The Latest on Columbia

With the war on in Iraq the newsmedia has scaled down their coverage to some degree of the shuttle disaster. Also a factor is that there has not been a great deal to report. New information from the recovered flight data recorder, and examinations of the remaining shuttles have shed new light into the disaster.

Much attention is still focused on Columbia's left wing and a theory rising rapidly in the ranks is that the shuttle was damaged before it even made it to the launch pad. Attention was given to the piece of foam insulation from the shuttle's external fuel tank, which fell and struck the left wing seconds after launch. But now, investigators are thinking damage may have been present even before that.

The leading edges of the shuttle's wings, those gray, curved sections are made of multilayered reinforced carbon-carbon (RCC.) They are designed to take the brunt of heat buildup during the shuttle's plunge into the atmosphere. Temperatures on the leading edges of the shuttle wings can reach 3000F during re-entry. Any gaps between those layers would be disastrous. Although every few years, NASA would do in-depth examinations of these layers, between flights, technicians simply carried out visual and tap checks to ensure there were no gaps between the panels' inner layers.

Image is from the Columbia Accident Investigation Board, it shows gaps between layers of the RCC panels on The Shuttle Atlantis.

In all fairness to NASA, these were experienced engineers who made these between flight checks and they were quite extensive. But they could not show what a CAT scan showed when the shuttle investigation committee had those same sections off Atlantis checked. Such scans showed minute gaps between the layers. As yet, it is unknown whether Columbia's wings had such gaps and if they could have been bad enough to cause failure during re-entry. Information from the flight data recorder seems to add weight to that theory. One NASA engineer commented that the in-depth checks had not shown cracks, and that, coupled with NASA's shrinking budget, forced them to do the less involved between flight checks.

Early analysis of the flight data recorder recovered from shuttle Columbia wreckage indicates the spacecraft descended into the Earth's atmosphere with pre-existing structural damage to the left wing, according to temperature readings pulled from the device on Sunday.

An analysis begun over the weekend shows an unexpected sharp temperature rise in the left wing's leading edge at 7:51:09, or 68 seconds earlier than previous indications of trouble, said Laura Brown, a spokeswoman for the Columbia Accident Investigation Board.

The temperature spike pulled from the recorder appears just 17 seconds after Columbia reached the start of the peak heating period of the re-entry, an indication the wing was already damaged, according to a source close to the investigation.

The high temperature readings gathered by the recorder came from sensors located behind carbon composite panels 9 and 10 that protected the aluminum leading edge of the left wing from frictional heating during Columbia's reentry. A total of 22 adjoining panels wrap around the length of the wing edge.

Engineers reconstructing the 45,000 pieces of debris found from Columbia are finding a lot of molten aluminum. NASA's Steven Altemus, a shuttle test director who is now heading the reconstruction effort explained the pieces found seem to have been through a rain cloud of molten aluminum.

At the time of the temperature spike, Columbia was high over the Pacific Ocean and had slipped into the Earth's atmosphere only seven minutes earlier. According to witnesses on the ground, the stricken shuttle began shedding pieces of debris 2 1/2 minutes later, though recovery efforts so far have failed to find any wreckage west of Texas.

The previous earliest sign of trouble was noted in data transmitted to Mission Control by the shuttle at 7:52:17 a.m. Those readings showed an abnormal temperature rise on the brake line of the inboard tire of the still-retracted left landing gear.

Investigators believe searing gases from the re-entry heating had already invaded the left wing by the time the brake line temperature began to rise. That indication was followed by a succession of left wing sensor failures, indications of rising temperatures and damage to the left wing.

For Columbia's final mission, the data recorder was linked to 721 sensors and activated 57 minutes before breakup. As of Sunday, data had been pulled from 420 sensors, and more than 100 experts were working on the analysis.

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