December 13, 2010, 10:33 AM — It won't be ready for the real world until the 2020s, but a successful test of the U.S. Navy's electromagnetic railgun may change the way big war is fought on both land and sea.
Railguns -- also called Gauss guns -- are popular in science fiction and video games, but haven't been practical for real-world battlefields, though they've been developed in various guises since 1800.
The railgun, which fires a solid, 20-pound aluminum projectile at up to seven times the speed of sound could destroy a target as far as 100 miles away if fired at the the record 33 megajoules of energy in last week's test. A megajoule is approximately equivalent to the energy of a one-ton vehicle slamming into a wall at 100 MPH.
The Navy is going for 64 megajoules and a range of 200 miles, but is more focused on getting a workable weapon onto ships, more than two decades after the Reagan-era Strategic Defense Initiative began developing electromagnetic railguns as serious weapons more than two decades ago. Its last test was an 8-megajoule version in 2007.
The current version is much smaller -- the size of a schoolbus instead of several railroad cars.
It consist of a pair of rails supporting a low-friction platform for the projectile. To fire, operators run high-voltage pulses of electricity through the rails to create powerful and opposing magnetic fields, which generate the force to throw the projectile forward.
Because the projectile is solid, Navy ships would have to carry fewer explosives, be safer and be able to carry far more ammunition than currently, according to interviews with Rear Admiral Nevin Carr, the chief of naval research.