cruise missile

Bibliography

See K. Werrell, The Evolution of the Cruise Missile (1985).

A Taurus KEPD 350 cruise missile of the German Luftwaffe

A cruise missile is a guided missile which uses a lifting wing and most often a jet propulsion system to allow sustained flight. A cruise missile is, in essence, a flying bomb. They are generally designed to carry a large conventional or nuclear warhead many hundreds of miles with excellent accuracy. Modern cruise missiles normally travel at supersonic or at high subsonic speeds, are self-navigating, and fly in a non-ballistic very low altitude trajectory in order to avoid radar detection. In general (and for the purposes of this article), cruise missiles are differentiated from unmanned aerial vehicles (UAV) in that the weapon is integrated into the vehicle, and the vehicle is intended to be sacrificed in the mission.

Concise history

In the period between the World Wars, the British developed the Larynx (Long Range Gun with Lynx Engine) which had a handful of flight tests in the 1920s. But it was Germany that would first deploy cruise missiles, during World War II. Introduced in 1944, the German V-1 was the first weapon to use the classic cruise missile layout of a bomb-like fuselage, short wings, a dorsally mounted engine, and a simple inertial guidance system. The V-1 was propelled by a crude pulse-jet engine, the sound of which gave the V-1 its nickname of "doodle bug". However, the V-1 was not particularly accurate. The V-1 and similar early weapons are often referred to as flying bombs. Also in World War II, the Imperial Japanese forces, in an effort to gain a tactical advantage against the allies, resorted to utilizing bomb-carrying conventional aircraft as kamikazes, which were supplemented by the purpose-built and piloted rocket engined Ohka, itself another early predecessor to the super-accurate cruise missiles of today.

Immediately following the war, the USAF had 21 different guided missile projects including would-be cruise missiles. Budget cuts forced cancellations leading to just four missile programs in 1948: the Air Material Command BANSHEE, the SM-62 Snark, the SM-64 Navaho, and the MGM-1 Matador. The BANSHEE design was similar to Operation Aphrodite, and like Aphrodite it failed and was soon cancelled in April 1949^[1].

During the Cold War, both the United States and the Soviet Union experimented further with the concept, deploying early cruise missiles from land, submarines and aircraft.

The main outcome of the U.S. Navy submarine missile project was the SSM-N-8 Regulus missile, based upon the V-1.

The U.S. Air Force's first operational surface-to-surface missile was the winged, mobile, nuclear-capable MGM-1 Matador, also similar in concept to the V-1. Deployment to overseas operating locations began in 1954. The Matador was first deployed to West Germany and then later to the Republic of China (Taiwan) and South Korea. On November 7, 1956, U. S. Air Force Matador units in West Germany, whose missiles were capable of striking targets in the Warsaw Pact, deployed from their fixed day-to-day sites to unannounced dispersed launch locations. This alert was in response to the crisis posed by the major Soviet attack on Hungary which brutally suppressed the Hungarian Revolution.

Between 1957 and 1961 the United States followed an ambitious and well-funded program to develop a nuclear-powered cruise missile, Project Pluto. It was designed to fly below the enemy's radar at speeds above Mach 3 and carry a number of hydrogen bombs that it would drop on its path over enemy territory. Although the concept was proven sound and the 500 megawatt engine finished a successful test run in 1961, no airworthy device was ever completed. The project was finally abandoned in favor of ICBM development.

While ballistic missiles were the preferred weapons for land targets, heavy nuclear and conventional tipped cruise missiles were seen by the USSR as a primary weapon to destroy US carrier battle groups. Large submarines (e.g. Echo and Oscar classes) were developed to carry these weapons and shadow US battle groups at sea, and large bombers (e.g. Backfire, Bear, and Blackjack models) were equipped with the weapons in their air launched cruise missile (ALCM) configuration.

Warhead

Most cruise missiles carry about 500 kg of explosives ^{[citation needed]}, because most were designed to sink ships and destroy bunkers^{[citation needed]}. Some carry a nuclear warhead.

Aerodynamics

The aerodynamics of a cruise missile are quite similar to those of an airplane, including the use of wings.

Engine

Most cruise missiles are propelled by a jet engine, with a turbofan engine being the most common due to its efficiency.

Guidance

The lowest cost system in wide use uses a radar altimeter, barometric altimeter and clock to navigate a digital strip map^{[citation needed]}. Some systems may now use satellite navigation or inertial guidance, but these are substantially more expensive^{[citation needed]}, and GPS systems are only slightly more accurate than a map-based system (TERCOM)^{[citation needed]}. Anti-ship cruise missiles like the RGM-84 Harpoon or the SS-N-12 Sandbox may also employ infrared or radar guidance.

Categories

Cruise missiles can be categorized according to many criteria. It is convenient to categorize them by size, speed (subsonic or supersonic), and range. Often, the same missile is adopted for different launch platforms (land, sea, or air). Sometimes, the air- and submarine-launched versions are a bit lighter and smaller than their land- and ship-launched cousins.

Guidance systems can vary across missiles, but often the same missile comes in several variants, each with a different navigation system (Inertial navigation,TERCOM, or satellite navigation). Larger cruise missiles can carry either a conventional or a nuclear warhead, while smaller ones carry only conventional warheads.

Hypersonic

Hypersonic cruise missiles fly at extreme high speed.

Examples:

• Brahmos-2 (India/Russia) (Under development)

Supersonic

These missiles travel faster than the speed of sound, usually using ramjet engines. The range is typically 100-500km, but can be greater. Guidance systems vary.

Examples:

• SLAM (not to be confused with the SLAM cruise missile) and SM-64 Navaho were U.S. early-cold-war era projects for strategic long-range cruise missiles. Neither was accepted into service.
• P-500 Bazalt (Soviet Union/Russia)
• P-270 Moskit (Soviet Union/Russia)
• P-800 Oniks (Soviet Union)
• P-700 Granit (Soviet Union/Russia)
• PJ-10 BrahMos (India/Russia)

Long-range subsonic

This is a popular category for cruise missiles. Several missiles of this type were developed by the United States and the Soviet Union. These missiles have a range of 1,000 or more kilometers and fly at about 800km/h. The missiles in this category typically have a launch weight of about 1,500kg. These missiles can carry either a conventional or a nuclear warhead. Earlier versions of these missiles had inertial navigation. Later, TERCOM and DSMAC systems were added to dramatically improve accuracy. Most recent versions can use satellite navigation.

Examples:

• AGM-86B (United States)
• BGM-109 Tomahawk (United States)
• Kh-55 Granat (USSR)
• Hyunmoo IIIC (South Korea)

Medium-range subsonic

These missiles are about the same size and weight as the above category. They also travel at about the same speed, but the range is (officially)^{[citation needed]} less than 1,000km. Guidance systems vary.

Examples:

• Taurus KEPD 350 (Germany/Sweden)
• Storm Shadow/SCALP (UK/France)
• Babur (Pakistan)
• Ra'ad ALCM (Pakistan)
• Hyunmoo IIIA/B (South Korea)

Short-range

These missiles weigh around 500kg and have range of 70-300km. Their speed is subsonic. Navigation systems are usually more simple than those of larger missiles. In fact, the word "cruise" is not always applied to these missiles.

Examples:

• AGM-84 Harpoon (United States)
• C-802 (China)
• Exocet (France)
• SS-N-25 Switchblade (Kh-35 Uran) (Russia)
• RBS15 (Sweden/Germany)

Employment

The most common mission for cruise missiles is to attack relatively high value targets such as ships, command bunkers, bridges and dams. Modern guidance system permit precise attacks.

(As of 2001) the BGM-109 Tomahawk missile model has become a significant part of the US naval arsenal. It gives ships and submarines an extremely accurate, long-range, conventional land attack weapon. Each costs about $1,900,000 USD. The US Air Force deploys an air launched cruise missile, the AGM-86. It can be launched from bombers like the B-52 Stratofortress. Both the Tomahawk and the AGM-86 were used extensively during Operation Desert Storm. The British Royal Navy (RN) also operates cruise missiles, specifically the Tomahawk, used by the RN's nuclear submarine fleet. Conventional warhead versions were first fired in combat by the RN in 1999, during the Kosovo War.

Both Tomahawk (as AGM-109) and ALCM (AGM-86) were competing designs for the USAF ALCM nuclear tipped cruise missile to be carried by the B-52. ^{[citation needed]} The USAF adopted the AGM-86 for its bomber fleet while AGM-109 was adapted to launch from trucks and ships and adopted by the USAF and Navy. The truck launched versions were later destroyed under the bilateral INF (Intermediate Range Nuclear Forces) treaty with the USSR which also saw the end of the Pershing II and SS-20 Intermediate Range Ballistic Missiles.

India and Russia have jointly developed the supersonic cruise missile BrahMos. There are three versions of the Brahmos: ship/land-launched, air-launched and sub-launched. The ship/land-launched version is operational whereas the air-launched and sub-launched versions are under development. The Brahmos has the capability to attack targets on land. Russia also continues to operate several other cruise missiles, like the SS-N-12 Sandbox, SS-N-19 Shipwreck, SS-N-22 Sunburn and SS-N-25 Switchblade. The UK and France operate the Storm Shadow, Germany and Spain the Taurus missile while Pakistan has developed its own cruise missile somewhat similar to Tomahawk cruise missile, named the Babur missile. Both the People's Republic of China and the Republic of China (Taiwan) have also designed several cruise missile variants, such as the well-known C-802, some of which are capable of carrying biological, chemical, nuclear, and conventional warheads.

Nuclear warhead versions

SSM-N-8 Regulus

The US has 460 AGM-129 Advanced Cruise Missiles (ACMs) with a W80 nuclear warhead (5KT or 150KT selectable yield) for B-52 Stratofortress (B-52H) external carriage. Also there are ca. 350 sea-launched cruise missiles with the same nuclear warhead. The range of the missile is 3000 km. They all remain in storage.

The SSM-N-8 Regulus was also designed for a nuclear warhead.

See also:

• The United States and weapons of mass destruction
• Intermediate-Range Nuclear Forces Treaty
• Woensdrecht

Russia has Kh-55SM cruise missiles, with similar to US AGM-129 range of 3000 km, but are able to carry more powerful warhead of 200 kt.

Efficiency in modern warfare

Cruise missiles are among the most expensive of single-use weapons, up to several million dollars apiece. One consequence of this is that its users face difficult choices in targeting, to avoid expending the missiles on targets of low value. For instance, Operation Enduring Freedom, the United States struck targets of very low monetary value with cruise missiles, which led many to question the efficiency of the weapon. However, proponents of the cruise missile counter that the same counterargument applies to cruise missiles as to other types of UAVs. That is, cruise missiles are still cheaper than human pilots when total training and infrastructure costs are taken into account^{[citation needed]}, not to mention the intrinsic value that the military forces would likely place on a human pilot's life.

References

External links

• The Evolution of the Cruise Missile by Werrell, Kenneth P.
• The Cruise Missile: Precursors and Problems by Werrell, Kenneth P.
• An introduction to cruise missiles – From the website of the Federation of American Scientists (FAS)
• Feasibility of Third World Advanced Ballistic & Cruise Missile Threat NDIA 155 slide presentation from 1999
• The DIY cruise missile
• The W80 Warhead
• Cruise Missile Fundamentals
• Tomahawk Variants
• Bypassing the NMD: China and the Cruise Missile Proliferation Problem (Kh-55)
• Video of cruise missile formation over Iraq

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