intercontinental ballistic missile (ICBM)

 
An intercontinental ballistic missile (ICBM) is a guided ballistic missile with a minimum range of 5,500 kilometres (3,400 mi) primarily designed for nuclear weapons delivery (delivering one or more thermonuclear warheads). Similarly, conventional, chemical, and biological weapons can also be delivered with varying effectiveness, but have never been deployed on ICBMs. Most modern designs support multiple independently targetable reentry vehicles (MIRVs), allowing a single missile to carry several warheads, each of which can strike a different target.

Early ICBMs had limited precision, which made them suitable for use only against the largest targets, such as cities. They were seen as a "safe" basing option, one that would keep the deterrent force close to home where it would be difficult to attack. Attacks against military targets (especially hardened ones) still demanded the use of a more precise manned bomber. Second- and third-generation designs (such as the LGM-118 Peacekeeper) dramatically improved accuracy to the point where even the smallest point targets can be successfully attacked.

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) and tactical ballistic missiles (TBMs). Short and medium-range ballistic missiles are known collectively as theatre ballistic missiles.


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 Anti-ballistic missile (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 the 1970s. Safeguard ABM facility was located in North Dakota and was operational from 1975 to 1976. The USSR deployed its ABM-1 Galosh 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 Alaska-based United States 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 Topol 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.
Artist's concept of an SS-24 deployed on railway

After launch, a booster pushes the missile 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 fueled all the time as the cryogenic fuel 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 United Kingdom invented the missile silo that protected the missile from a first strike and also hid fuelling operations underground.

Once the booster falls away, the remaining "bus" releases several warheads, each of which continues on its own unpowered ballistic trajectory, much like an artillery shell or cannonball. 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 many thousands of kilometers away from the launch site (and due to the possible locations of the submarines: anywhere in the world) within approximately 30 minutes.

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

As the nuclear warhead reenters the Earth's atmosphere its high speed causes compression of 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 a pyrolytic carbon-epoxy synthetic resin composite material heat shield. Warheads are also often radiation-hardened (to protect against nuclear-tipped ABMs or the nearby detonation of friendly warheads), one neutron-resistant material developed for this purpose in the UK is three-dimensional quartz phenolic.

Circular error probable is crucial, because halving the circular error probable decreases the needed warhead energy by a factor of four. Accuracy is limited by the accuracy of the navigation system and the available geodetic information.

Strategic missile systems are thought to use custom integrated circuits designed to calculate navigational differential equations thousands to millions of FLOPS 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—the Fractional Orbital Bombardment System—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. However, according to reports, Russia is working on the new Sarmat ICBM which leverages Fractional Orbital Bombardment concepts to use a Southern polar approach instead of flying over the Northern polar regions. Using this approach, it is theorized, avoids the US missile defense batteries in California and Alaska.

New development of ICBM technology are ICBMs able to carry hypersonic glide vehicles as a payload such as RS-28 Sarmat.

ICBMs can be deployed from transporter erector launchers (TEL), such as the Russian RT-2PM2 Topol-M


Specific ICBMs

Specific types of ICBMs (current, past and under development) include:

Type Minimum Range (km) Maximum Range (km) Country Status
LGM-30 Minuteman III
13,000 United States
LGM-30F Minuteman II
11,265 United States Decommissioned
LGM-30A/B Minuteman I
10,186 United States Decommissioned
LGM-118 Peacekeeper
14,000 United States Decommissioned
MGM-134 Midgetman
11,000 United States Decommissioned
Titan II (SM-68B, LGM-25C)
16,000 United States Decommissioned
Titan I (SM-68, HGM-25A)
11,300 United States Decommissioned
SM-65 Atlas (SM-65, CGM-16)
10,138 United States Decommissioned
RTV-A-2 Hiroc 2,400 8,000 United States Decommissioned
RS-28 Sarmat
10,000 Russia
RS-26 Rubezh 6,000 12,600 Russia
RS-24 "Yars" (SS-29)
11,000 Russia
RT-2UTTH "Topol M" (SS-27)
11,000 Russia
UR-100N (SS-19)
10,000 Soviet Union
R-36 (SS-18) 10,200 16,000 Soviet Union
RT-23 Molodets
11,000 Soviet Union Decommissioned
RT-2PM "Topol" (SS-25)
10,000 Soviet Union
RT-21 Temp 2S
10,500 Soviet Union Decommissioned
R-9 Desna
16,000 Soviet Union Decommissioned
R-16
13,000 Soviet Union Decommissioned
R-26
12,000 Soviet Union Decommissioned
MR-UR-100 Sotka 10,250 10,320 Soviet Union Decommissioned
UR-100
10,600 Soviet Union Decommissioned
RT-20
11,000 Soviet Union Decommissioned
RT-2
10,186 Soviet Union Decommissioned
R-7 Semyorka
8,000 Soviet Union Decommissioned
DF-4 5,500 7,000 China
DF-31 7,200 11,200 China
DF-5 12,000 15,000 China
DF-41 12,000 15,000 China
KN-08 1,500 12,000 North Korea
Hwasong-14 6,700 10,000 North Korea
Agni-V 5,000 8,000 India

Russia, the United States, China, North Korea and India are the only countries currently known to possess land-based ICBMs, Israel has also tested ICBMs but is not open about actual deployment.

The United States currently operates 405 ICBMs in three USAF bases. The only model deployed is LGM-30G Minuteman-III. All previous USAF Minuteman II missiles were destroyed in accordance with START II, and their launch silos have been sealed or sold to the public. The powerful MIRV-capable Peacekeeper missiles were phased out in 2005.

The Russian Strategic Rocket Forces have 286 ICBMs able to deliver 958 nuclear warheads: 46 silo-based R-36M2 (SS-18), 30 silo-based UR-100N (SS-19), 36 mobile RT-2PM "Topol" (SS-25), 60 silo-based RT-2UTTH "Topol M" (SS-27), 18 mobile RT-2UTTH "Topol M" (SS-27), 84 mobile RS-24 "Yars" (SS-29), and 12 silo-based RS-24 "Yars" (SS-29).

China has developed several long range ICBMs, like the DF-31. The Dongfeng 5 or DF-5 is a 3-stage liquid fuel ICBM and has an estimated range of 13,000 kilometers. The DF-5 had its first flight in 1971 and was in operational service 10 years later. One of the downsides of the missile was that it took between 30 and 60 minutes to fuel. The Dong Feng 31 (a.k.a. CSS-10) is a medium-range, three-stage, solid-propellant intercontinental ballistic missile, and is a land-based variant of the submarine-launched JL-2.

The DF-41 or CSS-X-10 can carry up to 10 nuclear warheads, which are MIRVs and has a range of approximately 12,000–14,000 km (7,500–8,700 mi). The DF-41 deployed in underground Xinjiang, Qinghai, Gansu and Inner Mongolia area. The mysterious underground subway ICBM carrier systems they called "Underground Great Wall Project".

Israel is believed to have deployed a road mobile nuclear ICBM, the Jericho III, which entered service in 2008. It is possible for the missile to be equipped with a single 750 kg (1,650 lb) nuclear warhead or up to three MIRV warheads. It is believed to be based on the Shavit space launch vehicle and is estimated to have a range of 4,800 to 11,500 km (3,000 to 7,100 mi). In November 2011 Israel tested an ICBM believed to be an upgraded version of the Jericho III.

India has a series of ballistic missiles called Agni. On 19 April 2012, India successfully test fired its first Agni-V, a three-stage solid fueled missile, with a strike range of more than 7,500 km (4,700 mi). The missile was test-fired for the second time on 15 September 2013. On 31 January 2015, India conducted a third successful test flight of the Agni-V from the Wheeler Island facility. The test used a canisterised version of the missile, mounted over a Tatra truck.



sources: wikipedia

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