A guided missile is an unmanned weapon that is controlled by some system, either internal or
external, from its launch until it hits its target. There are four types:
(1) surface-to-surface, (2) surface-to-air, (3) air-to-air, and (4) air-to-surface.
The first guided missiles were built in Germany during the Second World War. The first of these was the V-1, which was powered by a pulse-jet engine and flew at quite low speeds, making it easy to destroy in the air. The V-2 was a far more sophisticated weapon – rocket-powered, with an automatic pilot and electronic guidance; it could reach a height of 100 km (60 mi) and speeds of over 5,800 km/h (3,600 mph) and deliver a tonne of high explosive.
Postwar development of guided missiles improved upon the V-2, with missiles ranging from the huge intercontinental ballistic missiles (ICBMs) with ranges of 10,000 km (6,000 mi) and nuclear warheads, to small hand-launched antitank missiles. The main strategic capability of nuclear missiles resides in the submarine systems developed by the superpowers, the first of which was Polaris. The multiple independently targeted re-entry vehicles (MIRVs) – ICBMs with many independently targetable sub-missiles – were developed in the late 1960s.
The cruise missile can evade radar by flying at low heights and its computer guidance compares satellite photographs with the terrain over which it flies, bringing the missile potentially to within 10 m (30 ft) of its target.