On November 4, 2024, Japan took a significant step in enhancing its military communication capabilities by successfully launching a defense communication satellite aboard the H3 rocket from the Tanegashima Space Center in Kagoshima Prefecture. This fifth attempt, following several delays due to weather and technical issues, marks a turning point toward stable operational status for the H3 launcher, as noted by Makoto Arita, H3 project manager at the Japan Aerospace Exploration Agency (JAXA). Bloomberg also reported on the mission, citing JAXA’s confirmation of a successful launch.
The H3 rocket, developed in partnership with Mitsubishi Heavy Industries, deployed the X-band communication satellite Kirameki 3 for Japan’s Defense Ministry. As Japan’s second X-band defense satellite, it enables the military to exchange information crucial for operations planning and command and control. The satellite joins Kirameki 1 and Kirameki 2, completing the three-satellite configuration planned by the Defense Ministry to support the Self-Defense Forces (SDF) in missions requiring rapid data transmission, including ballistic missile launch alerts and live video from overseas peacekeeping missions and exercises.
Positioned in geostationary orbit, Kirameki 3 enhances Japan’s secure communication capabilities using the X-band frequency, which is less susceptible to interference and weather, ensuring stable communication. This infrastructure facilitates high-capacity, high-speed data exchanges essential for command and operational support for tactical units. According to Major General Yasuhiro Kato, Director of the C4 Systems Department for Japan’s Joint Staff, the X-band system enables rapid communication between Japan’s land, sea, and air SDF forces, as well as units deployed abroad.
The H3 mission, succeeding the H-IIA series slated for retirement after two final launches by March 2025, is a significant milestone for Japan’s space sector. Following its initial failed launch in 2023, when the rocket’s second stage failed to ignite, JAXA and Mitsubishi Heavy Industries conducted a comprehensive investigation and resolved the technical issues, resulting in a series of successful launches in 2024, thus bolstering the H3’s reliability and paving the way for commercial contracts.
Japan is expanding its military satellite network in response to rising regional tensions in the Pacific. In 2024, Japan also launched two reconnaissance satellites, IGS-Radar 8 and IGS-Optical 8, for radar and optical surveillance. Kirameki 3 is expected to enter service by the end of March 2025 after transfer to its designated geostationary orbit and a testing phase. Concurrently, the Defense Ministry is set to expand its ground-based communications infrastructure to support these satellites, while planning next-generation defense satellites capable of resisting interference to enhance operational resilience.
As Japan continues to advance its space sector, this mission reaffirms its commitment to building an independent and robust space industry, supporting both scientific exploration and national security needs. The launch of this defense satellite highlights Japan’s determination to modernize its military communication infrastructure while affirming its position in the global space industry amid rising regional security challenges.
