Board officials said the purpose of this first image was to label some of the payload bay hardware that appears to stick out over the wing, which many people have incorrectly interpreted as damage to the wing.

Foam insulation from Columbia's external tank fell and struck the left wing during the launch, but any damage to the wing's heat protection tiles or reinforced carbon-carbon leading edge could not be seen in any images recorded during the 16-day mission.

The second image released by the CAIB shows a piece of Columbia's left-hand main landing gear door, specifically the forward inboard corner of the panel.

The debris was delivered to Barksdale Air Force Base near Shreveport, La., on Feb. 7, 2003.

The picture shows eroded and damages tiles on the aluminum panel. A small strip where a thermal barrier would be is missing. Board officials could not say if there was any significance to that because it's unclear when the damage took place.

One of the theories investigators are considering is that the foam insulation struck the shuttle's belly near or on the left landing gear door. It's possible that damage could be worse than originally determined and allowed hot gases inside.

Columbia broke up more than 200,000 feet above Texas while still moving 18 times the speed of sound. Any debris from the shuttle was still subject to extreme heating as it fell, as well as the possibility of being struck by other debris on the way down.