By Ha Er-rui | 2026-04-02

Japan's Aegis System Equipped Vessel (ASEV) program has made significant progress in system integration, successfully completing its first live-target tracking exercise.

Aegis is a US-made integrated naval weapon system. The ASEVs, when completed, will carry Aegis and provide advanced missile defense at sea.

On March 17 and 19, the Japan Maritime Self-Defense Force (JMSDF), in collaboration with the US Department of War and the Missile Defense Agency (MDA), conducted Japan Flight Test Experiment Aegis Weapon System (JFTX-01).

The exercise, held at Lockheed Martin's testing facility in Moorestown, New Jersey, marked the first successful integration and target tracking using the new SPY-7 radar, which the ASEVs are supposed to carry.

The verification was part of a joint land-based integration testing program that has been under way since last September. This program is a collaborative effort between the MDA and Lockheed Martin, with support from the US Navy.

Lt. Gen. Heath Collins, director of the MDA, noted in a news release that the US-Japan collaboration on ASEV development "will provide Japan with the latest Ballistic Missile Defense capabilities and significantly bolster their defense against regional missile threats."

Parallel to the testing in the United States, Japan's Ministry of Defense confirmed on March 20 that construction of the lead ASEV is proceeding on schedule. Construction of the vessel began last July in Nagasaki. Construction of the second ASEV began in February in Yokohama.

Japan intends to procure two ASEVs.

From land to sea

In response to North Korea's frequent missile tests, Tokyo originally planned to install two Aegis Ashore sites on land. However, the government scrapped that plan in December 2020 because of local safety misgivings about interceptor boosters.

As a sea-based alternative, Japan is building two massive maritime platforms designed to serve as the backbone of its ballistic missile defense architecture. These ships will provide round-the-clock missile surveillance coverage across Japan, specifically engineered to intercept high-altitude threats launched on "lofted trajectories" from the sea.

The ASEV is a maritime giant and displaces 12,000 tons with a length of 190 meters. This scale makes the vessel approximately 1.7 times larger than the US Navy's latest Arleigh Burke-class (Flight III) destroyers. It provides a stable platform for advanced radar operations in heavy seas.

The ship's mammoth hull supports the SPY-7 multifunction radar and an expanded 128-cell Vertical Launch System (VLS). In comparison, existing Japanese vessels have 96-cell VLS's.

The 128-cell VLS will house Standard Missile-3 Block IIA interceptors and Tomahawk cruise missiles, supporting Japan's emerging counterstrike capability.

In the recent US testing, engineers used a four-face antenna configuration identical to the final ship design to collect high-fidelity data. The SPY-7 radar array used in the setup stands 4.3 meters tall.

Chandra Marshall, vice president of Multi-Domain Combat Solutions at Lockheed Martin, said the "successful completion of the first live-target tracking exercise of the ASEV system affirms that our integrated Aegis system is ready to detect, track and engage targets." It also showcases Lockheed Martin's ability "to deliver rapid solutions in partnership with the Department of War and Japanese allies," she added.

Relief for standard Aegis destroyers

Operational flexibility is a core objective of the program. The ASEV is intended to relieve the JMSDF's standard Aegis destroyers of continuous ballistic missile defense patrols, so they can take on broader maritime security missions across the Indo-Pacific.

This specialized capability has led to a surge in procurement costs. The Ministry of Defense now estimates the total investment for the two planned ASEVs at 783.9 billion JPY (approx. $5.23 billion), almost 1.6 times the initial 2020 projections, according to Naval News.

According to the current schedule, commissioning of the two ASEVs is planned for March 2028 and March 2029.