Japan Ministry of Defense


HOME > Japan Defense Focus > NO.8 DEFENSE POLICY

The Requisite Ballistic Missile Defense

A PAC-3 launcher deployed at Iruma Air Base
A PAC-3 launcher deployed at Iruma Air Base
The world today faces threats from weapons of mass destruction, ballistic missiles, and activities by international terrorist organizations. Under the circumstances, the National Defense Program Guidelines position the making of effective responses to these new threats and diverse contingencies as the primary role of defense force. The guidelines also illustrate the prompt and appropriate efforts the Ministry of Defense (MOD) and the Self-Defense Forces (SDF) should achieve. As one of those efforts, a response to ballistic missiles, which is particularly important, is taken as the subject of the following report.

Concept of BMD Deployment and Operation (Image diagram)

Basic Thinking on Ballistic Missile Defense
In recent years the international community has been engaged in a wide range of efforts to prevent the proliferation of ballistic missiles and weapons of mass destruction. Even so, proliferation is still continuing. When North Korea launched seven ballistic missiles in July 2006, the reality of the danger of ballistic missile attacks was reconfirmed.
    In the light of this situation, the government since 2004 has been working on the introduction of a system for ballistic missile defense (BMD) to further ensure its preparedness to respond to ballistic missile attacks, and it is striving to prepare the system at the early stage. This BMD system, which is designed to intercept incoming ballistic missiles in flight, is the most appropriate type of system for Japan's exclusively defense-oriented policy.
    The BMD system Japan is introducing is based on the concept of multitier defense, with Aegis vessels (SM-3) handling upper-tier interception and Patriot systems (PAC-3) handling lowertier interception. The work involved entails improving the capabilities of the Aegis vessels and Patriot systems being already in the possession of the SDF. To round out this multitier weapon system, sensors detect and track ballistic missiles flying toward Japan, while being effectively linked to the weapons, and thereby the entire system is formulated by command control and communications systems to counter ballistic missiles systematically.

Status of the BMD System's Introduction
In March 2007, MOD and the SDF deployed the Patriot PAC-3 at Iruma Air Base of the Air Self-Defense Force (ASDF), and in November they deployed the system at Narashino Subbase of the ASDF. The goal at present is to build up a system by fiscal 2011 (April 2011 to March 2012) consisting of 4 Aegis vessels (with an added BMD capability), 16 Patriot PAC-3 FUs (fire units, which are the minimum surface-to-air fire units), 4 FPS-5 warning and control radars, and 7 FPS-3 improved type radars, which are linked by command control and communications systems.

Joint Japan-U.S. Missile Development
In 1998 the government, with the approval of the Security Council of Japan, decided to embark on joint technical research with the United States in 1999 for a sea-based upper-tier system. Because it is conceivable that ballistic missiles in the future will be equipped with various countermeasures against the interceptors, the joint research is to design, manufacture trial prototypes, and carry out necessary testing in collaboration between Japan and the United States to provide interceptor missiles with higher capabilities. The research thus far has completed the verification of elemental technologies and confirmed the prospects of solving technical challenges. On this basis, the Japanese and U.S. governments reached agreement in June 2006 on moving forward to joint development, making use of the research results already obtained.

Outline of the Japan-U.S. Joint Development of Advanced Interceptor Missiles for BMD

The Three Principles on Arms Exports
The BMD system now being introduced into Japan consists of improving the capabilities of Aegis vessels and Patriot units now being in Japan's possession and doing other things, and so no conflict with the three principles arises. In the future, however, there is a possibility that the joint Japan-U.S. technological development, which aims at further improving the BMD capabilities, could involve the export to the United States of weapons connected to the BMD as part of the development. In this regard, when the government decided in 2005 to move on to the joint development, it determined that the three principles would not apply, under the condition that a framework for the provision of arms to be exported to the United States be developed through coordination with the United States and that strict control be secured.

Strengthening Japan-U.S. BMD Cooperation
Subsequent to its decision to introduce the BMD system, Japan's efforts have continuously gone into strengthening BMD cooperation with the United States. The Mid-Term Defense Program contains the following statement on measures for strengthening the Japan-U.S. security arrangements: "The government of Japan will strengthen Japan-U.S. cooperative efforts to enhance ballistic missile defense capabilities, and promote cooperation with the United States in the fields of policies, operations, and equipment and technology." In 2004, the then Defense Agency and the U.S. Department of State signed a Memorandum of Understanding on BMD cooperation. In addition, the U.S. forces in Japan deployed a mobilized radar for BMD at Shariki Subbase of the ASDF in June 2006, and they deployed PAC-3 units at Kadena Air Base and elsewhere in September 2006. Ever since August 2006, moreover, the U.S. forces have deployed Aegis vessels with a BMD capability in and around Japan.

Responding to the Missile Launch Incident
Prototype of the FPS-5 radar
Prototype of the FPS-5 radar
In the light of North Korea’s Missile Launches, it is clear that Japan needs to pursue diplomatic efforts, working in coordination with the international community, and also that it needs to build up the BMD system quickly, acting so as to enhance the Japan-U.S. alliance and operational posture and establish an informationsharing setup.
    While moving forward on the plan to introduce the BMD system, MOD and the SDF took additional measures in response to the latest Missile Launch incident. Those measures are to improve the EP-3, an electronic data gathering plane, to gain greater abilities to continuously collect and analyze information, and to promote research on advanced infrared sensors for detecting ballistic missiles. In addition, efforts are being made to strengthen the response posture by acquiring Patriot PAC-3 systems earlier than the timing in the original plan. In the operational area, meanwhile, the Japanese side, through its independent studies and operational consultations with the U.S. forces, is promoting consideration so as to establish a better operational setup for the BMD system.