Guided missile

A guided missile is a military rocket that can be directed in flight to change its flight path. In typical usage the term "missile" refers to guided rockets, and "rockets" to unguided ones. The differences between the two may be fairly minor other than the guidance system.

The first missiles to be used operationally were a series of German missiles of WW2. Most famous of these are the V1 and V2, both of which used a simple mechanical autopilot to keep the missile flying along a pre-chosen route. Less well known were a series of anti-shipping and anti-aircraft missiles, typically based on a simple radio control system directed by the operator.

Basic roles

Ballistic missiles

After the boost-stage ballistic missiles follow a trajectory mainly determined by ballistics, the guidance is for relatively small deviations from that.

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 do useful 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 miles. Today the ballistic missile represents the only strategic deterrent in most military forces; the USAFs continued support of manned bombers is considered by some to be entirely political in nature.

Cruise missiles

The V1 had been successfully intercepted during the war, 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 Navaho missile, and its Soviet counterparts, the Burya and Buran cruise missile. However these were rendered largely obsolete by the ICBM, and none was used operationally. Instead shorter-range developments have become widely used as highly accurate attack systems, such as the US Tomahawk missile.

Anti-shipping

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 turbojet powered cruise missiles known as "sea-skimmers". These became famous during the Falklands War when an Argentine Exocet missile sank a Royal Navy destroyer.

Anti-aircraft

The Stinger shoulder-launched surface-to-air missile system.

By 1944 US and British airforces were sending huge airfleets 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 SA-1 and SA-2 and French and British systems.

Air-to-air

German experience in WWII demonstrated that destroying a large aircraft was quite difficult, and they had invested considerable effort into air-to-air missile systems to do this. This gave birth to the Me262's R4M rockets. It was developed by the Luftwaffe during World War II, and used operationally for a very brief time just prior to the end of the war. 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. The US Navy and USAF used their superior electronics to deliver a number of such designs 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.

Anti-tank

By the end of WWII all forces had widely introduced unguided rockets using HEAT warheads as their major anti-tank weapon. However these had a limited useful range of a 100 m or so, and the Germans were looking to extend this with the use of a missile using wire guidance, the X-7. After the war this became a major design class in the later 1950s, and by the 1960s had developed into practically the only non-tank anti-tank system in general use.

Anti-ballistic

Like most missiles, the Arrow missile and MIM-104 Patriot for defense against short-range missiles, carry explosives.

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:

• Kinetic Energy Interceptor (KEI)
• Aegis Ballistic Missile Defense System (Aegis BMD) - a SM-3 missile with Lightweight Exo-Atmospheric Projectile (LEAP) Kinetic Warhead (KW)

Anti-satellite weapon (ASAT)

Also the proposed Brilliant Pebbles defense system would use kinetic energy collisions without explosives.

Guidance systems

Missile guidance systems generally fall into a number of basic classes, each one associated with a particular role. Modern electronics has allowed systems to be mixed on a single airframe, dramatically increasing the capabilities of the missiles.

See the main article at Missile guidance for details of the types of missile guidance systems.

See also

• Missile designation
• List of missiles