- - Friday, June 13, 2003

Accident investigators yesterday revealed a new danger to the fleet of space shuttles but said they are not changing their theory surrounding the probable cause of the Space Shuttle Columbia disintegration.

A 40-pound bolt that flew off Columbia should have been captured by a mechanism designed to contain it, said Air ForceMaj. Gen. John L. Barry, a member of the independent Columbia Accident Investigation Board.

Radar images detected the bolt 126 seconds after Columbia’s launch Jan. 16.

It is not clear whether the bolt hit Columbia. But because of its size and weight, the hardware could have caused serious damage if it struck the shuttle.

By comparison, investigators believe the foam that peeled off Columbia’s external fuel tank weighed 1.67 pounds.

“This particular item has the potential to be catastrophic,” Gen. Barry said after the board’s first public hearing in the District.

The massive bolts connect the solid rocket boosters to the external fuel tank. When the solid rockets expend their fuel, explosive charges separate the bolts and the boosters fall away from the fuel tank. A bolt catcher is supposed to catch them and prevent them from flying away and damaging the shuttle.

Retired Navy Adm. Harold W. Gehman, head of the board, said investigators tested the explosive force in the charge that causes the bolts to come off and allow the solid rocket booster and external fuel tank to separate. That experiment indicated the bolt catcher wasn’t strong enough to withstand the force of the explosive charge and catch the bolt.

“The bolt catcher is not as robust as it should be,” Adm. Gehman said. “We have a potential piece of debris here.”

Investigators said the bolt assemblies on Columbia’s solid rocket boosters and fuel tank were designed by a new supplier and testing on the hardware wasn’t done as well as it should have been.

Before attributing any damage to Columbia’s crippled left wing to the bolt, investigators must determine the trajectory of the hardware.

“We don’t have this as a direct tie to the mishap,” Gen. Barry said.

NASA will have to correct the problem before it can resume shuttle flights, the investigators said.

They lamented that the problem with the shuttle’s bolt assembly may be indicative of a larger problem with shortcomings in testing at the National Aeronautics and Space Administration.

The space agency must do better testing of all components, Gen. Barry said, not just the largest systems.

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