The initial investigation into the U.S. space shuttle Columbia disaster shows that something went terribly wrong on the orbiter's left side, minutes before it disintegrated on its return to Earth from orbit Saturday. Search teams hunting for shuttle debris on the ground have found remains of some of the seven astronauts killed in the disaster.
Mission control data from the doomed Columbia flight show that, just before it broke apart high over Texas, the temperature in its left landing wheel well jumped 20-30 degrees Fahrenheit. The left side of the orbiter got 60 degrees hotter. The temperature on the right side, by comparison, rose only the expected 15 degrees.
At the same time, increased drag, or friction, on Columbia's left side caused it to roll to that side, prompting the onboard automatic flight control system to command a roll in the opposite direction to stabilize the vehicle.
Shuttle Program Manager Ron Dittemore said the signs are consistent with loss of, or damage to, the thermal tiles designed to protect the shuttle from searing re-entry heat. But he insisted that it is still too early to determine a cause for the disaster. "All I am doing is putting together different pieces of the puzzle, and trying to understand what it means," he said. "I don't yet have the answer."
Protective tiles on the shuttle's left wing have been of concern since the beginning of the mission. At launch, they were struck by foam insulation flying off the big external rocket that lifted Columbia into orbit. Mr. Dittemore says an initial engineering analysis concluded the foam debris would have no effect on the mission.
But the head of the U.S. space agency NASA, Sean O'Keefe, said investigators are taking the incident into consideration, along with all other possible factors. "We're ruling nothing out at this stage, and we're not really concentrating on one theory versus another. We're looking at every possible permutation of what could have caused this," he said.
As NASA investigators carried out their probe, Mr. O'Keefe named U.S. Navy Admiral Harold Gehman to carry out an independent external probe of the Columbia disaster. Admiral Gehman chaired the Navy investigation of the October 2000 terrorist bombing of a U.S. destroyer in the Gulf of Oman.
The NASA investigation is using national, state, and local emergency response teams to scour the ground under the path of the shuttle in Texas and neighboring Louisiana, for any debris from the shuttle's breakup that can provide clues to the disaster. NASA's director of flight crew operations, Bob Cabana, said the search has turned up remains of Columbia astronauts. "We're treating those remains with the ultimate respect and care that they deserve," he said. "I just want you to know that we're honoring our fellow crew mates and we're taking care of them."
Mr. Cabana said NASA's astronaut office is working closely with the grieving families of the crew who perished. It has assigned a different official to help support each family.