Sean O'Keefe is the man who must lead the US space agency (Nasa) through its latest crisis.

On Saturday, the 47-year-old Nasa Administrator should have been congratulating the crew of the shuttle Columbia on nearly two weeks of excellent orbital science.

Instead, he had the awful task of explaining to their families that the space vehicle had broken up on re-entry and they would not be coming home.

Now, Mr O'Keefe faces immense pressure as two technical inquiries investigate the causes of the Columbia.

	:	Shuttle disaster
How Columbia broke up over Texas

He has only been in the job for two years - the 10th Administrator in Nasa history, taking over from Dan Goldin who ran the agency for a decade.

Mr O'Keefe is a specialist in budgets and administration. He came from the number two job at the White House Office of Management and Budget, where he was known for taking tough decisions.

He was sent into Nasa by George W Bush to correct what was seen as wayward spending - to put an end to the cost overruns that seemed to dog the agency's big projects, especially the International Space Station.

Although initially derided as a "bean counter" by some, he has earned respect in his reorganisation of the agency. His old Capitol Hill connections are seen as a major plus for an agency that has to justify its existence like never before.

New initiatives

He is regarded as friendly and approachable and a leader who likes to be visible, regularly visiting the various Nasa centres and attending launches and landings.

O'Keefe has to restore faith

It is said he also likes a bit of fun. It is reported that when he left his post as Secretary of the Navy under the first President Bush, he had a piper march in front of him as he walked out of the Pentagon building.

Recent initiatives have seen him put forward plans for an orbital space plane to replace the shuttle in some tasks, and rekindle the Teacher in Space programme which was cancelled after the death of Christa McAuliffe in the 1986 Challenger explosion.

Mr O'Keefe lives in Ashburn, Virginia, with his wife and three children.