The board investigating the Columbia disaster toured the Louisiana plant where the external fuel tank was built, while searchers scoured the mountains east of Albuquerque, N.M., Saturday, two weeks after the shuttle broke up 39 miles above the Earth.

Investigators also revealed Saturday that two more Columbia control jets, 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 any 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 on Feb. 1.

At about the same time, people near New Mexico's Sandia Mountains 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 there, but he didn't have details.

The shuttle broke apart about two minutes after it passed overhead.

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

Adm. Harold Gehman Jr., who is heading the now 10-member investigation board, said Saturday that a shuttle tile found about 20 miles west of Fort Worth was the farthest point west of any debris found so far.

Search crews also found a turbopump from the shuttle's 7,000-pound main engine in a crater outside Fort 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 so far 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 only be explained by an intrusion of the superheated gases that enveloped the shuttle during re-entry.

The board's newly named 10th member, Sheila E. Widnall, a former secretary of the Air Force and a professor of aeronautics and astronautics at the Massachusetts Institute of Technology, said Saturday her "gut reaction" was that it was that heat, and not aerodynamic stresses, that broke the shuttle apart.

How those gases -- heated to 2,000 degrees and more by the friction of re-entry -- 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 shuttle's 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.

On Saturday, 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."

Meanwhile, NASA continued to urged the public to come forward with any photographs or videotapes taken of Columbia from anywhere between Hawaii and Texas. The string of problems detected aboard Columbia began shortly after the shuttle entered the atmosphere over the Pacific Ocean.