According to the Japanese news agency Jiji Press, Japan’s Ministry of Defense (MoD) has decided that Mitsubishi Heavy Industries (MHI) will be in charge of building the first ASEV. Japan Marine United (JMU) will build the second one. In terms of weapon systems, The ASEV vessels will feature an impressive 128 Vertical Launch System (VLS) cells. These will be loaded with SM-3 Block 2A jointly developed by Japan and the United States. SM-3 is a surface-to-air missile used to destroy short- to intermediate-range ballistic missiles. The SM-6 is also mentioned as a missile type to be deployed by the ASEV vessels. It can perform anti-air warfare (including against cruise missiles and hypersonic weapons), ballistic missile defense and anti-surface warfare.
Previous reports have also mentioned the inclusion of a domestically produced upgraded Type 12 Surface to Surace Missile (SSM), but this one is expected to be mounted on top-side (deck-mounted) launchers rather than in the VLS. In addition, according to the MoD documents, in the future, Japan is also looking at fitting the ASEV with the Glide Phase Interceptor (GPI), which is currently under competition in the United States. The radar to be installed is the Lockheed Martin SPY-7, originally procured for Aegis Ashore, and the version of the Aegis system is the J7.B, which has been modified to integrate the SPY-7 into Baseline 9 (BL9).
According to media reports from January 2023, the ASEV will also feature the Cooperative Engagement Capability (CEC). This will allow both vessels to share radar information with JMSDF’s Maya-class DDGs and US Navy assets in real time. Naval News also learned from official sources during DSEI Japan 2023 that Japan’s Acquisition, Technology & Logistics Agency (ATLA) is planning to fit the “United Combined Radio Antenna (UNICORN)” on the ASEV. The UNICORN system is currently fitted aboard the FFM frigates of the JMSDF.
Original Japanese MoD plans called for the ASEV to be specialized ballistic missile defense (BMD) vessels, with some compromises such as slower speeds and an area of operation limited to coastal waters. However, to answer China’s military buildup, the plan was revised into a much more multifunctional vessel: ASEV now would take the form of a larger version of a regular Aegis destroyer. As such, the vessel is expected to be capable of dealing with ballistic missiles and hypersonic weapons, as well as cruise missiles, aircraft, and even submarines.
In the FY2023 defense budget, the MoD allocated 220.8 billion yen ($1.568 billion) for ASEV design and acquisition costs, including engines. The ASEV will respond to North Korean ballistic missiles and hypersonic weapons, relieving the burden of the Aegis destroyers of the JMSDF. These destroyers would in turn be more readily available to respond to Chinese military forces in the East China Sea.
Japan’s MoD has stated that the first ASEV will be commissioned by FY2027 and its sistership by FY2028. According to a report in the Japanese newspaper Mainichi Shimbun, building of the first ASEV will start in FY2024.