Astroscale Japan, a subsidiary of Astroscale Holdings Inc, the market leader in satellite servicing and long-term orbital sustainability across all orbits, has unveiled the client satellites and concept of operations for its ISSA-J1 mission, scheduled for launch in 2027, which will inspect two retired Japanese satellites in orbit.

The mission represents a major step forward for commercial in-orbit inspection and space situational awareness capabilities. By maneuvering to and inspecting two satellites in different orbits during a single mission, ISSA-J1 will demonstrate a world-first for a commercial company.

“On-orbit inspection provides critical insight into the condition of satellites that cannot be obtained from the ground,” said Nobu Okada, Managing Director of Astroscale Japan. “By inspecting multiple objects in different orbits in a single mission, ISSA-J1 will help demonstrate new capabilities that support satellite operators in understanding spacecraft condition and preparing for future servicing.”

Space situational awareness systems play a critical role in tracking objects and preventing collisions in orbit. However, ground-based observations and non-Earth imaging cannot reveal the detailed conditions of a satellite hundreds of kilometers above Earth. On-orbit inspection provides close-range imagery and characterization data that enable operators to better assess satellite health and make informed operational decisions.

This capability supports safer and more efficient satellite operations throughout the mission lifecycle, from anomaly response to preparation for future servicing. ISSA-J1 is being developed under Japan’s Small Business Innovation Research Program, specifically the Ministry of Education, Culture, Sports, Science and Technology Phase 3 Fund for large-scale technology demonstrations.

Client Satellites

The ISSA-J1 mission will inspect two retired Japanese satellites launched in the early 2000s. By approaching them in orbit, ISSA-J1 will observe their current condition more than 20 years after launch, including their attitude, rotation behavior and signs of degradation. The mission will conduct close-range observations of multiple objects, closer than traditional monitoring methods, demonstrating new possibilities for on-orbit inspection services.

Advanced Land Observing Satellite (ALOS)

• Japanese name: “Daichi”
• Operational period: Jan. 24, 2006 – May 12, 2011
• Dimensions: 6 m x 3.5 m x 4.5 m
• Solar array panel: 22 m × 3 m
• Mass: about 4 metric tons
• Orbital altitude: about 691 km

Advanced Earth Observing Satellite-II (ADEOS-II)

• Japanese name: “Midori-II”
• Operational period: Dec. 14, 2002 – Oct. 31, 2003
• Dimensions: about 5 m × 4 m × 4 m
• Solar array panel: 24 m × 3 m
• Mass: about 3.7 metric tons
• Orbital altitude: about 803 km – 820 km

Concept of Operations

Following launch, the ISSA-J1 spacecraft will be deployed into Earth orbit and undergo initial system and communication checks before beginning on-orbit operations. Once operational, the spacecraft will adjust its orbit and gradually approach the first client, ALOS. Because objects in low Earth orbit travel at extremely high velocity, ISSA-J1 will begin observations from a safe distance while carefully assessing ALOS’s motion and condition. The spacecraft will then progressively reduce the distance while maintaining safety, conducting close-range imaging and observation around ALOS without making physical contact.

After completing the first inspection, ISSA-J1 will depart from ALOS’s orbit and transition to a different orbit where the second client, ADEOS-II, is located. This orbital transfer will be carried out gradually through a series of trajectory adjustments. Upon arrival, ISSA-J1 will repeat the same step-by-step approach and inspection process. Through this sequence, ISSA-J1 will demonstrate the ability to approach multiple clients in different orbits within a single mission, repeating a cycle of approach, inspection, departure and orbital transition.

ISSA-J1 Spacecraft Specifications

• Name: ISSA-J1 (In-situ Space Situational Awareness – Japan 1)
• Dimensions: about 1,300 mm × 1,600 mm × 2,200 mm (solar arrays deployed: about 1,300 mm × 10,000 mm × 2,200 mm)
• Mass: about 650 kg (with propellant loaded)
• Thrusters: 12 total
• 10 chemical propulsion thrusters
• 2 electric propulsion thrusters

Click here to learn more about Astroscale's ISSA-J1 Mission