The biggest technical challenge to sending astronauts on farther and longer missions is biomedical: How do we keep them healthy?
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 think there's all kinds of life out there, including intelligent life, but the reason we haven't found each other is because of vast distances.
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.
I was a graduate student in 1984 when President Ronald Reagan called for the construction of a new space station. I knew then that I wanted to apply for the astronaut program, and this was an exciting development.
But a lot of that kind of work is done pre-flight, coordinating efforts with the flight directors and the ground teams, and figuring out how you're going to operate together.