Dismayed NASA managers effectively grounded the shuttle fleet Friday because of another fuel leak, this one aboard Atlantis, that will require a second-straight trip back to the hangar for repairs and another major launch delay.
With NASA already reeling from news that the $1.5 billion Hubble space telescope's mirrors are flawed, officials canceled Atlantis' flight readiness review Friday while engineers scrambled to pinpoint the source of a crippling fuel leak like one that grounded the shuttle Columbia last month."We can't fly. We won't fly until we understand it and have it fixed," said William Lenoir, NASA's associate administrator for space flight. "Probably the minimum time of delay (for Atlantis) is on the order of two weeks."
A statement released late Friday said until the cause of the leak is determined, work to ready Atlantis for launch "has been suspended" and that the shuttle will be returned to the Vehicle Assembly Building and removed from its external tank after engineers determine exactly what is wrong.
Columbia's launch last month on a 10-day astronomy mission was called off just six hours before liftoff when sensors detected explosive hydrogen gas spewing into the ship's engine room during fueling for a planned May 30 launch.
The leak later was traced to the area of a 17-inch "disconnect" fitting where the shuttle's primary hydrogen feed line enters the belly of the orbiter. Problems with the giant umbilical cannot be fixed at the launch pad and as a result, Columbia was hauled back to its hangar for repairs.
NASA managers, meanwhile, had proceeded with plans to launch Atlantis around July 16 on a secret military mission, but playing it safe, they ordered a special fueling test to make sure the spaceplane did not suffer from any leaks like the one that sidelined Columbia.
Early Friday, engineers pumped supercold liquid hydrogen rocket fuel into Atlantis's fuel tank and almost immediately sensors detected hydrogen gas around the 17-inch disconnect fitting, indicating some sort of generic problem, either with the hardware or with NASA's shuttle assembly procedure.
Atlantis's flight was put on hold indefinitely and with Columbia already out of action because of a similar problem, NASA's shuttle fleet was effectively grounded.
"I would hesitate to use the word `ground,' but there's no question, we won't fly until we understand it and have it fixed and have tested and verified it and are ready," Lenoir said.
The setback could not have come at a worse time for NASA, which is struggling to keep the decks clear for a high-priority October flight by the shuttle Discovery to ferry a European-build solar probe into space.
While Lenoir held out hope of launching both Atlantis and Columbia before then, NASA could be forced to delay one mission past the October flight, assuming the leak problem can be resolved.