The Navy Wants To Fire Its Ridiculously Strong Railgun From The Ocean

04-10-2014 • http://www.popsci.com, By Kelsey D. Atherton

In 2016, the U.S. Navy is going to test a railgun—a weapon that can repeatedly launch a projectile at more than 5,000 MPH—from a boat. In 2018, they're going to do it again. And in the 2020s, the Navy is going to figure out just what to do with a gun that seemed like science fiction decades ago.

Speaking at the Navy League's Sea Air Space exposition in National Harbor, Maryland, Rear Admiral Bryant Fuller told the assembled crowd of journalists, servicemen, and defense contractors that railgun shots cost 1/100th the price of a “standard” missile. (In the age of austerity, even something as futuristic as a railgun is sold on the premise of cost savings.)

A railgun works by generating a strong electromagnetic current that flows from one rail, through a U-shaped back end of the projectile, and into another parallel rail. This generates three magnetic fields—a parallel one around each of the rails, and a perpendicular one around the projectile. Squeezed forward by the magnetic fields, the projectile accelerates rapidly along the rails and is then launched forward, breaking the circuit. The end result is a large metal slug that can go very far, very fast.