US Navy begins test firing railgun prototype

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Engineers have fired the US Navy’s first industry-built electromagnetic railgun (EM Railgun) prototype launcher, marking one of the key steps towards eventually fitting the weapons on ships.

The firing at the Naval Surface Warfare Center Dahlgren Division (NSWCDD) kicks off a two-month-long series of tests by the Office of Naval Research (ONR) to evaluate the first of two industry-built launchers. The tests will bring the Navy closer to a new naval gun system capable of extended ranges against surface, air and ground targets, the Navy said yesterday.
“We are starting our full-energy tests to evaluate the barrel life and structural integrity of the prototype system,” said Roger Ellis, program manager of the EM Railgun, part of ONR’s Naval Air Warfare and Weapons Department. “It’s the next step toward a future tactical system.”

The EM Railgun launcher is a long-range weapon that fires projectiles using electricity instead of chemical propellants. Magnetic fields created by high electrical currents accelerate a sliding metal conductor, or armature, between two rails to launch projectiles at 4 500 mph to 5 600 mph.

However, there are challenges. At launch, heat deposited in the armature and near the surface of the rails due to high currents and friction, or viscous heating generated at the sliding interface, leads to temperatures sufficient to melt most metals including the armature material. If the heating and extreme pressures also damage the rail surface, it can destroy the contact surface and condemn the gun barrel.

The 32-megajoule prototype demonstrator, built by BAE Systems, arrived at NSWCDD on January 30 (one megajoule of energy is equivalent to a 1-ton car being thrust at 100 mph). The prototype is the first of two industry-built launchers to be delivered to the Navy. General Atomics is building the second launcher, scheduled for delivery in April. ONR previously relied upon laboratory-built systems to advance the technology.

After installing the BAE Systems launcher and outfitting it with a comprehensive suite of sensors, high-speed cameras and measuring devices, engineers fired successful low-energy test shots to prepare it for the evaluation. The team will conduct tests at 20 megajoules and 32 megajoules, shooting test projectiles similar to what was previously fired through NSWCDD’s laboratory launcher.
“The test series will characterize the gun’s performance by shooting several rounds through the barrel at various energy levels to fully exercise the capabilities of the prototype,” said Ellis.

When fully developed, the EM Railgun will give sailors a dramatically increased multimission capability, the Navy said. Its increased velocity and extended range over traditional shipboard weapons will allow them to conduct precise, long-range naval surface fire support for land strikes; ship self-defense against cruise and ballistic missiles; and surface warfare to deter enemy vessels. The Navy’s near-term goal is a 20- to 32-megajoule weapon that shoots a distance of 50 to 100 nautical miles.

To achieve this, the Navy is moving ahead with the EM Railgun programme’s next phase: to develop thermal management systems for both the launcher and pulsed power to facilitate increased firing rates of up to 10 rounds per minute. Toward this end, BAE and General Atomics have been contracted to begin concept design of a next-generation thermally managed launcher.
“The next phase of the development effort is to demonstrate the ability to operate at a firing rate of significant military utility,” Ellis said.

Additionally, ONR awarded contracts through Naval Sea Systems Command to General Atomics, BAE Systems and Raytheon Co to develop a pulsed power system capable of meeting the firing rate goal.

Various new and existing ship platforms are currently being analysed for future integration.

US warships, armed with a 127 mm gun, can currently only reach targets about 17 miles (20 km) away. Reports add it will take a further five to 10 years before the railgun is weaponised and ready for shipboard use.