On May 1, NASA announced that only one single failure scenario would explain all of the evidence contained in the debris, the OEX recorder, the telemetry received in Houston, and the videos provided by the public and other sources. Something—most likely the collision with the foam from the external tank—caused a breach in the leading edge of the left wing. This breach allowed plasma to penetrate the wing and erode it from the inside during the reentry. Whether the foam actually penetrated the leading edge—or if it pushed spacers apart and created a gap in the panels—will never be known.
