"He submitted his resignation earlier today, it was accepted by the White House, and he has ... offered to stay until the president finds a successor," NASA spokesman Bob Jacobs told Government Executive Monday.
O'Keefe, 48, has applied for the $500,000-a-year university position, and the search committee considers him a top candidate. Its final hiring decision is expected Thursday.
O'Keefe's departure comes at a critical time for NASA, which is struggling to recover from the February 2003 space shuttle Columbia disaster, and beginning work on an ambitious and expensive new set of exploration goals.
The former deputy director of the Office of Management and Budget was sent to NASA in December 2001 with explicit instructions to clean up a $5 billion cost overrun in the U.S.-led International Space Station program. O'Keefe served as Navy secretary in 1992, in the aftermath of the Tailhook scandal, and as Pentagon comptroller before that. Before joining President George W. Bush's administration, he was a professor of business and government policy at Syracuse University's Maxwell School of Citizenship and Public Affairs.
As NASA administrator, O'Keefe not only guided the space agency through a series of budget and ongoing organizational and safety culture reforms, but also used White House ties to focus NASA's exploration strategy. The plan is to return Americans to the moon by 2020, and then send them on a voyage to Mars.
"That will be his legacy, and that's pretty good work," said Jim Banke, speaking for a lobby known as the Coalition for Space Exploration. "Sean O'Keefe has done a remarkable job," said Banke, vice president of Florida operations for the nonprofit Space Foundation.
O'Keefe's departure also sets the stage for a reversal of two key decisions he made as administrator.
In the aftermath of the Columbia tragedy, O'Keefe accepted sight-unseen the recommendations of accident investigators and vowed to "raise the bar" by doing even more than investigators recommended to ensure the safety of astronauts when the shuttle returns to flight.
Shuttle program officials made it clear last week that they will not be able to keep O'Keefe's promise to equip future crews with a repair kit for the winged orbiters' fragile heat-resistant tile exterior. They said the technical challenges are too great to overcome.
Citing safety concerns, O'Keefe also resisted public and congressional pressure to mount a shuttle mission to repair the celebrated Hubble Space Telescope, opting instead to devise a mission to do the same work with robots. The National Academies of Science, which backed the proposal to employ humans in a report last week, urged NASA to reconsider.
The news of O'Keefe's departure surprised NASA employees and policymakers, many of whom expected him to stay until after the scheduled May or June flight of the space shuttle Discovery. NASA insiders and industry watchers also had anticipated a move to the Pentagon for O'Keefe, noting his close association with Vice President Dick Cheney.
Speculating about a possible replacement, news reports named several potential candidates, including retired Air Force Lt. Gen. Ronald Kadish, former director of the Ballistic Missile Agency; Robert Walker, former chairman of the House Science Committee; Ronald Sega, a former astronaut now serving as director of research and engineering in the Defense Department; Robert Crippen, former astronaut and former director of the Kennedy Space Center; and retired Air Force Brig. Gen. Simon "Pete" Worden, former deputy director of operations with U.S. Strategic Command and a University of Arizona research professor who most recently served as a congressional fellow on the staff of Kansas Sen. Sam Brownback.
Early Monday, a senior NASA official said none of the names being circulated in the press had any basis in fact.