Simulation Indicates Fuel Tank Debris Could Have Caused Disaster

It's the kind of gun used to fire all sorts of debris at aircraft parts, testing the results of impact. This time, the 35-foot long gun fired a piece of insulating foam at a wing panel from the space shuttle Discovery, causing the panel to bend and crack. Investigators trying to figure out what caused the shuttle Columbia to break up as it re-entered the Earth's atmosphere Feb. 1 say this is a big - perhaps crucial step - in finding out what killed the seven astronauts on board.

Using parts from Discovery, scientists at the Southwest Research Institute Saturday proved that, at least in theory, insulation foam from the shuttle's main fuel tank could have indeed caused catastrophic damage to the wing of shuttle Columbia.

Smoking Gun?

That unique test gun at the institute in San Antonio fired a 1.5 pound chunk of foam into panels from the leading edge of Discovery's wing. As members of the Columbia Accident Investigation Board looked on, the foam insulation cracked the wing panel and created a tiny gap between the panel and an adjoining seal.

The result of the three-inch crack? Super-heated gas could have seeped into the wing, causing a meltdown of vital structural components, leading to the destruction of Columbia on Feb. 1.

"We demonstrated for the first time that foam at the speed of the accident can actually break" shuttle wing components made from reinforced carbon, said Scott Hubbard, the head of NASA's Ames Research Center and a member of the Columbia Accident Investigation Board (CAIB). "To me, that's a step forward - maybe even a significant step forward - in our knowledge. We need to complete the test series to understand the whole story.

The foam sample in the lab hit the Discovery wing panel at 525 mph, the speed at which a suitcase-sized chunk of foam from Columbia's fuel tank hit the orbiter's left wing Jan. 16. Columbia disintegrated as it re-entered Earth's atmosphere Feb. 1, raining down debris from central Texas to western Louisiana.

Almost 100 people, two of them shuttle astronauts, along with 12 high-speed cameras, watched as the foam shattered along the 22-inch long wing panel. The crack was visible to the naked eye.

"If such a crack had been found on an inspection," said Hubbard, "you would not fly with it. You would not take a piece that is this damaged into space."

End Of The Investigation

With Saturday's test, the CAIB's active investigation ended. Now, the 13 board members will write their final report, due to the President, Congress and the American public by the end of next month. Already, an early draft of that report obtained by The Orlando Sentinel indicates NASA's problems extend far beyond the foam that insulates the external fuel tank. The Sentinel reports the draft portrays the Columbia tragedy as just the tip of the iceberg - a mountain of problems that the newspaper says included communication breakdowns and ignored or downplayed warning signs. The CAIB report indicates it was nothing sudden, but rather a gradual erosion of diligence that contributed to the Columbia disaster. The report also blames the White House and Congress for not, in board members' opinions, properly funding the shuttle program.

But closer to the actual disaster, a chapter in the CAIB report called "Columbia's Final Flight" contains a series of e-mail messages analyzing the Jan. 16 foam strike. The messages are sometimes angst-ridden as engineers ponder the measure of damage to the shuttle's wing and the risk it posed to the crew of seven.

FMI: www.caib.gov