US Antiballistic Missile Defense: Deployment
The U.S. ABM program actually had its genesis in the German V-2 missile attacks on Great Britain during World War II. Although schemes to intercept the V-2s in flight never advanced beyond theory, American scientists recognized that long-range missiles such as the V-2 would pose a potent threat in the future. After inspecting captured German missile plants and test facilities, in July 1945, the scientists recommended that the United States initiate a research and development effort to defend against rockets like the V-2. A May 1946 report issued by the War Department Equipment Board concluded that to defend against such a threat would require "guided interceptor missiles, dispatched in accordance with electronically computed data obtained from radar detection stations."The Army Air Forces, having reached a similar conclusion, had already begun two missile defense studies called Project Thumper and Project Wizard. Project Thumper was canceled in 1948, but Project Wizard, initially awarded to the University of Michigan, provided the theoretical foundation for development of an "anti-missile missile" capable of destroying a target traveling at speeds upwards of 4,000 miles per hour in the upper atmosphere. By the mid-1950s the Air Force had two consortia of defense contractors working on anti-missile missile development. Project Wizard survived until 1958.
The Army took a different approach toward developing an ABM. Rather than building a completely new missile system, it proposed adapting much of the same missile and guidance technology from its Nike Ajax and promising Nike Hercules antiaircraft missile systems for use in the antiballistic missile program. The new missile was the Nike Zeus.
With an eye toward the future, in March 1955, the Army hired Bell Laboratories to undertake a study projecting the evolution of defensive missile technology through the early 1960s. In late 1956, the Bell scientists reported that within the next several years the development of high-capacity computers and long-range, high-rate acquisition radar would enable a defensive missile to intercept an incoming ICBM.
At the same time the Army was exploring the feasibility of developing an ABM system, it was also locked in a fierce interservice battle with the Air Force over the future of air defense. Beginning in the spring of 1956, the Air Force launched an aggressive public relations campaign charging that the Army's Nike Ajax and soon-to-be-deployed Nike Hercules were unfit to guard the nation.
In an attempt to quell the vitriolic debate, in November 1956, Secretary of Defense Charles Wilson clarified the Army and Air Force roles in providing air defense. The secretary made the Army responsible for the "point defense" of specific geographic areas, cities, and vital military and industrial installations. Under the point defense concept, the Army was authorized to develop and deploy surface-to-air missiles such as the Nike Hercules with ranges up to 100 miles. To complement the Army's capability, Wilson gave the Air Force responsibility for the much broader area defense mission.
While Wilson's ruling resolved the air defense debate, it was silent on the question of which service would develop the ABM system. Both the Army and the Air Force were anxious to acquire the promising new mission. The Army initially had a head start because it was using much of its existing Nike hardware for the ABM. Based on the results of the Bell Laboratories study, in early 1957 the Army awarded Western Electric, and its research and development arm, Bell Laboratories, a contract to develop the Nike Zeus antiballistic missile system.
The Air Force was anxious to block the Army's ABM program, and it launched a public relations campaign against the Army missile system. The campaign was unsuccessful. In January 1958 Secretary of Defense Neil H. McElroy assigned the Army the lead role in ABM development based on the progress it had already made in the Nike Zeus program. At the same time McElroy ordered the Air Force to continue working on the radars and command-and-control system under Project Wizard so that these technologies could be incorporated into the Army program.
The Army designed the Nike Zeus system to defend population and industrial centers from a relatively light missile attack. The defensive missile system's most expensive component, and also its weakest link, were its four target-tracking and missile guidance radars. Those four radars were: (1) the Zeus Acquisition Radar (ZAR)-a highly accurate, three-dimensional long-range search radar that could detect small targets at extreme range; (2) the Discrimination Radar (DR)--a high-resolution radar designed to detect incoming warheads amidst the clouds of debris resulting from a missile attack, (3) a Target-Tracking Radar (TTR)---a precise, long-range, narrow beam radar designed to follow small, high-speed targets during the final phase of descent; and (4) the Missile-Tracking Radar (MTR)-a radar designed to track and guide the outbound Zeus to its target.
The Army was anxious to deploy the Nike Zeus system, but between 1959 and 1961 Congress and the White House refused to approve such a move. Instead, they authorized only enough money to sustain the research and development effort. Opponents of the Nike Zeus system, which included Hans Bethe of Cornell University and Jerome Wiesner of the Massachusetts Institute of Technology, argued convincingly against deploying the missile. They pointed out that the Nike's mechanical radars could track only a limited number of targets at once, making it relatively easy for the Soviets to "blind" the system by launching a barrage of missiles, some of which probably would have been equipped with decoy reentry vehicles. Another drawback was that the Nike Zeus was not designed for low-altitude intercepts. That drawback negated an important defensive advantage because target identification, the process of sorting out the real warheads from the decoys and expended stages, is easier at low altitude due to the fact that with the exception of the reentry vehicles, most of the other hardware burns up when it enters the earth's atmosphere.
The research and development effort yielded its first major success on July 19, 1962, when a Nike Zeus missile fired from Kwajalein intercepted an Atlas ICBM launched from Vandenberg AFB. The Army scored the test as successful because the Nike's dummy nuclear warhead came within 2 kilometers of the incoming Atlas. In a subsequent test on December 22, 1962, the Nike Zeus passed within 22 meters of the targeted reentry vehicle.
Despite a string of successful tests, Secretary of Defense McNamara did not believe the Nike Zeus system could defend against the large Soviet ICBMs that were expected to be deployed by the late 1960s. McNamara was concerned that the ABM system lacked the sophistication to discern between real and decoy warheads. Also, he believed the ABM could be overwhelmed in a saturation attack because the radars and computers could manage only one intercept at a time. Because of these flaws, in 1963 McNamara decided against deploying the Nike Zeus. Rather than cancel the program, however, he directed a program reorganization to field a more advanced ABM system. Accordingly, DOD ordered the Army to begin developing a new missile defense system with higher-speed, higher-capacity radars and computers, and a short-range interceptor missile fast enough to intercept an enemy warhead after it entered the earth's atmosphere.
In April 1964, DOD ordered the Army to begin work on a new defensive missile system called Nike X. The Nike X was to be a "layered" system. The first line of defense would be a reconfigured Nike Zeus missile, renamed Spartan, that would intercept the incoming warheads at an altitude of 70 to 100 miles. Next, the warheads that evaded the Spartan intercepts would be engaged by the new short-range Sprint missile. The 27-foot long Sprint would engage the targets at an altitude of 20 to 30 miles.
The key difference between the Nike Zeus and Nike X systems was Nike X's use of a phased-array radar pioneered under the Defense Department's Advanced Research Projects Agency (ARPA). The new radar was a technological breakthrough because, in contrast to the acquisition and tracking radars used by the Nike Ajax and Nike Hercules systems, phased-array radars could track several targets and direct multiple intercepts simultaneously, With advances in electronics and computer technology, integration of radar data on multiple targets could be swiftly translated into instructions for the Spartan and Sprint interceptors. Two types of phased-array radar would be used. The first, the perimeter acquisition radar, would be used for long-range target acquisition. The second, the missile site radar, would handle short-range target discrimination and interceptor guidance.
To test Nike X under combat conditions, however, would require resumption of atmospheric nuclear detonations in violation of the recently signed Nuclear Test Ban Treaty. In an October 1964 edition of Scientific American, Wiesner, along with former ARPA chief scientist Herbert York, argued strongly against atmospheric testing. Furthermore, they maintained that deployment of an ABM system actually increased the possibility of nuclear war: ABM deployment by one side would, they argued, encourage the other side to launch a preemptive attack if it foresaw a potential loss of ability to retaliate against a nuclear attack. This point would become a rallying cry for opponents of the ABM, and that opposition grew in proportion to public disenchantment with the United States' expanding role in Vietnam.
In 1963, McNamara formed a commission to look into how the ARM could affect nuclear warfare and United States-Soviet relations. Although the commission's report shed a positive light on ABM deployment, the opposition within the scientific community strongly influenced McNamara's views. He was committed to a deterrence-based strategy that assured the destruction of the Soviet Union in response to any nuclear attack. The ABM program distracted from that commitment; it also competed for funding needed to support the U.S. effort in Vietnam. Again in 1965 and 1966, McNamara approved funding only for continuing research of the Nike X program, overriding the Joint Chiefs of Staff recommendation for deployment. In 1966, however, Congress allocated partial funding for an ABM system. Although both houses approved the funding by wide margins, a small but vocal group of opponents within each chamber argued against deployment.