Possible Key to Shuttle Blast Recovered

Navy salvagers have hauled up a 500-pound rocket fragment from the ocean floor that could be a key piece of evidence in the explosion of the space shuttle Challenger, a Navy spokeswoman said Tuesday.

But a rocket engineer aboard the recovery ship was not able to determine whether the section of casing came from the right solid rocket booster, suspected of triggering the shuttle explosion seven weeks ago, or the left.

“If it’s from the right, it could be critical information,” said Lt. Cmdr. Deborah Burnette, the Navy spokeswoman.

The 4-by-5-foot rocket segment has been tentatively identified as a section of casing where a strut attaches the booster to the external fuel tank, just 20 inches below the joint believed to have failed on the right booster.

Although the casing was not found within debris trails from both boosters mapped out on the ocean floor, it is closest to other wreckage from the right booster, Burnette said.

The Stena Workhorse, a salvage ship that worked late into the night Monday to recover the booster segment, was expected to bring it and other rocket debris into port late this afternoon for positive identification.

Meanwhile, however, a key official in the National Aeronautics and Space Administration’s internal review of the Jan. 28 explosion said Tuesday that the agency expects to present its final findings on the accident within the next month, with or without recovery of the critical booster joint.

“Obviously, we’d very much like to get that segment, and I have to be somewhat optimistic that we will find it,” said James R. Thompson Jr., vice chairman of NASA’s data and design analysis task force, which is collecting and analyzing data on the accident for a presidential investigating commission.

But with photographs and data analysis already completed, Thompson said, “I feel confident we can arrive at the right conclusions even if we don’t have (the segment).”

Thompson, a former NASA engineer now on leave from Princeton University’s fusion research center, said the agency expects to present its findings to the presidential commission by April 18.

“I believe we will identify with high confidence the problem area. We will redesign that problem area,” he said.

The investigation so far has indicated a need to “take a re-look” at the joint segments on the rocket boosters, he said.

“There’s some things that we’ll do differently, and I think there’s certainly some room for improvement on building a margin into that, and I think you’ll see NASA looking at that,” Thompson said.

Thompson downplayed the need to examine data from flight recorders and computers recovered this week from Challenger’s crew cabin. “The problem I believe very clearly is down in the propulsion area,” he said.

Three computer specialists from Odetics Inc. of Anaheim, Calif., manufacturer of the flight recorders, arrived at Cape Canaveral this week to begin their examination of the sophisticated instruments that could have recorded Challenger’s last seconds.

Meanwhile, in Brigham City, Utah, astronaut Robert Stewart told a news conference that preliminary tests of seals like those in Challenger’s rocket boosters show that cold weather may have caused the seals to leak, letting hot gases escape and touching off the explosion. The tests, conducted by booster manufacturer Morton Thiokol Inc., indicate that putty surrounding the seal may have deteriorated because of heat and stress during takeoff, Stewart said.