US: The US space agency Nasa will hope to lay the ghosts of the Columbia disaster to rest this morning as it guides the shuttle Discovery back to earth at the end of America's first manned space mission for two-and-a-half years.
It says it will not celebrate until the orbiter is on the runway at the Kennedy Space Centre in Florida and the seven astronauts have safely disembarked after their 13-day trip.
But mission managers admit there will be some sense of triumph, mixed with huge relief, once Discovery completes the highly dangerous re-entry to Earth's atmosphere at temperatures of up to 1,650 degrees.
It was at this stage that the crippled shuttle Columbia broke apart in February 2003, killing all seven on board.
"I don't think I'd use the word euphoria because I'm trying to picture a bunch of geeky engineers getting euphoric," said Paul Hill, the mission's lead flight director. Having said that, we are going to be pretty darn happy to get to wheel-stop and see this good crew step off Discovery.
"And we are all going to feel a huge sense of accomplishment having got through the last two-and-a-half years and demonstrated that we still know how to do this very difficult and dangerous business."
The tension ahead of Discovery's potentially hazardous descent was playing on other Nasa managers yesterday.
The landing director, LeRoy Cain, who was on duty on the morning of the Columbia disaster, said: "If I come to do an entry and landing, with this flight or any flight, and I didn't have butterflies in my stomach, I would probably turn right around and find somebody else to do the job."
A safe landing for the Discovery commander, Eileen Collins, and her crew, scheduled for 4.47am local time, will allow Nasa only a brief celebration before it has to start work on getting the shuttle fleet flying again.
The mission to the International Space Station (ISS) and back took on an air of high drama within hours of lift-off when a large chunk of insulating foam broke away from the external fuel tank - the problem that doomed Columbia and that Nasa had thought it had fixed.
Fortunately, the debris did not strike Discovery, but Nasa announced that all future flights would be grounded until a solution was found, despite a tight timetable for missions to complete the construction of the ISS before the shuttle fleet is retired in 2010. An astronaut, Steve Robinson, removed two protruding "gap fillers" from the orbiter's underside.
The shuttle will stay in space for an extra 24 hours if weather conditions force a postponement of today's landing. - (Guardian service)