The Gorgon (SH-11/ABM-4), also known by its Russian designation, 51T6, is a long-range interceptor missile designed and manufactured by the Soviet Union.(1) At present, 32 Gorgon interceptors are deployed around Moscow as part of System A-135.
In 1978, the Soviet Union decided to build a new anti-ballistic missile system around Moscow. System A-135 was designed with two tiers of defense: (1) long-range exoatmospheric interceptors and (2) short-range endoatmospheric interceptors. The long-range 51T6 interceptor, developed and manufactured by the Fakel Machine Building Design Bureau, was an upgraded version of the Galosh (SH-04/ABM-1) missile deployed at System A-35, the predecessor to System A-135.(2)
By 1988, a total of 32 Gorgon interceptors had been deployed in four underground launch sites around Moscow containing eight interceptors each.(3) Including the 68 short-range Gazelle (SH-08/ABM-3) interceptors, System A-135 was technically compliant with the 1972 ABM Treaty, which allowed a total of 100 missiles. However, a loophole in the treaty allowed the Soviet missiles to protect both the capital city as well as nearby ICBM bases, thus maximizing System A-135’s functionality. Had the U.S. gone ahead with a similar system, for instance, it would have had to choose between defending either Washington, DC, or the ICBM silos in North Dakota: not both.
State acceptance tests of System A-135 were completed by the end of 1989. That same year, the Soviets decided to modernize the system even further to improve its combat performance. Thus, work continued on the new system during its period of experimental use, which lasted until the middle of 1994. At that point, the Gorgons were placed on full combat alert.(4)
As the exoatmospheric tier of System A-135, the Gorgon was designed to detonate a 1-megaton nuclear warhead just outside the Earth’s atmosphere and destroy any incoming ballistic missiles descending upon Moscow. In the event of an attack on Moscow, the idea was that the Gorgons would serve as a first line of defense and, if any warheads managed to evade them, the short-range Gazelle interceptors would provide a second layer of protection.(5)
The Gorgon was constructed with three liquid-fueled boosters, giving it a vertical range of approximately 350 kilometers. Special emphasis was given to radiation hardening, since it was presumed that the Gorgon would be operating in an environment of frequent nuclear explosions, whether from incoming re-entry vehicles or other Gorgon and Gazelle interceptor missiles. Due to its long-range capability, the Gorgon also had a limited anti-satellite capability against targets in low earth orbit.(6)
In early 1998, Russia announced that, in the interest of safety, it had removed the original nuclear warheads from its Gorgon interceptors replaced them with conventional high explosive warheads. Many had warned that if the Gazelle’s 1-megaton nuclear warhead was actually detonated above Moscow, its electromagnetic pulse would create havoc below, severely damaging all non-hardened electronic equipment. For instance, a blast at an altitude of 50 miles would affect a 500-mile radius, while a blast at 100 miles would affect a 900-mile radius. It is unclear, however, whether all of the Gorgons currently carry conventional warheads, or if some are still armed with 1-megaton nuclear warheads.(7)
In recent years, many in the U.S. and elsewhere have pointed out that, while the Gorgon and Gazelle interceptors might be effective against a single warhead attack, they would be quickly overwhelmed in the event of a multi-warhead strike.(8) Others have claimed that the interceptor missiles would have a difficult time distinguishing between warheads and other objects, a factor that severely limits the effectiveness of System A-135 in the present age of sophisticated decoys and countermeasures.(9)
In 2002, Anatoliy Sokolov, former commander of Russia’s missile and space defense army, confirmed U.S. suspicions that the Gorgon and Gazelle interceptors had become obsolete: “It makes no sense to maintain a dying system, as the existing antimissile defense is unable to provide efficient protection of the area, let alone the entire country.”(10)
