Video: Navy Test-Fires Electromagnetic Railgun

The U.S. Navy Office of Naval Research has released new video of a test of BAE Systems’ electromagnetic railgun, a hypervelocity weapon that has a maximum range exceeding 100 miles. 

The advanced system uses a massive pulse of electrical power to accelerate a sliding conductive armature down two parallel rails. The armature contains a slug, which breaks free of its sabot upon exiting the weapon at muzzle velocities of up to 4,500 miles per hour (6,600 feet per second). It is a kinetic energy weapon, and the projectile carries no explosive warhead. The Navy envisions its use in naval surface fire support, land strikes, ship defense and surface warfare. Previous announcements from ONR have suggested a potential role in ballistic missile defense as well. 

Unlike laser energy weapons, the railgun features over-the-horizon surface strike capability thanks to its projectile’s ballistic flight path. It also offers a key benefit for safety and survivability: with no explosive propellants or warheads, its ammunition magazines are not vulnerable to detonation in the event of a shipboard casualty or an enemy strike. In addition, its rounds are smaller than traditional shells, allowing a vessel to carry more ammunition in the same amount of space. And at $25,000 per round, firing it off is much less costly than expending a Tomahawk or SM-2 missile.

The railgun's energy requirements are part of the rationale behind the integrated electrical systems on the futuristic Zumwalt class destroyers. This complex ships' service system can divert electricity from the main engines to power the vessel's weapons at will, and the third vessel in the class may receive a railgun instead of one of its two 155mm cannon. 

General Atomics was developing a competing railgun design, but BAE Systems’ model was selected for the project’s second phase. General Atomics is privately funding its own research and test efforts for a land-based version, in coordination with the Army.

The Office of Naval Research says that its railgun technology is now moving towards the acquisition stage, but there are still several key "research opportunities,” including better thermal management for the gun's slender launch rails; extending the service life of the equipment; developing high-strength dielectric structural materials; and reducing the size of associated power systems and control electronics. Experts say that the limited durability of a railgun's rails under the stress of repeated firing is an especially serious challenge for the technology.