October 19, 2007
Astronauts Back NASA Launch Decision
CAPE CANAVERAL, Fla. -- The commander of next week's space shuttle flight said Friday that she and her crew back NASA's decision to skip wing repairs despite opposition from half the engineers who took part in the launch review.
The concern is over a possible degradation of three of the 44 panels that line Discovery's wings and serve as a thermal barrier to the searing atmospheric gases of re-entry. These panels are made of reinforced carbon-carbon, or RCC.
The crew "is totally confident that the RCC on Discovery is ready to protect us on our ride home," said retired Air Force Col. Pamela Melroy. Columbia was brought down in 2003 by a hole in these wing panels.
Melroy voiced her endorsement after arriving from Houston for the countdown, along with her six crewmates.
NASA's countdown clocks will begin ticking Saturday toward a liftoff late Tuesday morning. The two-week mission will deliver a new pressurized compartment to the international space station.
"There's a time when you need to talk and the flight readiness review was the time to talk," Melroy said. "And then there is a time to go do it, and I'm happy to say we're really here and ready to go do it."
Melroy, only the second woman to command a shuttle mission, noted that Tuesday's flight readiness review lasted 12 hours.
"At a 12-hour discussion, I feel very confident that everybody's voice was heard. Everybody discussed every element of the vehicle that needed to be discussed," she said.
The NASA Engineering and Safety Center argued that the mission be delayed to allow for more testing and possibly even replacement of the three suspect wing panels. A new inspection method picked up possible cracking just beneath the protective coating of these three panels, an apparently ongoing degradation problem that perplexes engineers.
But senior managers concluded it was "an acceptable risk" and said repairs - which would have taken two months to complete - were unnecessary.
NASA has only three more years to finish building the space station, and a lengthy launch delay would make that all the harder to accomplish. Shuttle program manager Wayne Hale said the decision to proceed with Tuesday's liftoff was not based on any schedule pressure.
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