Today the U.S. Army, Navy, and Air Force—under the aegis of the Missile Defense Agency—are involved in developing ballistic missile defense (BMD) systems and concepts. Ballistic missile defense, both theater and national, have high national priorities. And those concepts—the Army and Navy systems using interceptor missiles, and the Air Force system a laser weapon—all employ non-nuclear technologies.
These are in marked contrast with the previous U.S. efforts at ballistic missile intercept concepts, which were largely based on nuclear weapons. Indeed, some observers contend that all previous significant BMD schemes would have employed nuclear warheads. And, considerable resources were expanded on those systems, one of which became operational-for almost five months.
Two factors began to dominate the Soviet-U.S. strategic arms race during the late 1960s: ballistic missile defense and multiple warheads on strategic missiles. The two were closely related in that each was a counter to the other. The amount of destruction that each side could inflict became enormous with the proliferation of intercontinental ballistic missiles (ICBMs) and submarine-launched ballistic missiles (SLBMs) and the subsequent fitting of multiple warheads to those missiles.
Both superpowers had large proportions of their population and industrial capacity concentrated in cities. In February 1965, Secretary of Defense Robert S. McNamara announced a strategy of "assured destruction" against the Soviet Union in the event of a nuclear exchange. According to McNamara, the destruction of 200 American cities could kill more than one-half of the nation's population and eliminate three-quarters of its industrial capacity. The loss of 400 Soviet cities would mean that almost one-half of that nation's population and three-quarters of its industry could be destroyed. Thus, the numbers of cities were counted in the hundreds, while the available nuclear warheads soon numbered in the thousands because of the technology enabling multiple warheads to be delivered by a single missile. (See Table 1.)
At the same time, technologies were becoming available that gave promise of a ballistic missile defense whereby incoming ICBM warheads could be intercepted by anti-ballistic missile (ABM) systems. An active missile defense system consists principally of radars to detect and track incoming reentry vehicles and interceptor missiles to destroy them. Formal U.S. efforts to develop an ABM system began with the Army's Nike-Zeus system, initiated in 1956. This was a development of the service's existing Nike-Ajax and Nike-Hercules antiaircraft missiles, the latter being deployed in the United States and six European countries; it was fitted with the W31 nuclear warhead.
Although Nike-Zeus research and development enjoyed high priority in 1958-59, it failed to gain approval for production and deployment. When the Kennedy administration entered the White House in 1961, the Army proposed a 70-battery system with nearly 7,000 missiles to protect 27 major American cities at a five-year cost of $7.8 billion. The missiles would have the W50 nuclear warhead—with up to a 400-kiloton explosive force.1 After lengthy deliberations, Secretary of Defense McNamara directed that the Nike-Zeus missile program be reoriented and it never became an operational system.
The Nike-Zeus ABM system could have become operational by 1963-64, but would—according to subsequent estimates—have been obsolete by that time because of Soviet development of advanced reentry vehicles. Other ABM concepts were put forward in the United States in this period, including one for Polaris-armed missile submarines to fire their weapons in either a strategic offensive or an ABM defensive mode. That proposal was not pursued.
The Sentinel System
Based on the continuing concern by U.S. political and military leaders over Soviet advances in strategic missiles and in radar and intercept technologies, by 1969 the Department of Defense was advocating a ground-based missile defense system. It was first proposed in 1967 as the Sentinel system to provide a full-fledged, national defense against potential Chinese intercontinental missiles. In 1969 it was realigned to defend the 1,000 Minuteman ICBMs against a Soviet attack and renamed Safeguard as President Richard M. Nixon shifted his attention to the increasing Soviet missile threats. In August 1969 the Senate narrowly approved the Safeguard deployment with Vice President Spiro T. Agnew casting the tie-breaking vote.
Under the various ABM constructs the two defensive missiles being developed would both carry nuclear warheads. These would be the short-range Sprint (W65 and then W66 warhead) and long-range Spartan (W71 warhead).
The ABM concept was changed again by the U.S.-Soviet agreement resulting from the Strategic Arms Limitation Talks (SALT) of 1972. Under this agreement, each nation was allowed to build and operate one ABM site in defense of its national capital and another in defense of a single ICBM base. Each site was defined according to area, number of missile launchers, and types of radars. This aspect of SALT permitted the Soviet Union to maintain the Galosh ABM already emplaced around Moscow (which also defended some ICBMs in that area), and the United States to continue the construction of a Safeguard ABM being installed near Grand Forks, North Dakota, to defend 150 Minuteman ICBMs.2
The subsequent Soviet-U.S. protocol of 3 July 1974, reduced the number of ABM deployment areas from two to one, and the number of allowable interceptor missiles from 200 to 100.
Finally, on 1 October 1975, the Safeguard installation at Grand Forks became operational. The next day the House of Representatives voted to close the site because new Soviet multiple warheads being fitted to ICBMs and SLBMs could easily overwhelm it. Beyond the Safeguard's vulnerability to direct attack, technical problems, such as radar blinding by electromagnetic pulse from exploding nuclear warheads, made the system unreliable, and even threatened to damage the Minuteman ICBMs it was intended to protect. On 18 November 1975, the Senate also voted to terminate Safeguard.
In February 1976, the Safeguard system was closed down-it had been operational for 133 days! (Some Safeguard radars subsequently were incorporated into the North American Air Defense Command's warning and assessment network).
In the interim, the Soviet Union had continued to develop and deploy two ABM systems, one around Moscow and one around Leningrad. Subsequent to the 1974 protocol the Leningrad system was dismantled, followed two decades later by the Moscow system.
From SABMIS to Star Wars
Another ABM concept that received attention in the late 1960s was the U.S. Navy's proposal for a Sea-based Ballistic Missile Intercept System (SABMIS). This concept would deploy SABMIS ships in the North Atlantic and North Pacific where their interceptor missiles could shoot down Soviet- or Chinese-launched ICBMs. The advantages of the forward-deployed ships included early intercept, before multiple warheads fully separated and hence were easier to kill. Moreover the intercepts would take place over the sea and not the United States and Canada, as with land-based ABM systems. Launch of interceptor missiles would not interfere with ICBM launches from the United States, as would co-located ABM systems. Studies indicated that the SABMIS ships-working either independently or in collaboration with terminal defenses in the United States-would be both survivable and effective. But SABMIS was rejected, primarily because of U.S. interservice policies that favored maintaining Army leadership in continental air-missile defense; hence, only the (limited) Safeguard ABM program was put forward by the government for consideration.3
Low-level interest in a land-based ABM systems continued, with limited research being undertaken. Ballistic missile defense again received impetus when President Ronald Reagan, on 23 March 1983, in a nation-wide radio speech, asked: "What if free people could live secure in the knowledge that their security did not rest upon the threat of instant U.S. retaliation to deter a Soviet attack, that we could intercept and destroy strategic ballistic missiles before they reached our own soil or that of our allies?"
The President continued:
I know this is a formidable, technical task, one that may not be accomplished before the end of the century. Yet, current technology has attained a level of sophistication where it's reasonable for us to begin this effort. It will take years, probably decades of efforts on many fronts. There will be failures and setbacks, just as there will be successes and breakthroughs. And as we proceed, we must remain constant in preserving the nuclear deterrent and maintaining a solid capability for flexible response. But isn't it worth every investment necessary to free the world from the threat of nuclear war? We know it is.
The press quickly dubbed the President's proposed program as "Star Wars," after the epic science fiction films by George Lucas.
Although President Reagan was unable to garner sufficient public or congressional support for a full-scale ABM research and development program, investment continued at a significant level through the administrations of George H. W. Bush and Bill Clinton.
All of these programs were based on non-nuclear intercept technologies, the interceptor missiles developed by the Army and Navy using primarily kinetic energy for a "hard-kill" against an enemy ICBM or SLBM. At the same time, the Air Force sponsored development of an airborne laser intercept system that would be carried aloft in a Boeing 747 aircraft.
The Navy system would be based on the relatively effective Aegis air/missile defense system that was fitted in the 22 cruisers of the Ticonderoga (CG-47) class that had vertical-launch systems (VLS) and the eventual 62 destroyers of the Arleigh Burke (DDG-51) class that were similarly fitted with Aegis/VLS.
An Operational Capability
Subsequently, President George W. Bush announced early in his first administration that a limited ABM system would be operational by the winter of 2004, primarily to defend against ICBMs launched from "rogue states," especially North Korea. (At this writing North Korea has demonstrated neither that it possesses a nuclear weapon nor a missile with ranges that could reach Alaska or the continental United States.)
By 2009 there were 21 Army-operated interceptor missiles installed at Fort Greely (near Fairbanks), Alaska, and three interceptor missiles at Vandenberg Air Force Base in California. These were non-nuclear weapons that were to intercept and kill an incoming ICBM warhead in a high-speed collision. However, a series of embarrassing intercept failures delayed the program and raised more questions about the efficacy of ballistic missile defenses.
At the same time, under the joint Missile Defense Agency, the Navy had, by 2009, upgraded 5 cruisers and 16 destroyers with a BMD capability (the Japanese had similarly modified several Aegis destroyers). The potential capability of these ships was demonstrated on 21 February 2008, when the Aegis cruiser Lake Erie (CG-70) used a modified Standard SM-3 missile to shoot down a disabled American spy satellite. The official reason for the feat-believed to be the second time that a missile launched from the surface of the earth has shot down a space object-was to destroy a dangerous hydrazine fuel tank in the satellite. But it may also have been a message to North Korea, Iran, and other countries that the United States has a viable ballistic missile defense capability.
The Air Force entered the competition for an advanced missile defense system with an airborne laser concept that had the obvious problems of interference from clouds, the need to keep aircraft continuously airborne during a crisis, and kill-range limitations. Still, the Air Force persevered, flying a small-scale test aircraft in 2004, the YAL-1, a reconfigured Boeing 747. Of all of the candidate "Star Wars" systems, the airborne laser was the most complex and offered the least flexibility; accordingly, this single prototype aircraft is now considered strictly a research-and-development platform, and not the harbinger of an operational system.
Thus, after more than 50 years of research and development, and limited deployments, the United States now has operational limited land- and sea-based ballistic missile intercept systems. And, most significant, none of these "Star Wars" missile defense systems employ nuclear warheads as a kill mechanism.
1. The W50 was also used in the U.S. Army's Pershing 1a surface-to-surface missile; it was planned for the Navy's Hopi air-to-surface missile, which was cancelled prior to becoming operational.
2. Galosh ABM-1 was the NATO designation for the missile; the Soviet designation for this nuclear-tipped missile was UR96.
3. SABMIS is described in N. Polmar, "U.S. Navy: Ballistic Missile Defense. . . From the Sea," U.S. Naval Institute Proceedings, June 2003, pp. 86-87.