Star Wars research: the muzzle" (left) and holed 1-inch steel target plate of a railgun (Electromagnetic Launcher) under test at Maxwell Laboratories Inc. , San Diego, California, as part of the U. S. Government's research programme into space-based weapons capable of intercepting ballistic missiles - the Strategic Defense Initiative. Railguns use electromagnetism to accelerate a projectile towards its target, as opposed to rifles or rockets which use chemical energy as a propellant. This device is capable of firing a 0. 3 pound plastic projectile at about 3 kilometers per second (7,000 miles per hour)."