japan space
Japan's establishment of the Space Domain Mission Unit, which is planned to become fully operational in 2023, reflects the country's increasing reliance on space systems to meet its security needs. It could emerge as a key actor in the defence of space assets in the Indo-Pacific.

In April 2020, the Japanese Diet passed a bill to set up the Space Domain Mission Unit within the Japan Air Self-Defense Force (JASDF) by the end of the fiscal year, as it seeks ways to protect its satellites from kinetic and non-kinetic threats. With an initial strength of only 20 personnel, the new unit may appear small, but this is not a measure of its significance. Tokyo's increasing dependence on space, as well as the ever-growing emphasis placed on the domain by its closest ally, the United States, suggest that the unit will have an important role.

The establishment of the Space Domain Mission Unit reflects the Japan Self-Defense Forces' (JSDF) increasing use of satellites to meet its security needs. In 2017, the JSDF began operating its first X-band communication satellite as part of the modernisation of its command, control, communications, computers, intelligence, surveillance and reconnaissance (C4ISR) infrastructure. In 2019, its naval ships began to use precision timing signals from Japan's Quasi-Zenith Satellite System (QZSS) - satellite navigation constellation - as a back-up for the US Global Positioning System. Japan is also developing a space-based ballistic-missile early-warning system.

Located at Fuchu Air Base in Tokyo, the Space Domain Mission Unit will monitor the space environment, coordinating with US Space Command to 'ensure superiority in [the] use of space at all stages from peacetime to armed contingencies' It is planned to become fully operational in 2023.

Space threats and security in the Indo-Pacific

Today, at least two regional powers already have anti-satellite (ASAT) systems in their inventories. China carried out its first ASAT test in 2007 using what Washington designated the SC-19 ground-launched satellite interceptor. Over a decade later, much of the debris created by this test remains an in-orbit hazard. Russia is also developing a ground-launched interceptor known as Nudol, which the US identifies as PL-19, with a further test reportedly carried out on 15 April this year. In addition, Russia is developing an air-launched satellite interceptor, while Beijing and Moscow are also conducting ongoing research into laser-based satellite countermeasures. In 2015, the US Department of Defense further suggested that China is likely to have developed an ASAT weapon that could reach out to geostationary orbit - an altitude of more than 35,000 kilometres - where the JSDF's X-band satellites and the QZSS are located. India also carried out its first successful test of the ground-launched Prithvi Defence Vehicle Mark-II ASAT in March 2019, demonstrating its military ambition in space. The US demonstrated an ASAT capability as far back as 1985.

The threat from laser and other non-kinetic countermeasures, such as navigation signal-jamming and spoofing, are also gaining Tokyo's attention. The 2018 revision of Japan's National Defense Program Guidelines (NDPG) recognised China's rapid development of such capabilities in the electromagnetic domain. Furthermore, a 2019 Japanese Cabinet Office assessment highlighted China's establishment of vehicle-mounted long-range jammers on Fiery Cross Reef and the Spratly Islands in the South China Sea as potential threats to military communications systems in the region.

Investing in SSA

The JSDF's growing interest in space situational awareness (SSA) will benefit not only Tokyo, but also the US and Japan's other regional security partners. Development of a ground-based deep-space radar is underway, which will be capable of tracking objects in geostationary orbit. The radar is due to enter service by 2023. Furthermore, the FY2020 budget included funding for Japan's first SSA satellite to be fitted with an optical telescope to monitor both space debris and potential ASATs. This is due to be launched in the mid-2020s. Until now, the JSDF has depended on dual-use SSA provided by the Japan Aerospace Exploration Agency and unclassified data from the US Space Surveillance Network (US SSN). The latter is operated by the re-established US Space Command. Improved Japanese SSA will benefit the US since the US SSN has limited coverage in the Indo-Pacific. It is worth noting that the 2015 revision of the Guidelines for US-Japan Defense Cooperation highlighted strengthening bilateral SSA cooperation.
US space surveillance network
Alliance resilience

Japan's increased reliance on space systems to meet its security needs - a core element of what the US today calls multi-domain operations - underscores the importance of the JASDF's new unit. The scenario of the 2018 Schreiver wargame - US Strategic Command's tabletop space exercise involving the Five Eyes nations (Australia, Canada, New Zealand, the United Kingdom and the US), France, Germany and, for the first time, Japan - reportedly depicted US space and cyber domains in the US Indo-Pacific Command Area of Responsibility being exploited by a peer competitor. Exploration of Japan's role, along with other US allies and partners, in such a scenario indicates Washington's mounting interest in Japan's growing military space-surveillance and positioning capabilities. Japan's Space Domain Mission Unit could therefore emerge as a key actor in defending space assets in the Indo-Pacific. It may also act as a catalyst to bring yet closer cooperation between Tokyo and Washington in the space domain, as well as the wider defence realm.