I heard that on STS-105 they had a chunk come off of the external tank and wack one of the SRB's. After they recovered the SRB they found a very large dent at the point of impact.
Did you hear during the news conference that one of the astronauts (David Hall?) emailed his brother about their taking pics of the underside of the left wing during the mission. If this is true then NASA/AF did try to take pics of the damage. What did they know and when did they know it? Wonder how many bird cages will be lined with the shredded papers when they're done...