Air Force Bases

Peacekeeper (MX) Missile Summary



The Peacekeeper missile is America's newest intercontinental ballistic missile (ICBM). Its deployment fulfilled a key goal of the strategic modernization program and increased strength and credibility to the ground-based leg of the U.S. strategic triad.

With the end of the Cold War, the Department of Defense has recommended the deactivation of the Peacekeeper Weapon system beginning in fiscal 2003. The United States has begun to revise its strategic policy and review its nuclear posture.


The Peacekeeper is capable of delivering 10 independently targeted warheads with greater accuracy than any other ballistic missile.. It is a four-stage rocket ICBM system consisting of three major sections: the boost system, the post-boost vehicle system and the re-entry system.

The boost system consists of four rocket stages that launch the missile into space. These rocket stages are mounted atop one another and fire successively. Each of the first three stages exhausts its solid propellant materials through a single movable nozzle that guides the missile along its flight path.

Following the burnout and separation of the boost system's third rocket stage, the fourth stage post-boost vehicle system, in space, maneuvers to deploy the re-entry vehicles in sequence.

The post-boost vehicle system is the Peacekeeper Stage IV that has a guidance and control system and re-entry system. The post-boost vehicle rides atop the boost system, weighs about 2,500 pounds (1,333 kilograms) and is 3.5 feet (1.07 meters) long.

The top section of the Peacekeeper is the re-entry system. It consists of the deployment module, up to 10 cone-shaped re-entry vehicles and a protective shroud. The shroud protects the re-entry vehicles during ascent. It is topped with a nose cap, containing a rocket motor to separate it from the deployment module.

The deployment module provides structural support for the re-entry vehicles and carries the electronics needed to activate and deploy them. The vehicles are covered with material to protect them during re-entry through the atmosphere to their targets and are mechanically attached to the deployment module. The attachments are unlatched by gas pressure from an explosive cartridge broken by small, exploding bolts, which free the re-entry vehicles, allowing them to separate from the deployment module with little disturbance. Each deployed re-entry vehicle follows a ballistic path to its target.


The Air Force successfully conducted the first test flight of the Peacekeeper June 17, 1983, from Vandenberg Air Force Base, Calif. The missile traveled 4,190 miles (6,704 kilometers) before dropping six unarmed test reentry vehicles in the Kwajalein Missile Test Range in the Pacific Ocean.

The first two test phases consisted of 12 test flights to ensure the Peacekeeper's subsystems performed as planned, and to make final assessments of its range and payload capability. The missile was fired from above-ground canisters in its first eight tests. Thereafter, test flights were conducted from test launch facilities reconfigured to simulate operational Peacekeeper sites.

The Air Force achieved initial operational capability of 10 deployed Peacekeepers at F.E. Warren AFB, Wyo., in December 1986. Full operational capability was achieved in December 1988 with the establishment of a squadron of 50 missiles.

The Air Force Materiel Command's Ballistic Missile Office (now inactivated) began full-scale development of the Peacekeeper in 1979. This organization, formerly located at San Bernardino, Calif., integrated the activities of more than 27 civilian contractors and numerous subcontractors to develop and build the Peacekeeper system.

General Characteristics

Primary Function: Strategic deterrence
Contractor: Boeing
Power Plant: First three stages - solid propellant; fourth stage - storable liquid (by Thiokol, Aerojet, Hercules and Rocketdyne)
Warheads: 10
Load: Avco MK21 re-entry vehicles
Guidance System: Inertial; integration by Boeing North American, IMU by Northrop and Boeing North American
Thrust: First stage, 500,000 pounds
Length: 71 feet (21.8 meters)
Weight: 195,000 pounds (87,750 kilograms) including re-entry vehicles
Diameter: 7 feet, 8 inches (2.3 meters)
Range: Greater than 6,000 miles (5,217 nautical miles)
Speed: Approximately 15,000 miles per hour at burnout (Mach 20 at sea level)
Date Deployed: December 1986
Unit Cost: $70 million
Inventory: Active force, 50; ANG, 0; Reserve, 0

Point of Contact
Air Force Space Command, Public Affairs Office; 150 Vandenberg St., Suite 1105; Peterson AFB, CO 80914-4500; DSN 692-3731 or (719) 554-3731.

March 2003