Japan is poised to become a bigger military space player. It says this will protect against security threats from North Korea and China, and also fortify its alliance with the United States. Japan’s space-related capabilities are not in doubt. Nor is there dispute about official and top-level support for these directions.
One issue that has not gotten as much attention is how Japan intends to extend collective self-defense to outer space. Simply put, collective self-defense is the use of force to defend an ally or a friendly power. While Japan has had this right derived from the UN Charter, it chose not to exercise it in line with long-standing constitutional interpretations. This has changed. The Abe Cabinet’s Decision on 1 July 2014 reinterpreted Japan’s right to exercise collective self-defense.
To be sure, on the surface, this interpretive change is incremental. But operationally, it is also historic. Unlike the past, the reinterpretation has changed Japan’s ability to come to the aid of the United States or other like-minded allies. Specifically, Japan now has the circumscribed minimum capability to protect the weapons and other units of, say, the U.S. armed forces so long as they are contributing to the defense of Japan.
The reaction to the revision of the U.S.-Japan Defense Guidelines in April 2015 showcased what all these changes might mean in the context of the U.S.-Japan alliance. As U.S. Defense Secretary Ashton Carter put it, the U.S. can hope to cooperate with Japan in “new ways” both regionally and globally, as it had not been able to do before.
These new ways are not yet quite clear. But it is reasonably foreseeable that Japan’s new right to exercise collective self-defense will be implicated in the expanding U.S.-Japan military cooperation in the space domain.
Japan has steadily put a number of pieces in motion already. In 2008, Japan shifted its legal interpretation on peaceful purposes in outer space from “non-military” to “non-aggressive” uses. In 2009, Japan’s Ministry of Defense expressed interest in a range of space-based capabilities for national security purposes, and of the need for cooperating bilaterally with the United States. In 2011, Japan issued a joint statement with the U.S., stating interest in the protection of and access to space. The two countries identified space situational awareness (SSA), a satellite navigation system, space-based maritime domain awareness (MDA), and utilization of dual-use sensors as possible avenues of cooperation. Not to be forgotten is the long-standing cooperation over BMD, with its potential for offensive ASAT operations.
In 2013, Japan actually signed a SSA Services and Informational Agreement with the U.S. In 2014, the same Cabinet Decision that reinterpreted collective self-defense pointed also to the possibilities of impediments in utilizing and freely accessing outer space. And in 2015, the U.S.-Japan defense guidelines set out other avenues for cooperation on space, seeking seamless and effective ways for securing the heavens.
Themes of minimizing risks, building resilience, preventing damage, and deterring threats in outer space emerge with force across all these legal and policy changes. They certainly make sense. What is not clear is whether such moves will deter or spur Japanese and American rivalry in outer space with countries like China, North Korea, and even Russia.
Then there is something even less clear: If U.S. space assets that directly affect Japanese security are threatened or destroyed, how exactly does Japan plan to respond out there? This is worth thinking about.
