LGM-118 Peacekeeper

The LGM-118 Peacekeeper, first known as the MX for Missile, Experimental, was a MIRV-capable intercontinental ballistic missile deployed by the United States from 1986 to 2005. Martin Marietta received the prime contract for the missile in 1978. It could carry up to eleven Mark 21 reentry vehicles, each with a 300-kiloton W87 warhead, although treaties limited it to ten. The plan was to deploy up to 200 missiles, but cost and the unresolved question of basing cut procurement, and only 50 entered service, in existing Minuteman silos. It was the first US ICBM to use a cold launch system, in which gas pressure ejects the missile from its canister before the first stage ignites. The first flight test took place in 1983 and initial operational capability followed in 1986. Disarmament treaties led to its withdrawal, the last missile was deactivated on 19 September 2005, and the company Orbital Sciences later built the Minotaur IV launcher from retired Peacekeeper components.