Rockets and rocket-propelled, guided missiles are the essential component of any military arsenal. By definition, rockets are unguided and follow the laws of physics and trajectory; whereas missiles are guided, either remotely or internally. There are many different types of missiles, including anti-tank and anti-aircraft missiles, surface to air missiles, and fixed emplacement missiles. There are also ballistic missiles, like the Frog or the Scud, that follow a simple ballistic path from launch to target, much like the bullet from a gun. Then there are the long-range, Intercontinental ballistic missiles, which carry nuclear warheads and are the most feared of all, for obvious reasons.