The mental stress shouldn't be underplayed. When you're out there doing the work, you can't help but feel the pressure.

I had done everything I could do as an astronaut, and we have a long line of inexperienced astronauts waiting for their first missions, and so my role really should be to step aside and help them prepare for their missions, rather than to try to get another mission.

One of my challenges was to try to photograph the Great Wall of China. And I did actually take some photos, but it was hard to discern the wall with the naked eye.

Tinkering is something we need to know how to do in order to keep something like the space station running. I am a tinkerer by nature.

I hope that China will continue with space exploration. It would be logical to have international co-operation. I hope that it will come about and that I can be involved in it.

With the addition of the laboratory and docking compartments [since then], the station is quite a bit bigger,