THE CHALLENGER: AN AVOIDABLE TRAGEDY : Largest Recovery Operation Ever Attempted : Salvage Experts Found Vital Clues

For decades, it was the National Aeronautics and Space Administration that tested the frontiers of space. But after the space shuttle Challenger exploded, the grim, difficult task of recovering the wreckage fell to experts whose work involves another frontier, the oceans.

“We had the best of the best,” said Capt. Charles Bartholomew, the Navy’s supervisor of salvage, who coordinated the retrieval of underwater debris, including the crew compartment and critical parts of the right solid rocket booster.

The diverse collection of 6,000 civilian and military search and salvage experts, which provided vital information to the presidential investigating commission whose report was made public Monday, included divers, sonar specialists, oceanographic researchers and federal aviation accident investigators.

Used Nuclear Submarine

They relied on sophisticated underwater tracking equipment, remote-controlled underwater vehicles with video cameras, manned underwater vehicles that probed the murky depths and a Navy nuclear submarine, the NR1, whose survey of debris saved weeks of work by locating the vital pieces of the solid right booster rocket.

“No one had ever attempted a recovery of this magnitude before,” said Edward A. O’Connor, the Air Force colonel who had been on detail to NASA for six years and who directed the overall effort. “It was a tremendous number of assets to bring together in a short time.”

The search required studying radar and other data of the falling debris, taking sonar readings of 480 square miles of ocean floor and studying more than 720 sonar contacts to distinguish shuttle debris from other objects, including oil drums, shipwrecks and even a DC-3 airplane. Only one in eight contacts proved to be shuttle-related wreckage.

“You can’t just rush out and find these things,” Bartholomew said. “NASA had a hard time understanding that.”

NASA Called for Help

Experts who worked on the recovery and the reconstruction of the shuttle say that NASA was ill-equipped to handle the myriad details of this monumental task. So NASA called for help from such sources as the National Transportation Safety Board, whose more customary job is to investigate civilian air and rail accidents.

Terry Armentrout, the director of the NTSB’s accident investigation bureau, said that when NASA officials called him, he asked whether they had been washing shuttle debris with fresh water to prevent corrosion.

“Should we?” NASA officials asked him. “You do need help,” Armentrout recalled replying.

Ultimately, the salvage operation recovered more than 15 tons of debris, including at least 40% of the orbiter and more than than 50% of the rockets. The only major piece of wreckage still missing is the orbiter’s entire left wing.

Two Top Priorities

Recovery of the crew compartment and the right rocket booster, whose malfunction was identified Monday by the presidential commission reviewing the tragedy as the immediate cause of the disaster, were the top priorities for NASA and those who plowed the vast search area.

For nearly six weeks, searchers combed the debris-laden ocean floor hoping for some clue to the location of the Challenger crew compartment, but the sonar that was towed painstakingly back and forth by ships failed to reveal any large shape that might be the cabin. “We were bamboozled,” said one investigator.

Then one day in early March, an unmanned underwater vehicle relayed the visual image that searchers had been waiting for. A close-up picture showed a window frame, then the forward window structure from the right side of the cabin, then a piece of blue covering from a seat cushion. At last, the precious object had been found in 100 feet of water about 17 miles off shore.

Rejected Using Net

Recovery experts considered wrapping it in a shrimp net and hauling it to the surface but discarded the idea because there were too many small pieces that would slip through a net. Instead, military divers spent several days loading pieces into burlap bags, rubber garbage cans and large wire baskets.

Armentrout, a former fighter pilot, said he is certain that the crew compartment separated intact from the shuttle after the explosion. The cabin tumbled and slammed into the ocean with its nose down, he said, and was crushed upon impact with the water the way a plastic foam cup is smashed under the sole of a shoe. Reacting to the forces of the impact, the crushed cabin expanded slightly and filled with water.

Until further tests are completed on cabin materials, Armentrout said, it is impossible to determine how long the seven crew members may have lived. “We may never know,” he admitted.

Location of the right solid rocket booster--especially the critical joint where hot gases leaked through the booster and touched off the explosion--remained a nagging mystery until early April. Experts believed that the booster broke into several pieces after NASA ground control officials intentionally blew it apart after the accident to prevent its landing on an inhabited area.

Skeptical of Findings

As early as March 1, sonar identified a 10- by 20-foot section of debris, but it was regarded as unlikely to be part of the right solid rocket booster because it was several miles south of the radar trail left by the booster as it plunged to the sea.

Only in early April, after the Navy’s nuclear submarine made a videotape of the debris, did salvage officials recognize its significance. The two-ton chunk of the booster, scorched where the hot gases leaked through it, was retrieved at 5 a.m. on April 13 in 560 feet of water 35 nautical miles from Cape Canaveral.

All but 20% of the right booster has now been located, Bartholomew said. “We found everything that everybody wanted,” he said.

For the first 11 days after the accident, the Coast Guard headed up the search and recovery of surface debris. “At that point no one really knew what would be found,” said Cmdr. James G. Simpson, a Coast Guard spokesman. “The initial guidelines were to pick up as much as you could before it sunk.”

Used Sonar for Weeks

At the height of the recovery operations, Bartholomew, the Navy’s supervisor of salvage, coordinated 13 ships. For weeks, ships towed metal tubes containing sonar in straight lines across the search area--much like mowing a lawn--to pinpoint underwater objects. In a trailer on shore, Michael Kutzleb, owner of Steadfast Engineering in Falls Church, Va., analyzed the sonar images under a Navy contract.

Recovery efforts were complicated by the vast size of the search area and hampered by Gulf Stream currents of as much as five knots that pulled the unmanned underwater vehicles off course. “What made this more difficult than anything was weather and poor visibility, plus the Gulf Stream currents,” said Roy Truman, project manager for Eastport International of Lanham, Md., which does salvage work under contract to the Navy.

Facilitating the search was the fact that many members of the salvage team had worked together before, some on the recovery of the Air India jet that crashed into the Atlantic Ocean off the coast of Ireland last year.

‘A Small World’

“The underwater world is a small world,” said Susan Van Hoek of the Harbor Foundation, a non-profit oceanographic marine science organization in Fort Pierce, Fla., that provided research ships and small manned submarines. “The real professionals know each other all over the world.”

Tim Askew of the Harbor Foundation, who piloted one of the manned underwater vehicles and helped pinpoint some parts of the right solid rocket booster, was one of the newcomers to salvage work. “It was different for us because we were going down and looking for specific objects and not just looking around to see what we could find,” Askew said.

Col. O’Connor, who led the recovery operation, has nothing but praise for the diverse lot who joined the effort. “One of the hardest things was getting people to come back in and stop,” he said. “We were concerned that people were trying so hard that they would risk their lives.”

O’Connor himself, who knew three members of the Challenger crew (“I still get a strong twinge when I walk into the debris area.”) worked round-the-clock with little sleep, pushing aside the emotions of the tragedy. He recently took his first day off since the accident and slept for 17 hours. “It was a total emotional release,” he said.