KAUAI, Hawaii -- The possible impact of electromagnetic waves from land-based Aegis Ashore missile defense systems requires careful evaluation despite U.S. guarantees that the systems do not affect civilian communications or human health.
An Aegis Ashore test complex here was opened to Japanese news organizations for the first time on Jan. 10, local time (Jan. 11, Japan time) on the occasion of a visit by Japanese Defense Minister Itsunori Onodera. This came in the wake of a decision by the Japanese government in December last year to buy Aegis Ashore systems from the United States to counter the growing threat posed by North Korea's missile and nuclear weapons programs.
The complex is inside the Pacific Missile Range Facility (PMRF) in Kauai, the world's largest missile test facility with a total area of about 8.3 square kilometers. It is located on the eastern shore of the island, about a 50-minute car ride from Lihue, Kauai's largest town, and is surrounded by forests and farmland.
The Aegis Ashore system shown to the Japanese media comprised a cream-colored building with walls about 20 meters high. An octagonal antenna was affixed to the upper part of the wall and radar monitored activity in all directions. The structure had three layers of doors including in the fence, and mobile phones were prohibited inside.
Lt. Gen. Samuel A. Greaves, director of the U.S. Missile Defense Agency (MDA) who traveled from Washington, greeted Onodera at the PMRF and promised to extend all-out support for Japan's implementation of Aegis Ashore systems. For the U.S., Japan is not only an ally, but also a prized customer enthusiastic about buying state-of-the-art defense equipment.
Onodera said that Tokyo "hoped to confirm the system's performance as well as its possible impact on surrounding areas, and explain the need for it to the Japanese public."
The test complex successfully intercepted a missile for the first time in December 2015, and U.S. forces deployed the first operational Aegis Ashore system in Romania in May 2016, citing the need to counter Iran's ballistic missiles. Another system is set to be installed in Poland by the end of this year.
During the visit, Onodera asked Greaves if there was any impact on communications or human health from the electromagnetic waves emitted by Aegis Ashore's high-performance radar, as well as about noise. The MDA director replied that there were absolutely no such problems.
Although the radar was in operation when Onodera visited, it was so quiet outside the building that even the songs of wild birds could be heard. Still, there were radiation hazard warning signs on the complex's walls and the 2-meter-high fences that surrounded it. Noise was frequently heard on video recorded by the Mainichi Shimbun at the site, which may have been caused by electromagnetic waves.
The Japanese government plans to deploy an Aegis Ashore system each to Ground Self-Defense Force (GDSF) training areas in the city of Akita and the Yamaguchi Prefecture city of Hagi. However, since the system has an extremely short operational history, the government will be required to cautiously assess its impact on nearby people and communications.
In the meantime, the cost and timing of installing Aegis Ashore systems remain unclear even though the Cabinet of Prime Minister Shinzo Abe has approved their acquisition. The Defense Ministry has explained that it will cost some 100 billion yen to introduce just one of the systems. However, designing facilities to house them and the selection of radars have no yet shifted into full swing.
Onodera inspected a test complex for SPY-6, radar the U.S. is currently developing. The Defense Ministry intends to equip its Aegis Ashore batteries with SM-3 Block IIA interceptor missiles in fiscal 2021. SM-3 Block IIA is an improved version of the SM-3. But the current radar's ability to track missiles is insufficient to make full use of the SM-3 Block IIA's range, which is about twice that of the SM-3.
However, if Japan chooses the SPY-6 radar, it could further increase the cost of installing Aegis Ashore. Moreover, a U.S. government source says that the United States will likely introduce SPY-6 radars in 2023 at the earliest, meaning that if Tokyo selects the SPY-6 for its high performance, its deployment of Aegis Ashore could be delayed.