Lessons Learned in the Operation of the HIBARI: Variable Shape Satellite

We have developed the 50 kg microsatellite “HIBARI”. The satellite demonstrated a novel attitude control method called “Variable Shape Attitude Control (VSAC)”. VSAC is a method that can quickly control attitude and has low energy consumption using reaction torque by driving variable shape structures. HIBARI was launched in 2021 under the Innovative Satellite Technology Demonstration Program led by JAXA. We have been operating the satellite for two years and have demonstrated the VSAC mission. We achieved all minimum and full success criteria, including 30 deg/10sec agile attitude change.\nOn the other hand, we experienced problems like the degradation of satellite components and other problems that could not be confirmed by ground tests. There was degradation of the paddle drive unit and influence of the paddles on bus components, which are unique to variable shape satellites. In addition, there was a case in which a paddle collided with the satellite structure due to an operational error. After the collision, the satellite’s integrity was evaluated by taking images of the paddle with the onboard camera and checking the telemetry data before and after the collision. During more than two years of operation, we have obtained knowledge about possible failures and countermeasures for satellites with variable shape structures.