Japan’s Acquisition Technology & Logistics Agency (ATLA) has offered the first look at damage to a target ship after it was hit by projectiles fired from a prototype electromagnetic railgun in testing earlier this year. Japanese authorities say valuable data and experience were gleaned from the demonstration, which will feed into its continued push toward an operational railgun capability. This is an area of development where the U.S. Navy notably halted work in the early 2020s, despite having seen promising progress, due to significant technological impediments.
ATLA provided additional details about the at-sea railgun testing that took place this past summer during a presentation at its annual Defense Technology Symposium, which opened earlier this week. For the tests, the prototype weapon system was installed on the rear flight deck of the JS Asuka, a one-of-its-kind 6,200-ton-displacement testbed warship belonging to the Japan Maritime Self-Defense Force (JMSDF). Pictures of the railgun onboard Asuka first began to emerge in April. ATLA released an initial batch of imagery from the at-sea tests, along with a brief statement about the results, in September.
The prototype railgun used in the testing is an evolution of a design that ATLA has been developing since the mid-2010s. That work has included previous live-fire testing at facilities on land, as well as at least one earlier at-sea test that did not involve shooting an actual target vessel.
Railguns, in general, use electromagnets instead of chemical propellants to fire projectiles at very high velocities. Dart-shaped projectiles, each with four fins at the rear and no warhead, were fired during the at-sea tests earlier this year. The projectiles were initially held inside a sabot that broke apart after leaving the muzzle. There was also a metal armature at the rear that served to push the projectile in the sabot down the barrel, which fell away after firing.
A tug-like ship was used as the target for the railgun installed on the JS Asuka. The target vessel was moving during at least some of the test shots, but under tow behind another ship rather than its own power. It was struck multiple times, with the cross-shaped impact points showing the fin-stabilized projectiles flew in a stable manner, as seen in the images at the top of this story and below.
In addition to level shots at the target ship, the railgun was fired at a 45-degree upward angle to provide an opportunity to gather data on the basic ballistics of the weapon and round combination.
Operators aimed the railgun remotely using a camera mounted under the barrel. An additional high-speed camera and a small radar were also positioned on JS Asuka‘s flight deck to collect additional data. A drone filmed the testing from above. When ATLA first released imagery from the testing back in September, TWZ highlighted the presence of what was likely a small radar array, as well as electro-optical and/or infrared cameras, which has now been confirmed.
ATLA says that the testing also provided valuable new experience regarding the installation and operation of a railgun on an actual naval vessel. Of course, an operational naval railgun would likely be far more deeply integrated into a warship compared to the test arrangement on JS Asuka. A more traditional naval installation on any ship would require finding sufficient space above and below deck for the railgun and its associated systems, as well as making a host of other necessary modifications, which could be costly and time-consuming.
Otherwise, ATLA continues to work to improve various key underlying technologies as part of its ongoing railgun development efforts, including when it comes to power and cooling, as well as general wear and tear. Japanese authorities say they have now been able to demonstrate a barrel life of more than 200 rounds when firing projectiles at around 2,300 meters per second. As of 2023, ATLA had reportedly been able to fire projectiles from prototype railguns at around 2,230 meters per second and had said it was working toward a barrel life of 120 rounds.
The wear on barrels from the sustained firing of projectiles at very high speeds is one of a number of long-standing challenges for railguns, in general. A worn-out barrel can lead to the loss of range and accuracy, as well as increase the risk of a catastrophic failure.
Railguns also have significant power generation and cooling requirements, which have, in turn, historically made them very physically bulky. The installation on JS Asuka included four shipping containers full of additional systems and equipment to help meet those needs.
Kazumi Ito, principal director of the equipment policy division at ATLA, said his country’s railgun efforts were “progressing,” but acknowledged “various challenges,” while speaking through an interpreter at a panel discussion at the DSEI Japan 2025 exposition earlier this year,