This story was updated at 3:29 p.m. EDT.
NASA has delayed a high-priority moon mission to make way
for the space shuttle Endeavour to launch Wednesday.
The shuttle was originally intended to blast off June 13
toward the International Space Station, but was thwarted by a potentially dangerous
hydrogen
gas leak from a vent line off its external fuel tank. NASA thinks it can fix
the leak in time for a Wednesday liftoff at 5:40 a.m. EDT (0940 GMT) from
Launch Pad 39A at Kennedy Space Center in Cape Canaveral, Fla.
"The repair work is going well," NASA test
director Steve Payne said today at a briefing. "We expect to have all the
work completed by 3 p.m. [EDT] on Tuesday afternoon. Our teams have been working
very hard over the last couple of days to get this piece of equipment fixed."
This timeline will push back the planned flight of a pair of
unmanned
lunar probes which were scheduled to launch the same day from the nearby Cape
Canaveral Air Force Station. NASA decided to give Endeavour another chance to
fly before its window to align with the space station closes.
Clear skies
The weather for Wednesday looks favorable for the shuttle
launch, with an 80 percent chance of "go" conditions, shuttle weather
officer Kathy Winters said today. A slight chance of clouds poses the only
weather threat to liftoff that day.
"I do have good news for launch," Winters said. "Weather
is overall favorable."
The lunar
spacecraft - the Lunar Reconnaissance Orbiter
(LRO) and the Lunar CRater Observation and Sensing Satellite (LCROSS) - will
now aim to fly as early as Thursday at 5:12 p.m. EDT (2112 GMT), NASA launch
director Chuck Dovale said today.
If the shuttle must cancel its Wednesday launch attempt at
any time before midnight on that day, the moon probes can likely fly Thursday.
If Endeavour succeeds in getting
off the ground, LRO/LCROSS may launch either Thursday or Friday.
"Exciting times on the space coast," Dovale said.
Even if Endeavour is unable to lift off for any reason on
Wednesday, the shuttle management team has agreed to stand down until July 11 and let the lunar
mission proceed, as that launch has already been delayed about eight months for
various issues.
Familiar troubles
The leak problem plaguing the space shuttle is not new; a
similar problem stalled the launch of the shuttle Discovery's STS-119 flight in
March. That mission ended up blasting off four days later than planned after
ground crews swapped out the suspect seal between the vent pipe and the
shuttle. NASA hopes a similar fix on Endeavour will do the trick.
Though switching out the faulty seal has resolved the
problem in the past, no root cause for the leaks has been discovered.
"The only thing that we've seen is evidence of a little
compression, probably caused by the fact that [the seal] was a little misaligned,"
Payne said. "What's causing the misalignment is probably what we really
have to go after."
Challenging mission
Endeavour is slated for a 16-day mission to deliver the
final segment of the Japanese Kibo laboratory to the space station, as well as
drop off a new long-duration station crewmember, NASA astronaut Tim Kopra, who
will replace Koichi Wakata of Japan. Wakata is due to fly home aboard
Endeavour.
Endeavour's commander Mark Polanksy plans to lead his crew
of seven through a series of five challenging spacewalks and complicated
robotic maneuvers to install the new lab section as well as a horde of spare
equipment for the station.
SPACE.com is providing continuous coverage of STS-127
with Staff Writer Clara Moskowitz and Senior Editor Tariq Malik in New York. Click here for mission
updates and SPACE.com's live NASA TV video feed.
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