On the morning of February 1, 2003, space shuttle Columbia zipped over the California coast at a height of 44 miles, traveling 23 times the speed of sound.

The shuttle was coming home after a 16-day mission. In just a few minutes, it would be on the other side of the United States, landing at Kennedy Space Center in Florida.

At the runway, NASA administrator Sean OKeefe waited patiently with Columbias crew families. OKeefe, a cost-cutter who previously held top financial positions with the Navy and Department of Defense, had just spent the past year working to erase a $5 billion cost overrun for the fledgling International Space Station program. The space shuttles were vital in getting the new orbital laboratory up and running, and they would continue on in that role as the rest of the ISS was assembled.

Suddenly, communications with Columbia were lost over Texas. The landing countdown clock hit zero, but the shuttle didnt arrive. Then, news channels began broadcasting footage of debris falling from the sky.

Columbia, along with its seven crew members, was gone. A stunned OKeefe left the landing strip to notify president George W. Bush.

It was terribly emotional, very tragic, and very difficult to work through, OKeefe told me recently.