Captain Swoop's Virtual ICBM Tour presents...
How Do  They Build A Missile ?

Designation: LGM-30 (Launcher, Guided Missile, system #30)
  • LGM-30G (Minuteman III - only model in current use)
  • LGM 30F (Minuteman II - decommissioned 1998)
  • LGM-30A/B (Minuteman I - decommissioned)
Systems Contractors:
Physical Specifications
  • Length: 59.9 feet (18 meters)
  • Weight: 79,432 pounds (32,158 kilograms)
  • Diameter: 5.5 feet (1.67 meters)
Stage 1: Solid-propellant rocket motor
Stage 2: Solid-propellant rocket motor
  • Manufacturer: Aerojet-General
  • Length: 13.75 feet (4.18 meters)
  • Diameter: 4.33 feet (1.32 meters)
  • Thrust: 60,600 pounds (27,273 kilograms)

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Stage 3: Solid-propellant rocket motor
  • Manufacturer: United Technologies Chemical Systems Division (originally motor manufactured by Aerojet)
  • Length: 7.08 feet (2.15 meters)
  • Diameter: 4.33 (1.32 meters)
  • Thrust: 34,000 pounds (15,455 kilograms)

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Payload: Kickmotor, Guidance, Instrument, and Warhead packages
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  • Section 4: CTL Instrumentation Package (optional) - used for operational test launches only. Provides in-flight telemetry and command destruct capability for Range Safety Officer if flight termination is required because of malfunction or other control anomalies. Not used on operational missiles.

  • Section 3: Propulsion System Rocket Engine (PSRE) uses a restartable hypergolic rocket engine powered by mono-methylhydrazine (MMH) and nitrogen tetroxide. This section acts with the guidance computer to aim the warheads in flight when using MIRV capabilities and/or Time-On-Target options for simultaneous detonations. This gives the maximum target spread and damage possible.

  • Section 2: Missile Guidance Set (MGS) has a gyroscope and computer controlled inertial guidance system; targeting is programmed locally at the Launch Facility by tape transport or remotely from the Launch Control Center's storage data sets. Computer is liquid cooled and powered by support equipment until launch. Originally built by Autonetics Division of Rockwell International, now in replacement program by Boeing.

  • Section 1: Re-Entry System/ Re-entry Vehicle (RS/RV) General Electric MK 12 or MK 12A Re-entry Vehicle containing three +300KT warheads(reduced to one, per the Washington Summit Agreement in 1992), Multiple Independently Targeted Reentry Vehicle (MIRV) capable, with defense system penetration aids and Synchronized detonation, air or ground burst options.
  • Minuteman II used a Mk11C RV with a single warhead inside. There was a separate penetration aid section on some. One version of this contained an inflatable dummy warhead designed to simulate the RV's radar echo.
  • One Minuteman II base also had an Emergency Radio Communications System [ERCS] payload for some missiles; the UHF radio system was a hardened backup for the National Command Authority communications system. Also known as a 494L payload.
Flight Profile
  • Range: +8,000 miles (9,660 kilometers)
  • Speed: Approximately 15,000 mph (Mach 23 or 24,000 kph) at burnout
  • Ceiling Altitude: 700 miles (1,120 kilometers)

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Deployment (G-Missile)
  • Unit inventory and cost: Inventory: 515 @ $7 million
  • Date deployed (G-Missile): June 1970
  • Last missile produced: December 1978


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Missiles are geographically separated a minimum of 3 miles apart (7 miles from launch control centers) in hardened silos to protect against attack and connected to an underground launch control center (LCC) through a system of hardened cables. Launch crews, consisting of two officers, perform around-the-clock alert sealed in the launch control center. Each launch control center directly controls 10 missiles, and exercises backup control for 4 other launch control centers, giving it the capability to launch a total of 50 missiles. To launch under normal circumstances, each LCC must have 2 crew members turn launch keys simultaneously after inserting the proper launch code, and 2 LCC's in the same squadron of 5 are required to issue launch votes at the same time, as well. There are automatic timers that must be constantly reset to keep control within the squadron, too; if the timers are allowed to expire, control transfers to the Airborne Launch Control Center (ALCC). If command capability is lost between the launch control center and remote missile launch facilities, such as in an attack, specially-configured EC-135 ALCC automatically assumes command and control of the isolated missile or missiles. A variety of communication systems provide the National Command Authority with virtually instantaneous direct contact with each launch crew. Fully qualified airborne missile combat crews aboard airborne launch control center aircraft would execute the NCA orders.


The Minuteman Missile program was a revolutionary marvel in many aspects. Many modern programs owe their success to ground broken by the project's officers, and the continuing viability of the system is a tribute to how well they did the job. Here are a few of the highlights (and interesting oddities) of the Minuteman program:

  • On February 27, 1958 the USAF gets approval to start research and development on an ICBM program that will later be called "Minuteman." The original design concept consisted of a force of 1000 quickly launched missiles based in mobile launchers and hardened, unattended sites having very long periods in which no remove-and-replace maintenance was required. This would involve a smaller number of personnel, enhancing security. The force was to be remotely controlled (in the case of fixed silos), and be able to launch within 30 seconds of a signaled command. This would be a drastic change over the launch preparation times required for the liquid fuel ICBM's it was designed to augment and later, replace.

  • In 1960, the Air Force began developing a mobile version of the Minuteman to be put on railroad cars. Approximately one third of the Minuteman force was to be mobile, and two-thirds in the hardened and dispersed sites. Shortly after the concept engineering was developed, the mobile phase of the project was cancelled. The public was told that the mobile project was not technologically feasible, but in fact it was cancelled for political and budgetary reasons by the President. The concept was later revived for the Peacekeeper missile, and again cancelled for the same reasons.

  • The entire missile (including guidance package and warhead) was to be immediately transported to and installed in a silo, and if it failed to operate at any point, would be removed as a whole and transported back. This concept of a one-piece, no field maintenance Minuteman was known as a "Wooden Missile". Design changes were later instituted by military personnel to allow field removal of the guidance package and warhead, cutting maintenance time and increasing safety and security.

  • At Edwards Air Force Base, California, tethered, vertical launch tests of the Minuteman I rocket were conducted in underground test silos. Originally there were 16 launches planned to complete the test program; due to skillful planning and engineering, however, the program was completed in only 8 tests. The purpose of the tethered missile program was to validate and improve on the engineering designs for the silo to ensure that a missile would not be damaged by the blasts from its own engines as it launched. A full size and weight dummy missile was launched using a modified first stage having only a few seconds of fuel, and connected to the ground by a tether. Critical measurements of temperatures, pressures, and damage were taken on the silo and missile, and designs were adjusted. The tether system ensured the missile would fall back to earth in a known location, to facilitate damage studies.

  • Organizationally, Minuteman research, development, and deployment was innovative and original in concept. Many of the new ideas that came out of the massive project were later copied to bring success to other aerospace projects, most notably the Apollo Space program. It was one of the first large-scale military programs where multiple contractors were used to provide the system components. This was a parallel-development method that drastically shortened the time required to design, test, and install the system. The authority levels granted the project heads are unheard of today, however. A program such as Minuteman could never be implemented in the same time or for the same costs (if it could be done at all), because such a program would have oversight and micro-management by everyone from Congress to the Sierra Club.

  • The original security precautions designed for the Minuteman silos were woefully inadequate. To test the original designs for weaknesses where the site could be penetrated, Project Button Up was implemented. Test bed copies of Minuteman silo entry systems were constructed at Vandenberg AFB. A curious mix of contractors, Army demolition experts, and some of the world's best safecrackers (some on parole) were brought in. They were allowed to use anything they could load on a 6x6 truck and any number of people they wanted. The goal was to redesign the silo so it could not be penetrated in less than 30 minutes (the maximum response time for security forces). The initial access designs were breached by the entry team in minutes or even seconds in some cases. Eventually a multi-tiered entry system was devised, and extra reinforcing was given to the silo structure to prevent entry by blasting. The increased protection worked well: in the mid-80's, a group of anti-nuke protesters attacked a Launch Facility near Whiteman Air Force Base, Missouri. Due to the security response team being delayed by a previous alarm, they had nearly an hour to use vehicles with heavy chain, and a variety of drills and other tools including a jack hammer, to attempt entry. They managed to paint some graffiti, make some superficial gouges in the concrete, and damage a radar antenna before being arrested. Come on, people - it was built to withstand a BOMB BLAST, already!

  • Minuteman also evolved in the survivability department. The initial blast survival requirements for the Minuteman system was that Launch Facilities should stand 100 PSI overpressure, and Launch Control Centers withstand 300 PSI overpressure. Los Alamos National Labs in New Mexico constructed the headworks of Minuteman silos and subjected them to realistic overpressures with massive amounts of conventional explosives. It was discovered during these tests that the original construction would not survive a near hit, and the concrete was built up and reinforced to increase the strength of the silo.

  • Because the Soviets were continually improving their missile forces, constant improvements were made to the Minuteman system even as it was being installed. One particularly driving force was the news that the Soviets had begun to develop antiballistic missile systems. In 1961 research began for the development of penetration aids to enhance the ability of a re-entry vehicle to penetrate enemy defenses. This involved decoys and ultimately led to multiple re-entry vehicles, instead of using a single warhead. As guidance computers became more sophisticated, this eventually led to multiple independently guided re-entry vehicles, or MIRV's, as they are commonly known today.

  • Another initial design idea that changed drastically was called the "massive retaliation concept". This system had the launch control system devised so that it launched missiles in blocks of fifty. The launch controls were later redesigned so a commander could launch missiles one at a time. This improvement led to multiple targeting, enabling the programming of more than one target into a missile, and change the target under certain conditions without having to change or reprogram the guidance set. It also allowed more flexibility in the type of response to a given situation, so that retaliation level could match the threat.

  • February 1, 1961. The first Boeing LGM-30A Minuteman ICBM is launched from Cape Canaveral Missile Test Annex, Complex 31A traveling 4,600 miles to hit the target area. This is the first time a first-test missile is launched with all systems and stages functioning.

  • February 3, 1961. SAC's Boeing EC-135 Airborne Command Post ("Looking Glass") begins operations. The planes are scheduled so that at least one ABCP is always in the air to provide a backup means of launching the ICBMs in case a nuclear attack wipes out conventional command-and-control systems.

  • February 28, 1963. The first Minuteman squadron, the 10th Strategic Missile Squadron (SMS) at Malmstrom AFB, Mont., is declared operational.

  • April 11, 1963. The first successful launch of a Boeing LGM-30 Minuteman I ICBM is conducted at Vandenberg AFB, Calif. On October 17, 1963, the first operational test launch of a Minuteman is carried out at Vandenberg by a crew from Malmstrom AFB. The test is only a partial success, as the reentry vehicle overshot the target.

  • March 1, 1965 a Minuteman 1 was launched from a Launch Facility at the 44th Strategic Missile Wing , Ellsworth AFB, South Dakota. This was the only Minuteman (to date) ever launched from an operational silo. To reduce the possibility of an accident, a dummy missile using a modified first stage similar to those in the tethered missile program was utilized. This kept the missile's flight time to seven seconds or a range of about two miles. This successful launch demonstrated that a combat alert crew could fire a Minuteman I from an operational launch facility.

  • Other launch systems for a mobile ICBM were explored by the Minuteman developers. These included Skybolt, which was an air-launched ballistic missile, to be launched out of a B-52; this idea eventually became the Air Launched Cruise Missile. On October 24, 1974, a Minuteman missile was successfully launched by dropping it (on a parachute) from the back of a C-5A Galaxy off the coast of Vandenberg Air Force Base, where it was ignited in mid-air by remote control and hit the target area in the Pacific 20 minutes later.

  • Even some of the program's storm clouds had a silver lining. After a few years of less than stellar performance of the Minuteman guidance system, investigators began tracking failure rates and causes. Eventually caught between quality audits and tips from whistle-blowing employees, it was discovered that a contractor had been billing the government for MIL-Spec parts in the gyroscopic platform, but frequently using untested parts purchased from local electronics shops, such as Radio Shack. The scandal eventually led to many improvements and redesign of the gyro, greatly improving the life and reliability.


The current Minuteman III force is now based in "missile fields" around F.E. Warren AFB, Wyo., Malmstrom AFB, Mont., and Minot AFB, N.D. Ratification of Start I and the possible implementation of Start II will require removing the Peacekeeper (MX) ICBM's based at F.E. Warren from service by 2003. This means that Minuteman III may become the only land-based ICBM in the Nuclear Triad.


Various modernization programs gave expanded targeting options, significantly improved accuracy, and survivability under attack, and have kept the force fully operational well past it's original design limit. More upgrades are planned to keep the Minuteman system operating until at least 2015, which will make some of the launch installations as much as 53 years old. Some of these programs include: replacement of the aging guidance system, remanufacture of the solid-propellant rocket motors, replacement of standby power systems, refurbishment of launch facilities, and installation of updated, survivable communications equipment and new command and control consoles to enhance immediate communications.