Verification of RISING-2 attitude control system in generic Hardware-in-the-Loop Simulation environment

A micro satellite called "RISING-2" was developed by Space Robotics Laboratory (SRL) of Tohoku University, targeting scientific Earth observation on Sun-synchronous orbit using 5 m resolution telescope and technical demonstrations for future constellation by micro satellites. The attitude control system of the RISING-2 gives 3-axis zero-momentum stabilization by using three reaction wheels together with three magnetic torquers for dumping of body angular velocity. The attitude determination system is equipped with two star trackers, a gyro scope, sun direction sensors, a GPS, and a geomagnetic aspect sensor. Its behavior was evaluated by means of generic Hardware-in-the-Loop Simulation (HILS) and verification environment, which is described in detail below. RISING-2 was launched by Japanese 24^th H-IIA launch vehicle on May 24^th 2014 at 3:05:14 (UTC). This paper describes pre-flight evaluation results of RISING-2 in HILS environment and also includes quick reviews about the first operation in orbit. In general, micro satellites have potentials to be rapidly developed in low cost. To achieve this, A Model-based Environment for Verification and Integration of μ-Satellite named MEVIμS was set up at SRL in parallel with the development of RISING-2 and our third micro-satellite called "RISESAT". In this environment, all satellite subsystems are simulated in software based on actual components including attitude control as well as data handling and power control. MEVIμS is based on a real-time OS to realize real-time simulation of HILS environment. HILS of RISING-2 attitude control system was demonstrated by utilizing the satellite on-board computer and reaction wheels. The star tracker test system was introduced to include the failure detection and time delay. As the results, the system development became more efficient since the attitude control system verification could be carried out all of the time. From the acquisition of the RJSING-2 data in real operation, the reliability of the development environment will be increased by reflecting the results. Furthermore, it will contribute to produce next micro satellite under development. This paper puts an emphasis on the configuration and capabilities of the HILS environment including star tracker test system.