NASA is considering the possibility that Columbia was hit on orbit.

Could be. There’s a lot of junk floating around up there, though we’re doing better at keeping things clean, and most of the older stuff has deorbited. Of course, it could have been a natural object, a small meteoroid, in which case, it really was an act of God.

This all complicates life even more, because it’s no longer a matter of just watching launch films to see if there were any problems on ascent. It means that to really insure against this happening again, they have to have a way to do a tile inspection just prior to deorbit, and make it part of the deorbit procedure. Not a problem at station, but it’s more of a challenge for a mission like Columbia’s, which was on its own. And of course, they also would have to have a contingency plan if they can’t come back. More on that later.

On the other hand, one might simply be philosophical, and say that it’s not reasonable to design against every possible hazard. After all, my car could also be hit by a metorite, but that doesn’t mean that I armor my roof against such an eventuality.

I found this bit interesting.

After the report was issued, Fischbeck said NASA took steps to sharply reduce foam debris. The experts also urged NASA to find ways to improve tile safety, despite budget cuts.

“NASA must find ways of being cost-effective, because it simply cannot afford financially or politically to lose another orbiter,” the report cautioned.

Yes. NASA cannot afford to lose another orbiter. Note that it doesn’t say they can’t afford to lose another crew. Whether deliberately or inadvertently, they get it right. It’s the orbiter that has the value, not the astronauts, and reusable vehicles have to be reliable, or they’re unaffordable, regardless of their contents. That’s why talk of “man rating” a space transport, or that this will add cost to it, is utter nonsense.

[Update at 3:11 PM PST]

Jay Manifold has run the numbers on this.

[Another update at 3:38 PM PST]

Here’s a couple-year-old article about the subject, by Leonard David. I found this interesting, because I used to work on debris characterization over twenty years ago, at Aerospace, with Val Chobotov. It was my first job out of college. I worked with Bill Ailor, too, but he wasn’t doing debris analysis then.