Hydrogen Leak Discovered During Tanking

ANN Real-Time Update, 11.05.10, 1311: NASA managers have decided to postpone the next launch attempt for space shuttle Discovery to no earlier than Nov. 30 at 0405 EST.

Technicians will retrieve the ground umbilical carrier plate at Launch Pad 39A and begin a close look at it over the weekend after a leak in the apparatus prompted a scrub of Friday's launch attempt for space shuttle Discovery. Mike Leinbach, shuttle launch director, said the liftoff was postponed until no earlier than Nov. 30 so engineers could have time to consider the problem and inspect the GUCP more closely.

Mission managers also will look closely at a crack in the external tank foam that developed as supercold liquid hydrogen and liquid oxygen were being drained from the tank. The 15-story tall, orange external tank shrinks and expands as its temperature changes from the effects of the propellants. That change can cause the foam insulation on the outside of it to crack.

Mike Moses, chair of the Mission Management Team, said the crack did not develop until after the launch attempt was called off. However, he said the team will analyze the crack carefully.

Discovery's next possible launch opportunity comes Nov. 30 at 4:05 a.m. EST.

Ground Umbilical Carrier Plate (GUCP) -- Launch Pad 39A

Original Report: The final launch of Space Shuttle Discovery was scrubbed Friday morning at 0811 ET because of a hydrogen gas leak 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 earliest opportunity to attempt the launch has been pushed to Monday, Nov. 8, at 1253 EST, the last date Discovery can launch in this window. The next launch window for Discovery is Tuesday, Nov. 30 through Saturday, Dec. 5.

File Photo

Shuttle launch director Mike Leinbach characterized the leak as “significant,” similar to what was seen on STS-119 and STS-127, although Friday's rate was higher in magnitude and occurred earlier in the fueling process.

The external tank is being drained and will be inerted for about 20 hours before it is safe for technicians to look at the GUCP on Saturday.

The Space Shuttle Program Mission Management Team will meet Saturday after technicians have had the opportunity to troubleshoot the hardware. The MMT will determine if it is possible to achieve a launch attempt Monday.

FMI: www.nasa.gov