- The Washington Times - Monday, July 7, 2003

Accident investigators yesterday blew a hole bigger than a basketball in a space shuttle’s carbon panel, bolstering suspicion that a chunk of foam insulation caused enough damage to destroy the Space Shuttle Columbia.

“We have found the smoking gun,” Scott Hubbard, a member of the independent Columbia Accident Investigation Board, said following the test in San Antonio.

The impact from the foam insulation made a hole about 16 inches wide in the carbon panel. The shattering collision destroyed nearly the entire bottom section of the U-shaped panel.

The hole was so big that engineers who inspected the damage after the test were able to stick their heads inside the opening.

“I think foam striking the wing leading edge of the orbiter at 500 miles per hour is the direct cause,” Mr. Hubbard said.

It was the second experiment on a carbon panel that the Columbia Accident Investigation Board conducted at the Southwest Research Institute to test the strength of the thermal-protection tiles lining the shuttle wings. The first impact produced a series of cracks in a carbon panel.

NASA officials said they hope the high-speed-impact test improves their knowledge of the Feb. 1 loss of Columbia.

“We hope that the test, as with all elements of the investigation, contributes to a thorough understanding of what contributed to the accident,” NASA spokesman Glenn Mahone said.

On a firing range at the sprawling research facility, investigators shot a 1.67-pound piece of foam insulation from a nitrogen-powered gun at a section of wing with three carbon panels. The foam struck the panel at more than 500 miles per hour.

Investigators considered yesterday’s test more significant than one a month ago because they modified it to more closely resemble what they believe happened about 82 seconds after Columbia launched Jan. 16.

They shifted the piece of foam so an 11-inch edge struck the carbon panel. In the test last month, investigators aimed the foam so a corner of the rectangular piece hit the panel. This ensured that the impact would be greater than in the first test.

Investigators also targeted the panel they believe was damaged on Columbia during liftoff, using the corresponding piece — panel 8 — from the Space Shuttle Atlantis for the test.

Mr. Hubbard said the dramatic effect of the impact was surprising.

“I felt surprise at how it appeared, such a dramatic punch-through. But it is the kind of damage, type of damage, that must have occurred to bring down the orbiter,” he said.

The experiment cost $3.4 million.

Accident investigators for several months have suspected foam insulation peeled Columbia’s external fuel tank, hit the shuttle’s left wing and pierced the carbon panel on its leading edge.

Board member Roger Tetrault last month said more forcefully than before that foam probably led to the loss of Columbia and the seven astronauts on board. He also said he believes the foam hit panel 8.

Mr. Tetrault also predicted that the hole in Columbia’s left wing measured from 6 to 10 inches in diameter.

The panel that investigators shot at yesterday had been on 27 space flights, about as many as Columbia had completed before the breakup.

The other two panels on the wing mockup came from the Space Shuttle Discovery.

While investigators aimed for panel 8 and demolished it, they are also interested in measuring the effects of the high-speed impact on shuttle components near the bulls-eye.

In the first test one month ago, a piece of foam caused multiple fractures in a single panel and to wing pieces nearby. The piece of foam caused two cracks in the carbon panel, one measuring 5 inches and one measuring just under 1 inch.

This article is based in part on wire-service reports.

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