Physics of Folly

Ever since W. made missile defense a central feature of his campaign, boosters of all stripes have been salivating over the opportunity to get their various pet Star Wars projects funded. There are plans for putting missile defense in the ocean, in the air and in space. There are even researchers working on airplane-mounted lasers and killer satellites. Recently W. announced that he plans to expand Clinton’s already-contentious limited missile-defense research and deploy a comprehensive system over the objections of our allies.

The problem with all this is that none of it works. These systems use imprecise technology to track their targets, and most tests so far have failed. Last July, in the most recent trial run of the “hit to kill” vehicles currently being developed, the defensive rocket sailed wide of its target in an embarrassingly harmless arc high over the Pacific.

Ted Postol, a physicist and former Pentagon adviser who is now a professor of science, technology and national-security policy at MIT, is a leading critic of missile defense. Building a $60-billion-plus system, he argues, provides the worst of both worlds: no effective defense and less international stability. In a telephone interview from his MIT office, Postol explains why the so-called kill vehicles won‘t kill anything, why having them will make the world more dangerous, and why the whole scheme is as dumb now as when Ronald Reagan was seduced by the Star Wars fantasy.

L.A. WEEKLY: First, maybe you could describe a little bit about how the missile-defense system works.

TED POSTOL: Basically, it is a system of radars that try to track objects in space and an interceptor, which is a rocket booster with a device mounted on top called a kill vehicle. The kill vehicle weighs maybe 120 or 130 pounds, and it looks like a sort of telescope with small rocket motors on it. The kill vehicle gets launched towards the target of concern -- or targets, as you’d expect in a real-world scenario.

Does it all happen quickly?

Yes. The rocket booster accelerates the kill vehicle to a very high speed -- between 7 and 8-and-a-half kilometers per second -- and the incoming warhead is itself traveling near that speed. So the crossing speed is quite high. This is why accuracy is important. But the system is not very accurate. The kill vehicle is launched a few minutes before the actual flyby, but it is launched to a point in space where the system has calculated that it will be near incoming targets. And only there does the kill vehicle open its eyes, so to speak, to look for the targets. And when the kill vehicle opens its eyes, it‘s a very small field of view, perhaps 1 degree on a side. And then it has about 60 seconds to observe and home in on its target.

So the kill vehicle is not tracking the incoming missile the entire way. It goes to what it thinks is the vicinity, and then only has a brief moment to meet the target.

Right. It is a projected interception point calculated by the radar -- with some uncertainty, I might add.

I understand that the infrared sensors of the system are an issue too. The tracking system on the kill vehicle sees the incoming missiles as --

Points of light. Like little stars.

And the resolution of these sensors is not very good.

That’s part of the problem. There‘s no dimensional information.

Is that a technological limitation that can be overcome? Will we be able to make more accurate sensors in a few years?

No, that limitation will not be overcome, and even if it were improved, it would not entirely solve the accuracy problem.

And, if I understand correctly, the reason increased resolution wouldn’t solve the problem is that even a better image would still not allow the kill vehicle to distinguish between actual warheads and decoys.

Yes. For example, say there‘s a warhead flying through space, tumbling end over end as warheads do. And say there’s also a decoy balloon shaped like a warhead, also tumbling end over end. There would be no observable difference that would allow the sensor -- even a better one -- to determine which was the warhead. This is the fundamental problem. This kind of system is designed to work in the vacuum of space, and in the vacuum of space, the two would behave exactly alike. In space, it is extraordinarily easy to deploy decoys.

What other kinds of decoys are there, and how do they affect the infrared signals?

You could take a decoy balloon, for example, and paint big stripes on it so that its signal scintillates like that of a tumbling warhead. Or tethering objects to a warhead would be a way to defeat the system for sure. Tethered flares, for example -- they would completely dominate the infrared signal. You wouldn‘t be able to see the warhead at all. Or you could throw flares out freely, and the system would have no way of telling one from the other.