Japan has unexpectedly but temporarily suspended deployment of the U.S.-made Aegis Ashore ballistic missile defense system being constructed to defend the country against North Korean ballistic missile attacks.
The announcement was made Monday by Japanese defense minister Taro Kono. He said the suspension was mainly due to unresolved technical issues that will prevent harm to Japan's population. The rising cost of the multi-billion dollar system is also a heavy drain on the country's financial resources now focused on restoring the Japanese economy badly hit by the COVID-19 pandemic.
"I made a decision on Friday to suspend the process... For the time being, Japan will continue to counter (the threat) with Aegis-equipped ships" said Kono.
Kono said the main technical issue is the need to ensure the rocket boosters of the SM-3 Block IIA interceptor missiles that accelerate the missile to supersonic speeds following launch won't hit population centers following separation from the missile. The SM-3 is designed to intercept in space the warheads of North Korea's short- and intermediate-range ballistic missiles.
Kono said efforts to modify the software on the SM-3 Block IIA missiles to ensure correct booster separation have not been successful so far. He admitted expensive modifications to the missile hardware will be needed.
Japan's announcement suspending work on Aegis Ashore appears ill-timed. It comes amid growing military tensions between North and South Korea. North Korea demands the South halt North Korean defectors and their South Korean supporters from sending aerial balloons carrying propaganda material into its territory. On Tuesday, North Korea blew-up the joint liaison office in the border city of Kaesong to prove its readiness to back its threat with force.
Because of its suspension of the Aegis Ashore deployment, Japan will continue to rely on the guided missile destroyers of the Japan Maritime Self-Defense Force (JMSDF) for protection against North Korean ballistic missiles. The JMSDF has seven Aegis-equipped guided missile destroyers: four DDGs in the Kongō class; two DDGs in the Atago-class and one DDG in the Maya-class.
The Aegis Ashore land-based systems were meant to reduce the demands placed on the destroyers and their crews by the missile defense mission. Kono revealed Japan has already spent more than $1.02 billion on the development of the SM-3 Block IIA so far.
This advanced system is being developed jointly by Japan and the United States. The two planned Aegis Ashore systems will cost about $4.1 billion (439 billion yen) for operation and maintenance over the next 30 years.
In December 2017, Japan approved a plan to purchase two Aegis Ashore systems equipped with the AN/SPY-7(V)1 radar system based on Lockheed Martin's LRDR to enhance Japan's self-defense capability against North Korea. The system will control SM-3 Block IIA missiles, but can also guide SM-6 interceptors capable of shooting down cruise missiles.
Installation sites for Aegis Ashore are at a Japan Ground Self-Defense Force training area in Araya District, Akita Prefecture and the Mutsumi training area in Hagi, Yamaguchi Prefecture.
