The Navy has chosen joint high speed vessel USNS Trenton (JHSV 5) as the first ship to fire its high tech electromagnetic railgun at sea.

During tests next summer at Eglin AFB, Fla.,’s maritime test range, the service will fire a GPS-guided hypervelocity projectile from the gun and engage a floating, static, over-the-horizon target, said Capt. Mike Ziv, directed energy and electronic weapon systems program manager.

The electromagnetic railgun on display at the Naval Future Forces Science and Technology Expo. Photo: Defense Daily.
The electromagnetic railgun on display at the Naval Future Forces Science and Technology Expo. Photo: Defense Daily.

“This is a significant event, but it’s also something that’s a key learning point for us,” he told reporters April 14 at the Navy League’s Sea Air Space exposition.

For the first tests, the railgun will fire at a target about 25 to 50 miles away from the Trenton, he said. A total of 20 shots will be fired: 15 “ramp up” shots to understand the behavior of the system at sea, and five dedicated test shots at the target.

The JHSV was chosen as the test vessel because of its ability to house modular, containerized systems without needing to modify the ship, he said. It has a large flight deck on which to mount the gun, as well as a large mission bay that can accommodate other systems associated with the weapon.

The Office of Naval Research (ONR) has partnered with BAE Systems [BA] to develop the railgun and hypervelocity projectile. The Navy began designing the gun mount last April and will start detailed design soon, Ziv said.

Unlike traditional guns—which use chemical propellants to fire a bullet— the railgun uses electromagnetic energy to accelerate a sliding metal conductor between two rails, firing a projectile at Mach 6 speeds, according to information from ONR.

The railgun can be employed for a range of missions, including anti-surface warfare, anti -aircraft warfare and cruise and ballistic missile defense.

“The real advantage really comes down to cost per engagement,” Ziv said. “This is a technology where we’re engaging the threats at similar probabilities of kill for a cost that’s about two orders of magnitude less.” For instance, the Navy may one day be able to destroy oncoming enemy missiles with a blast from the rail gun instead of having to having to delve into its own missile stocks to intercept them.   

 It also eliminates the need for the explosive propellants on a ship, simplifying the logistics tail and increasing safety on a vessel.

An operational electromagnetic railgun could be fielded as early as the mid-2020s, but work is still needed to be done to develop the gun itself as well as the high-velocity projectile fired from it. The Navy is also in the process of analyzing which ships have the space and power necessary to house the massive weapon, which requires an enormous amount of electricity during a short time. The system releases a current of about 6,000-12,000 volts during a 10 millisecond time frame, Ziv said.

“We’ve looked at ships as small as a DDG-51s,” he said. “It takes something of that kind of size. This isn’t something that you can put on [the littoral combat ship].”

 The current school of thought is to equip destroyers and cruisers with the weapon, Ziv said. The service currently is conducting a study to evaluate the Zumwalt-class DDG 1000’s suitability. The vessel’s integrated power system—which generates electricity used to power its propulsion, combat systems, computers and other systems—make it an especially promising candidate. General Dynamics [GD] Bath Iron Works constructs the DDG-1000.

“From a space, weight and power perspective, it meets the requirements,” he said. “It is the ideal platform.” However, the Navy must evaluate the risks of putting the railgun on the DDG-1000 and develop ways to mitigate them before moving forward, he said.  

The final ship of the class, USS Lyndon B. Johnson (DDG-1002), is being eyed as the first vessel to be equipped with the railgun, Vice Adm. William Hilarides, the chief of Naval Sea Systems Command (NAVSEA), said in February. Installation of the gun would occur after the vessel’s delivery to the Navy in 2018.