David Brown, 46, was a Navy captain, pilot and doctor. He joined the Navy after a medical internship, then went on to fly the A-6E Intruder and F-18.
He became an astronaut in 1996. Columbia's mission was his first spaceflight.
When asked in a recent interview about the risk of flying in space, Brown, who was single, said: "I made a decision that is part of my job, I would incur some real risk as a routine part of my job when I joined the Navy and started flying airplanes off of ships, particularly airplanes off of ships at night. And I think that was a decision that I made some years ago and the decision to go fly in space is just an extension of that."