spacetoday.net: Shuttle debris shows evidence of extreme heating on left wing

Posted: Wed, Mar 5, 2003, 8:07 PM ET (0107 GMT)
STS-107 patch (NASA)

Analysis of shuttle debris shows that the interior of Columbia's left wing was subjected to extremely high temperatures during reentry, the latest evidence that a failure of the shuttle's thermal tiles caused the accident. Members of the Columbia Accident Investigation Board (CAIB) said Tuesday that they found a black residue, believed to be aluminum oxide, on shuttle tiles that had not been found on tiles before. Investigators said they also found a slag of molten aluminum and stainless steel on the interior surfaces of the reinforced carbon-carbon tiles on the leading edge of the left wing. The left wing landing gear tires also appeared to have exploded because of exposure to the intense heat, although the explosion likely did not occur until shortly before or after the orbiter's breakup. The tires from the right wing, by comparison, show no evidence of heat damage. The findings bolster the hypothesis that a breach in the shuttle's thermal tiles allowed hot plasma to get inside the left wing, causing a structural failure that led to the demise of the orbiter. CAIB members said that the evidence to date did not favor the leading edge or the left landing gear door as the point where the plasma entered the wing.