Video shows shuttle shedding debris

CAPE CANAVERAL, Fla., March 17 (UPI) -- Shuttle Columbia was shedding debris long before sensor malfunctions and unusual flight handling characteristics indicated the ship and its seven astronauts were in trouble, a video compiled by NASA and released Monday shows.

Imagery taken by more than a dozen amateur and professional sky-watchers captured the final minutes of Columbia's flight on Feb. 1 as it bolted like a shooting star across the dark and clear skies of the western United States.

A closer inspection, however, reveals at least 16 flashes of light emanating from the orbiter and interpreted by imaging experts as pieces of debris that had separated from Columbia and become free-falling objects. Combing through radar data from air traffic controllers helped investigators hone in on two pieces of debris in particular, neither of which has yet to be recovered.

Work so far has concentrated on what is thought to be a relatively large but lightweight piece of debris that probably is buried under snow somewhere in a remote 5-square-mile area of Nevada.

The video that shows the debris leaving the shuttle was shot with the planet Venus in the background, giving engineers a concrete reference point in time and space to correlate with a probably ground position.

The Columbia Accident Investigation Board, which held its second public hearing on Monday, was advised by an expert on spacecraft re-entry dynamics to concentrate on finding pieces of debris that came off the shuttle before its total disintegration over east Texas.

With close to 30,000 pieces of wreckage in hand, near uncertainty about what broke off when, and few hard facts about the highly dynamic process of atmospheric re-entry, finding the cause of the Columbia accident cannot be done simply by reconstructing the ship from its wreckage, said William Ailor, a spacecraft re-entry and debris expert with The Aerospace Corp.

"It's going to be tough to go back and put the debris together," he said. "The key is to look for early debris before the major breakup."

Added NASA flight director Paul Hill, who heads a team that compiled the Columbia re-entry video: "If you go look at (the debris) laying on the ground there (at Kennedy Space Center), you don't have a spacecraft laying there, you got a whole lot of nothing."

The brightest object in the video compilation is what NASA is calling Debris Event 14, which glows for 4.5 to 7.5 seconds before fading from sight.

"We still cannot say exactly what we see coming off," said Hill.

Preliminary findings indicate a structural breach allowed hot plasma to enter Columbia's left wing, creating a sort of blowtorch that melted the orbiter from the inside out. Investigators suspect the plasma got inside the wing from a breach in the left wing and made an exit hole around the wheel well door.

Although the video compilation has a short gap in coverage, Hill said he thinks it is likely the shuttle was shedding debris continuously as it flew over the western United States.

"From California on, you can see pretty much a steady stream of debris coming off the orbiter," said Hill.

"We continue to be shocked that we ... were dropping debris, clearly had an external breach in the vehicle and had hot gas somewhere in the left wing for that significant period of time and the vehicle flew perfectly -- no indication of what was going on in flight control and virtually no indication of what was going on in telemetery on the ground," he added. "The vehicle flew like (a) champ until right up until the breakup."