SSTL and IHI agree to develop Japanese ISR constellation

SSTL and IHI agree to develop Japanese ISR constellation
by Sophie Jenkins
London, UK (SPX) Sep 17, 2025

Surrey Satellite Technology Limited (SSTL) and IHI Corporation have signed an agreement to co-develop a small satellite constellation to strengthen Japan's intelligence, surveillance and reconnaissance capabilities. The deal was concluded on 10 September at DSEI in London, underscoring expanding UK-Japan cooperation in space and defence.

The partnership aligns with the 2023 Hiroshima Accord and commitments reaffirmed by UK and Japanese defence ministers in Tokyo in August 2025. SSTL and IHI will combine SSTL's flight-proven platforms and operational heritage with Japan's sovereign needs to accelerate delivery of resilient, responsive ISR from orbit.

Under the agreement, the companies will also explore sharing imagery and capacity between SSTL's UK-built constellations and IHI-developed systems in Japan. The approach is intended to improve coverage, ensure redundancy, and enhance tasking flexibility for both nations' security users.

Professor Sir Martin Sweeting, SSTL's Executive Chairman, said: "Space has become critically important for national security in recent years, and increasingly nations are deploying satellites in support of their Intelligence Surveillance and Reconnaissance requirements, as they can provide global reach, privacy and priority. SSTL is a recognized pioneer and leader in this area, and not only designs and manufactures spacecraft but also has demonstrated dependable and reliable services from those satellites."

Atsushi Sato, President of IHI's Aero Engine, Space and Defense Business Area, added: "Today's world is becoming increasingly unstable, and Japan's National Security Strategy recognises the importance of close cooperation with allied nations that share our strategic interests. This agreement with SSTL is an important first step towards developing the next-generation sovereign space capabilities that will be vital to Japan's national security in the years ahead."

For SSTL, the collaboration builds on TYCHE, the UK Ministry of Defence's first sovereign ISR satellite launched in 2024, and the follow-on JUNO spacecraft now under contract. Since 1985, SSTL has built and operated more than 70 satellites for government and defence customers worldwide, emphasizing rapid, innovative and cost-effective mission delivery.

The initiative is expected to bolster Japan's national security and catalyse growth across its domestic space sector, while deepening UK-Japan ties through shared technologies, joint operations and interoperable architectures.