Two years after BAE Systems was awarded a US$21 million contract from the Office of Naval Research (ONR) to develop an advanced Electromagnetic (EM) Railgun for the U.S. Navy, the company has delivered the first industry-built prototype demonstrator to the Naval Surface Warfare Center (NSWC) Dahlgren. The prototype launcher is now being prepared for testing which is scheduled to take place in the coming weeks.

Unlike weapons that rely on explosive chemical propellants such as gunpowder to launch a projectile, electromagnetic railguns accelerate a conductive projectile along metal rails using a magnetic field powered by electricity. While the muzzle velocity of gunpowder-propelled projectiles is generally limited to around 4,000 ft per second (2,727 mph/4,389 km/h), the U.S. Navy says its railgun will be capable of launching projectiles at velocities of 4,500 to 5,600 mph (7,242 - 9,012 km/h).

This kind of speed translates to greatly extended range. Navy planners are initially targeting a 50 to 100-nautical mile (57 to 115 mile/92 to 185 km) range, with a planned expansion up to 220 nautical miles (253 mile/407 km). The Navy says this will give Sailors extended capabilities, such as providing precise naval surface fire support, land strikes, and cruise missile and ballistic missile defense. The ONR is also touting the improved safety of the weapon for use on ships because it uses no explosives in firing or storage.

As you might expect, the high velocity of the armature causes a lot of friction. Add to this the resistance in the rails as the electric current passes through it, and massive amounts of heat are generated. This has made developing a weapon that can fire off just one shot without destroying itself a major hurdle - let alone one that can stand up to the stresses of multiple firings over a short period.

To address this problem, the next phase of the EM Railgun program is focused on developing automatic projectile loading systems and thermal management systems to facilitate increased firing rates of the weapon. The ONR recently awarded BAE Systems, General Atomics and Raytheon Corp., $US10 million contracts to develop a pulsed power system for launching projectiles in rapid succession. The contracts mark the start of a five-year effort to achieve a firing rate of six to 10 rounds per minute.

More immediately, however, all eyes will be on the 32-megajoule prototype demonstrator, which will begin test firing this month ahead of the delivery of a second prototype launcher built by General Atomics.

Source: ONR

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