No Shuttle Launch Before July 11
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By Madhu Unnikrishnan
KENNEDY SPACE CENTER, Fla. - The launch of NASA's space shuttle Endeavour on mission STS-127 will not happen before July 11, but the range is now clear for the agency's Lunar Reconnaissance Orbiter (LRO) to attempt a launch on June 18.
NASA mission managers scrubbed the launch of STS-127 when they discovered a leak of gaseous hydrogen from the ground umbilical carrier plate (GUCP) - the same issue that kept STS-119 from launching in March and prevented the first launch attempt for STS-127 on June 13. The June 17 launch was scrubbed at 1:55 a.m. EDT.
After the June 6 scrub, NASA engineers replaced the hardware and seals of the quick disconnect and installed shims at the GUCP, fixes that solved the problem for STS-119, according to Mission Management Team Chairman LeRoy Cain. These measures did not resolve the issue on June 17. It is too soon to tell if hardware or a more systemic problem caused the leak, he said. The tanks for the remaining shuttle missions use the same GUCP hardware.
The Atlas V carrying LRO is rolling out to the pad for its launch attempt June 18, with three one-second windows at 5:12, 5:22 and 5:32 p.m. EDT. Endeavour's latest aborted launch attempt, which had been scheduled for 5:40 a.m., started off on the wrong foot when thunderstorms delayed tanking by almost three hours. Fueling was to begin at 8:15 p.m., but only began at 11:02, after NASA gave the all-clear.
Using margin built into the schedule, the STS-127 launch team proceeded with tanking, which was 98 percent complete when the leak at the GUCP was discovered. Engineers attempted to clear the vent for more than an hour, but the issue "never cleaned up," said Mike Leinbach, STS-127 launch director. "The leak was way out of spec and beyond what we were comfortable with," he said.
Now, the earliest Endeavour can launch is July 11, after the end of an orbital sun-angle condition called a beta angle cut-out, which occurs between June 22 and July 10. According to NASA, the cut-out creates a thermal condition that prohibits docked operations of the shuttle and space station.
Cain does't foresee the slip affecting the planned launch of Discovery in August, nor does he see any "significant impact" on any future shuttle mission.
When Endeavour finally launches on its 16-day mission, the crew will perform five spacewalks and complete construction of the station's Kibo laboratory, including the installation of a platform on the outside of the module for exposed experiments.
Story corrected to reflect updated launch date for LRO.
Endeavour photo: NASA
