The impact left a three-inch (76-millimeter) crack in one of 22 thermal-protection panels covering the wing, and a smaller crack in a joint known as a T-seal between panels, investigators said.

"This is the first evidence that we have that a piece of foam that approximates what was observed in the accident can, in fact, crack and damage a piece of flight reinforced carbon panel," said Scott Hubbard, a member of the Columbia Accident Investigation Board.

"The meaning of this, whether or not this is sufficient to cause structural damage to the leading edge or whether it represents a thermal problem, is something that is yet to be determined."

Investigators will now dismantle the wing for an extensive analysis of the damage, to determine if the breach could have allowed superheated gasses to penetrate Columbia's wing when it re-entered the atmosphere on February 1.

A gas cannon shot the 26.7-ounce (757-gram) piece of foam at the wing at nearly 530 miles per hour (850 kilometers per hour) in an attempt to simulate what occurred seconds after Columbia's January 16 launch, when a piece of foam insulation broke off an external fuel tank and struck Columbia's left wing.

A similar test last week hurled a shard of foam at a fiberglass replica of the wing. This time, the leading edge of the wing was made of reinforced carbon-carbon, like an actual shuttle wing.

Last week's test produced even more extensive damage, creating a hole up to 0.6 centimeters (0.2 inches) wide and 55 centimeters (21 inches) long.

Investigators say they have not yet reached any final conclusions or determined the cause of the loss of the shuttle and crew.

However, test results and the shuttle's temperature data prior to the disaster appear to point toward the theory that a hole in the wing left it vulnerable to extremely high temperatures that caused the shuttle to break apart on February 1, killing all seven crew members on board.

The board will issue its final report later this summer.

SPACE.WIRE