Fuel Line Leak Scrubs Discovery Launch

Frank Morring, Jr. morring@aviationweek.com

Kennedy Space Center, Fla.

NASA will not attempt to launch the shuttle Discovery to the International Space Station before March 15, after scrubbing a launch attempt March 11 following a ground equipment leak on Pad 39A.

Space agency technicians detected the leak near a line that carries gaseous hydrogen from the shuttle's external tank into the pad and up to the flame stack, where it is burned off. The leak appears to be at a fixture known as the ground umbilical carrier plate, where the gaseous hydrogen line enters the tank near the top of the port side solid rocket booster.

The STS-119 mission management team believes the leak is on the outside of the plate, and may seal itself if the tank is refilled with liquid hydrogen. But if it is inside the plate, there is at least the potential that it can't be fixed at the pad.

Discovery must get off the pad by March 16 to avoid a conflict with an upcoming Russian Soyuz mission to deliver Expedition 19 crew members to the station. If Discovery can't be launched before the "Soyuz cutout," the mission will slip into April. The leak was detected about 20 minutes before crews would have finished filling the liquid hydrogen tank for a 9:20 p.m. liftoff March 11. The tank was later drained, but can be refilled in time for a 24-hour turnaround.

Discovery is poised to deliver the fourth and final U.S.-built solar array wing for the space station, as well as a replacement urine recycler

Photo: NASA