spacetoday.net: Columbia investigators focus attention on foam theory

Posted: Wed, Apr 23, 2003, 10:36 AM ET (1436 GMT)
STS-107 patch (NASA)

Members of the Columbia Accident Investigation Board (CAIB) said Tuesday that they are increasingly certain that a chunk of foam falling from the shuttle's external tank caused the damage that led to the loss of the orbiter. CAIB chairman Harold Gehman said that, after gathering data for 11 weeks, they now think the evidence on hand points to foam striking the leading edge of the left wing during liftoff, damaging panels and/or seals there. That evidence also shows that an object seen on radar floating away from the shuttle one day after launch was most likely a T-seal located between pairs of reinforced carbon-carbon panels on the leading edge. In addition, analysis of an external tank built at around the same time as the one used on Columbia's final flight revealed several dozen defects in the foam, primarily air pockets, that could make it easy for the foam to fall off during flight. The CAIB plans to continue its work into the summer, although Gehman said the work will shift from gathering evidence to analyzing what happened and making recommendations. The CAIB's final report will be released by the time Congress recesses for the summer in late July.