Someone may have posted this already, but here's what I found.
"On launch day, a piece of insulating foam on the external fueltank came off during liftoff and was believed to have struck theleft wing of the shuttle.
Leroy Cain, the lead flight director in Mission Control, had assured reporters Friday that engineers had concluded that anydamage to the wing was considered minor and posed no safety hazard."
Link to article
I hope I did this right. I'm still learning computer. :)