Strong Gulf Stream currents Sunday forced a recovery ship to abandon, possibly until Monday, efforts to locate a large submerged object and determine if it is all or part of space shuttle Challenger`s crew cabin.
The search of the ocean surface continued, and a Coast Guard helicopter brought ashore what appeared to be the second of Challenger`s two solid rocket boosters.
The right booster has become the center of speculation about the cause of Challenger`s explosion last Tuesday. The National Aeronautics and Space Administration`s acting administrator said Sunday that those boosters were considered to be so reliable that they were ”not susceptible to failure.”
Heavy steel casings on the boosters ”are some of the sturdiest parts of the entire shuttle system,” acting NASA administrator William Graham said on CBS–TV`s ”Face the Nation.”
He said they were such an ordinary part of the shuttle structure that it was deemed not necessary to monitor them during flight with sensors.
Graham said they were not susceptible to failure, ”or we thought them not susceptible.”
Everything possible in engineering was done to ”keep them from having any failure modes,” he said.
Graham appeared on all three network Sunday news interview programs, and defended shuttles` design and quality-control against questions of whether they had been made too lightweight or launched too quickly, to meet cost and schedule criteria.
He said on ABC–TV`s ”This Week” program, ”We don`t think there`s a major reconfiguration problem here. We think there`s an engineering problem somewhere that has to be taken care of.”
Currents forced the Liberty Star, the NASA ship searching for the large object with side-scan sonar, to leave the search site and join other debris-search ships closer to shore Sunday. The ship`s sonar will be equipped with longer cables before returning to the deep-water search area possibly on Monday, according to NASA spokesman Dick Young.
Coast Guard Lt. Cmdr. James Simpson said that 15 tons of debris had been brought ashore by Sunday to be evaluated as possible parts of the exploded shuttle.
Investigators released film and photos Saturday of what they described as ”an unusual plume” of flame in the lower part of the right solid rocket booster.
Although NASA officials stressed that they hadn`t established what caused the blast that killed Challenger`s seven crew members, it was the first official disclosure of factors considered important.
The announcement also supported growing speculation by official and outside sources that fire in the booster might have touched off the huge liquid fuel tank, causing Tuesday`s blast.
Hugh Harris, a NASA spokesman, said the plume appeared less than a minute into Challenger`s ill-fated 74-second ascent.
Harris wouldn`t elaborate on why the flame was considered unusual. But Jim Mizell, another NASA spokesman and former space program engineer, said what was abnormal in the observed plume was the appearance of ”additional white gases” where one normally sees a ”rather rosy or orange colored tinged in black.”
The whiteness indicates ”an additional gas flow. Something has been added there,” Harris said.
In Washington, Rep. Terry Bruce (D., Ill.) said the pictures appeared to lend weight to the theory that the spaceship`s trouble began with some sort of burn-through on the Challenger`s right booster.
He said the ”bright spot” apparent in the pictures never had been seen by experts on previous shuttle missions.
Bruce stressed that the spot ”does not mean that we have located the cause” of the explosion.
He said NASA also has about 4,000 pieces of ”telemetric information”
from Challenger sensors and monitors and that none of it has been analyzed. The pictures produced Saturday, he said, were taken on 70 mm. film with a camera that shoots 40 frames a second.
Bruce said NASA has film of the Challenger tragedy from 12 film cameras, four videotape cameras and between 75 and 80 stationary cameras deployed around the launch site. Bruce said that though the information provided Saturday by the photos is ”valuable,” it is ”by no means conclusive.”
”It is important,” he said, that ”we don`t jump to conclusions based on partial information.” Bruce also made clear that the House Committee on Science and Technology, on which he serves, will be conducting its own inquiry into the Challenger calamity.
