CAPE CANAVERAL, Fla. — Thousands of pieces from the space shuttle Columbia began arriving Wednesday at the Kennedy Space Center, where they will be spread out in a huge hangar and at least partially reconstructed by investigators trying to determine what went wrong.

The investigative board that will lead that investigation, headed by retired Navy Adm. Harold Gehman Jr., also arrived at the space center. Its members wanted to see the hangar, he said, as well as where shuttles are prepared for flight, launched and refurbished.

"A lot of people at NASA are telling us a lot of things; we need to see the things they're talking about," Gehman said. "This is an orientation visit."

The first shipment of debris, found scattered across Texas and Louisiana, arrived in two tractor-trailers shortly after 9 a.m.

The scope of the task was made clear by Navy Rear Adm. Stephen Turcotte, a member of the investigative panel.
"Looking at the complexity of this, it is huge," Turcotte said Tuesday. "It is one of the biggest debris fields that I think any of us have ever seen."

As commander of the Naval Safety Center, Turcotte is responsible for probing every aviation mishap in the Navy and Marine Corps.

The initial loads of debris left Barksdale Air Force Base in Louisiana on Tuesday. The debris will be laid out in a 50,000-square-foot hangar on a grid marked by yellow and blue tape. The nine-member inquiry board will have offices in the same hangar, although the board is based in Houston.

Gehman said Tuesday at Johnson Space Center in Houston no debris has been recovered west of Fort Worth, Texas. But he added: "We have reason to believe that we should keep looking west of Fort Worth."

Debris in west Texas could be especially significant because it could help explain how and when Columbia started breaking apart as it aimed for a Florida touchdown. All seven astronauts aboard were killed.

Separately, NASA also said officials from Johnson Space Center had called experts at its Langley research facility in Hampton, Va., on Jan. 27 to ask what might happen if the shuttle's tires were not inflated during a landing attempt.

NASA spokesman Keith Henry said the question was based on assumptions that damage to the shuttle's thermal protection system would cause the tires to deflate. The Langley experts said such a failure could cause broad damage to the shuttle's tires.

The evidence released so far suggests Columbia's troubles began in the left wing where a chunk of foam insulation struck shortly after liftoff Jan. 16. As the shuttle headed home 16 days later, temperatures in that area rose and sensors began failing in the final eight minutes of flight.

Part of the left wing has been found.

During the board's first news conference in Houston on Tuesday, Gehman wouldn't speculate on the cause of the shuttle's demise. "We don't have favorite theories. We're pursuing everything," he said.

He did say he was convinced the inquiry would determine the cause.

NASA Administrator Sean O'Keefe was on Capitol Hill on Wednesday and assured lawmakers, who had questioned NASA's close ties to the board, that the board would be able to act with genuine independence.

During its stay in Florida, the board plans to visit the facility that manufactures thermal protection tiles for the shuttle.

The silica tiles are based on a material first developed by Lockheed chemist Robert Beasley and originally produced at Lockheed's plant in Sunnyvale, Calif. From the earliest tests, some tiles fell off the orbiter.

Even so, production and installation became so refined the work was later done at Kennedy Space Center and elsewhere.