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Foam Cracks May Delay Shuttle Launch

An analysis of this photo, taken by Discovery's crew in July, showed that a large piece of foam separated from the fuel tank as the shuttle rose to orbit.
An analysis of this photo, taken by Discovery's crew in July, showed that a large piece of foam separated from the fuel tank as the shuttle rose to orbit. (Nasa Via Getty Images)
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The planned fix was to improve manual foam applications and develop new automated techniques. Hale at that time described elimination of the PAL ramp as an option.

But when they examined a tank that had been twice loaded with fuel and then emptied, engineers found nine vertical cracks in the lower, hydrogen, PAL ramp. Another tank that had not been cryoloaded had no such cracks.

NASA sources, who requested anonymity because they were not authorized to speak publicly about the investigation, said engineers who knew about the cracks immediately suspected they could indicate a serious problem.

But when Hale announced the findings at a Nov. 22 news conference, he said the next "one or two flights" would use the new, improved PAL ramp, while NASA tested the feasibility of flying without it. He said the testing would not finish before next fall.

In his e-mail five days later, however, Hale's tone was markedly more pessimistic. He said yesterday that he had seen a further report from his team showing that at least one of the cracks extended all the way down through the ramp and into the "acreage foam," the initial machine-applied insulation layer to which the ramp is attached.

"Further, cracks appeared in both old and new sprayed areas of the . . . PAL ramp, and therefore the new improved spray techniques do not provide protection from this phenomenon," Hale wrote in the e-mail. "It is hard to see how automated PAL ramp spray would provide any protection from these cracks."

Because of the potential pervasiveness of the cracking, "all efforts should be made to provide a no-PAL ramp flight condition," Hale said, including wind tunnel testing and computer models capable of analyzing the effects of eliminating the ramps.

Hale said yesterday, however, that he had directed his team to move ahead in investigating new spray techniques along with ramp removal, and that the May launch date "remains on the table" while planners study the options in preparation for a formal progress review in the next few weeks.


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