Endeavour Hydrogen Leak Repair Work Under Way

NASA engineers now believe they understand why a hydrogen gas vent line has been leaking, causing shuttle Endeavour’s STS-127 mission to be postponed twice. According to Space Shuttle Program Manager John Shannon, a plate that attaches the vent line to Endeavour’s external fuel tank is slightly misaligned, allowing a small leak to happen during the fueling process.

Teams at NASA Kennedy Space Center’s Launch Pad 39A will begin disconnecting the vent line from the Ground Umbilical Carrier Plate. Today, crews re-verified the exact measurements of the plate’s attachment to the external fuel tank and performed a leak check at ambient temperatures.

Technicians are preparing to test the repair plan by filling Endeavour’s external tank with liquid hydrogen and liquid oxygen in the next week and a half, just as they would for a launch. This “tanking test” will confirm whether the repairs will work before another launch attempt is made. Hydrogen leaks in the vent line postponed Endeavour’s launch attempts June 13 and 17, delaying its 16-day flight to the International Space Station. If the repairs are successful, Endeavour’s next launch attempt is targeted for July 11 at 7:39 p.m. EDT.