Bowersox becomes director of Flight Crew Operations. Photo: NASA

Cabana takes over from Brock "Randy" Stone, who is retiring after a remarkable 36-year NASA career that included work on the Apollo lunar missions, Skylab, the Space Shuttle, and the International Space Station.

"These two appointments really enhance the strong team we have leading us into the Space Shuttle's return to flight and continuing Space Station operations," said William Readdy, NASA's Associate Administrator for Space Flight.

"Bob and Ken bring a wealth of experience in human space flight and an understanding of the importance of space exploration. Their leadership will help us as we move forward in our journey of discovery," said Jefferson D. Howell, Jr., JSC Director. "As for Randy, I will miss him both personally and professionally. All of us wish Randy and his family the best in his retirement," Howell said.

A native Texan, Stone began his career with NASA in 1967, when JSC was known as the Manned Spacecraft Center. He started out working as a systems engineer supporting landing and recovery of the Apollo spacecraft.

He was a flight controller and flight director in NASA's Mission Control Center for almost 30 years and was named Chief of the Flight Director Office in 1989. From 1992 to 2001, he served as Director of Mission Operations, responsible for oversight of Space Station and Space Shuttle missions before assuming the role of Associate Director, Management (acting). He was named Deputy Director in November 2001.

Cabana was selected as an astronaut in 1985, flying twice as a Space Shuttle pilot and twice as commander, accumulating more than 1,000 hours in space. Cabana served in a number of management positions supporting the astronaut office and the International Space Station program, as well as serving as NASA liaison to the Russian space agency. He is a native of Minnesota and a 1971 graduate of the U.S. Naval Academy.

Bowersox is from Indiana and earned degrees from the U.S. Naval Academy and Columbia University. He joined NASA in 1987 and has flown on five space flight missions, including two to the Hubble Space Telescope. He spent more than five months on board the International Space Station as Commander of Expedition 6, returning safely to Earth last May. Bowersox will manage NASA's astronaut corps and aircraft operations at JSC.