The US Navy’s electromagnetic railgun programme has a chequered history of scientific breakthrough and budget busting. Berenice Baker profiles a warship weapon that can launch projectiles at Mach 10 without explosives, and explores whether investment is justified in hardware that guzzles energy and risks blowing itself to smithereens.
Railguns consist of two parallel metal rails, between which a projectile held in an armature is loaded, completing a circuit between them. A massive electrical current of the order of one million amperes is applied, creating an electromagnetic field, which in turn produces a force that accelerates the projectile along the rails.
A railgun offers a number of potential advantages over traditional explosive projectile weapons. The accelerating force is applied to the projectile for the entire time the projectile is between the rails of the launch device, as opposed to explosive forces which, however powerful, have a limited duration.