LGM-118A Peacekeeper

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Test launch of a Peacekeeper ICBM by the 1st Strategic Aerospace Division (1 STRAD), Vandenberg AFB, CA (USAF)

The LGM-118A Peacekeeper was a land-based ICBM deployed by the United States starting in 1986. Under the START II treaty, which never entered into force, the missile was to be removed from the US nuclear arsenal in 2005, leaving the LGM-30 Minuteman as the only type of land-based ICBM in the US arsenal. In spite of the demise of START II, the last of the LGM-118A "Peacekeeper" ICBMs were decommisioned on 19 September 2005.

The Peacekeeper was a MIRVed missile: each rocket could carry up to 10 re-entry vehicles armed with a 300-kiloton W87 warhead/MK-21 RVs (twenty-five times the power of the bomb dropped on Hiroshima during World War II).

The development of the Peacekeeper began with the intent of its being a counter-force, hard-target weapon. It was to be aimed at hardened enemy missile silos with first-strike capability. This requirement demanded outstanding accuracy, survivability, range and a flexibility that was not available in the Minuteman III. Design work began in 1972 on the MX (Missile-eXperimental).

In 1976, Congress refused to fund a silo-based system on grounds of vulnerability and the project was halted until 1979 when President Carter authorized development of a system of multiple protective shelters linked by rail. President Reagan cancelled the new shelter system in 1981 and pushed for a "dense pack" solution to speed deployment. This "dense pack" idea involved building super-hardened silos that would withstand more than 10,000 psi of overpressure and spacing them only 1800 feet apart. The reasoning behind this idea was that a nearby nuclear explosion would damage other incoming warheads in the same wave of attack and would allow a substantial portion of the missiles to survive. This idea was fundamentally flawed due to the relative ease with which the Soviets could modify their warheads and circumvent this design. Congress again rejected the silo-based system.

A compromise was developed in mid-1983, by which there would be swift deployment of 100 new missiles in existing Minuteman silos to show "national will", the removal of the venerable Titan II ICBM from use, and the later introduction of a new more mobile single-warhead ICBM.

Technicians secure a number of Mk-21 re-entry vehicles on a Peacekeeper MIRV bus.

Reagan pushed the name Peacekeeper, but the missile was officially designated the LGM-118A. It was first test fired on June 17, 1983, from Vandenberg AFB, California, traveling 4,200 nautical miles (7,800 km) to impact successfully in the Kwajalein Test Range in the Pacific. The operational missile was first manufactured in February 1984 and deployed in December 1986 to the Strategic Air Command, 90th Strategic Missile Wing at F.E. Warren AFB in Wyoming into retro-fitted Minuteman silos. Fifty working missiles had been deployed at Warren by December 1988. The planned deployment of one hundred missiles was cancelled by Congress in July 1985, again over the survivability issue. In that decision, Congress limited the deployment Peacekeeper ICBMs to 50 missiles until a more survivable basing plan could be developed.

The survivability issue was to be solved by a "rail garrison" system whereby 25 trains, each with two missiles, would use the national railroad system to conceal themselves. It was intended that this system would become operational in late 1992, but budgetary constraints and the changing international situation led to it being scrapped.

The project has cost around $20 billion (up to 1998) and produced 114 missiles, at $400 m for each operational missile. The "flyaway" cost of each missile is estimated at $20–70 million.

The missiles were gradually retired, with 17 withdrawn during 2003, leaving 29 missiles on alert at the beginning of 2004. At the start of 2005 only 10 remained on alert, scheduled to be retired by the end of the year. The last Peacekeeper was removed from alert on 19 September 2005 during the final deactivation ceremony when the 400th Missile Squadron inactivated as well.[1] The rockets are being converted to a satellite launcher role by Orbital Sciences, as the OSP-2 Minotaur IV SLV, while their warheads will be deployed on the existing Minuteman III missiles.

Operational test launches were performed by the men and women of the 576th Flight Test Squadron at Vandenberg AFB, California. This squadron is also the home of "TOP HAND", a board-selected professional development program for missile launch officers.

Testing at the Kwajalein Atoll of the Peacekeeper re-entry vehicles, all eight fired from only one missile. Each line, were its warhead live, represents the explosive power of twenty-five Hiroshima-sized (Little Boy) weapons.

LGM-118A Peacekeeper

Contractors: Boeing, Martin Marietta, TRW and Denver Aerospace
Power:
- First Stage: 2.2 MN (500,000 lbf) thrust Thiokol SR118 solid fuel motor;
- Second Stage: Aerojet General SR119 solid fuel motor;
- Third Stage: Hercules SR120 solid fuel motor,
- Fourth Stage: Rocketdyne restartable liquid fuel motor; storable hypergolic fuel
Length: 21.8 m (71 ft 6 in)
Diameter: 2.3 m (7 ft 7 in)
Mass: 87.75 metric tons (193,500 lb)
Range: 5,250 nautical mile (9,700 km)
Guidance: Inertial (AIRS), 100 m CEP
Payload: 3950 kg, up to 10 Avco Mk-21 re-entry vehicles each carrying a 300KT (1.25 PJ) W-87 warhead.