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.

Count me among the skeptics on the meteor strike hypothesis. Anything's possible, I suppose, but in this case it would have to be something small (so the orbiter wouldn't come apart in an instant) and it would have to hit the left wing where the trouble started. Sounds very far-fetched to me . . . . .

Btw, is there any truth to the report in the British press that Ramon's father is saying NASA thinks the astronauts had 60-90 seconds warning before the orbiter disintegrated? NASA says that the flight adjustments were within normal bounds prior to disintegration, but I'm not sure I believe that considering that the shuttle may have started coming apart over California.

You know I love ya Rand, but really!

I'm curious about this article from the SFGate. Says an amatuer photographer snapped pics of what appears to be a large electrical charge hitting the shuttle over California.

http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2003/02/05/MN192153.DTL

Might be nothing, but I certainly don't understand what could produce the kind of effect they're describing. Could it be a static buildup similar to lightning or St. Elmos? Of course, it could just be a glitch in the camera as they article suggests.

Now, the DU folks say George Bush had the shuttle destroyed to get the same popularity bump he got out of 9/11. He had just talked about missle defense in the SOTU! I think it's clear, he used Star Wars to take out the shuttle!

For the record, that previous paragraph was facetious. :)

Bob

I'm not sure what your problem is, Ken.

Not wanting to register for the LA Times so I can't read the article (yet). I would assume they are not saying the orbiter was hit by a meteor over Dallas, but that at some point during their 16 days in orbit, the underside of the left wing was hit hard enough to compromise the integrity of enough tiles to cause failure on reentry. Correct? Just as the foam/ice might have done damage on launch.

If at a shallow angle, this would also mean a linear set of tiles could be damaged, or a cone from the shock of the effect, leading to the "zipper" effect, and shedding across the western U.S.

I would suspect that we are going to hear about a concerted effort to recover tiles from texas in the coming weeks no matter what hypothesis proves to be correct-- we won't find the ones that were damaged, but we might be able to statistically figure out where and when and how big that damage was.

Also, is there any chance that such a strike would show up on telemetry during the mission? A sudden and unexplained attitude
shift, for example. (Opps, getting too close to technical speculation. Sorry.)

I'd like to hope that this solution has some merit, 'cause the foam is getting a little too close to O-ring territory, neither do Iwant to see people latch onto it as a way to shift blame away from those who might deserve it. But risk assessment is a trick business, and often you don't learn that you were wrong in your assumptions until too late.

Yes, Raoul, that's the theory.

By the way, I think that you can get into the Times with "laexaminer" as username and password.

Rand,

I understand your point of view regarding the relative worth of space craft and astronauts on a mission, but please reconsider the manner in which you phrase this viewpoint. Statements like It's the orbiter that has the value, not the astronauts... are just plain wrong. Both the craft and the crew are beyond dollar valuation of any amount. Perhaps a better way to state your viewpoint would be "The survival of the craft is more crucial to the program and its goals than the survival of the crew."

BTW: Count me as another skeptic of the "space debris" theory. The Times article you linked to succinctly summarizes the reasons why I find the theory to be nonsustainable. Anyone who is interested can reference the "Flight Director's Nightmare" commentary for my thoughts regarding the matter.

"Count me among the skeptics on the meteor strike hypothesis. Anything's possible, I suppose, but in this case it would have to be something small (so the orbiter wouldn't come apart in an instant) and it would have to hit the left wing where the trouble started. Sounds very far-fetched to me..."

Just to be Devil's Advocate -- there's certainly plenty of space gravel floating around that could be big enough to do the requisite damage and small enough not to smash the orbiter to bits instantly. And there's no one place on the orbiter that is less vulnerable, statistically, than any other if the relative motions of it and the rock are "right".

The orbiter's own direction of movement WRT earth's surface isn't level -- the nose is high so as to present the relatively smooth underside to most of the atmospheric friction. Which does mean that a meteor approaching from ahead would be more likely to miss the wing than hit, but a meteor overtaking from behind would be a different matter.

My doubts about the meteor theory center on how deep Columbia was in the atmosphere at the time of the supposed collision. Something still big enough to cause fatal damage by then would have been much bigger before the impact. Shouldn't someone have seen its own ionization tail?

Oops, sorry Rand. I didn't read the whole thread. But wouldn't an impact while in orbit have gotten the attention of the crew? Not a "crash" sound of course, but a sudden, sharp vibration?

And then there's the small problem of how the meteor theory could ever be proved.

I don't know what the acoustic environment of the orbiter is, but ISS is pretty loud, with all the machinery (to the point that it's a real problem). It could have occurred during some other event and gotten confused with it. Of course, it's even more unlikely, but it could have occurred during entry itself, in which case, it really was an act of God that no one could do anything about, any more than if it hit an airliner.

Re: getting into LA Times registered section:

For many websites, the user/pass combo "cypherpunk" works.

I have no problem Rand, "It's the orbiter that has the value, not the astronauts..." seems a bit insensitive, thats all. Even Spock would resist making such a statement! ;-) But perhaps I am being overly sensitive. How can I tactfully state my premise that engineering and human feeling do not need to be mutually exclusive? I don't know the answer to that.

Back on topic...
http://www.foxnews.com/story/0,2933,77870,00.html

The "electrical discharge" and "meteor strike" theories seem like desperate attempts to avoid admitting the deaths were caused by a previously-known problem. It's known that something did strike the left wing of the shuttle--the chunk of tank insulation. There's no need to suppose something further into existence, unless it can be absolutely proven that it didn't cause the damage (and that's going to be rather hard to do).

More to the point: even if the chunk didn't cause this particular accident, why not address the issue? It would seriously suck if there were unexpected failure modes where the insulation did cause problems.

All this really says they need to either provide some way to inspect and repair the tiles while in orbit, or make the tiles sturdy enough to survive such incidents. (I realize that #2 is extremely unlikely.) Tile-related problems have been happening for years, and it's been luck more than anything else that they've managed to survive this long.

I agree that not everything can be protected against, and there will always be a high degree of risk. Obviously they can't protect against the Shuttle striking something on reentry. However, one shouldn't knowingly get into a Pinto unless it's an emergency and there's absolutely no other transportation available.

Hmmm. "Space Shuttle--the modern-day Pinto". Has kind of a ring to it...