NASA has released presentation slides analyzing the external debris impact observed by cameras 82 seconds after launch of Columbia on STS-107.NASA has released presentation slides analyzing the external debris impact observed by cameras 82 seconds after launch of Columbia on STS-107.
Slide 10 offers several scenarios where one tile is lost, and in each, they conclude "no issue", even though in the same block on the table they site temperatures approaching double the design temperatures (F). Aluminum melts at 1221F, but it gets brittle before then. The same frigging slide notes the design max temp at 350F.
My theory: Tile was significantly damaged by the foam as per case 1 in the analysis, and on reentry, the airframe heated to the 790F temperature they predicted. It vibrated, wiggled, and finally broke under the force of the atmosphere - about 8 minutes prior to LOS. After the airframe broke beneath one tile, plasma entered the wing, exiting as very hot gas by the aft sensors that failed first, then the plasma carried heat to the wheel well where we observed more failures. All the while, plasma was eating away at the airframe holding other tiles, and the zipper effect happened.