Foreign Policy

Winter 1999–2000

National Missile Defense: An Indefensible System

By George Lewis, Lisbeth Gronlund, and David Wright

This abstract is adapted from an article appearing in the Winter 1999-2000 issue of Foreign Policy magazine.

Next summer, President Clinton will decide whether the United States should begin deploying a national missile defense (NMD) system intended to protect the entire country from limited attacks by intercontinental ballistic missiles (ICBMs) armed with nuclear, biological, or chemical warheads.

Such attacks, ranging from a few to a few tens of missiles, fall into three categories: a small accidental or unauthorized launch from Russia, a deliberate or unauthorized attack from China, or a deliberate attack from a hostile emerging missile state that might acquire ICBMs. This last threat—focused on Iran, Iraq, and North Korea—has emerged as the primary argument for a near-term NMD deployment.

The planned national missile defense is more down-to-earth (literally and figuratively) than former President Ronald Reagan’s Strategic Defense Initiative (SDI), which was intended to create a space-based shield against a massive Soviet nuclear attack. In contrast, the current system would use ground-based interceptors to destroy incoming warheads by colliding with them. Indeed, because it is intended to counter a more limited threat than the SDI system, and because it would use existing rather than speculative technology, many assume that, unlike SDI, the NMD system would work against the threat at hand. Moreover, although many observers agree that SDI deployment might well have aggravated the U.S.-Soviet arms race, they assume that, with the end of the cold war and Russia’s declining economy, deploying the NMD system will result in few security costs.

However, neither assumption about the security benefits and costs is warranted. Given today’s technology, the United States can certainly build a system that could destroy one or several ICBM warheads under controlled conditions, in which the characteristics of the target warhead are known and no serious effort is made to defeat the defensive system. However, the essential question is whether the system will be operationally effective—that is, whether the defense would be effective in the real world, where the characteristics of the attack would not be completely known in advance and where the attacker would develop countermeasures to defeat the defense. Many NMD proponents argue that countermeasures are hard to develop and implement. However, there are many countermeasures that are much easier to build and deploy than either an ICBM or nuclear warhead small enough to be delivered on an ICBM.

It is doubtful that any of the tests planned by the Pentagon will attempt to assess the operational effectiveness of the system against real-world countermeasures. To do so, the countermeasures used would have to be designed by a truly independent group, and the NMD intercept tests would have to be conducted without the operators knowing in advance what countermeasures they would face. There is no indication that such a testing program is even under consideration.

Building a national missile defense system will also incur far-reaching security costs. Despite the much-trumpeted end of the cold war, the United States and Russia continue to rely on nuclear deterrent policies based on deploying large numbers of nuclear-armed missiles ready for immediate launch. The deployment of an NMD system that Russia believes could undermine its deterrent will almost certainly provoke a reaction that will undermine U.S. security.

Many influential military and political leaders in Russia warn that the United States’ disregard of their strategic interests seriously undermines relations between the two countries, especially following the expansion of NATO and the bombing of Kosovo—cases in which Russia also believes its concerns were ignored. Some warn that U.S. NMD plans could become an important issue in the June 2000 presidential election in Russia and lead to the election of a hard-liner.

To maximize its number of survivable missiles, Russia would probably resist "de-alerting" measures to reduce the rapid-launch status of its nuclear forces and might even increase the fraction of its missiles on high-alert status. Such steps would have the side effect of increasing the risk of an accidental or unauthorized Russian missile launch, which arguably presents the greatest threat to U.S. security.

China may be even more alarmed than Russia. China’s small deterrent force of roughly 20 ICBMs would be directly threatened by even the first phases of the NMD system. China clearly is capable of expanding its offensive forces in the next few decades by building more missiles and deploying multiple-warhead missiles to overwhelm a national missile defense system. While some modernization of China’s missile forces is likely in any event, deployment of a U.S. missile defense will influence both the timing and scope of those efforts. To preserve its option to enlarge its nuclear arsenal, China might also refuse to participate in a fissile material production cutoff.

In the medium to long run, the price of a national missile defense system deployed by the United States may well be a world with more ICBMs and weapons of mass destruction. Compared with these large and nearly certain security costs, the benefits the planned nmd system would provide are both too small and too uncertain to justify its deployment.

References

Joseph Cirincione’s "Why the Right Lost the Missile Defense Debate" (Foreign Policy, Spring 1997)

Cirincione’s "Rush to Failure" (Bulletin of the Atomic Scientists, May/June 1998)

Richard L. Garwin’s "The Rumsfeld Report: What We Did" and Lisbeth Gronlund and David Wright’s "The Rumsfeld Report: What They Didn’t

Do" (Bulletin of the Atomic Scientists, November/December 1998)

John Issacs’ "Missile Defense: It’s Back" (Bulletin of the Atomic Scientists, July/August 1999)

George N. Lewis, Theodore A. Postol, and John Pike’s "Why National Missile Defense Won’t Work" (Scientific American, August 1999)

Lewis and Postol’s "Future Challenges to Ballistic Missile Defenses" (IEEE Spectrum, September 1997)

Foreign Policy

Winter 1999–2000

Hitting Them Where It Works

By Theodore Postol

Whether or not one believes that the threat from emerging missile states such as Iran, Iraq, or North Korea is serious enough to require deployment of a national missile defense (NMD), it makes no sense for the Clinton administration to advocate a defense concept that not only will fail to work against these countries but also will provoke negative reactions from Russia and China. But there is a way to provide a defense that would likely be effective and also much less provocative to Moscow and Beijing. A "boost-phase" missile defense—jointly built and operated by Russia and the United States"would target intercontinental ballistic missiles (ICBMs) in their first few minutes of flight, while they are still being accelerated up to speed by their rocket engines. This strategy differs from the planned NMD, which is a mid-course system that can easily be defeated by countermeasures released from target ICBMs after they end powered flight. A boost-phase defense could only be devastating from a relatively short range and only over a relatively small region of the earth (to a range of perhaps a thousand kilometers). Consequently, the system would be unstoppable when used against geographically small emerging missiles states, but it could neither be effective against, nor expanded to defend against, missiles launched from geographically vast countries such as Russia or China. This boost-phase missile defense would consist of very fast interceptors placed in hardened underground silos or on offshore platforms at distances of hundreds of kilometers from North Korean, Iranian, or Iraqi launch sites. Silos might be deployed in the region near Vladivostok (to defend against North Korean launches) or in Turkey, Azerbaijan, or the Caspian Sea (to defend against Iranian launches).

When an ICBM is launched, it would be detected and tracked by sensors placed on the ground, in unmanned airborne vehicles or aircraft, or on satellites orbiting the earth. The missile defense system would then launch boost-phase interceptors that would accelerate to 8 to 8.5 kilometers per second in a little over a minute. Even if the launch of the interceptors were delayed for a minute or more after the launch of an ICBM in order to establish its trajectory, the interceptors could still destroy the ICBM while it was in powered flight, causing its warhead to fall far short of its target.

Unlike the Clinton administration’s proposed system, this boost-phase defense would be difficult to counter. Countries seeking to defeat it might try to reduce the boost-phase flight time, thereby narrowing the window of opportunity for a successful intercept. But that would require the development of highly advanced solid propellant ballistic-missile technology—an innovation that is in a completely different league than the liquid-fueled Scud-missile technology that is now the foundation for the missile programs of states such as North Korea, Iran, and Iraq. Moreover, in contrast to the administration’s proposed mid-course NMD system, this boost-phase system could destroy an ICBM before it released submunitions carrying biological or chemical agents. In addition, the technology needed to implement this defense is far less demanding than that needed for mid-flight intercepts. Because boost-phase interceptors would only need to detect the very hot plume of the booster and not the cooler warhead or decoys, such interceptors could use higher resolution short-wavelength sensors that are easier to build and much less costly than the long-wavelength sensors used by the kill vehicles of the planned NMD system. The ICBM booster target is large and would be destroyed by a hit almost anywhere, so the probability of a successful intercept would be very high.

A boost-phase defense system would face significant policy obstacles. Getting countries such as Azerbaijan or Turkey to allow basing of interceptors on their territory could be a challenge. Such a program would also require close cooperation between Russia and the United States, which would increase existing Chinese concerns about a U.S.-Russian alliance. Moreover, a boost-phase defense deployment near North Korea would be able to intercept long-range missiles launched from a relatively small part of China.

Perhaps more serious, however, would be Chinese concerns that the boost-phase defense could be turned into a mid-course defense capable of intercepting ICBMs launched from anywhere in their country. China could easily build countermeasures to deal with such a contingency, and Russia and the United States could implement transparency measures to reassure China, but the possibility that the system could be rapidly modified might remain a concern. However, these problems are all far more manageable than those raised by the administration’s planned NMD system. Even the first phase of the administration’s fragile and easily defeated NMD will create serious problems with both Russia and China—and may well lead to the collapse of the entire international regime of arms control treaties.

Theodore Postol is professor of science, technology, and national security policy at the Massachusetts Institute of Technology.

Foreign Policy

Winter 1999–2000

Balloons, Decoys, and Shrouds

The U.S. National Missile Defense (NMD) system would employ interceptors that operate above the earth's atmosphere. In the vacuum of space, there is no atmospheric drag, and both heavy objects such as warheads and much lighter objects travel on identical ballistic trajectories. This fact, and other characteristics of the space environment, make possible a wide range of relatively simple but effective countermeasures against the planned NMD system. Such countermeasures could be used alone or in many combinations.

One often discussed countermeasure is lightweight replica decoys. The attacker would release large numbers of these objects along with the real warhead. Unless the defensive system could determine which of the objects was the actual target, it would have no choice but to fire at all of them, which would quickly exhaust its supply of interceptors. Otherwise, it would risk letting the warhead penetrate unchallenged. One way to make replica decoys would be to use warhead-shaped balloons with a thin metal coating on their outer surfaces to reflect radar waves. Such decoys might also contain heaters to simulate the heat emission of the warhead and small weights to give spinning and tumbling motions similar to that of the warhead.

Less discussed, but likely more effective, is a technique known as anti-simulation. Rather than make all the decoys look like the warhead, the attacker would disguise the warhead. For example, the attacker could cover the warhead with irregularly shaped pieces of metallic foil to make it look like a piece of missile debris. Alternatively, the warhead could be released inside a metal-coated balloon, along with large numbers of similar, but empty balloons. These balloons would differ slightly in size-and by varying their shapes and surface coatings, they would have different equilibrium temperatures. The defense would then face the nearly impossible task of telling which of them was the real target. As an alternative to decoys, the warhead could be enclosed within a thin metallic shroud that would be cooled with a small amount of liquid nitrogen. This technique could reduce the range at which an infrared-homing kill vehicle could detect the warhead by a factor of at least a thousand, in effect blinding the kill vehicle, and thus defeating the defense.

–G.L.,L.G., D.W.