In 1983, NASA invited Canada to fly three payload specialists, in part because we had contributed the robotic arm that is used on the shuttle.

I like the opportunity to travel the world and work in close company with other people.

The most fun to do in the weightlessness is going down the ladder headfirst, walking on the ceiling, chasing after M&M's that you throw up into the air - they're just bouncing around all over the place and you go around like a fish eating them. I often tell kids that when you go into space and experience weightlessness, the serious adult in you gives way to the child you used to be, who had imagination, who had no bounds on what was possible.

You're in orbit over the Earth. And suddenly it's very, very quiet. It's dramatic. You realize you're floating in the straps in your chair. And you take off your seat belt and float over to the window and look out, and you realize, "I'm not looking at a picture, here." I couldn't process it all. Even if I forget everything else in my life, that will stay with me, burned into my brain until the day I die.

I would love to see the world's space programs continue toward sending humans to an asteroid or to Mars, with, of course, a full plan in place to bring them back. That excites me. And one of the things that excites me most about space is that we can go up there and put spacecraft in orbit with sensors that will help us measure the health of our planet, which is becoming particularly important. Our planet needs to be observed.

Canada's a huge country, so to be able to unite the country through communication satellite technology or to be able to observe it through remote sensing technology from space is a natural fit for a country like Canada.

Well, my father was in the Army and we traveled quite a bit when I was growing up, and I thought that I would like to have a military career, although I was drawn more towards the Navy.