A piece of insulating foam shot at a mocked-up shuttle wing opened a long slit in its leading edge, which may help to explain what caused the loss of the space shuttle Columbia, investigators said today.

They were trying to recreate the circumstances at the Columbia's launching, when a piece of insulating foam from the external tank slammed into the shuttle wing at similar speed.

The Columbia Accident Investigation Board said a piece of debris from the main fuel tank damaged the shuttle wing on takeoff and mandated requirements that have to be met before the craft could fly again.

The study included a detailed map of the shuttle wing and provided a calculation, in feet per second, of how fast the foam debris from the external tank would have been moving if it hit that spot.

Root aimed a second piton dart at the shuttle wing.

In last week's experiment, the researchers shot a 1.7-pound piece of foam at a mock-up shuttle wing at 531 miles per hour, roughly the speed of the chunk of foam that hit the Columbia wing about 81 seconds after liftoff.

Forced convection is often encountered by engineers designing or analyzing heat exchangers, pipe flow, and flow over a plate at a different temperature than the stream (the case of a shuttle wing during re-entry, for example).

The panels are numbered from the root of the wing to the tip; the foam is believed to have struck the shuttle wing between panels 5 and 12, where the wing broadens away from the fuselage.

"The proof is the Columbia accident," Dr. Roland said, noting that engineers had had warnings on prior flights of the fuel tank debris that damaged the shuttle wing and led to the craft's fatal disintegration.

The document was first described today by The Orlando Sentinel, and an official of the investigation board discussed it for reporters here in a lull in preparations for shooting foam at a mock shuttle wing.