The partnership will be formally sealed at a signing ceremony on 10 September during the DSEI defence exhibition in London. The deal comes as the UK and Japan deepen defence and space cooperation under the 2023 Hiroshima Accord.
The two governments reaffirmed that commitment at a ministerial meeting in Tokyo last month, pledging closer collaboration on emerging technologies, including satellite-based intelligence, surveillance and reconnaissance (ISR) and space domain awareness.
SSTL, a University of Surrey spin-out founded in 1985 and now a subsidiary of Airbus Defence and Space, is regarded as a pioneer in small satellite technology. The company has built more than 70 spacecraft for clients worldwide, including Tyche, the UK Ministry of Defence’s first sovereign ISR satellite, launched in August 2024. A follow-on satellite, JUNO, is already under contract.
Under the agreement, IHI will leverage SSTL’s proven satellite buses and on-orbit track record to accelerate Japan’s ISR constellation. The deal also opens the door for shared imagery and satellite capacity between the UK and Japan, boosting interoperability and resilience.
The constellation is expected to eventually include a mix of optical, synthetic aperture radar (SAR), radio frequency, infrared, hyperspectral and VDES satellites, providing land and maritime tracking and target detection.
IHI is positioning itself as a key player in Japan’s growing space industry. It is already working with Finnish firm ICEYE to build a constellation of up to 24 SAR satellites for defence, civil and commercial use.
Atsushi Sato, IHI’s director and managing executive officer for aero engine, space and defence, said the deal reflected Japan’s push to strengthen its national security in a more unstable world.
“Japan’s National Security Strategy recognises the need to expand cooperation with allies and partners who share our strategic interests,” he said. “This agreement with SSTL is the first step towards building the next generation of sovereign space capabilities that will be critical to Japan’s security in the years ahead.”
SSTL executive chairman Professor Sir Martin Sweeting said space had become “critically important” for national security.
“Nations are increasingly turning to satellites for ISR because of their global reach and assured access,” he said. “This teaming agreement between IHI and SSTL harnesses the strengths of UK and Japanese industry to deliver complex space missions and operational services in support of shared security priorities.”