Space Hygiene

I see the US Navy has been "requested" to shoot down the disabled US spy satellite before it finally comes out of orbit on its own. Yeah, I'm sure they had to ask the Navy more than once if they wanted to cue up an SM-3 missile and light the fuze...

The expression "shoot down" doesn't make any sense in this case because the SM-3 missile uses a so-called "hit to kill" warhead, also known as a "kinetic kill vehicle". It doesn't contain any explosives; it just smacks into the target at a very high rate of speed and causes damage by kinetic energy. As someone who was struck in the head with a brick (well, technically, a cement shingle, but the same spirit) I can attest to how much impact energy inert projectiles can generate.

But it's not like Star Trek, where we shoot the offending spacecraft with a blue-green beam, we listen to a restless whirring sound, and then the offending dingus simply vanishes. Would that it were so, but it aint. Instead we smash the equivalent of a high-tech brick into it and try to smash the target as throughly as possible.

And I have no doubt than an SM-3 KKV will do a very thorough job on the satellite, which I'm sure was designed to be only just barely stout enough to withstand the stresses of launch; the KKV will probably go in one side of the satellite and right out the other and convert big chunks of it into confetti.

But let's be serious a moment. This has nothing to do with the sudden fear that the satellite's monomethyl hydrazine fuel might accidentally land in a public school cafeteria. The satellite is going to break up at very high altitude - 400,000 feet or more - and as it tears itself apart, the fuel tanks will come apart, all the source gas will vent, and the relatively small load of MMH will dissipate into the upper atmosphere.

What this SM-3 shot is really all about is trashing the "sensor" in the spy satellite so thoroughly that Country X (pick your adversary) will be able to learn nothing from it even if they get their hands on all the debris. The National Reconnaissance Office and the various intelligence agencies want the "sensor" (they never call it a "camera") thoroughly wrecked, and what better way to wreck the camera than by A) pretending that they're doing a bit of orbital hygiene, and B) teaching the Navy's SM-3 missile system a new trick? I have no problem with that, especially if they wait until the absolute last minute so reduce the load of debris the test will produce.

The Russians used to put a self-destruct system in their spy satellites in case they fell into Yankee hands, but as far as I know, the system was never used. All it ever seemed to do for them was cause their spy satellites to blow up prematurely when the self-destruct systems got confused during launch.

Doh.