the opposite direction with an equal force.

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.

Will we go explore? Absolutely. That's what humans have been doing since we left the caves in Ethiopia. Why? Because this is part of our nature. We're curious. We want to push the envelope. That will never stop. We will see people on Mars, hopefully in our lifetime. My hope is that the endeavour is so large, so complex, so technically challenging, so demanding and so uplifting, that it will be done with a consortium of nations. I hope the people who do set foot on Mars will do so for all mankind, and not just one nation in particular.

A lot of people, I think, would love to see the earth from above, wear a spacesuit. Certainly, when I was a kid, I wanted to wear a spacesuit.