Foam wedges into wing in shuttle test
By Marsha Walton
CNN
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Foam shards wedged into a replica space shuttle wing in tests designed to help figure out what destroyed the orbiter Columbia.
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(CNN) -- The Columbia Accident Investigation Board released results Wednesday from tests that documented significant damage when a small piece of foam struck a mock shuttle wing panel.
The tests were part of the panel's effort to determine what caused Columbia to break apart February 1, killing all seven astronauts onboard.
Investigators theorize that a piece of foam, which separated from the external fuel tank and hit the shuttle's left wing shortly after takeoff, caused damage to the orbiter's heat-resistant tiles or a seal between the tiles.
On re-entry, the suspected breach would have allowed hot gases to enter and ultimately destroy the shuttle.
Board member G. Scott Hubbard, director of NASA's Ames Research Center, told reporters Wednesday in Houston, Texas, that he was surprised by the results of the latest round of tests.
"When I saw it, I thought, oh my God, this is something. This is not just a light force. This is a really significant effect," Hubbard said at the Center for Advanced Space Studies.
The tests were conducted at the Southwest Research Institute in San Antonio, Texas. Researchers shot a piece of foam weighing 1.67 pounds at fiberglass panels from space shuttle Enterprise at a speed of 779 feet per second. That impact is comparable to catching a basketball thrown at about 500 miles per hour, researchers said.
When the foam struck the fiberglass, it lifted and shifted the seal between two panels. The width of that opening was up to a quarter inch in some places.
The foam itself broke into hundreds of small pieces, some of which lodged into panel gaps. The impact altered the surface of the fiberglass, leaving an indentation of about a tenth of an inch, investigators said.
The final report won't be complete until late summer, but Hubbard said test results like this one move the board closer to the conclusion that foam that fell off the shuttle 81 seconds into the flight could have been the initiating event that led to the catastrophic breakup of the spacecraft.
Thursday at the San Antonio facility, researchers will conduct another series of tests similar to the ones done on the fiberglass panels.
Foam will be shot at reinforced carbon-carbon panels taken off the space shuttle Discovery, which had flown about 30 missions, comparable to Columbia.
