- The Washington Times - Wednesday, April 30, 2003

Accident investigators plan to issue a working hypothesis as early as the end of next week, explaining why the Space Shuttle Columbia burned up during re-entry Feb. 1.
Harold W. Gehman Jr., the retired Navy admiral who heads the 13-member independent Columbia Accident Investigation Board, said yesterday the panel at the same time will issue recommendations to improve shuttle safety.
"We will announce a hypothesis which narrows the down the options of how heat got into the left wing," Mr. Gehman said.
Last week investigators met privately in Houston with NASA's accident-investigation team to begin analyzing details of the Columbia disintegration, but they emerged without a consensus on what caused the accident that killed seven astronauts.
The two teams have agreed that foam insulation fell from Columbia's external tank and hit the shuttle's left wing 81 seconds after launch. They also agreed that a hole in the same wing let gases penetrate the orbiter, initiating its breakup.
They still must link the foam strike to the damage to the left wing.
Before accident investigators can issue the working hypothesis, they must consider any evidence that might contradict it and rule out any evident error, Mr. Gehman said.
"We can't have any evidence that says our hypothesis is no good," he said.
Mr. Gehman also said the panel will not withhold making recommendations to improve shuttle safety even if members think the suggestions may be too expensive to implement.
"If we come up with a series of recommendations that we think will be prudent and it's too expensive for the nation to bear, so be it," Mr. Gehman said.
Whether to spend the money on the recommendations is someone else's decision, he said.
Investigators will begin tests this week that could help link the foam strike and damage to the left wing. Researchers will fire foam insulation at various shuttle parts in tests that begin tomorrow to measure the impact of foam strikes on the shuttle's heat tiles and carbon panels.
Researchers will use a nitrogen-powered rifle to fire foam at shuttle parts at an estimated 520 miles per hour.
Investigators are zeroing in on the location of the hole that formed in Columbia.
"I feel we probably are within 30 inches of where the actual breach occurred," said Roger Tetrault, a member of the accident investigation board.
Mr. Tetrault said investigators believe the breach is the result of a broken carbon panel panel 8 or broken carbon T-seal on either side of the panel. He also said yesterday the hole probably occurred farther inboard than once thought.
A fragment of that carbon panel shows a pattern of metal deposits. The slag could be aluminum from Columbia's skin that melted when scorching gases penetrated the shuttle's wing.
The top portion of the panel also shows evidence of heat damage.
Mr. Tetrault said the discovery of a new fragment of T-seal carbon stripping between each of the carbon panels lining the front of the shuttle's wings has complicated the investigation because it is not clear where it fits. It probably goes between carbon panels 8 and 9 or panels 10 and 11.
The new fragment was found west of the Dallas-Fort Worth area, one of the few pieces found that far west.



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