I thought I was prepared for space, and it still absolutely defied every expectation and dream. It is an incredible thing to put yourself on a rocket and launch off the planet. It is an amazing thing to see the planet from space. This blue sphere is almost indescribably beautiful.
From as young as I can remember, I wanted to be - in order - an astronaut, a geologist, and a biologist.
When you go to vacuum in the airlock and you take the hose off the front of your space suit, there's a little bit of water in there, and you can see that sublimate and ice crystals form and fly away. My thought at that moment was, 'Oh, we are not kidding at vacuum here; we are really in space.'
There's a world of insights to be gained into human health and disease by understanding how gravity and space radiation influence biology.
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.
I was the one with a subscription to 'Sky and Telescope' magazine as a kid while my friends were reading 'Tiger Beat.'
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.
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.