Missile

A missile is an airborne ranged weapon capable of self-propelled flight. Most missiles use a propellant, a jet engine, or a rocket motor to move through the air.

The term is derived from the Latin word "missilis," which means "that may be thrown." Historically, the word described any projectile thrown or shot at a target. In modern military terms, a missile is specifically an airborne weapon that uses self-propulsion to reach a target. This distinguishes it from unguided rocket artillery, or explosive devices without propulsion, such as shells or bombs.

A complete missile system typically consists of five essential components. First, the targeting system identifies the intended goal. Second, the guidance system manages the path of the flight. Third, the flight system handles the physical maneuvering of the weapon. Fourth, the engine provides the necessary thrust for propulsion. Finally, the warhead carries the explosive or destructive payload.

These parts must work together perfectly to ensure the weapon reaches its destination with precision.

The guidance system is critical for effectiveness and operates through four specific steps. It begins by tracking the target and then computing directions based on that tracking information. Next, it directs these computed inputs to the steering control. Finally, it steers the missile by directing those inputs to motors or flight control surfaces.

Guidance can be classified as active, semi-active, or passive. In active homing, the missile carries its own equipment to illuminate the target. In semi-active systems, an outside source, like a ship or aircraft, provides the radiation to guide the missile. Passive systems rely solely on information emitted by the target itself.

Missile propulsion relies on different types of engines and fuels. Rockets may use solid propellants, which are easier to maintain and allow for faster deployment. These propellants consist of a fuel and an oxidizer mixed in specific proportions. Larger missiles often use liquid-propellant rockets, where propulsion comes from one or more liquid fuels. Some systems use a hybrid approach, combining solid fuel with a liquid oxidizer.

Cruise missiles, however, typically use jet engines, such as the turbojet, because they are simple and have a low frontal area.

Missiles are classified by their launch platform and their intended target. Common categories include surface-to-surface, surface-to-air, air-to-surface, and air-to-air missiles. Specialized versions include anti-ship missiles (AShM), which target large vessels like aircraft carriers, and anti-satellite missiles (ASAT), which target objects in space.

Tactical missiles are short-range systems used for limited strikes in small areas. In contrast, strategic missiles are long-range weapons designed to hit targets far beyond the immediate vicinity.

There are two primary ways that missiles travel: ballistic trajectories and cruise trajectories. A ballistic missile is powered by rockets during an initial boost phase. It then follows an unpowered trajectory that arches upward before descending toward the target. This flight includes a mid-course phase and a terminal phase where the warhead detaches.

A cruise missile flies differently by staying within the atmosphere. It uses jet engines to maintain a constant speed and a flatter trajectory, often flying close to the Earth's surface to avoid detection.

The history of rocketry dates back to 10th-century China, where rockets were used to propel arrows. In the 18th century, the Kingdom of Mysore and the Maratha Empire used iron-cased rockets in India. Modern development accelerated in the early 20th century with the work of Robert Goddard and Hermann Oberth. During World War II, Nazi Germany developed the V-1 flying bomb and the V-2 rocket, which used mechanical autopilot.

Since the Cold War, the need for accuracy and long range has driven continuous technological advancement.

Because of their power, the spread of long-range missiles is strictly monitored. Agreements like the Missile Technology Control Regime (1987) and the International Code of Conduct against Ballistic Missile Proliferation (2002) attempt to control this spread.

These are voluntary agreements rather than legally binding treaties. Currently, more than 140 countries participate by providing information on their missile programs and tests. Modern concerns include the rise of hypersonic glide vehicles and dual-use missiles capable of carrying both conventional and nuclear warheads.