Shuttle Inquiry, Search Proceed on New Fronts

The board investigating the space shuttle Columbia disaster Saturday toured the Louisiana plant where the orbiter’s external fuel tank was built, while searchers scouring the mountains of New Mexico -- west of where any debris has been found -- were coming up empty.

Investigators also revealed that two more Columbia control jets, making at least four in all, continued to fire in a desperate attempt to stabilize the shuttle during its final minutes.

The jets fire automatically when flaps on the shuttle’s wings and tail are inadequate to control abnormal motions encountered at supersonic speeds. The information was coaxed from the final 32 seconds of ragged data sent from Columbia as it was breaking apart, investigators said.

The last voice communication from the shuttle’s seven astronauts came as Columbia streaked across New Mexico during reentry Feb. 1 before breaking apart about two minutes later.

People near New Mexico’s Sandia Mountains, east of Albuquerque, reported hearing a whooshing sound, said Peter Olson, a spokesman for the New Mexico Department of Public Safety. He said there also was radar evidence that debris could have fallen in the state, but he didn’t have details.

About 140 searchers concentrated Saturday on a rugged 2-square-mile area of Embudito Canyon, walking a few feet apart. Nothing was found as teams began wrapping up by afternoon; one searcher picked up a small disc of melted metal that was later identified as part of a beer can. Two helicopters from White Sands Missile Range that criss-crossed the area also came up empty.

The Embudito Canyon search was expected to last only a day, but NASA could search elsewhere in the state, officials said.

A tile found about 20 miles west of Fort Worth was the farthest point west where any debris has been found, Adm. Harold Gehman Jr., who is heading the 10-member investigation board, said Saturday.

Most of the debris has been found in East Texas, where rain hampered the search again Saturday.

Search crews found a turbopump from the shuttle’s 7,000-pound main engine in a crater outside Ft. Polk, La., and one of the shuttle’s five general-purpose computers, though the equipment was badly damaged.

“General-purpose computers have no hard drive, so investigators held out little hope of extracting additional information,” a NASA statement said. The agency has said the computers, which were the brains of Columbia, might contain data that would allow investigators to reconstruct what was occurring aboard the spacecraft.

Some of the most significant finds have been parts of the shuttle’s left wing and landing gear, where sensors showed temperature rises in Columbia’s final minutes.

The investigation board has said the abnormal temperatures could be explained only by an intrusion of the superheated gases that enveloped the shuttle during reentry.

One board member, Sheila Widnall, a former secretary of the Air Force and a professor of aeronautics and astronautics at MIT, said her “gut reaction” was that it was heat, and not aerodynamic stresses, that broke the shuttle apart.

How the gases -- heated to 2,000 degrees and more by the friction of reentry -- could have penetrated Columbia’s thermal protection layer remains unclear.

The board is considering the possibility that a falling chunk of hard insulation foam stripped from the external fuel tank during liftoff might have breached the spacecraft’s skin. An analysis conducted during Columbia’s 16-day mission concluded the impact did not create a risk to the shuttle and its crew, but investigators are not ruling it out.

Meanwhile, board members visited the Lockheed Martin Space Systems Co. plant outside New Orleans, where the external fuel tank was made.

Gehman said a smaller team would return in the next week to gather data. He stressed that the investigation would treat “all possible causes of the accident with equal vigor.”