Whether or not one believes there is any threat serious enough to require deployment of a national missile defense, it makes no sense to advocate a concept that will not work. There is a way, though, to provide a defense that would likely be highly effective, a strategy that avoids the serious and as yet unsolvable problems posed by space-deployed decoys that I have discussed.
A “boost-phase” missile defense would target intercontinental ballistic missiles in their first few minutes of flight, while they are still being accelerated up to speed by their rocket engines. Because such a system would consist of very fast, short-range (perhaps a thousand kilometers) interceptors positioned only a few hundred kilometers from the “rogue” nations likely to attack the United States, it would be effective only over a relatively small region of the earth. While the system would be devastating when used against geographically small emerging missile states, it would be largely useless against missiles launched from vast countries such as Russia or China; it would simply not be feasible to position enough interceptors close enough to their launch sites. This is good news too, however, since it would allow the U.S. to target the Third-World states it claims to be most concerned about without provoking negative reactions from Russia and China.
In the case of North Korea, ships or converted Trident submarines could serve as launch platforms for these interceptors. Silos deployed in eastern Turkey would be effective for covering launches from inside Iraq. If a defense were required against Iran, its larger size and location would require defense sites in Turkey, Azerbaijan, Turkmenistan or the Caspian Sea.
When an ICBM was launched, it would be detected and tracked by sensors on the ground, in unmanned aircraft, aboard ships or on satellites. The interceptors would accelerate to 8 to 8.5 kilometers per second in a little over a minute. At these speeds, even if their launch were delayed for a minute or more in order to establish the enemy missile’s 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 proposed space-based system, this 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-fuel, Scud missile technology that is currently the foundation for the missile programs of North Korea, Iran and Iraq. In addition, the technology needed to implement this defense is far less demanding than that needed for midflight intercepts in space. 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 exoatmospheric kill vehicles of the planned nuclear-missile defense system. Finally, 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.
Some boost-phase defense systems would certainly face significant geo-political obstacles. Getting countries such as Azerbaijan or Turkey, for instance, to allow basing of interceptors in their territory could be a challenge. If a deployment against Iran were needed, it would also require close cooperation between Russia and the United States, which would likely increase existing Chinese concerns about a U.S.-Russia alliance.
However, these and other problems are all far more manageable than those raised by the currently planned space-based nuclear-missile defense system. Even the first phase of this fragile and easily defeated defense is threatening to create serious problems with both Russia and China-while providing the U.S. with essentially no meaningful protection against them or any other potential enemy state.
A Plea for Scientific and Political Leadership
In the wake of the terrifying attacks on the World Trade Center and Pentagon, the entire civilized world will need to work to defeat the forces of ignorance, intolerance and destruction. In my view, the current attitude of the Bush administration that “we can go it alone” is one of the most dangerous and ill-considered security policies to be adopted and pursued by the United States in recent memory.
The current U.S. approach to missile defense is a direct outgrowth of the irrational idea that “we” can deal with the world without working with others. It is not only an irrational position when examined in terms of social realities, it is also irrational in terms of basic principles of physical science. It is sad and disturbing that the most technologically advanced and wealthy society in human history has displayed so little scientific and political leadership on matters that will almost certainly affect every aspect of global development in the 21st century.