From as young as I can remember, I wanted to be - in order - an astronaut, a geologist, and a biologist.
You absolutely know you're in space when you're doing a spacewalk. That was pretty interesting because you can feel vacuum. It actually changes your vocal cords because the pressure inside the suit drops quite a bit, so your voice feels different.
As an undergraduate majoring in biology at the University of California, San Diego, I worked on infectious diseases at the nearby Salk Institute for Biological Studies.
I was the one with a subscription to 'Sky and Telescope' magazine as a kid while my friends were reading 'Tiger Beat.'
For long-duration exploration missions, NASA is looking for folks with a lot of operational, hands-on experience, people who have been in field-type situations such as military deployments. In my case, I worked in the Congo and in Biosafety Level 4 labs on smallpox.
There's a world of insights to be gained into human health and disease by understanding how gravity and space radiation influence biology.
