WASHINGTON — NASA told a presidential commission today that "no concerns were expressed" about solid rocket booster seals before the launch of the ill-fated space shuttle Challenger last month, despite erosion on earlier flights of some rings used to join sections of the rockets.
Lawrence Mulloy, solid rocket booster project manager at the Marshall Space Flight Center, said the space agency had found erosion on six of 171 O-rings used in earlier space flights, presumably the effects of the gases produced by the burning solid rocket fuel.
He said "it wasn't disturbing from a standpoint of safety," adding that NASA "hadn't seen any erosion" for a year before flight 51-L ended in an explosion that destroyed Challenger and killed its seven-member crew.
But Mulloy was swiftly contradicted by Richard C. Cook, a NASA budget analyst, who told the panel he understood there had been some erosion of the rings last year. Cook said that during development of the solid rocket boosters, "the O-ring charring problem" was "considered a potential budget threat" by NASA officials.
Cook wrote a memorandum last summer cautioning that "the charring of seals" posed "a potentially major problem affecting both flight safety and program costs." He was subjected to tough questioning by commission Chairman William P. Rogers concerning whether he was qualified to judge engineering and safety questions.