They use magnetic fields created by large electrical currents to accelerate a sliding metal conductor (the armature) between two rails to launch projectiles at 7,240–9,000 km/h.
Last year, a prototype railgun was tested successfully at tactical energy levels – around 32 MegaJoules (shown above). This would be enough energy to to fire a missile over a distance of 200km. (1MJ is equivalent to a 1-tonne car travelling at 160 km/h.)
The new project (Phase 2) will advance the technology by upgrading the launcher and its pulsed power supply from a single-shot operation to a multi-shot capability, and incorporating auto-loading and thermal management systems.
If the railgun technology reaches the stage where it can be deployed as a weapon, it will be able to fire a projectile more than 370km with a muzzle velocity of 7.5 times the speed of sound and an impact velocity of five times the speed of sound. It will destroy a target by its kinetic energy, rather than by using conventional explosives.
The plan is to mount the electromagnetic railguns on board naval vessels. Safety is a big attraction because the ships will not need to use propellant to fire the missiles, and will not need to store explosive rounds on board.
“We’re committed to developing this innovative and game-changing technology that will revolutionise naval warfare,” says Chris Hughes, vice-president and general manager of Weapon Systems at BAE Systems. “The railgun’s ability to defend against enemy threats from distances greater than ever before improves the capabilities of our armed forces.”
Phase 2 of the development programme will start immediately with initial prototypes due to be delivered in 2014. The programme will be carried out by BAE Systems in the US, with its partners IAP Research and SAIC.
ONR-supported scientists are also working on related technologies including silicon carbide (SiC)-based transistors, transformers and power converters. “SiC is important because it improves power quality and reduces size and weight of components by as much as 90%,” explains Sharon Beermann-Curtin, who leads the ONR’s power and energy science and technology division. “This is a critical technology enabler for future Navy combatant ships that require massive amounts of highly controlled electricity to power advanced sensors, propulsion and weapons such as lasers and the electromagnetic railgun.”