Improvement of sail storage and deployment mechanism for spin-type solar power sail

Deployable membrane structures are expected to be used for large-area space structures, such as solar propulsion sails, magnetoplasma sails, drag-deorbiting sails, membrane antennas, and solar power sails. They are lightweight and can be compactly stored at launch. One achievement of the Japan Aerospace Exploration Agency (JAXA) was the successful deployment of a 200 m ${}^2$ sail using centrifugal force in the IKAROS mission, which was the first solar propulsion sail-craft in history. JAXA has long been studying the technology of spin deployment of sail membranes, and is currently planning the spin deployment of a class sail larger than 2000 m ${}^2$ as the next step in the development of the IKAROS technology. This paper discusses the unexpected behaviors during on-orbit sail deployment by IKAROS, as well as problems with the sail holding method, and proposes an improved sail storage structure and deployment mechanism for the OKEANOS mission.