Sean O'Keefe, whose three roller-coaster years as NASA administrator saw the tragedy of the Columbia space shuttle disaster and the glory of the Mars rover and Cassini expeditions, resigned from the agency Monday.
O'Keefe, a self-professed "bean counter" brought in by President Bush to bring NASA's spiraling budget under control, represented a sharp departure from previous administrators: He had no background in astronautics.
He embraced the president's vision of putting men on Mars, but said that using a manned shuttle to repair the Hubble Space Telescope was too dangerous.
O'Keefe, 48, will interview Thursday for a position as chancellor of Louisiana State University and is expected to be approved for the job this week.
The position at the Baton Rouge campus would pay $500,000 a year, compared with the $158,000 he receives at NASA. O'Keefe has three children nearing college age, and he has spent most of his career in the federal bureaucracy, where salaries are generally lower than in industry and academia.
"I owe [my children] the same opportunity my parents provided for me to pursue higher education without the crushing burden of debt thereafter," he wrote in his resignation letter to the president. "I can't do that if I remain in public service."
His departure comes in a period of turmoil for NASA. The agency is still trying to resume shuttle flights after the Columbia accident in 2003, in which all seven astronauts died during re-entry.
Food supplies on the International Space Station are running low and garbage is piling high because of the lack of shuttle flights. A top government science agency last week rejected as unworkable NASA's scenario of using a robotic mission to repair the Hubble.
O'Keefe said he would stay on the job until a successor was appointed by the president and approved by the Senate, but said he hoped that the process would be completed by the end of February.
The list of potential successors circulating unofficially in Washington includes Air Force Lt. Gen. Ronald Kadish, who was in charge of the Missile Defense Agency until September; former Pennsylvania Rep. Robert S. Walker, a member of the president's Moon-Mars exploration commission and a former chairman of the House Science Committee; and former astronauts Charles Bolden, Robert Crippen and Ronald Sega.
O'Keefe was deputy director of the Office of Management and Budget before he was sworn in at NASA on Dec. 21, 2001. He was considered a calming influence after the turbulent decade of direction by Daniel S. Goldin, and was known to have a close relationship with Vice President Dick Cheney.