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Intercontinental ballistic missile

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A Minuteman III missile after a test launch. An intercontinental ballistic missile, or ICBM, is a very long-range (greater than 5,500–km or 3,500 miles1) ballistic missile typically designed for nuclear weapons delivery, i.e., delivering one or more nuclear warheads.

ICBMs are differentiated by having greater range and speed than other ballistic missiles: intermediate-range ballistic missiles (IRBMs), short-range ballistic missiles, and the newly-named theatre ballistic missiles. Categorizing missiles by range is necessarily subjective and the boundaries are chosen somewhat arbitrarily, and so exact boundaries between range classes are not (and never can be) authoritative except within a community which has agreed to a set of definitions.

The following nations currently have operational ICBM systems: Russia, the United States, France [link], the United Kingdom, and People's Republic of China. India has IRBMs but is developing ICBMs (see ballistic missiles of India). Pakistan has IRBMs but is also researching ICBMs (see Pakistan's ballistic missiles). North Korea is believed to be developing an ICBM; two tests of somewhat different developmental missiles in 1998 and 2006 were only minimally successful.

In 2002, the United States and Russia agreed in the SORT treaty to reduce their deployed stockpiles of ICBMs to not more than 2,200 warheads each.

Contents

Flight phases

The following flight phases can be distinguished: See also Missile Defense Agency, missile defense classified by trajectory phase, countermeasure.

History

The progenitor of the ICBM was the German A9/10, which was never developed but only proposed by Wernher von Braun. The progenitor of the IRBM was the German V2 (Vergeltung, or "vengeance") rocket designed by von Braun that used liquid propellant and an inertial guidance system. It was launched from a mobile launcher in order to make it less susceptible to Allied air attacks. Following World War II von Braun and other lead Nazi scientists were secretly transferred to US to work directly for the U.S. Army through Operation Paperclip developing the V2 into the Redstone IRBM and Jupiter IRBM. Due to treaty agreements the U.S. was able to base these IRBMs in countries close to the USSR within strategic range.

The USSR had no similar territory in the 1950s, so under the direction of reactive propulsion engineer Sergei Korolev a program to develop an ICBM (which started in Russia well before WWII) was accelerated. Korolev was given access to some captured V2 materials but found the V2 design weak and developed his own distinct design, the R-7, that was tested in August 1957 and on October 4, 1957 placed the first Sputnik (satellite) in space -- thus opening the era of space exploration for mankind.

In the USA, competition between the U.S. armed services meant that each force developed its own ICBM program, slowing progress. The U.S.'s first ICBM was the Atlas, operational in 1959. Both the R7 and Atlas required a large launch facility, making them vulnerable to attack, and could not be kept in a ready state. Early ICBMs formed the basis of many space launch systems. Examples include: Atlas, Redstone rocket, Titan, R-7, and Proton, which was derived from the earlier ICBMs but never deployed as an ICBM. The UK built its own ICBM Blue Streak but it was never made operational due to the difficulty of finding a launch site away from population centers. Under the direction of Robert McNamara the U.S. initiated the LGM-30 Minuteman, Polaris and Skybolt solid fuel ICBMs. Modern ICBMs tend to be smaller than their ancestors (due to increased accuracy and smaller and lighter warheads) and use solid fuels, making them less useful as orbital launch vehicles. Deployment of these systems was governed by the strategic theory of Mutually Assured Destruction.

In the 1970s development began on Anti-Ballistic Missile Systems by both the U.S. and USSR but these were restricted by treaty in order to preserve the value of the existing ICBM systems. President Ronald Reagan launched the Strategic Defense Initiative as well as the MX and Midgetman ICBM programmes. This led to the agreement of a series of Strategic Arms Reduction Treaty negotiations.

Countries in the early stages of developing ICBMs have all used liquid propellants for the sake of simplicity.

Modern ICBMs

RT-2UTTH Topol M mobile launcher - Russia's latest ICBM
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RT-2UTTH Topol M mobile launcher - Russia's latest ICBM

Modern ICBMs typically carry multiple independently targetable reentry vehicles (MIRVs), each of which carries a separate nuclear warhead, allowing a single missile to hit multiple targets. MIRV was an outgrowth of the rapidly shrinking size and weight of modern warheads and the Strategic Arms Limitation Treaties which imposed limitations on the number of launch vehicles (SALT I and SALT II). It has also proved to be an "easy answer" to proposed deployments of ABM systems – it is far less expensive to add more warheads to an existing missile system than to build an ABM system capable of shooting down the additional warheads; hence, most ABM system proposals have been judged to be impractical. The first operational ABM systems were deployed in the 1970s, the U.S. Safeguard ABM facility was located in North Dakota and was operational from 1975–1976. The USSR deployed its Galosh ABM system around Moscow in the 1970s, which remains in service. Israel deployed a national ABM system based on the Arrow missile in 1998 [link], but it is mainly designed to intercept shorter-ranged theater ballistic missiles, not ICBMs. The U.S. Alaska-based National Missile Defense system attained initial operational capability in 2004.[link]

ICBMs can be deployed from multiple platforms:

The last three kinds are mobile and therefore hard to find.

During storage, one of the most important features of the missile is its serviceability. One of the key features of the first computer-controlled ICBM, the Minuteman missile was that it could quickly and easily use its computer to test itself.

In flight, a booster pushes the warhead and then falls away. Most modern boosters are solid-fueled rocket motors, which can be stored easily for long periods of time. Early missiles used liquid-fueled rocket motors. Liquid-fueled ICBMs were generally not kept fueled all the time, and therefore fueling the rocket was necessary before a launch. This annoying procedure was a source of significant operational delay, and therefore might cause the rockets to be destroyed before they could be used. It also provided opponents with intelligence because it was a definite observable event that indicated the start of an attack.

Once the booster falls away, the warhead falls on an unpowered path much like an orbit, except that it hits the earth at some point. Moving in this way is stealthy. No rocket gases or other emissions occur to indicate the missile's position to defenders. Also, it is the fastest way to get from one part of the Earth to another. This increases the element of surprise. The high speed of a ballistic warhead (near 5 miles per second) also make it difficult to intercept.

Many authorities say that missiles also release aluminized balloons, electronic noisemakers, and other items intended to confuse interception devices and radars.

The high speed can cause the missile to get very hot as it reenters the atmosphere. Ballistic warheads are protected by heatshields constructed of materials such as pyrolytic graphite, and in early missiles, thick plywood. Plywood approaches the strength per weight of carbon fiber/epoxy composites and chars slowly, protecting the missile.

Accuracy is crucial, because doubling the accuracy decreases the needed warhead energy by a factor of four. Accuracy is limited by the accuracy of the navigation system and the available geophysical information. Many authorities believe that most government-supported geophysical mapping initiatives such as GPS, and ocean satellite altitude systems such as Seasat, probably have a covert purpose to map mass concentrations and determine local gravitic anomalies, in order to improve accuracies of ballistic missiles.

Strategic missile systems are thought to use custom integrated circuits designed to calculate navigational differential equations thousands to millions of times per second in order to reduce navigational errors caused by calculation alone. These circuits are usually a network of binary addition circuits that continually recalculate the missile's position. The inputs to the navigation circuit are set by a general purpose computer according to a navigational input schedule loaded into the missile before launch.

One particular weapon developed by the Soviet Union (FOBS) had a partial orbital trajectory, and unlike most ICBMs its target could not be deduced from its orbital flight path. It was decommissioned in compliance with arms control agreements, which address the maximum range of ICBMs and prohibit orbital or fractional-orbital weapons.

Low-flying guided cruise missiles are an alternative to ballistic missiles.

Specific missiles

Land-based ICBMs and cruise missiles

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.
Enlarge
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.

The U.S. Air Force currently operates just over 500 ICBMs at around 15 missile complexes located primarily in the northern Rocky Mountain states and the Dakotas. These are of the LGM-30 Minuteman III ICBM variant only. Peacekeeper missiles were phased out in 2005[link]. All USAF Minuteman II missiles have been destroyed in accordance to START, and their launch silos have been sealed or sold to the public. To comply with the START II most U.S. multiple independently targetable reentry vehicles, or MIRVs, have been eliminated and replaced with single warhead missiles. However, since the abandonment of the START II treaty, the U.S. is said to be considering retaining 800 warheads on 500 missiles.[link]

The United States Air Force awards two badges for performing duty in a nuclear missile silo. The Missile Badge is presented to commissioned officers while the Space and Missile Pin is awarded to silo ground and support personnel.

Sea-based ICBMs

Trident missile launch at sea from a Royal Navy submarine.
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Trident missile launch at sea from a Royal Navy submarine.

Current and former U.S. ballistic missiles

Soviet/Russian

Specific types of Soviet/Russian ICBMs include:

People's Republic of China

Specific types of Chinese ICBMs called Dong Feng ("East Wind").

Ballistic missile submarines

Specific types of ballistic missile submarines include:

See also

External links

  1. [link]
  2. [Estimated Strategic Nuclear Weapons Inventories (September 2004)]
  3. [Intercontinental Ballistic and Cruise Missiles]

List of missiles
Air-to-air missile (AAM) | Air-to-surface missile (ASM) | Surface-to-air missile (SAM) | Surface-to-surface missile (SSM)
Ballistic missile | Intercontinental ballistic missile (ICBM) | Submarine launched ballistic missile (SLBM) | Anti-ballistic missile (ABM)
Cruise missile | Anti-ship missile (AShM) | Anti-submarine Rocket (ASROC) | Anti-tank guided missile (ATGM) | Anti-satellite weapon (ASAT) | Anti-radiation missile
Wire-guided missile | Infrared guidance | Beam riding | Laser guidance | Active radar guidance | Semi-active radar guidance


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