Air Force: Initial Findings "Significant"

"We're not drawing any conclusions," said Air Force Lt. Col. Woody Woodyard, a spokesman for the Columbia Accident Investigation Board, Friday. "We've got to analyze the data and evaluate all the data before we can draw any conclusions." But, he described the results of impact testing on a simulated shuttle wing Thursday as "significant."

The test, which has been months in the making and involves rare, if not impossible-to-find, shuttle materials, show significant damage to the leading edge of one of the space plane's wings after it was hit by insulating foam - the kind of foam that struck the left wing of the shuttle Columbia 82 seconds after lift-off Jan. 16.

A Difficult, But Revealing Simulation

At the Southwest Research Institute in San Antonio (TX), Thursday, scientists fired a 1.67 pound chunk of real insulating foam - the type used to control the temperature aboard the shuttle's huge external fuel tank - at the fiberglass leading edge of a space plane wing. The foam was launched at the approximate speed it would have tumbled from the fuel tank into th leading edge of Columbia's left wing - 553 mph. Lt. Col. Woodyard (USAF) said the foam struck the wing's sixth panel, opening a 22-inch gash in the leading edge. Almost since the day after Columbia disintegrated upon re-entry Feb. 1, suspicions about the cause of the accident have centered on the shuttle's left wing.

Finding something resembling the shuttle wing without dismantling the only other three space planes still in service was a major undertaking. Finally, scientists in San Antonio used a piece of the prototype shuttle Enterprise's (above) wing for the experiment. Since the fiberglass used in the Enterprise's wing is 2.5 times more resilient than the tile insulation aboard a flying shuttle, the real-world damage to Columbia is thought to have been much worse than in the simulation.

On the second day of Columbia's final flight, scientists had noticed a piece of debris float away from the spacecraft. After Thursday's simulation, they're almost certain now that it was part of a left-wing seal found along the leading edge. It's departure from the spacecraft would have left a horizontal slit along the leading edge - the perfect place for superheated gases to force their way inside the Colubmia's wing structure and lead to its catastrophic delamination.

FMI: www.caib.gov