LGM-118 Peacekeeper

Peacekeeper at the start of Vandenberg Air Force Base

The LGM -118 Peacekeeper (English for peacekeepers ), also known by the development name MX Missile or short only MX, was a land-based intercontinental ballistic missile of the U.S. armed forces. From December 1986 to September 2005 she was operated by the Space Command of the U.S. Air Force (USAF).

Development and introduction

The U.S. saw its own silo-based Minuteman threatened by increasingly precise and MIRV -carrying Soviet intercontinental ballistic missiles such as the R -36M - exposed to the risk of a first strike - and therefore feel compelled to respond. The development of the missile began in 1972 under the name of MX ( Missile eXperimental ). Between 1976 and 1983 the introduction of the system by the U.S. Congress was delayed, which voted against the construction of new missile silos. In the spring of 1983, a compromise solution was reached, after which the spectrum released by the retirement of older Minuteman missile silos were used for the new rocket. On June 17, 1983, the first test launch of a Peacekeeper from Vandenberg Air Force Base in California took place. The first ten operational missiles were made ​​in December 1986 on the Francis E. Warren Air Force Base, in Wyoming, in service. 1985 curtailed the Congress on the program for the time being 50 missiles, to a way of increasing the survivability of deployed missiles was found in case of an attack. Until 30 December 1988, 50 missiles were ready for use. As a result of reductions in the procurement plans have been drawn up which provided for a deployment of two rockets on a total of 25 trains using the national rail network. This project was in 1992 but finally discarded. A total of 114 missiles were produced during the 20 billion -dollar program.


The Peacekeeper was a four-stage intercontinental ballistic missile. The steps consisted of three main propulsion stages with solid rocket motors. The fourth drive stage for re-entry support ( engl. Post Boost Vehicle) had a liquid rocket engine. The driving stages were mounted one above the other and set fire sequentially. The main drive levels had a swiveling nozzles to control. The shell of the rocket consisted of composite materials (such as kevlar -reinforced epoxy resin). The missile was stored in its missile silo in a protective case, which should be the rocket against negative environmental influences, damage and fallout (see also second-strike capability ) protect. The Peacekeeper was started cold in contrast to the Minuteman missile. By means of gas pressure, the Peacekeeper was ejected from the silo at a height of about 100 meters. Only then lit the first rocket stage. This method made ​​it possible to launch the Peacekeeper missile from silos, which were originally built for the three-meter smaller Minuteman III missiles. The control of the Peacekeeper was carried out by various independent working inertial navigation platforms. After burning the first three stages drive the rocket reached an altitude of some 212 km and a speed of about 24,140 km / h. The fourth level continued to rise to a height of around 1,100 km. There, the nose cone was carried away by a small rocket motor in the tip and the re-entry vehicle was exposed. Now this could make the last position changes. The ten Avco MK 21 MIRV re-entry were attached with explosive bolts on re-entry support and were started by a small charge of compressed gas from the carrier. The re-entry vehicles were fired in a sequence, in which the carrier between each led by course corrections to their individual ballistic trajectories. The Avco MK 21 re-entry vehicles were equipped with a W87 thermonuclear warhead. This had an explosive power of 300 kt and was fired in the air or on the ground. The re-entry reached a precision (CEP ) of 90-100 m (depending on the shooting distance ). The Peacekeeper had the highest hit accuracy of all land-based U.S. ICBMs.


Under the START II Treaty ( Strategic Arms Reduction Treaty ), the USAF began in October 2002 with the reduction of Peacekeeper missiles. On 19 September 2005 difference with the deactivation of the last remaining copy of the Peacekeeper from active service. The driving levels are for satellite launches (see Minotaur IV rocket) or continue to be used for target practice by missile defense weapons.