This is what I was referring to:
"Immediately after the Columbia rolled to a stop, the inspection crews began the process of the post flight inspection. As soon as the orbiter was approached, light spots in the tiles were observed indicating that there had been significant damage to the tiles. The tiles do a fantastic job of repelling heat, however they are very fragile and susceptible to impact damage. Damage numbering up to forty tiles is considered normal on each mission due to ice dropping off of the external tank (ET)"
"The pattern of hits did not follow aerodynamic expectations, and the number, size and severity of hits were abnormal. Three hundred and eight hits were counted during the inspection, one-hundred and thirty two (132) were greater than one inch. Some of the hits measured fifteen (15) inches long with depths measuring up to one and one-half (1 1/2) inches. Considering that the depth of the tile is two (2) inches, a 75% penetration depth had been reached. Over one hundred (100) tiles have been removed from the Columbia because they were irreparable. "
"During the STS-87 mission,
there was a change made on the external tank. Because of NASA's goal to use environmentally friendly products, a new method of "foaming" the external tank had been used for this mission and the STS-86 mission. It is suspected that large amounts of foam separated from the external tank and impacted the orbiter. This caused significant damage to the protective tiles of the orbiter. Foam cause damage to a ceramic tile?! That seems unlikely, however when that foam is combined with a flight velocity between speeds of MACH two to MACH four, it becomes a projectile with incredible damage potential. "
This is why I am PO'd at the 'green' movement, was it worth it?
How true: "You can lead a man to knowledge, but you can't make him think. " ( from another TDR member)
MORE:
http://www.newsmax.com/showinsidecover.shtml?a=2003/2/4/174925