I'm really quite annoyed with the Discovery mission. As noted toward the end of a recent blog entry response, the shuttle is a profoundly resilient vehicle. The ships are more than capable of withstanding numerous missing tiles, damaged tiles, and other issues.
For instance, the first launch of the shuttle was Columbia in 1981. When the solid rocket boosters ignited, they caused a blast wave which blew off 16 tiles and damaged 148 others. The ship obviously landed without incident . . . and then on her next mission she had 12 tiles damaged, and this was considered okay. According to the Houston Chronicle, a 1985 discovery mission involved a similar amount of damage, including a hit to the left wing . . . damage that was somewhat overshadowed by a front tire blowout on landing. Then there's the 1992 incident with a gouge in the left wing of Atlantis.
Yes, the Columbia accident is a tragedy, and there's no denying that an analysis of the entire system was needed in order to make sure that the ship remained safe to fly.
However, in my opinion the shuttle managers and most reporters have become altogether paranoid. Now, for instance, an extraordinary amount of attention is being paid to various tile "scuffs" and (gasp!) a whole entire nick to a tile. If that weren't enough, they're planning to send a guy with scissors and a hacksaw down beneath the ship so as to cut off a tiny piece of gap filler that is sticking out between two tiles, on the grounds that it might disrupt the laminar flow and produce extra heating downwind.
Even per the shuttle mission managers, worst-case scenarios featuring gap filler in the past have done nothing more than to make pre-existing damaged tile issues ever so slightly worse. No tiles blown off the ship, no reinforced carbon-carbon panels heating past 3220 degrees Fahrenheit, no tiles heating beyond 2300.
In other words, despite clear historical evidence, they're treating the shuttle as if she's absurdly fragile, incapable of surviving even the slightest scuff without a review board and computer models to declare her safe.
And so they're going to send a guy in a spacesuit attached to a big heavy arm and armed with various sharp pointy objects to go play with these tiles they're so worried about. Because, you know, that makes sense.
I can understand some caution about things after Columbia, but dammit . . . these are good ships and good crews and they should be allowed to go up without everyone freaking out if there's a scratch on the paint.