March 14, 2009

NASA Set For Sunday Launch of Discovery

NASA managers said Saturday that space shuttle Discovery is ready for Sunday's launch opportunity as repairs on a leaking gaseous hydrogen vent line are moving along smoothly.

"I think we're in really good shape," said Mike Moses, chairman of the Mission Management Team that reviewed the shuttle's readiness.

Mike Leinbach, shuttle launch director, said the work to replace a suspect quick disconnect assembly on the launch pad is about three hours behind schedule, but that will not delay the countdown. Leak checks will be performed later tonight.

"We feel really good and we're really excited about launching tomorrow," Leinbach said.

The weather forecast continues to call for an 80 percent chance of acceptable conditions, said Kathy Winters, shuttle weather officer.

Launch controllers will begin preparing to pump fuel and oxygen into the external tank Sunday at 10:18 a.m. EDT. Launch time is 7:43 p.m.

Discovery was supposed to liftoff Wednesday night with a crew of seven and one final set of solar wings for the space station.  However, NASA called everything off once again after a hydrogen gas leak began while fueling the shuttle.

The leak occurred near the line in which vents hydrogen gas out of the external fuel tank.  Workers were removing the quick-disconnect unit at that location and a pair of seals on Thursday, and plans to replace the parts Friday.

Allard Beutel, NASA spokesman, said shuttle managers have "high confidence" that the repair work can be done in time to launch Discovery at 7:43 p.m. Sunday. A Russian Soyuz spacecraft will be lifting off on March 26.

The Soyuz is a higher-priority mission.  It will deliver a new crew to the space station.

The initial plan was for the Discovery to spend 14 days in orbit.  If the launch happens on Sunday, then the mission will be reduced to 13 days and there will be three spacewalks instead of the planned four, Beutal said.

Discovery must be flying by Tuesday because of the impending Soyuz mission.  Otherwise, the shuttle will have to wait until April.

Originally, liftoff was targeted for mid-February, but NASA kept pushing back the flight because of concern over hydrogen gas valves in Discovery's engine compartment.  More tests were ordered to ensure that the three valves in Discovery were safe to fly and would not break like the one that did in November.


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