GUEST PERSPECTIVE (Inside Missile Defense, July 12, 2000) (Posted with the permission of Inside Missile Defense) Boost-Phase Intercept -- Not If, But When Richard L. Garwin, July 2000 While the National Missile Defense interceptors confront very limited countermeasures in flight tests, the mid-course U.S. NMD system under development today would fail catastrophically if North Korea launched a few primitive intercontinental ballistic missiles fitted with penetration aids that are far easier to make than the ICBMs themselves. In contrast, no biological warfare or nuclear payload on a "rogue nation" ICBM -- the stated reason for building the NMD system -- will reach the United States if the missile is intercepted before it gets to full speed, while its rocket engine is still firing. Intercepting a North Korean ICBM could be achieved through use of existing satellites and the deployment of large interceptors based as much as 1,000 kilometers from North Korea -- on U.S. military cargo ships or on Russian territory. I have long proposed such a ground- or sea-based boost-phase intercept capability to handle potential ICBM launches from North Korea, Iraq or Iran. This system, which would be operable only in specific locations, would also require a simple protocol modification of the Anti-Ballistic Missile Treaty. In July 1998, the Rumsfeld Commission, of which I was a member, judged that rogue nations or "states of concern" could build a few unreliable, inaccurate intercontinental ballistic missiles within five years -- if they began a concerted, well-financed program immediately and received substantial foreign technological help. Further, the United States might not know for most of that five-year period that such an acquisition program was under way. The commission also found that any of these states could threaten the United States more readily and more cheaply by developing or acquiring short-range ballistic or cruise missiles that could be launched from cargo ships near U.S. shores. These would have better accuracy and greater payload than a primitive ICBM. We also warned that these states would increase the strategic effectiveness of any biological warfare payload, like anthrax, by loading it into hundreds of bomblets rather than a single, massive warhead. Further, we were critical of the intelligence community for basing its threat assessments largely on what was actually observed, without serious consideration of what might be going on under cover of denial and deception -- D&D. Our report has been misused by those who support the ongoing NMD program. We judged only the capability of these states to mount such an ICBM program; the feasibility of a defense against any of these threats was totally outside our charter. U.S. National Intelligence Estimates (NIE) since mid- 1998 have recognized the impact of D&D, and they are designed to judge the actual status of ICBM programs rather than their potential. Since 1991, I have warned that the proposed midcourse, hit-to-kill defensive concepts -- first the Global Protection Against Limited Strikes (GPALS) system and later the NMD system -- would not counter the anthrax threat even of early ICBMs, because any state capable of building ICBMs could far more readily outfit them with anthrax bomblets released on ascent--increasing its effectiveness over a larger, single anthrax warhead. Similarly, a nuclear warhead from these states would penetrate the defense by the use of multiple empty balloons, together with an "anti-simulation" balloon around the real warhead. In April, with 10 other independent physicists, I published "Countermeasures", a 175-page report providing details culled from open sources on anthrax bomblets, anti-simulation and decoy balloons and a warhead shroud cooled by liquid nitrogen -- all designed to defeat the hit-to-kill NMD mid- course interceptor. A single ICBM that distributes 50 or 100 anthrax-filled bomblets as soon as it gets up to speed will ensure that few or none of them can be intercepted by the proposed NMD system. A missile with a nuclear warhead would launch dozens of inflated, aluminized mylar balloons, with the warhead itself inside a similar balloon; neither the radars nor the infrared sensors on a U.S. interceptor could distinguish one balloon from another. And a cooled shroud would render the warhead invisible to a homing kill vehicle, which could therefore not collide with it. In a June 20 press conference, Under Secretary of Defense for Acquisition, Technology and Logistics Jacques Gansler acknowledged that the United States would have to launch interceptors at every multiple warhead or bomblet. Some excuse the NMD system, because it is "not designed to defend against bomblets." Ballistic Missile Defense Organization and Office of the Secretary of Defense officials characterize those who say the NMD system as incapable of dealing with countermeasures as "na„ve" and "unaware" of intelligence information on the threat, or of the tools and technologies available to the NMD program to counter these penetration aids. Neither of these adjectives fits me; the Rumsfeld Commission, by law and in fact, had access to all intelligence information available to the U.S. government. BMDO claims that North Korea, for example, could not actually deploy anthrax bomblets and anti-simulation balloons for several years, when unstated counter-countermeasure technologies are supposed to be able to deal with them. I say two questions must be asked: First, when will North Korea be able to deploy anthrax bomblets -- assuming it already has anthrax in warheads weighing 500 kilograms or more -- as well as decoys and a nuclear warhead in an anti-simulation balloon, assuming the country has a nuclear warhead? Second, when will the United States have a deployed capability to deal effectively with these penetration aids? The first can be answered not through highly sensitive intelligence gathering but by two approaches advocated by the Rumsfeld Commission: THINKINT and TRYINT. This is what the authors of the Countermeasures volume tried to do in some detail. Whether these pen-aids are effective is the second question, which we addressed by using general physical arguments, assuming the best possible performance of radars, infrared seekers and the like. According to TRW and BMDO documents, the mid-course NMD system under development today would rely for discrimination purposes on mission data loads based on current intelligence. Some argue that the United States will know more about an adversarys pen-aids than it does itself. This might be true if pen-aids were tested in flight, but those described in the Countermeasures report could be thoroughly tested on the ground. An adversary would be foolish to test them in flight. None of these problems applies if intercept can occur before the ICBM reaches a speed that would carry its payload to the United States. If an ICBM can be struck in its boost phase by an interceptor traveling at 10 kilometers per second, it will be destroyed by an impact of energy corresponding to half a ton of explosive. And if the missiles burn time is cut short by as little as 10 seconds, the payload will fall short by 5,000 kilometers -- well shy of the United States or Canada. The system I have advocated since 1991 would use the Defense Support Program satellites that detected every ballistic missile launch during the Gulf War -- even SCUD missile launches in the 300- kilometer range -- and feature NMD-class 15-ton interceptors based within about 1,000 km of prospective ICBM launch sites. North Korea -- a state the size of Mississippi -- would be an ideal target for such an incremental deployment system because it abuts Russian territory south of Vladivostok and is near vast regions of ocean available for sea-based interceptors. The interceptors would be deployed at a joint U.S.-Russian anti-ballistic missile site or on U.S. military cargo ships hundreds of kilometers from North Korea. I assume that interceptors are launched within 100 seconds of ignition of the ICBM, for which I assume a 250-second burn time; considerably longer burns are expected for such a liquid-fueled early ICBM. A ground-based interceptor (GBI), which could also be based at sea, could reach 8 kilometers per second within 100 seconds -- an average acceleration of 8 Gs, or gravity forces -- and could easily detect the ICBMs enormous booster flame as soon as the GBI leaves the atmosphere. To the GBIs seeker, the booster rocket would appear 1,600 times brighter at 1,000 kilometers that it would to DSP satellites at 40,000 km. Further, an uncooled seeker that is sensitive in the visible spectrum is ideal for the initial stage of homing. As the GBI approaches the booster flame, the homing point must shift from the brightest portion of the flame to the nearby missile body. A thermal infrared seeker of very limited capability should suffice to see the booster hard body and complete the intercept; this seeker may or may not be cooled. Such a deployment is not compatible with the letter of the ABM Treaty, but a simple protocol added to it would accommodate this system. This addendum, for example, need only state that the parties to the treaty agree on further deployments of ABM systems that do not use ABM radars and rely instead on boost-phase interceptors at jointly operated sites, or of agreed design and operable only in areas such as the Japan Basin. Notably, Russian President Vladimir Putin recently spoke of Russian willingness to help allay U.S. concerns about North Korean ICBMs by cooperating on a system designed to intercept such launches in their boost phase. We should be able to take yes for an answer. The system I propose would not use the Upgraded Early Warning Radars, X-band radars, Space- Based Infrared Systems Low component, or other aspects of the NMD system. It might not satisfy some who would not support the NMD if it worked perfectly against rogue states but had no capability against Russia or China, nor those who support boost-phase intercept only as an adjunct to a layered system. We should defer a decision to deploy the NMD system until there is credible and demonstrated evidence that it can deal with the pen-aids that I have described. We should slow the hectic pace of development, and transfer funds and attention to analysis and demonstration of boost-phase intercept capabilities based on DSP and a large NMD-class interceptor. Small research contracts should be let to allow companies to demonstrate, within months, low-resolution visible-band seekers that will operate during 30 G interceptor boost. Also, existing non-ABM radars should be analyzed for their utility in detecting ICBMs at altitudes of 50 km. or more. I believe this kind of BPI system could be available sooner than the U.S. NMD system now under development. More importantly, it has a good chance of working against the missiles that can be fired at us from emerging missile powers. Richard L. Garwin is a fellow emeritus at IBM's Thomas J. Watson Research Center in Yorktown Heights, NY, and the Philip D. Reed Senior Fellow for Science and Technology at the Council on Foreign Relations, New York. He has been a consultant to the U.S. government on nuclear weapons and national security since 1950. His writings on ballistic missile defense, arms control and other national security issues are available at the Federation of American Scientists web site ( The April 11, 2000, "Countermeasures" UCS-MIT report cited above is available at the Union of Concerned Scientists web site (, in hard copy and on CD-ROM.