Rockets and missiles are two closely related types of powered munitions which utilise an internal propulsion method, typically a rocket motor, to maintain their rate of travel after launch. Rockets and missiles are typically relatively long and thin—with lengths ranging from 50 centimetres to 6.5 metres. Rockets are unguided those fitted with guidance systems are usually referred to as missiles. Missiles sometimes use propulsion methods other than rocket motors, such as turbojets. The effective range of rockets varies from as little as one kilometre to more than 40 kilometres, while missiles typically have a longer range — some more than 250 kilometres.