The report “Making Sense of Ballistic Missile Defense” published in September by the National Academy of Sciences (NAS) is one of the most significant studies released on this topic. For years, critics from the academy and the arms control community denigrated missile defense on political and technical grounds, stressing the “insolvable” issue of countermeasures to “prove” their point. According to them, all midcourse missile defenses in development today are not viable on account of “simple and cheap” countermeasures that could be easily developed and deployed by nonindustrialized countries without even first testing them in real flight. Only boost phase intercepting systems could be viable, according to those critics. By implications, then, the huge sums spent on current midcourse missile defense programs are wastefully enriching the defense sector.
For years, the missile defense community, aware of the intelligence risks to national security, refused to show its hand and kept mum in the face of such criticism. Now the NAS report is redressing this one-sided debate by openly discussing the countermeasures issue and how to deal with it. Its team of authors is eminently qualified to do so, consisting as it does of top experts in the U.S. industry, several with proven records in cutting-edge ballistic missile and missile defense programs. The result is a classic that is sure to become a textbook for future missile defense designers.
The report offers three meticulously argued and well-articulated conclusions: First, in most real-life scenarios, boost phase intercept (BPI) is impractical. Second, countermeasures are a problem but not a show-stopper. Third, the defense of U.S. territory should be decoupled from that of Europe. The last point is argued on technical grounds yet its political implications are not ignored.
BPI is intuitively very appealing: Why not kill an ICBM while it is still accelerating, when its glowing rocket motors present big, fat targets to heat-seeking interceptors and before it deploys its countermeasures? Unfortunately, in most cases there is not enough time to do it. The name of the game in missile defense is time: time to detect the target, and time to fly to the intercept point. The boost phase in ICBM ends just a few minutes after takeoff, when the ICBM is still relatively near its launch pad often still above the aggressor’s territory. To be able to hit it during its short boost phase, a surface-launched interceptor must be fired from close vicinity, which in most cases means unfriendly territory or dangerous waters. Space-based BPI requires expensive arrays of orbiting interceptors to maintain a continuous presence above suspected launch sites. Simply put, BPI is either impractical or unaffordable. The report puts to rest all schemes of BPI — surface-launched, space-launched or air-launched (with the latter having some niches of utility). In this it corroborates the U.S. Missile Defense Agency’s strategy of exclusively focusing on midcourse and terminal interception systems.
Unsurprisingly, BPI proponents did not take this kindly. In an article Sept. 20 in the Bulletin of Atomic Scientists titled “The astonishing National Academy of Science missile defense report,” Theodore A. Postol and George N. Lewis accuse the NAS authors of bias in using nominal ICBM burn times in their calculation. In their view, North Korean and Iranian ICBMs will be no more than slow-burning space launch vehicles lugging bombs instead of satellites; the long burn time of such first-generation ICBMs will allow distant hence secure BPI deployment. This criticism misses the point: Any BPI system specialized against such hypothetical slow-burning launch vehicles will become totally useless once the aggressors pull their act together and deploy second-generation ICBMs with more-efficient, fast-burning upper stages — as they are sure to do in time.
The critics also complain about the NAS report’s selection of conservative interceptor speeds. Yet their hypothetical 10-kilometer-per-second interceptor is today no more than a gleam in the eye of the engineer. Considering the practical difficulties of such ultrafast interceptors, the NAS authors did well to stay within the realm of practicality.
The groundbreaking part of the NAS report is the discussion of countermeasures and discrimination. Without trivializing the challenge, the report outlines strategies for dealing with the problem. The key is long-duration sensing at several wavelengths. The threat should be detected as soon as it takes off, and any object ejected from it should be carefully noted and tracked. Optical sensing should be added to and correlated with radar sensing. A dynamic target object map should catalogue all threat-related objects, from which the identity of the authentic target could be deduced and sent to the interceptor via two-way communication links. Finally, the defense should adopt a shoot-look-shoot policy rather than salvo fire, to provide for a second chance in case of the first interceptor hitting the wrong target.
The authors soberly conclude that there is no silver bullet here, and the balance of discrimination versus countermeasures is fluid in essence a “Wizard War,” as in World War II. The outlined strategy probably would be less effective against salvoes of superpower ICBMs but would have a fair chance to work against fewer ICBMs from less-industrialized powers. Countermeasures exist, but they are neither simple nor cheap — and are not always reliable. As the NAS report says, “U.S. (and U.K.) experience with the development of high-confidence penetration aids during the Cold War was of mixed success.” Moreover, recent revelations indicate that the cost of the “Chevaline” countermeasure suite developed for U.K.-owned Polaris submarine-launched ballistic missiles amounted to billions of dollars.
Postol and Lewis argue that the radars planned for the European Phased Adaptive Approach (EPAA) system are too short-ranged to fulfill discrimination tasks. This again misses the point. The proposed strategy is universally applicable to missile defense at large, not only to EPAA. In any case, indications are that the radar modeling done by the critics tends to underestimate real-life performance.
Finally, the NAS report argues that the battlespace for West Coast interceptors defending the East Coast is too restricted, while any prospective interceptor defending the U.S. homeland from Europe will be too large to fit in the currently planned EPAA launcher. A number of solutions can be envisaged, one of which is to decouple U.S. homeland defense from that of Europe, and build a third site on the East Coast. While the costs, timelines and political implications of such a step can be debated, the technical logic is impeccable. Interestingly enough, Postol and Lewis, sharp critics of EPAA as they are, keep silent on this point.
The NAS report is a landmark of clear thinking in the best American tradition of good engineering practice. Against the backdrop of murky criticism often based on wishful thinking, it is a breath of fresh air in the public debate on one of the most crucial aspects of national security for the United States and other countries alike.
Uzi Rubin was the first director of the Israel Missile Defense Organization and is currently an international consultant on missile defense.
