Space agency officials said this evening that they were still uncertain whether the wing section, which they described as a little more than two feet long, was from the left wing. That is where sensors indicated ever-worsening signs of distress as the doomed craft sped over California to central Texas, where it disintegrated. The wing section was found near Fort Worth, but NASA did not announce the exact location.

The fact that it was discovered so far west of where the bulk of the shuttle debris was found suggests that it was among the first pieces of the orbiter confirmed to have hit Earth, one reason investigators that suspect it could be part of the first section of the shuttle to fail.

"If it's left wing," said Ron D. Dittemore, the shuttle program manager, "I think that would be more significant. Certainly we're more interested in the left wing."

Determining whether it is from the left wing should not be that difficult, because the leading edge was still attached to 18 inches of structure that included heat-resistant tiles. Each tile is marked with a unique code.

NASA also released a photograph taken from a secret Air Force installation in Albuquerque, N.M., about a minute before contact was lost with the crew. The picture, taken from a camera in a telescope normally used to test how to photograph satellites, is almost a silhouette of the orbiter. It appeared to show a slight bulge or deformity along the front edge of the left wing, and plume emanating from the back of the wing that does not match the plume on the right side.

This afternoon in Houston, Mr. Dittemore, whose day-by-day accounts of the investigation are being ended today, said, "That does look a little different to us, and that's an area of investigation."

But he said that it was unclear whether the bulge indicated a jagged break in the wing or a mirage caused by distance and atmospheric distortion.

As a result, Mr. Dittemore said, he was not persuaded that the photograph would yield significant information about the cause of the disaster. But he said he was hopeful that it would tell investigators something about the state of the vehicle in the final moments before it broke up.

"All by itself, I don't think it's very revealing," he said. "These things are not black and white."

The very fact that the Air Force was training its equipment on the shuttle was unusual. Richard Garcia, a spokesman for the Air Force Research Laboratory's Starfire Optical Range at Kirtland Air Force Base, said, "We don't routinely image the shuttle, no."

Mr. Garcia declined to say why the shuttle was photographed on this mission or which of the telescopes at the range took the picture. The range's 3.5-meter and 1.5-meter telescopes are typically used to help researchers reduce atmospheric distortion to take clearer pictures of objects in space like satellites.

"It's the equivalent of a spy satellite's looking up, not down," said John Pike of global security.org, a space and military research organization.

While Mr. Dittemore cautioned against rushing to conclusions, the combination of the photos and the finding of the wing section, if, in fact, it is part of the left wing, so far west of most of the wreckage may, within days, give greater credence to theories that the front or underside of the wing was breached. If it was, the cause of the damage is unclear. But much of the focus has been on foam insulation that broke free from the external tank on liftoff and hit it at tremendous speed.

NASA engineers examined the issue and concluded, before the seven-member crew began the descent, that whatever damage had occurred as the foam hit the wing was tolerable. Now, Mr. Dittemore said, they are revisiting that finding, conducting extensive tests to determine whether the judgment was hasty and could have led to the deadly outcome.

If there was a breach, engineers said, superheated air and gasses could have permeated the wing structure, perhaps accounting for the increase in temperature recorded by sensors in the wheel wells. But there could also be other explanations, and the issue is being turned over to an investigative board.

The leading edge of the wing is made of 22 pieces of carbon-carbon, a lightweight material that is designed to withstand temperatures from minus 250 degrees Fahrenheit to 3,000 degrees Fahrenheit. The purpose is to handle the enormous heat and stress of re-entry into the atmosphere.

Like the O-rings that failed in the Challenger disaster, the carbon-carbon and the heat-resistant tiles on the underside of the orbiter are considered elements whose failure could lead to disaster and death. There is no backup if those materials fail.

NASA engineers discussed potential damage to the reinforced carbon-carbon and tiles from debris was discussed at a routine meeting in Houston on Jan. 28, the 12th day of the Columbia flight, NASA officials confirmed today. While a written report said an analysis found "the potential for a large damage are to the tile," it also said the likely structural damage raised "no safety of flight issue."

NASA officials said that the engineers discussed the issue briefly, but that no one disagreed with the analysis.

Mr. Dittemore said that the briefing today would be his last and that the independent investigative committee, which is taking over the inquiry, would conduct any future briefings. One effect of his statement was to remove from the stage and from daily questioning the head of the team that launched the Columbia and approved its re-entry.

Mr. Dittemore also presented the most detailed chronology yet of unusual temperature readings and failures of sensors along the left wing in the final eight minutes of the shuttle flight. He showed slides of the locations of the sensors and temperature spikes, but said the pattern did not point to a single cause for all the problems. He said the wires to most of the affected sensors were bundled together in the wing, raising a possibility that the sensor failures could be traced to wiring problems.

"Maybe the wire bundles are a connecting link," Mr. Dittemore said. But he added that he did not know whether the failures would point to a cause of the shuttle's problems or were merely showing the effects of some other event.

Mr. Dittemore said that NASA had received 350 reports of shuttle wreckage found outside of the main debris in East Texas and Louisiana, but that none had been confirmed as shuttle parts. He said that of 132 reports from California, four had been investigated and found unreliable. Of 150 reports from Arizona and New Mexico, 16 had been found irrelevant to the Columbia investigation.

Mr. Dittemore spent a considerable amount of time discussing the week's events and what was apparently seesawing between theories of what caused the catastrophe. He said that he was allowing the news media, and through them the public, "to look over our shoulders" as NASA experts began the painstaking process of reconstructing the accident.

He repeatedly cautioned against jumping to conclusions and said all complex inquiries move by fits and starts. He acknowledged that he had provided information as quickly as he received it, often without thorough analysis. He described some of that early information as "somewhat ragged and unreliable" and pleaded for patience as engineers worked through their complex analyses.

Mr. Dittemore noted that the responsibility for the investigation had moved into the hands of the independent review panel that is led by Harold W. Gehman Jr., a retired admiral who was a chairman of the investigation of the attack on the destroyer Cole.

Reflecting on the week since the accident, Mr. Dittemore said that emotions had been running high throughout the space agency and that the early stages of the investigation had been frustrating because there would be no clear and quick answer to the mystery of the shuttles destruction.

"The disappointment cannot be overstated," he said.

Comment from Loring Wirbel:

Yesterday, I posted an AP story on the observation of the shuttle which carried the prefatory note that the ground-based military system had to be GEODSS.  This morning, the NY Times (does not provide free URL access to its stories) identified the telescope as the Starfire Optical Range facility at Kirtland.  This is very significant in confirming the military role Starfire can play in NMD, ASAT weapons, etc.

Bob Anderson has been warning us about Starfire for years.  The telescope uses the "adaptive mirrors" (mirrors with bendable, adjustable focal planes and thicknesses) which were developed for the free-electron laser program for Reagan's original SDI program.  (NOTE: When I wrote a series for the Albuquerque Tribune on Star Wars in 1983, I mentioned adaptive mirrors, and the Air Force public relations office wrote a letter to the paper calling the technology a figment of my imagination.  Ten years later, the technology was declassified.  I never got an apology.)  When Starfire was built, Bob, Camy, and others in NM were skeptical of the claims that Air Force Research Labs would use this solely for peaceful research and astronomical study.

The fact that Starfire, rather than GEODSS, was used to look at ths shuttle, and the fact that lab spokesman Rich Garcia did not want to reveal any details on resolution for security reasons, suggests that Starfire will be playing a very active role in the Missile Defense Agency in the future.  Once again, we must watch out for those "dual use" facilities.

Loring Wirbel
CPIS/PPJPC
lwirbel@aol.com
8 February 2003