NASA is preparing to manufacture and install an improved bipod fitting that connects the forward underside of the Space Shuttle orbiter to the upper section of the external tank (ET) for launch.

Insulation foam shed from the bipod during launch of the orbiter Columbia, which hit the vehicle's left wing leading-edge, was the prime cause of the loss of the Shuttle and its seven crew during re-entry on 1 February.

NASA knew of the potential problem because it was revealed that redesign concepts were being developed before the STS 107 mission, after an incident in October 2002 when the orbiter Atlantis lost insulation foam from the same region during the STS 112 launch.

The new bipod will be fitted to an external tank at the Kennedy Space Center in preparation for the return-to-flight mission STS 114 Discovery, which will take place no earlier than the second quarter of 2005. The new bipod design addresses the Columbia Accident Investigation Board's recommendation to reduce the risk of debris falling from the Shuttle stack during launch.

The design eliminates the foam covering from the bipod fitting and replaces it with four rod-shaped heaters that will serve the same primary function as the foam, preventing ice build-up on the bipod fittings on the ET. The heaters will be below the bipod fitting, protected by covers made of a nickel, chromium and iron alloy. They will be between the fitting and a hard dense material that separates the heater from the tank.


Source: Flight International