Japan Opens Up Way For Military Use of Outer Space

(Written for and appearing in Foreign Policy Digest)


Japan’s Diet (legislature) passed a new Basic Law on Space on May 21 (the bill can be found in the index on-line here, and in pdf here ), which will permit Japan for the first time to use space for the purposes of contributing to national security. This constituted a marked departure from an almost 40 year old policy of strict non-military use of outer space.

While the passing of the law received some passing coverage in the Western press , the significance of this development remains largely unexplored. The move is important in two respects – the first being its place in a systematic widening of the scope of Japanese military activity notwithstanding constitutional constraints, and the second is the extent to which it may contribute to an escalation in the militarization of space among East Asian countries. This article focuses on the first aspect.


To put all of this into context one has to begin with the Japanese constitutional constraints on the use of force and maintenance of armaments. Article 9 of the 1947 Constitution provides that Japan forever renounces war and the threat or use of armed force for the purposes of settling international disputes. It also, in Art. 9(2), declares that it shall never maintain land, sea, or air forces or any other war potential, and that the rights of belligerency will not be recognized.

The government’s own long-standing interpretation of these provisions is that while Japan maintains the right of self-defence under international law, and may maintain the minimum military forces necessary to exercise this right of self-defence, it may not use force in any act of aggression, nor may it participate in collective self-defence operations or in collective security operations under the authority of the U.N. Security Council. Moreover, the use of force in combat or other military contexts will not enjoy the immunity from the operation of domestic or other international law normally extended to belligerents under the law of armed conflict.

Article 9 has effectively constrained both the development and operation of Japanese foreign policy, as well as, to a lesser extent, the development of its military. While it currently has sophisticated military forces , with a defence budget that ranks it among the top five in the world (depending on the source and method of calculation ), internal political constraints driven by Article 9 have ensured that its forces are largely defensive in nature (as difficult as it is to make that distinction). For instance, Japan has no long-range bombers, ballistic missile capability, or aircraft carriers, to mention a few of the more important systems of power projection. Even within the U.S.-Japan Security Treaty, last renewed in 1960, Japan is under no obligation to defend U.S. forces or U.S. interests outside of Japanese territory, thus preserving the prohibition on collective self-defence.

In 1969, in accordance with the understanding of Article 9, and shortly before Japan ratified the U.N. Treaty on the Principles Governing Activities in Outer Space (the Space Treaty ), the Diet passed a resolution limiting Japan’s use of space to “peaceful purposes.” This in turn was interpreted to mean strictly non-military purposes in order to comply with Article 9. The resolution has constrained Japanese use of space in a number of ways ever since. The government has been precluded from launching satellites for the purpose of defence, which in turn has left Japan reliant upon the U.S. and others for satellite-based intelligence. It also precluded the development and sale of military-grade space technology to other countries, all of which left Japan’s aerospace industry in a relatively underdeveloped state.

A number of events in the 1990s shook Japan’s sense of security and has led to a re-thinking of security issues in a number of ways. In particular, the revelation in 1993 that North Korea was pursuing a nuclear weapons capability, followed by the North Korean firing of a Taepodong 2 missile over Japan in 1998, had a profound impact on Japanese threat perception. In 1997, Japan and the U.S. negotiated new guidelines to govern the alliance under the U.S. Japan Security Treaty (the 1997 Guidelines ), which extended the sphere within which the Japanese Self-Defence Forces (the SDF) might be required to operate in cooperation with U.S. forces.

In the post-9/11 world, Japan has come under increasing pressure from the U.S. to contribute further to American security interests. This has included strong pressure on Japan to participate in U.S. ballistic missile defence (BMD) systems. After considerable debate and in the face of some significant internal criticism, the Japanese government agreed to participate in the development of the U.S. BMD shield, and is in the process of developing a two tiered system, comprising of a sea-based SM-3 atmospheric defence system, and a land-based PAC-3 patriot missile lower level defence system. Japan has successfully tested its SM-3system in the shooting down of a ballistic missile in space in December, 2007 .


The current move provides authority for the use of outer space for the purposes of national security, and is yet another step in what may be seen as a steady erosion of the constraints on the scope and nature of Japanese military activity. Japan sent the SDF abroad for the first time to support “anti-terrorism” operations in Afghanistan in 2002. This was followed by an unprecedented deployment of SDF forces to provide support in a combat zone, with the dispatch of 400 troops and three planes to Iraq in 2003. Japan even launched military spy satellites in 2003, notwithstanding the 1969 Resolution, to monitor North Korean activities.

All of this has led to considerable debate within the country over the extent to which these developments are contrary to Article 9. One question that received particular attention within the BMD debate, was whether the Japanese interception of a ballistic missile that was targeting the U.S. or U.S. forces not within Japanese territory, would be a violation of the prohibition on the use of force for the purposes of collective self-defence. Similarly, after yet another series of North Korean missile tests in 2006, there was discussion of whether the right of self-defence extended to pre-emptive strikes against missile sites poised for an attack on Japan. There was even talk of re-interpreting the Constitution, and all these scenarios, including that of “reinterpreting” the Constitution are inconsistent with the provisions of the Constitution itself.

The new Basic Law on Space, while asserting the requirement to comply with the Constitution, as well as the peaceful-use provisions in the U.N. Space Treaty (Art. IV of the Space Treaty), clearly provides that the use of space may be used to contribute to the national security of Japan (Art. III of the Basic Law). Moreover, the Basic Law on Space provides for the development of a space strategy and the establishment of institutional oversight of the program centered in the prime minister’s office.

This needs to be considered in the context of the language of the 1997 Guidelines, which specified that U.S.-Japanese cooperation could extend to “situations surrounding Japan”, a term that was explained at the time as being conceptual rather than geographic. In other words, the scope for Japanese support of U.S. military activity, and the area in which it was authorized to act for its own defence, was ambiguously and circularly defined as being anywhere in which there were circumstances that might trigger Japanese security requirements. Now, with the Basic Law on Space, the “situations surrounding Japan” for such purposes has been extended to outer space.

In addition to North Korea’s attempts in July 2006 to test a Taepodong 2 missile, with a range that could reach the continental U.S., the Chinese recently surprised the world last year by testing its own satellite-killer capabilities. Now, with Japan opening the door to developing its own military space program, the potential for an escalating arms race in space among the East Asian neighbors has become all the more real.