Intercontinental ballistic missile

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An intercontinental ballistic missile, or ICBM, is a very-long-range (greater than 5500 km) ballistic missile typically to deliver one or more nuclear warheads. It uses a ballistic trajectory involving a significant ascent and descent, including sub-orbital flight. ICBMs are differentiated by maximum range from other ballistic missiles: intermediate-range ballistic missiles (IRBMs), short-range ballistic missiles, and the newly named theater ballistic missiles. 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. The following nations currently have operational ICBM systems: Russia, the United States, France [1], the UK, and China. India has IRBMs but is developing ICBMs, see ballistic missiles of India. (Pakistan's ballistic missiles are IRBMs.)

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

Contents

Flight phases

The following flight phases can be distinguished:

  • boost phase - 3 to 4 minutes (for a solid rocket shorter than for a liquid-propellant rocket); altitude at the end of this phase is 150 -200 km, typical burn-out speed is 7 km/s
  • midcourse phase - ca. 25 minutes - suborbital flight in an elliptic orbit, i.e. the orbit is part of an ellipse with vertical major axis; the apogee (halfway the midcourse phase) is at an altitude of typically ca. 1200 km; the semi-major axis is between one half of the radius of the Earth and the radius; the projection of the orbit on the Earth's surface is a great circle - the missile may release several independent warheads, a large number of decoys, and chaff
  • reentry phase (starting at an altitude of 100 km) - 2 minutes

See also Missile Defense Agency.

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 2 von Braun and his lead scientist went to work directly for the US Army through Operation Paperclip developing the V2 into the Redstone IRBM and Jupiter IRBM. Due to treaty agreements the US 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 Sergei Korolev a crash programme to develop an ICBM began which at one stage consumed 5% of the entire Soviet military budget. Korolev was given access to captured V2 materials but evolved a distinct design, the R-7, that was declared 'operational' in 1957. Competition between the US armed services meant that each force developed its own ICBM programme slowing progress. The US'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, derived from the earlier ICBMS, but never deployed as an ICBM. The UK built its own ICBM Black Knight but it was never made operational due to the difficulty of finding a launch site away from population centres. Under the direction of Robert McNamara the US 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 of Anti-Ballistic Missile Systems by both the US 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 simplicity's sake.

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 only operational ABM systems were deployed in the 1970s, the US 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.

ICBMs are based:

  • 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. 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 speeds 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.

The low flying, guided cruise missile is an alternative to ballistic missiles.

Specific missiles

Land-based intercontinental ballistic missiles (ICBMs) and cruise missiles

The US 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 and Peacekeeper ICBM variants. Peacekeeper missiles are being phased out by 2005. All USAF Minuteman II missiles have been destroyed in accordance to START, and their launch silos sealed or sold to the public. To comply with the START II most US 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.[2]

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

  • The French Navy constantly maintains at least four active units, relying on two classes of nuclear-powered ballistic submarines (SSBN): the older Redoutable class, which are progressively decommissioned, and the newer Triomphant class. These carry 16 M45 missiles with TN75 warheads, and are scheduled to be upgraded to M51 nuclear missile around 2010.

Current and former US ballistic missiles

  • Atlas (SM-65, CGM-16) former ICBM launched from silo, now the rocket is used for other purposes
  • Titan I (SM-68, HGM-25A)
  • Titan II (SM-68B, LGM-25C) - former ICBM launched from silo, now the rocket is used for other purposes
  • Minuteman I (SM-80, LGM-30A/B, HSM-80)
  • Minuteman II (LGM-30F)
  • Minuteman III (LGM-30G) - launched from silo - as of June 28, 2004, there are 517 Minuteman III missiles in active inventory
  • LG-118A Peacekeeper / MX (LG-118A, MX) - silo-based; 29 missiles were on alert at the beginning of 2004; all are to be removed from service by 2005.
  • Midgetman - has never been operational - launched from mobile launcher
  • Polaris A1, A2, A3 - (UGM-27/A/B/C) former SLBM
  • Poseidon C3 - (UGM-73) former SLBM
  • Trident - (UGM-93A/B) SLBM - Trident II (D5) was first deployed in 1990 and is planned to be deployed past 2020.

Soviet/Russian

Specific types of Soviet/Russian ICBMs include:

People's Republic of China

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

  • DF-3 - cancelled. Program name transferred to a MRBM.
  • DF-4 (CSS-3) - silo, 7,000km range
  • DF-5 CSS-4 - silo, 12,000km range (replaced now with DF-5A 13,000km)
  • DF-6 - cancelled
  • DF-22 - cancelled by 1995.
  • DF-31 CSS-9 - silo and road mobile, 8,000km range (DF-31A 10,000km)
  • DF-41 CSS-X-10 - in development.

Ballistic missile submarines

Specific types of ballistic missile submarines include:

See also

External links

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


Lists of Aircraft | Aircraft manufacturers | Aircraft engines | Aircraft engine manufacturers

Airports | Airlines | Air forces | Aircraft weapons | Missiles | Timeline of aviation

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