Missile Propulsion

The Propulsion system of a missile may power it until it reaches the intended target or for only a small proportion of the flight time. The role of the missile will dictate the choice of propulsion system and if a combination of systems is required. There are several types of propulsion system, some of which are outlined below:

Turbojets - Ramjets - Pulsejets

Jet engines are in common use in missiles, although the use of a jet engine does require a large missile body. If a Ramjet is used, a system will be required to bring the missile to a minimum operating speed. Pulsejets were used in the V1, giving the "buzz-bomb" the infamous resonating sound. However, pulsejets are not in common use today. Turbojets are in use in many missiles, particularly in missiles required to cruise at subsonic speeds within the atmosphere for vast distances.

Rockets

Rocket propulsion must be used if the missile needs to leave the atmosphere, as air-breathing jets can only operate within the atmosphere. There are two main categories of rocket, namely liquid-propellant and solid-propellant. Liquid-propellant rockets are either bi-propellant systems consisting of a fuel and a separate oxidant, or a mono-propellant system using an unstable liquid which is made to decompose under controlled conditions.

Solid-propellant rockets employ such propellants as cordite, and are basically very simple; this simplicity can however make refinement difficult.

Boosters

Booster motors are used whenever extremely rapid acceleration is required, (defensive missiles) or when a missile needs to be accelerated to a sufficient operating speed for Ramjet operation. Booster motors are usually solid-propellant rockets for simplicity and are discarded as soon as they are spent.