That's a good question. If they know what caused the launch damage, would they have time to fix the problem before launching the second Shuttle? Seems unlikely. On the other hand, if they don't know what caused the damage, then the investigation could take weeks before they could implement a fix.

Some of this might depend on the likelihood of a repeat occurrence. If the first Shuttle was damaged by a freak accident, say a birdstrike (or foamstrike?), what are the chances of the same thing happening to the second flight?

Are they planning on always having a second Shuttle ready to go within a few weeks of any Shuttle mission, or is this only for the first mission? If they're always planning on having a backup Shuttle ready to go for any mission, that could really put a strain on mission prep.