In military terminology, a missile is a guided airborne ranged weapon capable of self-propelled flight usually by a jet engine or rocket motor. Missiles are thus also called guided missiles or guided rockets (when a previously unguided rocket is made guided). Missiles have five system components: targeting, guidance system, 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-submarine, anti-tank, etc.), surface-to-air missiles (and anti-ballistic), air-to-air missiles, and anti-satellite weapons.
Airborne explosive devices without propulsion are referred to as shells if fired by an artillery piece and bombs if dropped by an aircraft. Unguided jet- or rocket-propelled weapons are usually described as rocket artillery.
Historically, the word missile referred to any projectile that is thrown, shot or propelled towards a target; this usage is still recognized today.
History of rockets and missiles
The first missiles to be used operationally were a series of missiles developed by Nazi Germany in World War II. Most famous of these are the V-1 flying bomb and V-2 rocket, both of which used a mechanical autopilot to keep the missile flying along a pre-chosen route. Less well known were a series of anti-ship and anti-aircraft missiles, typically based on a simple radio control (command guidance) system directed by the operator. However, these early systems in World War II were only built in small numbers.
Guided missiles have a number of different system components:
Guidance system
Targeting system
Flight system
Engine
Warhead
Missile guidance
The most common method of guidance is to use some form of light, 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 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).