In a modern military, a missile is a self-propelled guided weapon system, as opposed to an unguided self-propelled munition, referred to as just a rocket. Missiles have four system components: targeting and/or guidance, flight system, engine, and warhead. Missiles come in types adapted for different purposes: surface-to-surface and air-to-surface missiles (ballistic, cruise, anti-ship, anti-tank, etc.), surface-to-air missiles (anti-aircraft and anti-ballistic), air-to-air missiles, and anti-satellite missiles. All known existing missiles are designed to be propelled during powered flight by chemical reactions inside a rocket engine, jet engine, or other type of engine.[citation needed] Non-self-propelled airborne explosive devices are generally referred to as shells and usually have a shorter range than missiles.
Guidance systems
Missiles may be targeted in a number of ways. The most common method is to use some form of
radiation, such as
infrared,
lasers or
radio waves,
to guide the missile onto its target. This radiation may emanate from
the target (such as the heat of an engine or the radio waves from an
enemy radar), it may be provided by the missile itself (such as a radar)
or it may be provided by a friendly third party (such as the radar of
the launch vehicle/platform, or a laser designator operated by friendly
infantry). The first two are often known as
fire-and-forget as they need no further support or control from the launch vehicle/platform in order to function. Another method is to use a
TV camera—using either
visible light
or infra-red—in order to see the target. The picture may be used either
by a human operator who steers the missile onto its target, or by a
computer doing much the same job. One of the more bizarre guidance
methods instead used a
pigeon to steer the missile to its target.
Many missiles use a combination of two or more of the above methods,
to improve accuracy and the chances of a successful engagement.
Targeting systems
Another method is to target the missile by knowing the location of the target, and using a guidance system such as
INS,
TERCOM or
GPS.
This guidance system guides the missile by knowing the missile's
current position and the position of the target, and then calculating a
course between them. This job can also be performed somewhat crudely by a
human operator who can see the target and the missile, and guides it
using either cable or
radio based remote-control, or by an
automatic system
that can simultaneously track the target and the missile. Furthermore,
some missiles use initial targeting, sending them to a target area,
where they will switch to primary targeting, using either radar or IR
targeting to acquire the target.
Flight system
Whether a guided missile uses a targeting system, a guidance system
or both, it needs a flight system. The flight system uses the data from
the targeting or guidance system to maneuver the missile in flight,
allowing it to counter inaccuracies in the missile or to follow a moving
target. There are two main systems: vectored thrust (for missiles that
are powered throughout the guidance phase of their flight) and
aerodynamic maneuvering (wings, fins, canards, etc.).
Engine
Missiles are powered by an engine, generally either a type of rocket or jet engine. Rockets are generally of the
solid fuel type for ease of maintenance and fast deployment, although some larger ballistic missiles use
liquid fuel rockets. Jet engines are generally used in
cruise missiles, most commonly of the
turbojet type, due to its relative simplicity and low frontal area.
Turbofans and
ramjets
are the only other common forms of jet engine propulsion, although any
type of engine could theoretically be used. Missiles often have multiple
engine stages, particularly in those launched from the surface. These
stages may all be of similar types or may include a mix of engine types -
for example, surface-launched cruise missiles often have a rocket
booster for launching and a jet engine for sustained flight.
Some missiles may have additional propulsion from another source at launch; for example the
V1 was launched by a catapult and the
MGM-51 was fired out of a tank gun (using a smaller charge than would be used for a shell).
Warhead
Missiles generally have one or more
explosive warheads,
although other weapon types may also be used. The warhead or warheads
of a missile provides its primary destructive power (many missiles have
extensive secondary destructive power due to the high kinetic energy of
the weapon and unburnt fuel that may be on board). Warheads are most
commonly of the
high explosive type, often employing
shaped charges to exploit the accuracy of a guided weapon to destroy hardened targets. Other warhead types include
submunitions,
incendiaries,
nuclear weapons,
chemical,
biological or
radiological weapons or
kinetic energy penetrators. Warheadless missiles are often used for testing and training purposes.
Basic roles
Missiles are generally categorized by their launch platform and
intended target. In broadest terms, these will either be surface (ground
or water) or air, and then sub-categorized by range and the exact
target type (such as anti-tank or anti-ship). Many weapons are designed
to be launched from both surface or the air, and a few are designed to
attack either surface or air targets (such as the
ADATS missile). Most weapons require some modification in order to be launched from the air or surface, such as adding
boosters to the surface-launched version.
Surface-to-Surface/Air-to-Surface
Ballistic
After the boost-stage, ballistic missiles follow a
trajectory mainly determined by
ballistics. The guidance is for relatively small deviations from that.
Ballistic missiles are largely used for land attack missions.
Although normally associated with nuclear weapons, some conventionally
armed ballistic missiles are in service, such as
ATACMS.
The V2 had demonstrated that a ballistic missile could deliver a
warhead to a target city with no possibility of interception, and the
introduction of
nuclear weapons
meant it could efficiently do damage when it arrived. The accuracy of
these systems was fairly poor, but post-war development by most military
forces improved the basic
inertial platform concept to the point where it could be used as the guidance system on
ICBMs flying thousands of kilometers. Today the ballistic missile represents the only
strategic deterrent in most military forces, however some ballistic missiles are being adapted for conventional roles, such as the Russian
Iskander or the Chinese
DF-21D anti-ship ballistic missile. Ballistic missiles are primarily surface launched from
mobile launchers,
silos,
ships or
submarines, with
air launch being theoretically possible with a weapon such as the cancelled
Skybolt missile.
The
Russian Topol M (SS-27 Sickle B) is the fastest (7,320 m/s) missile currently in service
[2]
Cruise missile
The V1 had been successfully intercepted during World War II, but this did not make the cruise missile concept entirely useless. After the war, the US deployed a small number of nuclear-armed cruise missiles in Germany, but these were considered to be of limited usefulness. Continued research into much longer ranged and faster versions led to the US's SM-64 Navaho, and its Soviet counterparts, the Burya and Buran cruise missile. However, these were rendered largely obsolete by the ICBM, and none were used operationally. Shorter-range developments have become widely used as highly accurate attack systems, such as the US Tomahawk missile, the Russian Kh-55 the German Taurus missile and the Pakistani Babur cruise missile.The BrahMos cruise missile which is a joint venture between India and Russia. The Brahmos is different in this class as it's a supersonic cruise missile which can travel much faster(2-3m) than other cruise missile which are subsonic.
Cruise missiles are generally associated with land attack operations, but also have an important role as anti-shipping weapons. They are primarily launched from air, sea or submarine platforms in both roles, although land based launchers also exist.
Anti-ship
Another major German missile development project was the anti-shipping class (such as the Fritz X and Henschel Hs 293), intended to stop any attempt at a cross-channel invasion. However the British were able to render their systems useless by jamming their radios, and missiles with wire guidance were not ready by D-Day. After the war the anti-shipping class slowly developed, and became a major class in the 1960s with the introduction of the low-flying jet- or rocket-powered cruise missiles known as "sea-skimmers". These became famous during the Falklands War when an Argentine Exocet missile sank a Royal Navy destroyer.
A number of anti-submarine missiles also exist; these generally use the missile in order to deliver another weapon system such as a torpedo or depth charge to the location of the submarine, at which point the other weapon will conduct the underwater phase of the mission.
Surface-to-air
Anti-aircraft
By 1944 US and British air forces were sending huge air fleets over occupied Europe, increasing the pressure on the Luftwaffe day and night fighter forces. The Germans were keen to get some sort of useful ground-based anti-aircraft system into operation. Several systems were under development, but none had reached operational status before the war's end. The US Navy also started missile research to deal with the Kamikaze threat. By 1950 systems based on this early research started to reach operational service, including the US Army's Nike Ajax, the Navy's "3T's" (Talos, Terrier, Tartar), and soon followed by the Soviet S-25 Berkut and S-75 Dvina and French and British systems. Anti-aircraft weapons exist for virtually every possible launch platform, with surface-launched systems ranging from huge, self-propelled or ship-mounted launchers to man portable systems.
Anti-ballistic
Like most missiles, the
Arrow missile,
S-300,
S-400,
Advanced Air Defence and
MIM-104 Patriot are for defense against short-range missiles and carry explosive warheads.
However, in the case of a large closing speed,
a projectile without explosives is used, just a
collision is sufficient to destroy the target. See
Missile Defense Agency for the following systems being developed:
Air-to-air
Soviet RS-82 rockets were successfully tested in combat at the Battle of Khalkhin Gol in 1939.
German experience in World War II demonstrated that destroying a large aircraft was quite difficult, and they had invested considerable effort into air-to-air missile systems to do this. Their Me-262's jets often carried R4M rockets, and other types of "bomber destroyer" aircraft had unguided rockets as well. In the post-war period the R4M served as the pattern for a number of similar systems, used by almost all interceptor aircraft during the 1940s and '50s. Lacking guidance systems, such rockets had to be carefully aimed at relatively close range to successfully hit the target. The US Navy and U.S. Air Force began deploying guided missiles in the early 1950s, most famous being the US Navy's AIM-9 Sidewinder and USAF's AIM-4 Falcon. These systems have continued to advance, and modern air warfare consists almost entirely of missile firing. In the Falklands War, less powerful British Harriers were able to defeat faster Argentinian opponents using AIM-9G missiles provided by the United States as the conflict began. The latest heat-seeking designs can lock onto a target from various angles, not just from behind, where the heat signature from the engines is strongest. Other types rely on radar guidance (either on-board or "painted" by the launching aircraft). Air to Air missiles also have a wide range of sizes, ranging from helicopter launched self-defense weapons with a range of a few kilometers, to long range weapons designed for interceptor aircraft such as the Vympel R-37.
Anti-satellite
