Here we go again...

[VampyreGTX]

Tiles have ALWAYS come off during launch. It's designed to be able to handle a couple missing tiles. This ISN'T what brought down the Columbia. That was the huge HOLE in the wing that was created by the insulation that came off during takeoff. They have known for years that some tiles are lost during the ascent. They just want to make sure the white debris (not the peice from the external tank that was large enough for radar to detect) that was seen coming off the orbiter was just the white tiles from the top of the orbiter and not something else vital.

 

[ms6073]

That was the huge HOLE in the wing that was created by the insulation that came off during takeoff.

I know there was never a definitive reason for the accident and not to rehash past history but my understanding was that the insulation that impacted the tiles of the wing during launch caused several tiles to distort as well as the possible loss of some of the ceramic tiles. The result was the formation of a small gap between tiles, and as the orbiters underside heated up during rentry, the 'gap' in the tiles began to expand enough to allow the external temperatures to penetrate various structural components until such time as the strucutre of the wing root was compromised and subsequently departed the orbiter.

 

[VampyreGTX]

...but my understanding was that the insulation that impacted the tiles of the wing during launch caused several tiles to distort as well as the possible loss of some of the ceramic tiles. The result was the formation of a small gap between tiles, ...

This didn't just knock/distort some tiles, it left a hole in the wing well over a foot long (22"). The results were shocking to say the least, but the follow-up computer analysis of the hole created during testing showed an outcome almost identical to what happpened, with the failures of the sensors, etc. However, the test wing was actually made of fiberglass and NOT the carbon composite of the shuttle wing. The fiberglass is 2.5X stonger than the CC so the damage to Columbia was probably significantly worse.

The only thing that bothers me is the sensors picked up abnormal heating at the impact point starting at the same time the insulation impacted the wing and continuing throughout the climb. If there was excess heat entering the wing during climbout when the friction and heat forces are miniscule compared to re-entry, how could they not expect the unsustainable heat that would affect that same wing on re-entry?

Anyway, RIP to the Columbia crew and good luck to the Discovery crew! Looking forward to a safe return to earth in about 12 days.