This kind of weapons system has obvious advantages over a single-warhead device delivered to the same area. It greatly diminishes the likelihood of a failed mission, because if one or even two bombs fail to detonate, the remaining live warheads can accomplish the task. Finally, MRVs can address inaccuracy issues by offering payload redundancies. The United States first deployed MRVs in the mid-1960s on Polaris A-3 SLBMs. The Soviet Union first began using MRVs on their SS-9 Mod 4 ICBMs.
In the late 1960s and early 1970s, the MRVs were eclipsed by a new type of MRV, the multiple independently targeted reentry vehicle (MIRV). As nuclear delivery systems' reliability, payloads, and accuracy all markedly increased, the need for hitting one target with multiple warheads became far less important. Instead, scientists and defense experts now sought to get more bang for the buck by placing multiple warheads on a single missile capable of striking multiple targets. Most U.S.-built MIRVs carried anywhere from three to twelve independently targeted warheads. The Soviets more than matched the American MIRVs. MIRVs accomplished two key goals: first, they rendered antiballistic missile (ABM) systems relatively useless, as an onslaught of incoming MIRVed missiles would likely overcome any ABM site; and second, MIRVs were more efficient and cost-effective in the long run because significantly fewer missiles were needed to carry out a nuclear attack. Although the precise details of the functioning of MIRVs are a well-kept secret, it is believed that MIRVs can release decoys designed to fool enemy radars and interceptors. Over the years, MIRVs became ever more accurate as scientists made use of Global Positioning Satellites (GPSs) and custom-integrated circuits that make constant in-flight adjustments to ensure that MIRVs hit their targets dead on.
Paul G. Pierpaoli Jr.
Polmar, Norman. Strategic Air Command: People, Aircraft, and Missiles. Mount Pleasant, SC: Nautical and Aviation Publishing Company, 1979.