Japan to Build New SAR Satellite Constellation: ICEYE and IHI Sign Major Agreement

In an important move for Japan’s space and defense ambitions, Finnish space technology company ICEYE and Japan’s leading industrial group IHI Corporation have signed a memorandum of understanding (MoU) to jointly develop a powerful Synthetic Aperture Radar (SAR) satellite constellation. This new satellite network will be designed to serve military, civilian, and commercial needs in Japan and across the Asia-Pacific region.

The agreement was signed during the DSEI Japan 2025 defense exhibition, held at Makuhari Messe near Tokyo. Under this collaboration, both companies aim to establish a dedicated satellite manufacturing facility in Japan, with operations to be managed domestically. This step is seen as crucial in enhancing Japan's space capabilities and national security resilience, especially amid rising geopolitical tensions in the Indo-Pacific region.

What is a SAR Satellite?

A Synthetic Aperture Radar (SAR) satellite uses radar waves instead of traditional optical cameras to capture images of the Earth. Unlike normal imaging satellites, SAR satellites can observe the planet day or night and through clouds, rain, or smoke — making them highly reliable for military surveillance, disaster response, infrastructure monitoring, and maritime tracking.

About the Planned Satellite Constellation

According to the MoU, the companies plan to build a constellation of up to 24 SAR satellites. Once operational, this network will allow for rapid revisit rates over Japan and surrounding regions, enabling the collection of fresh imagery and data multiple times a day. This is particularly useful for monitoring natural disasters, security threats, and maritime activity in real-time.

Expected Specifications (based on ICEYE’s current SAR technology):

• Radar Type: X-band Synthetic Aperture Radar (SAR)

• Ground Resolution: As fine as 25 centimeters in spotlight mode

• Revisit Time: Multiple times per day with a full constellation

• Weight per Satellite: Approximately 100 kilograms

• Operational Altitude: Around 500-600 kilometers (Low Earth Orbit)

• All-weather, Day-Night Imaging: Able to capture images through cloud, fog, and darkness

Strengthening Japan’s Space and Defense Infrastructure

The collaboration comes at a time when Japan is actively expanding its domestic space industry while also seeking partnerships with friendly nations. Japan’s National Defense Strategy emphasizes the importance of building sovereign capabilities in space and leveraging international cooperation to secure the country’s interests.

Rafal Modrzewski, Co-founder and CEO of ICEYE, expressed his confidence in the partnership, saying that ICEYE has enjoyed a strong relationship with Japan since 2018. He highlighted that this agreement will not only boost Japan’s defense capabilities but also strengthen the strategic ties between Finland and Japan.

Atsushi Sato, President of IHI’s Aero Engine, Space & Defense division, added that with today’s uncertain global security environment, it’s vital for Japan to enhance its sovereign capabilities in space technology. This MoU, he noted, marks the first step toward building the next generation of satellite-based security infrastructure for Japan.

Future Outlook

While the agreement is currently a memorandum of understanding and still subject to final approvals, it sets the stage for significant developments in Japan’s space sector. Once the satellite manufacturing facility is built and the first satellites are launched, Japan will have one of the most advanced, high-frequency Earth observation constellations in the region.

Such a capability will serve not only defense needs but also support disaster management, infrastructure planning, environmental monitoring, and maritime security — areas in which Japan has long been a regional leader.

This partnership is another example of how countries are rapidly modernizing their space assets to meet both national and international security demands in a changing world.