Flight data salvaged from Columbia debris appear to show that hot gases began to destroy the shuttle's left wing very soon after re-entry began, investigators disclosed Sunday.
The new information, recovered from a device called the Orbiter Experiments, or OEX, recorder, indicates the shuttle was threatened by ferocious heat more than a minute before other sensors were indicating temperature spikes in the wing.
The data, released without analysis, may support the theory that the shuttle accident began to unfold during launch in January. Large pieces of foam insulation broke off the external fuel tank 82 seconds after liftoff and struck at or near the leading edge of the wing.
The information could help investigators trying to learn whether the shuttle already was badly damaged when re-entry began shortly before 9 a.m. Feb. 1. The damage could have allowed a plume of searing gases to penetrate the wing.
"There are a couple of temperature sensors that go way up and then go to zero," said Laura Brown, spokeswoman for the board investigating the accident.
An intrusion of heated gases, coming at nearly the hottest moment of re-entry, may have destroyed the sensors or their wiring.
NASA engineers working on the data at Johnson Space Center during the weekend learned that rapid temperature rises were detected by a pair of sensors on the leading edge near the point of collision.
Those sensors were behind leading-edge panels 9 and 10. Suspected foam damage was near panels 6, 7 and 8.
The U-shaped panels are made of a high-strength carbon material. Insulated panels behind the leading edge may also have been damaged.
Columbia's left wing contains dozens of temperature sensors, but it was unclear Sunday how many are near where damage may have occurred.
"We're very interested in what happens in the early part of the [re-entry] data," Brown said. "That will help tell us what was happening to the wing."
Amateur videotapes of the shuttle's re-entry show that it was shedding pieces as soon as it crossed California for a landing in Florida.
Within days after Columbia broke up over Texas, NASA officials identified the OEX recorder as having potential to offer key clues to what happened. The recorder, first used in the early 1980s for a variety of experiments, was found March 19 on a hillside in east Texas.
Until its data became available during the weekend, investigators had been relying on more-limited sensor readings that were radioed to the ground during flight.
Ordinarily, readings from 721 heating, pressure and stress sensors were stored by the OEX recorder during launch and re-entry and played back by engineers after landing.
So far, National Aeronautics and Space Administration engineers have determined that the recorder's magnetic tape preserved readings from at least 420 pressure and heating sensors.
Data stored from other sensors, including those that measure stress on the shuttle's surfaces, have been sent to other laboratories for more-sophisticated analysis, Brown said.
Officials hope to learn many more details through this week from the data analysis.
Kevin Spear can be reached at 407-420-5062 or email@example.com.