Space Shuttle Discovery Launch Postponed to no Earlier than November 30

By Marc Boucher
November 5, 2010
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Location of hydrogen leak.

NASA has decided to postpone the launch of Discovery to no earlier than November 30. This is a result of the hydrogen leak that occurred early in tanking of the shuttle external tank. It also turns out there was a crack in the foam of the external tank.

The leak was at the Ground Umbilical Carrier Plate, or GUCP, an attachment point between the external tank and a 17-inch pipe that carries gaseous hydrogen safely away from Discovery to the flare stack, where it is burned off. The leak was significant enough that the time needed to remove the fuel from the external tank, diagnose the cause, repair the problem and do it safely would have most likely taken more time than was available in the launch window which was to close Sunday. Managers had considered extending the launch window into Monday but never had to make a final decision on that option.

Mike Leinbach, space shuttle director, compared today’s leak to what they had seen on STS-119 and STS-127 “the leaks we had in the past occurred once we got in the topping sequence, today they were, we were still the fast-filled sequence when we got into the leak. The leak occurred sooner, than we had in the past, and and the magnitude of the leak was higher, the concentrations were higher.”

After a decision had been made to scrub the mission for the day NASA also discovered a crack in the foam of the shuttle external tank. The crack is locate on the front side of the tank facing the orbiter and just above the bipod where Discovery’s nose is attached according to Mike Moses. This is not the first time this happened. Even had no leak occurred, the ice team, which are the final inspection team, would have noticed the crack at which time managers would have had to take time to discuss the issue and in of itself might have caused a delay in the launch. “I don’t know if that would have passed our criteria to be go for launch, but it certainly would have been something that would have generated a whole lot of discussion,” said Mike Moses, chair, Prelaunch Mission Management team.

Location of crack in the foam on the external tank.

Engineers will now have time to address the new problems as well as potentially looking at the circuit breaker problem which delayed the launch earlier. While November 30th is the beginning of NASA next launch window which extends to December 5th, there is no guarantee the shuttle will be ready. Managers want to make sure they address all the problems first and if the shuttle is ready they will try to launch on November 30th. The launch would be a night launch occurring at 4:05 am EST.

If the shuttle was not ready for the next launch window, the launch would be moved to the end of February replacing Endeavour which is schedule to launch on STS-134 on February 27th. Endeavour would then slip to potentially a window in April.

The astronauts who have been in quarantine since arriving at Kennedy Space Center will leave this afternoon for Houston to resume training for the mission.

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