Crack issue not settled, but shuttle chief optimistic Columbia will launch on time
By Chris Kridler
FLORIDA TODAY
CAPE CANAVERAL -- Shuttle managers aren't yet satisfied with tests on parts like one that was cracked in Discovery, but the shuttle program chief is optimistic Columbia will launch Jan. 16 as scheduled. "The shuttle is OK to fly in every other respect," said Jessica Rye, a spokeswoman for shuttle contractor United Space Alliance. "But a decision on whether the parts are safe won't come until a review Tuesday."
Shuttle mission managers held a formal launch readiness review on Thursday at Kennedy Space Center, but they decided more testing was needed before Columbia is cleared for launch, shuttle program manager Ron Dittemore said.
"We don't have any real indications that look like this is going to be a show-stopper for us," he said.
Shuttle managers will review data from tests Sunday afternoon to make sure they are ready to proceed with the countdown, which gets under way overnight Sunday. The crew goes into quarantine today and will fly into Kennedy Space Center on Sunday.
The cracked part was a ball in a support inside a liquid oxygen line in Discovery, found during the orbiter's continuing overhaul. Inspectors found no cracks in Columbia, Atlantis or Endeavour.
There are three sizes of balls in liquid oxygen and hydrogen line supports, called ball strut tie rod assemblies. They range from 2 1/4 inches to 1 1/4 inches, and there are 18 in each shuttle.
Since Columbia is on the launch pad, shuttle managers hope to avoid inspecting it, which could cause a launch delay. Instead, they want to be sure that even if any of the balls are cracked, they won't pose a danger to the orbiter.
Laboratory tests were used to induce surface cracks in spare parts, and engineers experienced with similar problems -- namely, the cracked fuel-pipe liners that grounded the fleet last summer -- found their expertise useful in analyzing the balls, Dittemore said.
"The most likely scenario is that we have a ball in a vehicle that has a small surface defect, and that, under load, over time, has propagated into a small crack," he said.
New inspection techniques found small defects in spare balls that were missed two decades ago when the shuttles were put into operation, he said.
There are no immediate plans to remove the cracked ball from Discovery, he said, but NASA will have to evaluate whether some balls should be replaced if the shuttles are expected to fly for 20 more years. < /end of story >
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This story says cracks weren't found in Columbia, but Columbia wasn't even inspected.
Yes, a certain amount of damage is normal. Columbia actually sustained quite a bit of tile damage on her first mission. 16 were knocked off and another 148 were damaged. (The shockwave from the SRBs igniting caused the damage. This lead to the waterfall sound suppression system that's turned on just before launch.) It would take quite a bit of damage to the tiles to cause a catastrophic failure.