In this Jan. 28, 2007 photo provided by the U.S. Navy, an Electromagnetic Railgun (EMRG) laboratory launcher, or railgun is shown at the Naval Surface Warfare Center, in Dahlgren, Va. Future U.S. Navy ships will be powered by electric drive propulsion, making EMRG - which uses electricity rather than chemical propellants to launch projectiles - possible, according to the U.S. Navy. The railgun works by sending electric current along parallel rails, creating an electromagnetic force so powerful it can fire a metal projectile at tremendous speed. (AP Photo/U.S. Navy, John F. Williams)