As an astronaut, you have a very defined set of tasks to do. Those tasks may require you to work 60, 70 or 80 hours a week.

Sometimes people ask me how difficult the astronaut program was, but being in Sierra Leone, being responsible for the health of more than 200 people, seven days a week, 24 hours a day, 365 days a year, at age 26 - that prepared me to take on a lot of different challenges.

I went to school at night in L.A. to brush up on my engineering while I applied to the astronaut program. I really did not know if I would get in. It was the year after the Challenger accident in 1987.

When I left NASA, I was looking at how you could use space technologies for developing countries' work.

The drills we do, where you're telling kids to memorize things, don't actually work. What works is engaging them and letting them do things and discover things.

What we find is that if you have a goal that is very, very far out, and you approach it in little steps, you start to get there faster. Your mind opens up to the possibilities.