And that makes the flyaway foam from the shuttle's fuel tank, during launch, an even stronger suspect for breaching the leading edge of the wing, an official close to the investigation said, speaking on condition of anonymity.
A chunk of foam, perhaps containing ice or other debris, broke off the tank during Columbia's liftoff on Jan. 16 and sideswiped some of the heat-resistant carbon panels on the leading edge at 500 mph and possibly also some of the metal and tiles underneath.
"This is a machine that records data from something like 721 sensors, all over the shuttle," said Harwood. "This is data that's not radioed down to the ground, so investigators had high hopes that when they went back through it, they would gain some new insights into what happened to Columbia, and it looks now as if that was good data; the sensors were working."
The high temperatures occurred more than a minute earlier than previously reported.
"The data on this tape shows that there was high heat in the left
wing leading edge area, within about 16 seconds of the point when the shuttle entered the region of maximum heating out over the Pacific Ocean, well off the coast of California," said Harwood. "That indicates that either a leading edge panel or something in that immediate area either fell off, almost immediately during entry, or perhaps the condition was already present, and the heat got in right away and started doing its damage."
Data transmitted from Columbia to Mission Control during the final minutes of the doomed flight indicated a temperature surge in the left main landing gear just before the shuttle crossed the California coast on its way to a Florida touchdown.
"The temperature sensors in that leading edge suddenly climbed and dropped right offline," said Harwood, "which indicates either something fell off the wing right away or the condition was already there."
"What we've got looks very good," Columbia Accident Investigation Board spokeswoman Laura Brown said. She noted that the analysis of the recovered tape will continue throughout this week, and that investigators hope to learn a little more each day about what happened to Columbia just before it broke apart over Texas. All seven astronauts were killed.
The data recorder, found intact on a damp slope in East Texas on March 19, held 9,400 feet of magnetic tape that was duplicated at Kennedy Space Center last week. A copy of the tape was flown Friday to Johnson Space Center in Houston, where 100 engineers and other experts spent the weekend analyzing it.
One board member, Scott Hubbard, said last week that the tape from the data recorder could hold "a gold mine of information," and Brown said it looks more and more like that may prove true.
The data recorder, located beneath the lower floor of Columbia's crew cabin, collected measurements not only during virtually the entire descent but also of the Jan. 16 launch. It was running up until just a few seconds before the shuttle disintegrated.
CBS News Space Consultant William Harwood has covered America's space program full time for more than 15 years, focusing on space shuttle operations, planetary exploration and astronomy. Based at the Kennedy Space Center in Florida, Harwood provides up-to-the-minute space reports for CBS News and regularly contributes to Spaceflight Now and The Washington Post.