Space Security in Japan’s New Strategy Documents

This commentary is part of the Exploring New Horizons: Japan’s Defense Priorities project, a CSIS Japan Chair initiative featuring analysis by leading Japanese and American scholars examining the implications of Japan’s new national security and defense strategies and opportunities for bilateral cooperation.

The National Security Strategy (NSS), National Defense Strategy (NDS), and Defense Buildup Program (DBP), hereafter referred to as Japan’s three strategic documents, approved by the Japanese government in December 2022, address security issues in new domains, including space. This commentary looks at how Japan’s space security policy will change in the future.

Long-Standing Restrictions in Japan

For many years, the principle of the peaceful use of space has been accepted as a quasi-legal limitation of Japan’s national policy that states that space development shall be conducted “exclusively for peaceful purposes.” The basis for this was a Diet resolution adopted in 1969, when the National Space Development Agency of Japan (NASDA), now called the Japan Aerospace Exploration Agency (JAXA), was established. According to this Diet resolution, the Japan Self-Defense Forces (JSDF) were not allowed to use satellites for intelligence gathering and communications, nor were they allowed to develop, launch, and operate satellites and rockets. Whereas in other countries space development was closely linked to national security, in Japan there was a sharp disconnect between the two.

However, as security technology advanced to the point where it was no longer possible to operate weapons or maintain a chain of command without GPS and satellite communications, this “peaceful use principle” became a major stumbling block. In particular, the more U.S. military operations relied on space infrastructure, the more difficult it became for the Ministry of Defense (MOD) and JSDF to avoid any involvement in space when conducting joint exercises and coordinated actions as allies. In 1985, Japan’s chief Cabinet secretary adopted the “generalization principle,” which states that “satellites whose use is generalized and satellites with similar functions” can be used, making it possible to use commercial satellite services. In addition, the Basic Space Law, enacted in 2008, stipulates that the use of satellites “contributes to the maintenance of international peace and security as well as to Japan’s national security.” In this way, Japan has finally resolved the disconnect between security and space development and can now develop a space security policy similar to those of other countries.

Nevertheless, there is a gap between what is possible and what is actually accomplished. Since 1969, the MOD and JSDF have retained the ability to operate without the use of space systems. The JSDF’s primary mission is generally defensive mobilization to defend Japan’s own territory, which is known as “exclusive defense.” In other words, the JSDF can maintain its chain of command by utilizing its own ground facilities and limiting the use of satellite systems to exceptional circumstances (e.g., participation in UN peacekeeping operations based on the International Peace Cooperation Law). In addition, the Information Gathering Satellite (IGS) system operated by the Cabinet secretariat is in operation, and the necessary information for operational planning is available to MOD. Thus, it should be understood that although Japan has resolved the disconnect between security and space exploration in theory, the MOD and JSDF have not systematically made use of space.

Introduction of Space Situation Awareness

A major change in this situation came with China’s 2007 anti-satellite (ASAT) weapons test. This became a major issue because modern military operations are centered on weapons supported by space systems. Command and control, intelligence, surveillance, and reconnaissance (C4ISR) for military operations cannot function without space systems, and the U.S. military in particular relies heavily on them. Furthermore, because space systems carry more fuel and equipment at launch, the satellites themselves are extremely lightweight and vulnerable to external physical attack. Therefore, ASAT weapons are extremely threatening, as they target vulnerable systems that can easily degrade military capabilities if destroyed.

Japan has no satellites for military purposes that it operates on its own (the JSDF exclusively uses communications satellites, but they are operated by private companies), and its strategic assets (space assets) include IGS and QZSS (Quasi-Zenith Satellite System, a regional positioning satellite system) satellites. In the event of a military conflict between the United States and China, China might use ASAT capabilities to launch attacks against U.S. military assets, thereby degrading the U.S. military’s ability to conduct military operations and reducing Japan’s ability to respond to threats. To prevent such a situation from occurring, it is necessary to protect not only Japanese assets but also U.S. assets in space.

An important means of achieving this is space situational awareness (SSA), which uses radar and other means to detect orbiting space objects, quantify their position and direction of flight, predict their future trajectories, and obtain the data necessary to calculate the likelihood of collisions with satellites. Having such an SSA capability is essential for space security. To this end, Japan has established a Space Operations Group in the Japan Air Self-Defense Force to analyze SSA information provided by the United States and other friendly nations and to operate an SSA radar under construction in Yamaguchi Prefecture. Although it is named the Space Operations Group, it is not a unit that conducts activities in outer space, but rather a unit for conducting SSA.

The 2018 National Defense Program Guidelines

Although the MOD took its first steps into space activities through its involvement in SSA, it had to wait for the 2018 National Defense Program Guidelines (NDPG, now referred to as the National Defense Strategy), which addressed space activities for defense purposes clearly for the first time and demanded the MOD to become more active. However, the 2018 NDPG only mentioned the enhancement of information gathering, communications, and positioning using satellites; the strengthening of SSA capabilities; and guaranteeing satellite functionality (i.e., ensuring that satellites continue to function through alternative means in the event of an attack) and did not propose any new activities beyond what the MOD had been doing.

However, it did reference the enhancement of capabilities to ensure the superiority of space utilization at all stages from peacetime to contingencies, including the ability to interfere with the other party’s command and control and information and communications via satellite—in other words, to have an offensive capability against other countries’ space systems. This was the first time Japan mentioned offensive capabilities in outer space, though there has been no significant debate on this point since and it has not attracted much public interest. There is no indication that specific projects or technical studies have been undertaken to build such a capability to date.

New Developments: Security from Space

Although space security was not fully discussed in the 2018 NDPG, the three 2022 strategic documents mark an unprecedented leap forward.

First, the documents divide space security into three areas: (1) ensuring security from space (e.g., strengthening space utilization by the JSDF and Japan Coast Guard); (2) ensuring security in space (i.e., responding to threats to the stable environment of outer space); and (3) supporting and fostering the space industry.

Second, in terms of security from space, the documents introduce the concept of incorporating satellite constellations to monitor potential foreign targets. Until now, image collection by reconnaissance satellites has been focused on strategic surveillance by IGS, such as monitoring long-term changes in order to utilize the information for diplomatic and security strategies. However, the decision to acquire so-called counterattack capability—to attack enemy missile bases and other targets by means of standoff missiles—as described in the three strategic documents creates the need to identify and monitor potential targets for such attacks. This requires the construction of a satellite constellation system that operates a large number of small satellites simultaneously to improve SSA and information-gathering capabilities.

Third, the three strategic documents also reference the need to build a system that can detect, track, and intercept hypersonic weapons, such as hypersonic glide vehicles (HGVs), in real time. The number of satellites required for this purpose is thought to number in the thousands, and it would be extremely difficult for Japan alone to build such a system.

Therefore, cooperation with the United States in the area is essential. As allies, Japan and the United States, both threatened by HGVs, need to work together to build such a satellite constellation for HGV detection and tracking. However, there is an ongoing debate in the United States about whether the government or the private sector should be entrusted with developing and operating such satellites. This is because the U.S. government itself does not possess constellation technology, which is instead owned by the private sector. Therefore, when Japan and the United States cooperate, it is an anomalous situation in which the U.S. private sector and the Japanese government would cooperate, requiring a new method of cooperation.

Security in Space

The three strategic documents have dramatically strengthened plans for the use of space by the JSDF and other organizations. The documents discuss the development and operation of space domain awareness (SDA) satellites, which are equipped with sensors to monitor orbiting objects on artificial satellites, in addition to the SSA radars already being operated, mainly by the MOD. In addition to monitoring from the ground, collecting information on space objects from outer space will enable Japan to detect and analyze the movements of other countries’ satellites to reveal their intentions. The goal is to deter threats in space and ensure stability by enhancing such surveillance capabilities.

In addition, in order to strengthen the resilience of Japan’s own positioning system, Japan aims to further expand its current fleet of seven satellites to create a system that can operate without being affected by interference from other countries. The QZSS is also compatible with the U.S. GPS system and can serve as a backup in case GPS is attacked, thus enhancing the resilience of the Japan-U.S. alliance.

Furthermore, strengthening the “capability to disrupt opponent’s command, control, communications and information,” which was put in the 2018 NDPG, was also included in the 2022 NSS. Specific projects will be defined in the future, but there is no doubt that the range of capabilities that Japan should acquire in space, including developments in this regard, is broad and will require considerable investment.

Shortcomings of the New Strategy

Faced with a drastically changing international environment, Japan has revised its security strategy and is now facing a major turning point with regard to space security. However, Japan needs to overcome various obstacles to realize this new space strategy. First, the MOD has not been involved in space over recent decades. Since the passage of the Basic Space Law in 2008, efforts have been made to accumulate technical knowledge through cooperation with JAXA, but the level of such knowledge is still at a low level. It is difficult for the MOD to autonomously define and design its own system architecture since it does not have enough technical capabilities or knowledge.

Second, despite the lack of such technical knowledge, the plans to build the space system envisioned in the three strategy documents, especially the use of satellite constellations to detect and track HGVs, are far too ambitious. JAXA does not possess satellite constellation technology, and although several private Japanese space ventures have attempted to do so, it is yet to become a reality.

Third, although the MOD’s space budget will increase dramatically with the proposed increase in overall defense spending (to 2 percent of GDP by 2027), it will only increase by ¥1 trillion ($7.15 billion) by FY 2027, or ¥200 billion ($1.43 billion) per year. That budget is still relatively small, and it is questionable whether it will be able to cover all the costs required to build large-scale systems such as satellite constellations and SDA satellites.

Fourth, there is also the question of whether there will be an adequate supply of the human resources needed to build, operate, and protect a new system. Cybersecurity capabilities in Japan are limited, and there is no security clearance system in place to share information with the United States and other allies, especially regarding sensitive cyber incidents, which is necessary for cyber defense. Although the JSDF has its own cybersecurity capabilities, its primary purpose has been to protect systems on the ground, and it does not have the expertise to protect satellite systems.

In addition, the failure of Japan’s H3 rocket, Japan’s first attempt to launch a satellite in 2023, has significantly changed the schedule for future satellite launches. The possibility that defense-related satellite launches will not go as planned is increasing, and if financial resources are concentrated on rocket development, ambitious space security plans will become more difficult to realize.

The Future of Space Security in Japan

The 2018 NDPG and the three strategic documents of 2022 constitute a new phase in Japan’s approach to the use of space for national security. Nevertheless, Japan’s strategic ambitions are limited by the scope of Japan’s constitution. In other words, the JSDF’s activities are primarily for territorial defense and are not envisioned to be deployed globally. Although Japan can now escort U.S. forces in existential crisis situations and can exercise the right of collective self-defense, Japanese forces are not assumed to operate beyond the territory surrounding Japan. In other words, for the JSDF, which does not deploy globally, space is only complementary. If, like the U.S. military, the JSDF were to have bases around the world, deploy troops in other countries’ territories, or conduct military operations using drones, it would need a broader range of space capabilities, but space is not necessarily essential for the JSDF, which is primarily concerned with territorial defense. Therefore, it is more important for Japan to build and operate space systems with the United States, rather than build its own space capabilities, and facilitate cooperation and joint operations among allies. Japan has a framework for discussing a wide range of issues from security to space exploration through the Comprehensive Space Dialogue, involving the United States but also France and other countries, but it will be necessary to further refine this framework to create an alliance or coalition of willing countries interested in space security.

Furthermore, as noted in the NSS, international rulemaking is important for security in space. The Open-Ended Working Group on Reducing Space Threats held at the Conference on Disarmament in Geneva focuses on responsible behavior in outer space and on making such conduct into legally binding rules. In these international negotiations, a coalition of willing nations, led by Japan and the United States, should cooperate closely to build a stable order in outer space.

Space is a global commons that transcends national boundaries and is utilized for civilian and military purposes. In order to enable the orderly use of space, Japan’s new defense strategy must simultaneously advance two tasks: (1) establish a rules-based international order and promote the stable and sustainable use of space; and (2) develop infrastructure to ensure security capabilities on the ground. The latter is a long-term objective requiring urgent attention to rules and norms in coordination with the United States and other countries.

Suzuki Kazuto is professor at the Graduate School of Public Policy at the University of Tokyo, Japan, and director of the Institute of Geoeconomics at International House of Japan.

This project is made possible with support from the Government of Japan.

Suzuki Kazuto

Professor, Graduate School of Public Policy, University of Tokyo, Japan and Director, Institute of Geoeconomics, International House of Japan