In 2003 after the breakup of during re-entry, the "Columbia" Accident Investigation Board conducted tests at Southwest Research Institute, which used an air cannon to shoot foam blocks of similar size, mass and speed to that which struck "Columbia" at a test structure which mechanically replicated the orbiter wing leading edge. They removed a section of fiberglass leading edge from "Enterprise" wing to perform analysis of the material and attached it to the test structure, then shot a foam block at it. While the leading edge was not broken as a result of the test, which took place on May 29, 2003, the impact was enough to permanently deform a seal and leave a thin gap long. Since the strength of the reinforced carbon–carbon (RCC) on "Columbia" is "substantially weaker and less flexible" than the test section from "Enterprise", this result suggested that the RCC would have been shattered. A section of RCC leading edge from "Discovery" was tested on June 6, to determine the effects of the foam on a similarly aged leading edge, resulting in a crack on panel 6 and cracking on a "T"-shaped seal between panels 6 and 7. On July 7, using a leading edge from "Atlantis" and focused on panel 8 with refined parameters stemming from the "Columbia" accident investigation, a second test created a ragged hole approximately in the RCC structure. The tests clearly demonstrated that a foam impact of the type "Columbia" sustained could seriously breach the protective RCC panels on the wing leading edge.