Columbia sits on Pad 39A prior to STS-107 launch. The circled portion of the wing notes the area where a USAF camera in the southwestern U.S. imaged serious damage to left wing leading edge. The gray portions of the leading edge are carbon sections. These are bolted on, unlike black tiles, which are glued on.
	The scene in Mission Control immediately after the loss of Columbia shows data and map displays projected on the back wall, while controllers and managers confer.

	Sequence of three launch-tracking camera images shows two pieces of debris separate from the tank.
	The debris move toward inboard leading edge of left wing.
	In the third photo, debris has fragmented under wing after striking vehicle.
	Diagram from 1994 tile risk study spells out what has been obvious since the program's start: Under worst-case conditions, tile damage can propagate.

Special Report: Columbia Disintegrates