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Hi Luis, hope all is well for you these days.

"NASA knew from the second day of Columbia's 16-day research mission that a piece of the insulating foam on the external fuel tank had peeled off just after liftoff and struck the left wing, possibly ripping off some of the tiles that keep the ship from burning up when it re-enters Earth's atmosphere." http://www.washtimes.com/national/20030203-87326768.htm

http://ltp.arc.nasa.gov/space/team/journals/katnik/sts87-12-23.html
"Damage numbering up to forty tiles is considered normal on each mission due to ice dropping off of the external tank (ET) and plume re-circulation causing this debris to impact with the tiles. But the extent of damage at the conclusion of this mission was not "normal."

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."

http://www.arnold.af.mil/aedc/newsreleases/1999/99-041.htm
"According to NASA, during several previous Space Shuttle flights, including the shuttle launched Nov. 29, 1998, the shuttle external tank experienced a significant loss of foam from the intertank. The material lost caused damage to the thermal protection high-temperature tiles on the lower surface of the shuttle orbiter."

Thanks for the info. If I recall from back in the day when I actually paid close attention to flights, losing a number of tiles on both take-off and re-entry was common-place. Columbia even lost some on her maiden voyage, and while it is known that something (I didn't know they knew for sure what it was) struck the wing on take-off, they are not saying for certain that it damaged the ship.

Space exploration, while we would like to think otherwise, is still in its infancy, and frought with danger. All in all, NASA's record is great, seventeen deaths out of hundreds of missions. Great when you consider that we suffer more deaths in toothpick related accidents in a year, than NASA has in their entire existence.

Let's hope that the reasons for the accident are found, and corrective measures taken.

Some of the hits measured fifteen (15) inches long with depths measuring up to one and one-half (1 1/2) inches.

That's some tough foam. But then it's hard to imagine foam impacting something at mach 2 or more (I'm assuming the atmosphere would've decelerated the foam so that the difference in speed between the orbiter and the dislodged foam by the time it hit the orbiter was mach 2 or more).