Development of Deployable Solar Panels for the 3U CubeSat HOKUSHIN-1

The 3U CubeSat, HOKUSHIN-1, is currently under development as a technology demonstrator for future deep space missions beyond the lunar orbit. Three key technologies are essential for enabling deep space exploration at the CubeSat scale: (1) orbit determination using a compact ground station, (2) a user-friendly propulsion system, and (3) deployable solar panels capable of generating high power. The Muroran Institute of Technology is responsible for the development of high-power deployable solar panels and a corresponding holding and release mechanism. Deep space missions at the CubeSat scale require efficient power systems to support navigation, communication, and propulsion. Achieving these capabilities presents significant technical challenges due to the constraints of launch-induced vibration and thermal environments post-deployment. Furthermore, conventional retention mechanisms using Teflon fuse links suffer from limitations in tension control and reusability. To address these issues, we designed a novel deployable solar panel system and a reusable holding/release mechanism. This paper presents the design methodology, structural analysis, and the results of vibration tests conducted on both the engineering model (EM) and flight model (FM) of the solar panels and release mechanism.