Japan successfully tests electromagnetic railgun at sea with record projectile speed

The railgun, described as the most advanced of its kind in the world, was installed on the experimental ship Asuka (ASE 6102). Supporting equipment was placed inside four 20-foot containers, including one housing a power generator and three containing capacitor banks with a total capacity of around 15 MJ.

The target for the tests was the retired tug ex-YT 68, which was towed in motion rather than anchored. According to ATLA, the projectiles achieved a muzzle velocity of approximately 2,500 m/s, equivalent to Mach 7.35 or about 9,000 km/h.

For comparison, Armour Piercing Fin-Stabilised Discarding Sabot (APFSDS) rounds fired from the Rheinmetall 120 mm L/55 tank gun of the Leopard 2 reach 1,750 m/s. The Japanese railgun, however, has a much smaller 40 mm calibre, firing 320 g projectiles around 16 cm in length.

The kinetic energy generated by such a projectile is about 1 MJ, comparable to that of a 1,000 kg car travelling at 140 km/h. ATLA’s demonstration builds on the weapon’s first public unveiling in April this year, marking a significant step in Japan’s railgun development programme.

Electromagnetic railguns operate using two parallel rails between which a conductive armature is placed. When a high-intensity current—reaching several million amperes—is passed through the circuit, a strong magnetic field of around 10 Tesla is generated. Lorentz forces then accelerate the armature and projectile to extreme speeds in just 10 milliseconds.