TOKYO -- Japan will adopt a system in 2020 that allows its defense forces to simultaneously share information on enemy missiles with the U.S. military, enabling the allies to better track and destroy them.
Cooperative engagement capability, or CEC, is already used by America's armed forces to see what each other sees. Currently, even Japanese ships equipped with the Aegis missile defense system can shoot down missiles only after they are visible on their own radar. CEC will integrate Japanese forces into the U.S. military's radar and sensor network.
The Japanese Maritime Self-Defense Force's seventh and eighth Aegis-equipped destroyers, set to enter service in 2020 and 2021, will feature CEC.
The Defense Ministry is also considering adding the capability to the E-2D early-warning and surveillance aircraft it plans to deploy as early as next year, as well as to land-based Aegis Ashore installations that it aims to bring online in fiscal 2023.
Japan's ballistic-missile defenses now rely on U.S. early-warning satellites to detect missiles shortly after launch. Aegis ships and the Air Self-Defense Force pick up the tracking from there and supply the information to American forces.
The small time lag involved in relaying this data keeps Japan's Aegis ships from intercepting missiles they cannot pick up on their own radar.
CEC enables information on a missile's location, direction and speed to be shared among ships and aircraft simultaneously. This direct link will sharply increase the range that Japanese forces can monitor.
CEC will be central to the plans for integrated air-and-missile defense capabilities that the Defense Ministry is drawing up.
Aegis vessels and Patriot Advanced Capability-3 interceptors are designed to shoot down ballistic missiles, rather than threats such as drones and cruise missiles that can fly lower and change direction, making them harder to track. Once Japan's Aegis ships are equipped with SM-6 missiles -- which feature built-in targeting radar -- they will be able to take advantage of CEC to intercept cruise missiles as well.
Employing CEC will link Japanese and U.S. forces more closely, strengthening their alliance. Japan envisions using its ships to intercept missiles headed for U.S. Navy vessels, and vice versa.
But some worry the U.S. could use data shared by Japan via CEC for offensive operations outside the boundaries of collective self-defense -- a controversial topic under Japan's pacifist constitution. And the more the two countries integrate their defense operations, the greater the risk that Japanese forces will be targeted for attack along with the U.S. military.