During a mission status news conference yesterday, Entry Flight Director Leroy Cain was asked about any possible damage to the shuttle's thermal tiles during launch. The tiles are what protect the shuttle during the fiery reentry into Earth's atmosphere.
Tracking video of launch shows what appears to be a piece of foam insulation from the shuttle's external tank falling away during ascent and hitting the shuttle's left wing near its leading edge.
But Cain said engineers "took a very thorough look at the situation with the tile on the left wing and we have no concerns whatsoever. We haven't changed anything with respect to our trajectory design. It will be a nominal, standard trajectory."
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I have always wondered why NASA didn't put shields, or pants, on the leading edges of the Shuttle. These shields would be on the nose and leading edges of the wings and tail, and would stay in place during ascent and orbit, then jettisoned just prior to re-entry.
NASA put a full cover shield over the Apollo command module vehicles that was jettisoned just prior to reaching orbit.
The wings and tail act as aerodynamic stabilizers during liftoff. My guess is that the computers of the day were unable to come up with a way to compensate for the additional unaerodynamic drag of a shield on the leading edges, and thus used thicker black tiles there.
I'll wager that this gets looked at again.