When you're a little different than others, it takes a little more time to fit in. If you really want to be there, there are no ingredients you need other than effort, perseverance and teamwork.

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.

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.

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.

Nobody is going anywhere in 10 years.

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.

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.