The theory that the most likely cause of the Columbia disaster was insulation striking the shuttle's left wing was proven in a test.
Scott Hubbard, a member of the Columbia Accident Investigation Board said, "this is the first evidence that a piece of foam can, in fact crack and damage a carbon-reinforced piece of tile."
The foam shattered on impact, leaving dark streaks, hairline cracks, and what appear to be bits of foam in the panel.
Hubbard said, "you would not take a piece this damaged and fly it in space."
This is the first time NASA has tested the impact of foam on an actual section of the shuttle's reinforced carbon wing. The section tested was taken off the shuttle discovery.
Eighty-one seconds into Columbia's launch, a piece of foam broke off from an external fuel tank and struck the shuttle's left wing. During the test, a nitrogen-powered cannon fired a one-and-a-half-pound piece of insulation traveling 531 mph at the wing to simulate the moment of impact.
Even with the dramatic results, investigators say they still need to gather more information.