The US State Department has approved a proposed sale to Japan of equipment and services to support its program to develop hypersonic weapons.
In an announcement on 10 March, the Defense Security Cooperation Agency (DSCA) said the possible sale to Japan of unspecified equipment and support of its indigenous Hyper Velocity Gliding Projectiles (HVGP) program, will cost an estimated $318.8 million.
The items requested included test preparation, test, and transportation support as well as coordination meetings in the United States and Japan.
Japan’s HVGP is one of two hypersonic weapons system it is developing. This is essentially a boost-glide weapon with a solid-fuel rocket engine booster that will launch it warhead payload to a high altitude before separation, where it will then glide to its target using its altitude to maintain high velocity until impact.
The Japanese Acquisitions, Technology and Logistics Agency (ATLA) had previously announced it had conducted a pre-launch test of a HVGP in California in March and April 2024, stating that the activity was to validate the measurement units for an actual test.
Initial deployment of the HVGP is scheduled for 2026, with Mitsubishi Heavy Industries (MHI) selected to the manufacture of the system. It will be a land-based mobile system that will be launched from a truck, with an initial Block 1 variant to have a range of 500km.
There are plans for future increments of the HVGP to have its range extended to as far as 3,000km around the 2030 timeframe, and it will serve alongside a second type of hypersonic weapon Japan is developing.
This is currently known as the Hypersonic Cruise Missile and will be powered by a scramjet engine and appears similar to a typical missile, albeit one that cruises at a much higher speed while capable of traveling at long ranges.
Both hypersonic systems will be equipped with warheads for anti-ship and land-attack warheads, with the anti-ship payload having an armour-piercing warhead designed specifically for penetrating the deck of an aircraft carrier.
Meanwhile, the land attack warhead will utilise multiple high-density, explosively formed projectiles, or EFP, for area suppression.
Japan also plans to put into service a network of satellites to enable continuous positioning for its self-defence forces, which will enable it to provide continuous navigation data without relying on foreign satellites.
It will enable its stand-off weapons systems like its hypersonic missiles to navigate using satellite navigation, with both hypersonic systems planned to have an inertial navigation system as backup.
Terminal guidance is expected to be achieved using radio-frequency imaging converted from doppler shift data — which ATLA previously said will be able to identify stealthy naval targets in all weather conditions — or an infrared seeker capable to discriminating specific targets.