Shuttle exterior was penetrated during...

Shuttle exterior was penetrated during descent: "The space shuttle's skin almost was certainly pierced, allowing superheated air inside the left wing and possibly the wheel compartment during Columbia's fiery descent through Earth's atmosphere, investigators said Thursday. In its first significant determination, the accident investigation board announced that heat damage from a missing tile would not be sufficient to cause unusual temperature increases inside Columbia minutes before it disintegrated. Sensors detected an unusual heat buildup of about 30 degrees inside the wheel well before the accident."