An intercontinental ballistic missile (ICBM) is a ballistic missile with a long range (greater than 5,500 km or 3,500 miles) typically designed for nuclear weapons delivery (delivering one or more nuclear warheads). Due to their great range and firepower, in an all-out nuclear war, land-based and submarine-based ballistic missiles would carry most of the destructive force, with nuclear-armed bombers having the remainder.

ICBMs are differentiated by having greater range and speed than other ballistic missiles: intermediate-range ballistic missiles (IRBMs), medium-range ballistic missiles (MRBMs), short-range ballistic missiles (SRBMs)—these shorter range ballistic missiles are known collectively as theatre ballistic missiles. There is no single, standardized definition of what ranges would be categorized as intercontinental, intermediate, medium, or short.

With the advent of multiple independently targetable reentry vehicles (MIRVs) in 1970, deployed in Minuteman ICBMs and Poseidon SLBMs, a single missile had the capability of carrying several warheads, each of which could strike a different target.

While the warheads of theater ballistic missiles are often conventional, ICBMs have been nearly inseparable from their connection with nuclear warheads. 'Nuclear ICBM' was seen as a redundant term. Strategic planning avoided the concept of a conventionally tipped ICBM, mainly because any ICBM launch threatens many countries and they are expected to react under the worst-case assumption that it is a nuclear attack. This threat of ICBMs to deliver such a lethal blow so rapidly to targets across the globe means that there has never been any end-to-end test of a nuclear-armed ICBM. The speed and range of an ICBM means that it is the only means by which military action can be taken promptly anywhere in the world, though the United States Prompt Global Strike effort is designed to allow for similar flexibility with conventional weapons.

History

World War II

The development of the world's first practical design for an ICBM, A9/10, intended for use in bombing New York and other American cities, was undertaken in Nazi Germany by the team of Wernher von Braun under ''Projekt Amerika''. The ICBM A9/A10 rocket initially was intended to be guided by radio, but was changed to be a piloted craft after the failure of Operation Elster. The second stage of the A9/A10 rocket was tested a few times in January and February 1945. The progenitor of the A9/A10 was the German V-2 rocket, also designed by von Braun and widely used at the end of World War II to bomb British and Belgian cities. All of these rockets used liquid propellants. Following the war, von Braun and other leading German scientists were secretly forced to the United States to work directly for the U.S. Army through Operation Paperclip, developing the IRBMs, ICBMs, and launchers.

Cold War

In 1953, the USSR initiated, under the direction of the reactive propulsion engineer Sergey Korolyov, a program to develop an ICBM. Korolyov had constructed the R-1, a copy of the V-2 based on some captured materials, but later developed his own distinct design. This rocket, the R-7, was successfully tested in August 1957 becoming the world's first ICBM and, on October 4, 1957, placed the first artificial satellite in space, Sputnik.

In the USA, competition between the U.S. armed services meant that each force developed its own ICBM program. The U.S. initiated ICBM research in 1946 with the MX-774. However, its funding was cancelled and only three partially successful launches in 1948, of an intermediate rocket, were ever conducted. In 1951, the U.S. began a new ICBM program called MX-774 and B-65 (later renamed Atlas). The U.S.' first successful ICBM, the 1.44-megaton Atlas D, was launched on July 29, 1959, almost two years after the Soviet R-7 flight.

Military units with deployed ICBM would first be fielded in 1959, in both the Soviet Union and the United States. The R-7 and Atlas each required a large launch facility, making them vulnerable to attack, and could not be kept in a ready state. The first US base to host ICBMs was F. E. Warren Air Force Base, in Wyoming; the base hosts an ICBM and Heritage Museum.

These early ICBMs also formed the basis of many space launch systems. Examples include Atlas, Redstone, Titan, R-7, and Proton, which was derived from the earlier ICBMs but never deployed as an ICBM. The Eisenhower administration supported the development of solid-fueled missiles such as the LGM-30 Minuteman, Polaris and Skybolt. 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.

The Western view of the deployment of these systems was governed by the strategic theory of Mutual Assured Destruction. In the 1950s and 1960s, development began on Anti-Ballistic Missile systems by both the U.S. and USSR; these systems were restricted by the 1972 ABM treaty. The first successful ABM test were conducted by the USSR in 1961, that later deployed a fully operating system defending Moscow in the 1970s (see Moscow ABM system).

The 1972 SALT treaty froze the number of ICBM launchers of both the USA and the USSR at existing levels, and allowed new submarine-based SLBM launchers only if an equal number of land-based ICBM launchers were dismantled. Subsequent talks, called SALT II, were held from 1972 to 1979 and actually reduced the number of nuclear warheads held by the USA and USSR. SALT II was never ratified by the United States Senate, but its terms were nevertheless honored by both sides until 1986, when the Reagan administration "withdrew" after accusing the USSR of violating the pact.

In the 1980s, President Ronald Reagan launched the Strategic Defense Initiative as well as the MX and Midgetman ICBM programs.

Post–Cold War

In 1991, the United States and the Soviet Union agreed in the START I treaty to reduce their deployed ICBMs and attributed warheads.

, all five of the nations with permanent seats on the United Nations Security Council have operational ICBM systems: all have submarine-launched missiles, and Russia, the United States and China also have land-based missiles. In addition, Russia and China have mobile land-based missiles.

India is reported to be developing a new variant of the Agni missile, called the Agni V, which is reported to have a strike range of more than 6,000 km. There is also speculation that India may be developing the Surya missile, with a possible range of up to 16,000 km.

It is speculated by some intelligence agencies that North Korea is developing an ICBM; two tests of somewhat different developmental missiles in 1998 and 2006 were not fully successful. On April 5, 2009, North Korea launched a missile. They claimed that it was to launch a satellite, but there is no proof to back up that claim.

Pakistan, is also said to be seeking ICBM capability and the development of a 7000 km range ICBM called Taimur is said to be under development.

Most countries in the early stages of developing ICBMs have used liquid propellants, with the known exceptions being the planned South African RSA-4 ICBM and the now in service Israeli Jericho 3.

Flight phases

The following flight phases can be distinguished:

boost phase: 3 to 5 minutes (shorter for a solid rocket than for a liquid-propellant rocket); altitude at the end of this phase is typically 150 to 400 km depending on the trajectory chosen, typical burnout speed is 7 km/s.

midcourse phase: approx. 25 minutes—sub-orbital spaceflight in an elliptic flightpath; the flightpath is part of an ellipse with a vertical major axis; the apogee (halfway through the midcourse phase) is at an altitude of approximately 1,200 km; the semi-major axis is between 3,186 km and 6,372 km; the projection of the flightpath on the Earth's surface is close to a great circle, slightly displaced due to earth rotation during the time of flight; the missile may release several independent warheads, and penetration aids such as metallic-coated balloons, aluminum chaff, and full-scale warhead decoys.

reentry phase (starting at an altitude of 100 km): 2 minutes—impact is at a speed of up to 4 km/s (for early ICBMs less than 1 km/s); see also maneuverable reentry vehicle.

Modern ICBMs

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 U.S. during 1970s. 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, 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.

ICBMs can be deployed from multiple platforms:

in missile silos, which offer some protection from military attack (including, the designers hope, some protection from a nuclear first strike)

on submarines: submarine-launched ballistic missiles (SLBMs); most or all SLBMs have the long range of ICBMs (as opposed to IRBMs)

on heavy trucks; this applies to one version of the RT-2UTTH Topol M which may be deployed from a self-propelled mobile launcher, capable of moving through roadless terrain, and launching a missile from any point along its route

mobile launchers on rails; this applies, for example, to РТ-23УТТХ "Молодец" (RT-23UTTH "Molodets"—SS-24 "Sсаlреl")

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. Many liquid-fueled ICBMs could not be kept fuelled all the time as the cryogenic liquid oxygen boiled off and caused ice formation, and therefore fueling the rocket was necessary before launch. This procedure was a source of significant operational delay, and might allow the missiles to be destroyed by enemy counterparts before they could be used. To resolve this problem the British invented the missile silo that protected the missile from a first strike and also hid fuelling operations underground.

Once the booster falls away, the warhead continues on an unpowered ballistic trajectory, much like an artillery shell or cannon ball. The warhead is encased in a cone-shaped reentry vehicle and is difficult to detect in this phase of flight as there is no rocket exhaust or other emissions to mark its position to defenders. The high speeds of the warheads make them difficult to intercept and allow for little warning striking targets anywhere in the world within minutes.

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

As the nuclear warhead reenters the Earth's atmosphere its high speed causes friction with the air, leading to a dramatic rise in temperature which would destroy it if it were not shielded in some way. As a result, warhead components are contained within an aluminium honeycomb substructure, sheathed in pyrolytic graphite-epoxy resin composite, with a heat-shield layer on top which is constructed out of 3-Dimensional Quartz Phenolic.

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.

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

Only Russia, the United States, and China are currently known to possess land-based ICBMs.

The United States currently operates 450 ICBMs in three USAF bases. The only model deployed is LGM-30G Minuteman-III.

All previous USAF Minuteman II missiles have been destroyed in accordance with 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. The powerful MIRV-capable Peacekeeper missiles were phased out in 2005. However, since the abandonment of the START II treaty, the U.S. is said to be considering retaining 800 warheads on an existing 450 missiles.

China has developed several long range ICBMs.

Israel is suspected of deploying the nuclear armed Jericho 3 ICBM.

Submarine-launched

All current designs of submarine launched ballistic missiles have intercontinental range. Current operators of such missiles are the United States, Russia, United Kingdom, France and China.

See also

Air Force Space Command

Anti-ballistic missile

Anti-Ballistic Missile Treaty

Atmospheric reentry

Countermeasure

Dense Pack

Fractional Orbital Bombardment System

France and weapons of mass destruction

General Bernard Adolph Schriever

Heavy ICBM

High-alert nuclear weapon

People's Republic of China and weapons of mass destruction

India and weapons of mass destruction

Israel and weapons of mass destruction

Pakistan and weapons of mass destruction

List of ICBMs

Missile Defense Agency

Nuclear disarmament

Nuclear navy

Nuclear warfare

Nuclear weapon

Russia and weapons of mass destruction

SLBM

Strike Force (France)

Submarine

Throw-weight

United Kingdom and weapons of mass destruction

United States and weapons of mass destruction

References

External links

Ballistic missile characters

Estimated Strategic Nuclear Weapons Inventories (September 2004)

Intercontinental Ballistic and Cruise Missiles

"A Tale of Two Airplanes" by Kingdon R. "King" Hawes, Lt Col, USAF (Ret.)

Category:Ballistic missiles Category:Russian inventions

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