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Last Updated: April, 2018

Japan does not have a ballistic missile development program, but its advanced space program includes a number of technologies that could potentially be adapted to create long-range missiles. [1] Japan’s rockets are primarily used to launch satellites into space. [2]

Japan is steadily improving its capability in the area of ballistic missile defense, and partners with the United States to research, develop, and deploy ballistic missile defense systems (BMD). Due to the persistent threat posed by North Korea, Japan is one of the most active participants in the field of BMD. Tokyo has deployed a multi-layered missile defense system consisting of the Aegis system and the Patriot Advanced Capabilities-3 (PAC-3) system. Japan is a member of the Missile Technology Control Regime (MTCR), and participated in drafting the Hague Code of Conduct Against Ballistic Missile Proliferation (HCOC). [3]

Missile Defense Capabilities

Aegis System

The Aegis system is a sea-based and land-based midcourse missile defense system, intended to intercept missiles before they reach the terminal phase of their flight. The Aegis system features the Standard Missile-3 (SM-3) Block IA, a three-stage missile with a range of 1000km, designed to intercept a short to intermediate-range ballistic missile in space.

The sea-based Aegis component includes two Aegis destroyer classes: the older Kongo-class and the upgraded Atago-class. Japan, in cooperation with the United States Missile Defense Agency, has conducted four sea-based Aegis System flight tests. Japan became the first country other than the United States to succeed in intercepting a mock missile with the Aegis system in December 2007. [4] Japan’s most recent test was conducted on 28 October 2010 from the Kirishima, Japan's fourth destroyer equipped with the Aegis BMD system, which successfully intercepted a mock ballistic missile.

With this successful test, the Ministry of Defense completed the deployment of all four Kongo-class Aegis-equipped destroyers (Kongo, Chokai, Myoko, and Kirishima) armed with SM-3 Block IAs by April 2011, as originally scheduled. [5]

Japan’s 2010 National Defense Program Guideline called for the modernization of the sea-based Aegis system. It announced that Japan will increase the number of Aegis-equipped destroyers with interceptor missile equipment from four to six. [6] The initiative to upgrade two Atago-class destroyers (Atago and Ashigara) began shortly thereafter and continued into 2017. The upgrades will allow the deployment of the new SM-3 Block IIA missile onto both classes of Aegis destroyers. Moreover, the Defense Ministry decided to procure two more Aegis equipped destroyers with BMD capabilities using the FY2015 and FY2016 budgets to increase the total fleet of Aegis destroyers to eight ships by FY 2020. [7]

The SM-3 Block IIA, a more advanced missile interceptor, was jointly developed by the United States and Japan for deployment in 2018. [8] It is designed for use with both Japan’s sea-based Aegis system and the land-based Aegis Ashore system. The United States aims to deploy the SM-3 Block II A in the United States, Europe and elsewhere to field a comprehensive missile defense system by 2020. [9] In order for the United States to deploy the system to third-party nations, Japan eased its self-imposed “Three Principles on Arms Exports” barring the export of materiel. In April 2014, Japan adopted the new “Three Principles on Transfer of Defense Equipment and Technology,” since the transfers would contribute to Japan's national security and global peace and stability. The new policy enabled Japan and the United States to more comprehensively cooperate on missile defense systems. [10]

To supplement the existing sea-based Aegis systems, Japan procured two land-based Aegis Ashore batteries in December 2017 that are expected to be operational by 2023. [11] Like the sea-based Aegis systems, the Aegis Ashore system is an upper-tier system designed to intercept missiles before their re-entry into the atmosphere. The land-based Aegis system is compatible with the sea-based Aegis system and, together, will allow for a greater protected area and for more opportunities to intercept an incoming short- to intermediate-range missile. [12]

Patriot System

Patriot, or PAC-3, is a ground-based lower-tier missile defense system intended to intercept missiles in their terminal phase. It is therefore designed to engage with missiles following their re-entry into the atmosphere, if the upper-tier, mid-course Aegis system fails to intercept them.

The United States first deployed a ground-based PAC-3 unit at Kadena Air Base in Okinawa in October 2006 following North Korea's first nuclear test and its July 2006 missile launches. [13] In 2010, the NDPG called for the deployment of additional PAC-3 interceptor missiles to supplement the three air defense missile groups already in Japan. [14] By 2013, in response to ongoing North Korean missile tests, the Japanese government spent an additional $681 million on the acquisition and modernization of its missile defense technology. [15]

The location of the land-based Patriot systems changes based on Japan’s perceptions of the threat from North Korea. Japan has relocated the mobile PAC batteries depending on where North Korea flies its missile test launches. For example, in mid-2017, the DPRK threatened to fly its missiles over western Japanese territory en route to the U.S. territory of Guam. In response, the Japanese Ministry of Defense announced in August 2017 that it would relocate four PAC-3 systems from eastern Japan to the western prefectures of Hiroshima, Kochi, Shimane and Ehime. [16] However, later that month on 28 August and again on 15 September, North Korea flew its Hwasong-15 missile over the northern Japanese island of Hokkaido. This prompted Japan to again reconsider the location of its PAC-3 systems and, within days after the 15 September test, the Ministry of Defense deployed a PAC-3 battery to an Air Self-Defense Force base in Hakodate, Hokkaido. [17]

Tokyo has also enhanced its cooperation with the United States on advanced PAC-3 missile interceptors. Japan's Air Self-Defense Force (JASDF) conducted its first successful multinational tests of the PAC-3 interceptor at White Sands Missile Range in New Mexico, one on 17 September 2008 and another on 17 September 2009. The second test involved a Japanese-produced interceptor missile. [18] Since then, Japanese Self-Defense Forces have engaged in multiple cooperative tests. By coincidence, Japan and the United States conducted their first PAC-3 anti-missile drill at a U.S. base on Japanese territory just hours after North Korea’s test launch of the Hwasong-15 flew over Hokkaido in August 2017. [19]

Space Launch Vehicles

In recent years, Japan has become more assertive in its space activities. On 20 June 2007, Japan's ruling coalition submitted the "Basic Space Bill" to the House of Representatives, subsequently passed as the Basic Space Law on 27 August 2008. The law lifted the previous ban on the Japanese government's use of space for defensive purposes. Under the 2008 Basic Space Law, Japan’s Self Defense Force (SDF) can manufacture, possess and operate its own satellites to support its defensive military operations, including ballistic missile defense.

As a result, the SDF is pursuing advanced satellite technology, specifically reconnaissance satellites, early warning satellites, and tracking and communications satellites. The Japan Aerospace Exploration Agency (JAXA) uses its two rocket-launch complexes, the Tanegashima Space Center and the Uchinoura Space Center, to send satellites into orbit. The most recent Basic Plan for Space Policy in 2015 discusses development and deployment plans for a variety of optical, radar, meteorological and communications satellites. Japan successfully launched the smallest rocket ever to deliver a satellite into orbit on 3 February, 2018. [20]

In 2013, Japan unveiled the Epsilon, an advanced three-stage, solid fuel rocket that can be used to launch large satellites into orbit. After its initial launch in 2013, Japan utilized the Epsilon to launch two satellites on December 20, 2016 and January 18, 2018. The Epsilon is a descendent of the M-V rocket, a large, solid-propellant rocket that was retired in 2006. Compared to the M-V, however, the Epsilon is more sophisticated, efficient and cost-effective. Its standard configuration is a three-staged solid-fuel rocket, but it also has an optional liquid-propellant fourth stage. [21] Some experts suggest that Epsilon’s new capabilities, such as its ability to use solid-propellant and its shortened pre-launch timeline, could allow it to be converted to an ICBM. [22] Numerous technological modifications would be necessary, however, specifically in the area of guidance and payload delivery. The political aversion to offensive weapons would also be a major constraint with any potential Epsilon ICBM conversion.

[1] Japan Missile Program, Globalsecurity.org.
[2] Japan Missile Program, Globalsecurity.org.
[3] "Status of Japan's Participation in Treaties and Organizations," www.nonproliferation.org.
[4] Reiji Yoshida, "PAC-3 Missiles Debut at Iruma Air Base," The Japan Times, 31 March 2007.
[5] Mari Yamaguchi, "Japan Cabinet OKs $147 Billion Extra Budget," The Associated Press, 15 January 2013, www.lexisnexis.com.
[6] "Japan Succeeds in Testing Domestically Made PAC-3," Jiji Press Ticker Service, 17 September 2009, in LexisNexis, www.lexisnexis.com.
[7] “The ICBM Underlay,” Missile Defense Advocacy Alliance, 10 October, 2017, www.missiledfenseadvocacy.org; Defense of Japan 2017, www.mod.go.jp.
[8] Richard Scott, "Japan Joins U.S. to Make First Sea-Based BMD Interception," International Defence Review, 1 January 2008.
[9] Bureau of Arms Control, Verification, and Compliance, “United States European Phased Adaptive Approach (EPAA) and NATO Missile Defense,” Fact Sheet, U.S. Department of State, May 3, 2011, www.state.gov.
[10] Japanese Ministry of Defense, "Defense of Japan 2010: Annual White Paper," www.mod.go.jp.
[11] “Japan to expand ballistic missile defense with ground-based Aegis batteries,” Reuters, 18 December, 2017, www.reuters.com.
[12] Mari Yamaguchi, “Japan to buy Aegis Ashore missile defense system,” Defense News, 19 December 2017. www.defensenews.com.
[13] Japanese Ministry of Defense, "Summary of National Defense Program Guidelines, FY2011," www.mod.go.jp.
[14] Japanese Ministry of Defense, "Summary of National Defense Program Guidelines, FY2011," www.mod.go.jp.
[15] "Japan Approves New Defense Policy that Permits Action with Allies," Global Security Newswire, 1 July 2014, ww.nti.org; Masami Ito, "Government goes ahead with easing arms export ban," The Japan Times, 28 December 2011, www.japantimes.co.jp.
[16] “PAC-3 systems deployed in case missiles stray off course to Guam,” The Asahi Shimbun, 12 August 2017, www.asahi.com.
[17] “PAC-2 interceptors relocated to Hakodate due to North Korean missile threat,” The Japan Times, 19 September 2017, www.japantimes.co.jp.
[18] Kiyoshi Takenaka and Nobuhiro Kubo, "Japan relaxes arms export regime to fortify defense," Reuters, www.reuters.com.
[19] “Japan holds PAC-3 military drill in U.S. base hours after North Korea’s missile launch,” Reuters, 28 August 2017, www.reuters.com.
[20] “Japan successfully launches world’s smallest satellite-carrying rocket,” Japan Times, 4 February 2018. www.japantimes.co.jp.
[21] “Epsilon Launch Vehicle,” Japan Aerospace Exploration Agency, 18 January 2018, www.global.jaxa.jp.
[22] Doug Tsuruoka, “Can Japan’s Epsilon rocket be used as an ICBM?” Asia Times, 23 January 2018, www.atimes.com; Saadia M. Pekkanen, “The Next-Generation Rockets that Japan Could Use to Protect Itself,” Forbes, 17 December 2016, www.forbes.com.

Get the Facts on Japan
  • Possesses a reprocessing plant capable of separating eight tons of Pu per year
  • State party to the BWC, but experimented on human subjects with biological agents during WWII
  • Possesses technological capabilities which could be adapted for the production of long-range ballistic missiles

This material is produced independently for NTI by the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies at Monterey and does not necessarily reflect the opinions of and has not been independently verified by NTI or its directors, officers, employees, or agents. Copyright 2018.