In September 2026, the manufacturing and environmental testing of the Flight Spare (FS) model of the Thermal Infrared Imager (TIRI) were successfully completed, marking the completion of the TIRI FS development program (Figure 1).
The FS is built to the same design as the Proto-Flight Model (PFM) currently onboard the Hera spacecraft. Initially, the FS was intended to serve as a ground-based reference unit for verification and validation activities during the Hera mission. However, it has now been selected for contribution to the RAMSES (Rapid Apophis Mission for Space Safety) asteroid exploration mission, a joint mission between the European Space Agency (ESA) and JAXA.
Figure 1. The Flight Spare (FS) of the Thermal Infrared Imager (TIRI)
Before shipment of the FS, members of the Meisei Electric TIRI development team, the Hera JAPAN project team, and the JAXA Safety and Mission Assurance (S&MA) team gathered for a commemorative photograph (Figure 2).
The TIRI FS can be seen as the black instrument placed on the table in the center of the clean room. Although three and a half years have passed since the completion of the TIRI Engineering Model (EM) development, the team continues to work together as One Team toward the successful advancement of the mission.
Figure 2. The TIRI Flight Spare (FS) just before shipment (center), with members of the Meisei Electric TIRI development team and JAXA (©JAXA)
The TIRI FS will soon be transported to the European Space Research and Technology Centre (ESTEC), where it will undergo integrated system testing as part of the RAMSES spacecraft development program.
Scheduled for launch aboard a JAXA H3 rocket in FY2028, the RAMSES spacecraft will rendezvous with asteroid Apophis and carry out continuous observations around its historic close approach to Earth on April 13, 2029. These observations are expected to provide valuable scientific insights and contribute to international planetary defense activities.
With one TIRI already on its way to asteroid Didymos and its moon Dimorphos aboard the Hera spacecraft and a second TIRI now destined for Apophis aboard RAMSES, we look forward to exciting new discoveries from the observations of these fascinating asteroids.
October 2, 2026
Yuri Shimaki,
Hera JAPAN