NASA Widens Look at Shuttle Heating
Tuesday, February 4, 2003
NASA investigators yesterday offered a new interpretation of the sudden heating the shuttle Columbia experienced on its left wing and side as it descended toward its destruction, speculating the fatal damage began elsewhere on the spaceship.
They have been studying the possibility that the shuttle's insulating tiles had been damaged as early as the first minutes of the flight when a piece of foam insulation appeared to break off from the shuttle's massive external tank and strike the underside of the left wing near the wheel well, where instruments recorded unusual warming just prior to the disaster.
At a late-day briefing in Houston, shuttle program manager Ron Dittemore said it is also possible the spaceship was breached someplace other than the wheel well, where the temperature increases were first registered. He said engineers were baffled as to how the modest temperature increases observed in the left wheel well and fuselage "end up with an event that lost the vehicle."
The evidence, he said, leaves engineers thinking "there's some other missing link that we don't have yet that's contributing to this temperature increase."
That missing link is the subject of a massive, round-the-clock search through telemetry readouts and other records as well as through farms, fields and lakes -- an effort that promises to go on for weeks or months.
Late yesterday, authorities found the tip of the shuttle's nose cone in a thickly forested area, which they secured. "We were just elated that we were able to recover that," said Sabine County Sheriff Tom Maddox, who added that the cone was "in pretty good condition."
NASA yesterday set up a second base of operations at Carswell Air Force Base near Fort Worth to collect the thousands of fragments of debris, in addition to one already established at the Barksdale Air Force Base in Louisiana.
Engineers have been directed to consider the giant external tank as a possible root cause of the accident, Dittemore said. But they will also continue to investigate a range of possible alternative causes, from inspection procedures to wiring and computer controls.
As they declared a day of mourning today for the seven fallen astronauts, NASA's shuttle managers settled in for a top-to-bottom review of their flight designs and practices. In light of new data, NASA yesterday appealed for the public farther back along the shuttle's flight path, beginning in California, to look for debris. "We are extremely interested in any debris upstream of the primary impact area," Dittemore said. Pieces have been found as far west as Fort Worth.
Officials hoped to find a single crucial piece that would reveal how the disaster began, but conceded that the odds were against it. The shuttle crossed California at 220,000 feet or so, descending rapidly and braking from 20 to 18 times the speed of sound. It was traveling 12,500 mph when it was lost.
"Let's say we did shed a tile or two," Dittemore said. "A tile maybe six by six inches. Where are they? That's a tough problem."
The tiles are individually coded, so engineers could readily tell what part of the shuttle they came from.