CAPE CANAVERAL, Fla. -- Extensive factory inspections of wing panels between flights could add as much as three months to the time it takes to prepare a space shuttle orbiter for launch, NASA and contractor engineers said Friday.
But in response to the Feb. 1 Columbia disaster, the agency is trying to develop techniques that could enable inspections to be performed at Kennedy Space Center.
And that capability might negate the need to send panels to their manufacturer in Texas after every flight.
"We're in the infancy of that," NASA vehicle manager Scott Thurston said.
"Obviously the vendor has got very good, solid techniques they use to do those inspections," he said. "Will we ever get to the point where we can do it here versus at the vendor? We don't know. We're trying to figure that out."
The exact scope of inspections that will be required between missions after NASA returns its shuttle fleet to flight is undecided, Thurston said.
Shipping them back to the factory would extend the time it takes to prepare a shuttle for launch from four to seven months, he added. And at least for now, that's the plan.
"Right now, on the books, the way we'll do this is pull (wing panels) off every time, between every mission," Thurston said. The Columbia disaster was traced to a wing panel breach that enabled hot gasses to tear the ship apart during an ill-fated atmospheric re-entry.
Accident investigators found periodic visual inspections and "touch tests" done at KSC between flights were not adequate to gauge the structural integrity of the shuttle's Reinforced Carbon Carbon panels.
Twenty-two of the U-shaped panels form the leading edge of each of the shuttle's wings and protect them from intense heat encountered during atmospheric re-entry.
The investigators recommended NASA "develop and implement a comprehensive inspection plan to determine the structural integrity" of the panels, taking advantage of advanced non-destructive inspection technology in doing so.
As part of its effort to return the shuttle fleet to flight, NASA plans to send all wing panels from its three remaining orbiters -- Atlantis, Discovery and Endeavour -- back to manufacturer Lockheed Martin in Grand Prairie, Texas.
Once there, the panels will be subjected to ultrasound, x-ray and eddy current inspections to detect any defects.
The latter technique involves sending an electromagnetic current through panels. An interrupted current serves as an indication of an unseen defect.
All 44 of the panels from Atlantis -- which is slated to fly NASA's first post-Columbia mission -- either have been, or are being, inspected in Texas.
The 22 panels from the shuttle's left wing were returned to KSC. Four of those were reinstalled on Atlantis. Right wing panels will be shipped back to KSC and put back on the shuttle later this year.
Thurston said no significant defects were found in the inspected panels. "We haven't found anything that the vendor or the engineers consider out of character," he said.
Shuttle program managers, meanwhile, are evaluating techniques that could enable inspections to be performed without removing panels from the shuttle.
The techniques that show the most promise are ultrasound and thermography, the latter of which employs infrared imaging devices to spot hidden flaws. But it remains to be seen whether they will be adequate.
Atlantis is in one of KSC's three shuttle processing hangars. The orbiter is expected to be ready for a move to the 52-story Vehicle Assembly Building on Feb. 9.
However, the scheduled move is based on a tentatively planned launch March 11, which senior program managers are expected to push back next month.
NASA's first post-Columbia flight likely will be rescheduled for launch in July
Published under license from FLORIDA TODAY. Copyright © 2003 FLORIDA TODAY. No portion of this material may be reproduced in any way without the written consent of FLORIDA TODAY.
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