MX missile

MX missile. The LGM-118A Peacekeeper, commonly known as the MX missile, was a Cold War-era Intercontinental ballistic missile developed by the United States to ensure the credibility of its strategic nuclear deterrent. Designed to carry a formidable payload with exceptional accuracy, it was a central element in the strategic arms competition with the Soviet Union. Its protracted development was marked by intense political debate over its basing mode, reflecting broader tensions between military requirements and domestic concerns.

Development and design

The program originated in the early 1970s from United States Air Force requirements to counter improving Soviet defenses and the hardening of key targets like SS-18 silos. A key design objective was to achieve a very high probability of destroying these hardened sites, necessitating both a large MIRV payload and unprecedented accuracy. Prime contractors TRW and Martin Marietta developed a missile using advanced solid-propellant stages from Thiokol and Aerojet, with a sophisticated Inertial navigation system augmented by stellar sensing. The most distinctive feature was its deployment system, where a launch canister was ejected from its protective shelter by high-pressure gas before the first-stage motor ignited, a "cold launch" technique. This design allowed for potential reuse of the silo and reduced thermal stress on the launch infrastructure.

Operational history

The first flight test occurred at Vandenberg Air Force Base in June 1983, following years of political delays and controversy surrounding its proposed basing in the Great Basin. Despite the cancellation of its elaborate Multiple Protective Structure basing plan, the Reagan Administration secured congressional approval in 1982 to deploy an initial force in existing Minuteman silos. Full operational capability was declared in December 1986 with the first ten missiles stationed at Francis E. Warren Air Force Base in Wyoming. Over the next several years, a total of 50 missiles were deployed, with the final batch becoming operational in 1988. The system remained on continuous alert, integrated into the wider command and control network of the Strategic Air Command and later United States Strategic Command.

Technical specifications

The missile was approximately 71 feet long, weighed about 195,000 pounds, and had a diameter of 7.7 feet. Its three-stage solid-fuel rocket propulsion system could deliver a payload of up to ten W87 thermonuclear warheads, each with a yield of 300 kilotons, to a range exceeding 6,000 miles. The advanced Mark 21 reentry vehicle, developed by General Electric, provided exceptional accuracy, with a reported CEP of less than 400 feet. This precision, combined with the high yield of the W87, gave it a formidable hard-target kill capability against even the most fortified installations. The guidance system incorporated an inertial measurement unit and could receive update data from external sources, including the Navstar Global Positioning System.

Strategic role and basing modes

The primary strategic role was to pose a credible first-strike counterforce threat to Soviet ICBM fields, thereby complicating attack planning for the Soviet Strategic Rocket Forces and strengthening deterrence. The quest for a survivable basing mode dominated its political history, with proposals ranging from a dense pack cluster in super-hardened silos to a vast network of shelters in the Nevada and Utah desert, where missiles would be shuttled between hiding places. The eventual rail-garrison scheme, developed in the late 1980s, involved deploying missiles on specially designed trains that would disperse from their bases at Malmstrom Air Force Base and other locations during a crisis. This mobile concept was intended to enhance survivability without the massive environmental footprint of earlier plans.

Retirement and legacy

The retirement of the system was mandated by the 1993 START II treaty, which banned multiple-warhead land-based missiles, though the treaty itself never entered into force. The deactivation process began under the Bush Administration in 2002 as part of a broader nuclear posture shift, and the last missile was removed from its silo at Francis E. Warren Air Force Base in September 2005. Its W87 warheads were retained and are now deployed on a single-warhead Minuteman III fleet. The Peacekeeper's legacy is that of a technologically superb but politically contentious weapon; its development saga highlighted the profound difficulties of reconciling strategic imperatives with domestic politics and arms control objectives during the final decades of the Cold War.

Category:Intercontinental ballistic missiles of the United States Category:Cold War missiles of the United States Category:Nuclear weapons of the United States