Mark Kelly

At one point, my house was a school for autistic children. I opened up my doors to about 30 kids and their families at the time. I was turning into Mary Poppins because I had to do something for these kids who have nowhere to go. So my house was the school for two years.

As an astronaut, when you're getting ready to go out of that hatch, you know that's the pinnacle of both your career and your life. The view completely blows you away. The real challenge is getting past the excitement and getting focused and down to work.