Before U.S. Navy Commander William McCool began his 16-day scientific mission, he explained what was most important about the work he would be doing in space.

"Most of what we're doing is enabling technology for the future," he said. "And the folks who are going to use that technology and then continue the wheels turning are the children today. There's no greater experience, at least in my career thus far, than to see the excitement and the eyes light up when you talk to kids about experiments."

McCool was born in San Diego, Calif., in 1961. After graduating from Coronado High School, Lubbock, Texas, in 1979, McCool went to the U.S. Naval Academy in Annapolis, Md. He graduated in 1983 with a bachelor's degree in applied science, and then, went on to earn a master's degree in computer science in 1985 from the University of Maryland, and a master's degree in aeronautical engineering from the U.S. Naval Postgraduate School in 1992.

In 1986, McCool began his flying career with the Navy. He flew 24 different aircraft, including the EA-6B Prowler, and had more than 400 carrier landings. He became a test pilot in 1992. The pilot served on two aircraft carriers, the USS Coral Sea and the USS Enterprise, and had more than 2,800 hours of flight time.

McCool became an astronaut candidate and reported to Johnson Space Center in Houston, Texas, in 1996. McCool said his experiences in the Navy helped with his transition to NASA.

"We operate as a crew in the same way as we did back in my Navy days in the EA-6B Prowler," he said. "The Astronaut Office, the folks here at JSC, operate in the same fashion that we had learned to operate as a team within the squadron and within the air wing. So I think [they] dovetail quite well."

STS-107 was the first space flight for Pilot William McCool, who joined the astronaut corps in 1996. This feature video was produced before STS-107 launched on Jan. 16, 2003. Video Format QuickTime Netshow Video - 28K / 56K RealVideo - 28K / 56K

While at NASA, McCool gained the respect of his peers. According to Astronaut Office Chief Kent Rominger, McCool was a talented astronaut and was known for his respect for others.

"Willie was incredibly humble, with exceptional talents," Rominger said. "He was especially gifted at quickly learning and mastering technical information, but was also known for his tremendous consideration for others. He enjoyed surprising people with flowers and Hawaiian leis."

McCool's first flight was STS-107 -- a mission that featured more than 80 experiments. McCool, who served as pilot, and his six crewmates perished as Space Shuttle Columbia broke up over Texas while re-entering Earth's atmosphere on Feb. 1, 2003. He spent 15 days, 22 hours and 20 minutes in space.

In his life outside of NASA, McCool enjoyed spending time outdoors with his wife and sons. "My most enjoyable experience is: I really can't pinpoint one," he said. "But I can kind of say as a category my most enjoyable experiences are going out with my wife and my boys back-country backpacking in the Olympic Mountains or … the canyon lands in Utah and just enjoying life without outside distractions. And enjoying each other, and enjoying the environment. And we love to do that frequently, whenever we can."

During a memorial service held at Johnson Space Center, Texas, President George W. Bush described McCool as dependable and respected by his friends. "The Columbia's pilot was Cmdr. Willie McCool whom friends knew as the most steady and dependable of men," Bush said. "In Lubbock today they're thinking back to the Eagle Scout who became a distinguished naval officer and a fearless test pilot. One friend remembers Willie this way, 'He was blessed. And we were blessed to know him.'"

Near the end of his flight, on Jan. 29, 2003, McCool and some of his crewmates were awakened by John Lennon's classic song "Imagine." He had these words about the unique view of Earth that he and his crewmates had from Columbia and their hopes for humanity: "From our orbital vantage point, we observe an Earth without borders, full of peace, beauty and magnificence, and we pray that humanity as a whole can imagine a borderless world as we see it, and strive to live as one in peace."