Bringing Columbia Home: The Untold Story of a Lost Space Shuttle and Her Crew

by Michael D. Leinbach

Space shuttle wing leading edge panels are large, expensive, and made to order. The reinforced carbon-carbon (RCC) material also wears and becomes more brittle over time, so SwRI could not use newly manufactured panels to get an accurate assessment of potential damage in its impact tests. The test panels would have to come from the wings of Discovery and Atlantis, the two orbiters that had flown about as many times as Columbia. NASA decided to test the process first using fiberglass wing panels from Enterprise, which was not designed to fly in space. Several test shots at Enterprise’s fiberglass panels—which were stronger than the RCC panels on the flight-worthy shuttles—produced scuff marks from the foam blocks, but no breakage. After getting its process and equipment calibrated, SwRI was now ready to try the tests with the space-flown RCC panels. First, a foam block was fired at panel 6 from Discovery. The impact created a crack nearly six inches long in a rib supporting the leading edge, and it moved the panel enough to create a small gap in the T-seal between panels 6 and 7. This test proved that foam could damage the RCC material. However, the damage incurred in this test would not have been severe enough to create the burn-through seen on Columbia. NASA estimated a hole of at least ten inches in diameter would have been needed for the wing to ingest a plasma stream large enough to create the damage seen in Columbia’s debris. The next test target was panel 8, which ha...