spacetoday.net: Dramatic test offers "smoking gun" in Columbia investigation

Posted: Tue, Jul 8, 2003, 8:50 AM ET (1250 GMT)
STS-107 debris impact test (CAIB)

A dramatic test Monday where a chunk of foam hit a model of the leading edge of a shuttle wing and left a gaping hole has provided investigators with what they consider to be the "smoking gun" in their search for the cause of the Columbia accident. The test, the last in a series performed at the Southwest Research Institute in San Antonio, used a piece of foam the same size as the one that struck Columbia during its January launch, fired from an air cannon at the same velocity at an actual reinforced carbon-carbon (RCC) panel taken from another orbiter. The test was similar to past tests, but this time used RCC panel number 8, the same one struck by foam during the launch. The impact left a gaping hole approximately 40 centimeters across in the panel, big enough for a person to stick his head into. The damage was far greater than predicted, and investigators called it a "smoking gun" that the impact did indeed cause enough damage to doom Columbia upon reentry. The size of the impact has also raised questions about whether damage that great could be repaired in space; the Columbia Accident Investigation board has recommended that NASA develop ways to repair tile damage while the shuttle is in orbit.