But of course it does! Almost every engineer who looked at the problem knew it was eminently possible to design an anti-ballistic missile system, once high-speed computers and miniaturized seekers were developed (not to brag, but I wrote something to that effect back in 1986). A ballistic missile (or a decaying satellite) is a very predictable object; it acts in accordance with basic laws of physics, so that, after tracking it briefly, one can extrapolate its state vectors and predict where it will be in space at any point in time. After that, it’s equally easy to figure out where in space to aim your interceptor missiles. The trick comes in the end game, when small errors can result in significant miss distances. That is why, during the 1950s and 60s, U.S. and Soviet ABM systems relied on nuclear warheads. By the 1980s, miss distances had come down to the point that we could either use high explosive warheads throwing out large numbers of high velocity fragments, or, better still, use a “hit-to-kill” approach. Now, we have gotten to the point that hitting the bullseye at a combined velocity of more than 15,000 mph is becoming routine. The difficulties of the missile defense problem have always been more operational than technical. We don’t have to deal with one incoming warhead in isolation, but more likely with several to many coming in simultaneously and aimed at different places. That means detecting multiple objects, classifying them as threats, allocating missiles to each object, generating a fire control solution, launching the missiles, guiding them to the target, evaluating the end game, and re-engaging any targets that were missed. That takes a lot of computing power and RF bandwidth–but we can do it now, at least for small-to-medium sized attacks. In the past, the main problem was the impossibility of defeating a large-scale attack by the USSR. Not only did the Soviets have so many missiles that at least some would get through, but most of them carried multiple warheads, so that we were dealing with tens of thousands of reentry vehicles. And the Soviets could have made the problem more difficult by deploying decoys (known as “Penetration Aids” or “PENAIDS”) to further confuse the radar picture. While individually it is rather easy to discriminate between a PENAID and a live warhead (unless you want to make your PENAID almost as complex, expensive, and heavy as a real warhead), collectively they act like grit in the machine, slowing down defensive response times. The Soviets also experimented with “Maneuvering Reentry Vehicles” (MARVs) which could alter their course in flight, greatly complicating the defensive problem. Fortunately, MARVS were both heavy (cutting into missile payloads) and exorbitantly expensive. Still, on the balance, when dealing with a superpower adversary with a large missile force, the cost balance weighed heavily in favor of the attacker. Today, of course, our potential adversaries have just a minuscule fraction of the Soviet Union’s ballistic missile capability. And, with their smaller economic and technical bases, they certainly don’t have the wherewithal to deploy thousands of missiles with multiple warheads and complex PENAIDS, so a relatively modest missile defense system can deter attack by small and medium-sized nuclear powers, or defeat an accidental launch or deliberate attack by a suicidal rogue state. It’s a very worthwhile investment, on par with buying fire insurance for your house. The recent successes of the Aegis/Standard III system have implications beyond forces afloat. Both the SPY-1 radar system and the Mk.41 Vertical Launch System (VLS) from which the Standard III missile is fired, are self-contained units. There is nothing that says they must be deployed aboard ships–they could just as easily be emplaced on land. Indeed, travelers up the Jersey Turnpike are familiar with the “Cruiser in the Cornfield”–the Lockheed Martin Aegis testbed at Moorestown, NJ. One could easily build similar facilities in Allied countries, connect them by fiber-optic link to a battery of Mk.41 VLS that could be buried in hardened concrete pits, and voila! Instant ABM system, capable of taking down short-to-intermediate range ballistic missiles. This would have a significant effect of extending U.S. deterrence to threatened friendly countries such as South Korea, Japan, Iraq, Israel (and, dare I say it?) Taiwan. It would go a long way to preventing nuclear intimidation by countries such as Iran and North Korea, and prevent the decoupling of the U.S. from its regional allies in times of crisis.
