Ground tests and on-orbit results of the power system of nano-satellite Horyu-II

The Kyutech (Kyushu Institute of Technology) Satellite Project developed a high-voltage demonstration satellite called “Horyu-II” between 2010 and 2012. Horyu-II is a nanosatellite 350 mm x 310 mm x 315 mm (X*Y*Z) in size, with a mass of only 7.1 kg. This satellite was launched on May 18, 2012 as a piggy-back payload of the 21st H-IIA launch. Its missions are the demonstration of high-voltage technology in orbit, mitigation of electrostatic discharge (ESD), and so on. In this paper, we describe the design of the power system and its verification through various ground tests. The power system is equipped with a thin-film double-junction GaAs solar cell, with an efficiency of 20%, as the primary power source for the first time in orbit. The satellite also carries Ni-MH batteries for power storage. The power system architecture was simplified as much as possible with failure prevention mechanisms, such as over-current protection and various switches related to safety and debris mitigation. We present the analysis of the telemetry data obtained after the launch and validate the effectiveness of the design and verification processes.29th International Symposium on Space Technology and Science (ISTS), June 2nd-June 9th, 2013, Nagoya-Aichi, Japa