Story updated at 10:40 p.m. ET

WASHINGTON -- NASA Administrator Sean O'Keefe resigned Monday to pursue a job as chancellor at Louisiana State University.

NASA spokesman Robert Jacobs said that O'Keefe submitted his letter of resignation to the White House Monday but "plans to stay on until the administration finds a successor."

O'Keefe, 48, is traveling to Baton Rouge on Wednesday to tour LSU's main campus and to interview with the university's selection committee. Charles Zewe, a spokesman for LSU's board of supervisors, said Monday that O'Keefe is the university's top pick for the job. "No one else is being interviewed. No one else is being brought to campus," Zewe said.

"This was the most difficult decision I've ever made, but it's one I felt was best for my family and our future," O'Keefe explained in a NASA press release issued late today from NASA Headquarters in Washington, D.C.

In his resignation letter to President Bush, the NASA Administrator wrote: "I will continue until you have named a successor and in the hope the Senate will act on your nomination by February."

Steven Squyres, a Cornell astronomer and leader of the science team for the twin Mars Rovers, said Monday that O'Keefe has been a "strong supporter" of the rover team, providing support before launch and during the mission. "Sean O'Keefe was an absolute pleasure to work with," Squyres said.

O'Keefe's resignation follows closely a come from behind budget victory. Congress approved a $16.2 billion budget for NASA in late November, a remarkable turnaround from the $1 billion cut lawmakers in the U.S. House of Representatives had recommended over the summer.

"Mr. O'Keefe has taken the ball and made a good run downfield and for that everyone in the space community is grateful," said George Whitesides, executive director of the National Space Society, the Washington, D.C.-based space advocacy group. "But we have a ways to go, so all eyes will be on who comes next."

O'Keefe was sworn in on Dec. 21, 2001 by his political mentor Vice President Dick Cheney and given a mandate to clean up NASA's financial management.

O'Keefe's focus shifted abruptly with the Feb. 1, 2003 loss of the Space Shuttle Columbia. O'Keefe unhesitatingly pledged the agency to comply Columbia Accident Investigation Board's sweeping recommendations for resuming shuttle flights.

In the aftermath of the Columbia accident, the White House formulated a new space exploration vision for NASA and on Jan. 14, with a speech by President George W. Bush, it became O'Keefe's charge to start refocusing the agency in order to make the vision happen.

The vision, like the effort to return the space shuttle to flight and overhaul of the U.S. space agency's finances, remains a work in progress as O'Keefe prepares to leave the post he's occupied for three years.

SPACE.com's Robert Roy Britt and Anthony Duignan-Cabrera contributed to this report.