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.

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.

If anything, when you're up in space and you're inside a space ship, which is your home, and without which you would not survive, you know that Earth is your home. This is the only place you can return. In fact we're very meticulous. Part of our job is to maintain the spaceship. If we apply the same kind of model to Earth maybe we'd have a different outlook.

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 prerequisite that people have a scientific or engineering degree or a medical degree limits the number of female astronauts. Right now, still, we have about 20 per cent of people who have that prerequisite who are female. So hey, girls: Embrace the very fun career of science and technology. Look at computer science. That's what I did.

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

I am definitely a little more nervous for my colleagues when I'm working at mission control than I am myself, on the shuttle.