Sen. Sam Brownback Crossing over California minutes before it broke apart, the space shuttle Columbia heated abnormally on its left side at about the time that an astronomer observed a large, bright object dropping from the spacecraft.
The rising temperatures, together with evidence of increasing wind resistance on Columbia's left side, suggest that heat shield tiles on the shuttle's left side were damaged, NASA officials said at a news conference yesterday.
The unusual cascade of problems began near where a piece of fuel tank insulation struck the spacecraft Jan. 16 during launch.
Shuttle program manager Ron Dittemore cautioned against jumping to conclusions about the cause of the shuttle's destruction Saturday morning. "We've got some more detective work," he said. "We haven't ruled out anything at this point."
As NASA engineers began poring over telemetry and other data from the shuttle's final moments, Dittemore spoke with the California astronomer who watched from the ground Saturday as blobs of light appeared to separate from the shuttle as it streaked across the sky.
"I just imagined they were [heat shield] tiles falling off," said Anthony J. Beasley, a radio astronomer at the California Institute of Technology. But 30 seconds before the shuttle disappeared over the eastern horizon, "there was a single very bright thing falling. ... I said, 'Well, that's a very big tile.'"
NASA officials said yesterday that remains of all seven astronauts had been recovered from the debris field that spread along a 500-mile swath across East Texas and northwestern Louisiana.
Investigators hope that the debris, coupled with information beamed from the shuttle in the final seconds before its destruction, will provide important clues. The information will be examined both by an internal NASA "Mishap Investigation Team" and a panel named by NASA administrator Sean O'Keefe, who asserted that it would operate independently.
Yesterday, he named a retired Navy admiral, Harold W. Gehman Jr., who led an inquiry into the terrorist attack in Yemen on the destroyer USS Cole to head the new Columbia accident investigation board. Critics immediately questioned whether a board named by NASA could be truly independent.
More inquiries are being mounted by a growing list of congressional committees, including the House Science Committee, and the Senate Commerce, Science and Transportation committees.
"The key issue for us in Congress is why did it happen, how did it happen, how do we fix it and then how do we project on forward with manned space flight," said Sen. Sam Brownback, a Kansas Republican. "We need to continue that for the vision of the country and the vision of the world."
Nearer the disaster scene, federal investigators from NASA, the Federal Emergency Management Agency, the National Transportation Safety Board, the Department of Defense and other agencies were gathering at Barksdale Air Force Base, near Shreveport, La., which will be the site of initial stages of the inquiry.
Hundreds of pieces of debris have been located, and investigators have begun to truck them to Barksdale for temporary storage and preliminary study.
Residents were repeatedly warned not to handle the debris, which could be toxic. Although there was no immediate evidence of a link, more than 40 people in Nacogdoches County complained of various ailments, and at least eight people were hospitalized with burns and breathing problems in Hemphill, according to Nacogdoches County Judge Sue Kennedy.
Robert Cabana, the director of flight crew operations at the Johnson Space Center in Houston, said NASA was working with the Israeli Embassy to assure that Israeli payload specialist Ilan Ramon's remains are handled properly. Jewish tradition normally calls for burial within 24 hours, followed immediately by mourning rituals.
Other astronauts killed when the spacecraft broke apart returning from a 16-day scientific mission were shuttle commander Rick Husband, mission specialists Michael Anderson, David Brown, Kalpana Chawla and Laurel Clark, and pilot William McCool.
President Bush will honor them at a memorial service tomorrow in Houston.
At a briefing yesterday, Dittemore said that seven minutes before contact with the shuttle was lost, telemetry showed that temperatures in the shuttle's left wheel well had risen 20 to 30 degrees in five minutes.
"This was the first occurrence of a significant thermal event," he said. Other sensors in the area quit working.
Columbia was passing the hottest portion of re-entry, when surface temperatures on the shuttle reach 3,000 degrees Fahrenheit.
As the minutes ticked by, other sensors reported that temperatures in the fuselage - also on the left side - had climbed 60 degrees in five minutes, four times the expected amount. Temperatures in the crew compartment and payload bay remained normal.
At 8:58 a.m. Eastern time, Columbia's computer-driven flight controls began tugging the ship to the right, compensating for increased drag, or wind resistance, on the left side.
It was the proper response to the wind drag, Dittemore said, and there was no evidence the crew was alarmed by it. But it "could be an indication of rough tile, or missing tile [on the left]. We're not sure yet," he said.
At 8:59 a.m. the shuttle's computers pulled the ship even harder to the right to compensate for the increasing drag on the left. Columbia was correcting with greater force than NASA engineers had ever seen on prior flights, Dittemore said.
The combination of rising temperatures and increasing drag could point to worsening thermal tile damage as the ultimate cause of the accident.
Voice communications with the shuttle were lost at 9 a.m., but Dittemore said NASA has 32 seconds of additional telemetry data that engineers had not yet examined.
NASA investigators were considering whether fuel tank insulation that struck the shuttle's left wing during liftoff might have damaged some thermal tiles.
Dittemore said the incident at liftoff on Jan. 16 wasn't noticed until launch films were examined the next day. Engineers had seen similar debris hits in the past, and they concluded this time that the damage was not a flight safety issue.
NASA discarded years ago the idea of sending astronauts on spacewalks to inspect or repair such damage. It is difficult and dangerous for them to move to the underside of the spacecraft. And it was feared that such activity might do more damage to the fragile tiles.
"We're helpless to do tile repair" in orbit, Dittemore said. And telescopic photos from the ground would not have revealed enough to be useful. "So, we didn't take any pictures."
Dittemore said NASA investigators had interviewed Beasley, the Caltech radio astronomer who reported seeing debris falling away as Columbia passed over the state.
The information is "important," Dittemore said, and investigators were trying to correlate what Beasley saw with the erratic temperature readings from the shuttle.
"Hopefully the two of them will help us piece together a path that will help lead us to a cause," Dittemore said.
Like 'tiles falling off'
In a telephone interview yesterday before he spoke with NASA, Beasley said he stepped outside his Bishop, Calif., home just before 6 a.m. Pacific time and stood with his wife and mother-in-law watching Columbia cross the dark, cloudless sky.
Columbia appeared as a light far brighter than any star or planet, creating a white condensation trail.
"The light was flickering and changing as it passed over the valley. Smaller lights were falling off and dropping down," Beasley said.
Because he had heard that shuttles sometimes lose tiles during re-entry, Beasley said, "I just imagined they were tiles falling off." He noted the time: 5:53 a.m. local time, or exactly when the shuttle telemetry was suggesting trouble on the left side of the craft.
Beasley wondered whether something had gone wrong, but "the shuttle just kept plowing on." Only 45 minutes later, when he arrived at his office at the Owens Valley Radio Observatory did colleagues tell him that the shuttle had broken up over Texas.
The search for debris expanded yesterday along a 100-mile stretch of eastern Texas. The terrain there includes dense woods, rivers and two reservoirs that together cover about 300,000 acres.
A piece the size of a compact car was reported to have splashed into one of them, Toledo Bend Reservoir, but divers could not find it yesterday.
As officials tried to keep up with hundreds of reports of debris sightings, volunteers and law enforcement officers searched on foot and on horseback, in four-wheel-drive vehicles and aircraft. Searchers recorded a 7- to 8-foot doorlike fragment and a piece of debris resembling part of a windshield in Cherokee County, Texas.
In San Augustine County to the east, they identified a large sphere containing liquid, apparently from the shuttle. Near the edge of a forest, a chunk of metal was spotted dangling from a limb.
Debris was also found near the pitcher's mound of a baseball field.
The location of each new piece is being recorded using a Global Positioning System that will aid NASA in reconstructing how the shuttle broke up.
By late afternoon yesterday, searchers had marked 1,413 fields of debris in five Texas counties. Nacogdoches County Sheriff Thomas Kerss said more than 800 debris fields and 1,200 pieces of debris had been found in his county alone.
"It won't surprise me if that number doubles, or maybe even more than that," said Kerss. "I don't know that we'll ever find all these pieces."
The Columbia disaster has touched Americans far from the counties where the spacecraft went down.
They gathered in their houses of worship yesterday to pray, not only for the seven members of the space shuttle Columbia, but also for the nation, grappling with yet another tragedy so soon after Sept. 11.
Ministers who had planned to address the prospect of war with Iraq, the economy and other topics dominating public discussion instead spoke of the sacrifice the astronauts had made to further science.
Impromptu memorials - many of them at space museums - appeared in other parts of the country yesterday as Americans paid respects to the fallen astronauts.
The entrance to the Johnson Space Center was turned into a shrine for the fallen astronauts as mourners left flowers, candles, teddy bears, American flags and notes.
Attendance was up at the National Air and Space Museum in Washington, as visitors paid tribute with flowers, candles and a copy of the Jewish holy book, the Torah. A handwritten note praised the crew for making the "ultimate sacrifice in the pursuit of knowledge."
Sun staff writers Scott Shane, Lane Harvey Brown and Dennis O'Brien, and wire services contributed to this article.