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.
Thanks for your reply. :-)