Lift off

Yesterday the space shuttle Discovery successfully lifted off. Now the concern is getting that thing back onto the ground in one piece. They're poring over the video to see if some foam may have hit the shuttle again. That was the cause of the disaster on the last space shuttle flight some 2+ years ago.

I just want to know why this was NEVER mentioned, nor a concern in all the years prior? For 20 years these beasts have ascended and descended and the foam was never an issue. A solid rocket booster gasket, however, prove to be deadly many years ago.

They won't call this flight a success until the craft and crew are safe again on the ground.