The Standard for Missile Defense Cooperation
Over the weekend, the United States and Japan completed the first intercept test of the Standard Missile-3 (SM-3) Block IIA. SM-3 Block IIA is being developed cooperatively by the United States and Japan to defeat ballistic missiles up to the intermediate-range and features several upgrades that improve upon previous variants. This test not only demonstrates a significant increase in U.S. missile defense capability but an outstanding example of cooperation with a critical ally. The SM-3 Block IIA project represents the best case study of equal funding and engineering on a missile defense system that will benefit both the United States and Japan.
The threat from North Korea’s ever-increasing ballistic missile and nuclear arsenals has been the impetus for Japan’s interest in missile defense. Over the years, debris from Pyongyang’s missile tests has flown over or near Japan’s territory. Notable examples have included the 1998 test of the Taepong-1, which flew across Japan and into the Pacific, and a 2016 test in which debris from a Nodong medium-range missile landed within Japan’s economic exclusion zone.
Pyongyang is believed to field numerous short- and medium-range ballistic missiles capable of reaching much of Japan’s territory. These missiles have been rigorously tested, and their road-mobility increases launch area uncertainty, reducing the warning time prior to launch. Among these capabilities is the Musudan intermediate-range ballistic missile, which has a range of around 3,500 km. If launched at a high arch trajectory, the Musudan can strike targets in Japan at very high speeds, increasing the challenge of missile defense intercept. North Korea tested the Musudan eight times in 2016, with at least one test being successful. These tests represented a significant leap forward in North Korea’s ballistic missile technology, highlighting the critical need to continue improving missile defense capabilities to stay ahead of the progressing missile threat. North Korea has also maintained that it is ready to test an intercontinental ballistic missile, debris from which could once again threaten Japan’s territory.
With the North Korean threat in mind, the United States and Japan began co-development of the SM-3 Block IIA interceptor in 2006. Planned improvements to the SM-3 Block IIA missile include a new 21-inch diameter rocket that will increase velocity, range, and operation time. The interceptor’s enhanced kill vehicle will have heightened seeker sensitivity and increased divert capability. Tests of the SM-3 Block IIA will take place through its scheduled deployment in 2018. The interceptor is expected to be fielded on Aegis BMD 5.1 ships and with the Aegis Ashore system, including the planned site in Poland.
Japan has worked closely with the United States to become a world leader in missile defense. The country already fields Patriot/PAC-3 batteries and Aegis BMD ships, aboard which Tokyo plans to deploy the new SM-3 Block IIA interceptor.
Japan has also considered adding additional capabilities to create a more robust, layered missile shield. Future additions might include the Aegis Ashore and Terminal High Altitude Area Defense (THAAD) systems. Late last year the Japanese Defense Ministry initiated a study on whether to adopt THAAD and at the beginning of 2017, Defense Minister Tomomi Inada visited Andersen Air Force Base in Guam and inspected the THAAD battery deployed there. Should Tokyo move forward with the decision, THAAD would add an upper-tier layer of defense that would complement Japan’s current Aegis destroyers and PAC-3 systems.
Secretary of Defense James Mattis highlighted the importance of Japan as a U.S. ally, as well as the severity of the North Korean threat when he chose to first visit the Asia-Pacific region upon taking leadership of the Pentagon. The United States must continue to cooperate with Tokyo and support Japan’s efforts to bolster its missile defense capabilities. A critical partnership that could serve as an example of best practice for dealing with ballistic missile threats around the world.