Solar-powered flapping wing. Artwork of the solid state aircraft concept developed for the NASA Institute for Advanced Concepts by researchers at the Ohio Aerospace Institute, USA. Here, it is being used as a communications relay (not shown to scale). The aircraft would use thin-film solar arrays and an ionic polymer-metal composite material. The composite material would deform in an electric field, like a muscle, allowing a flapping motion. It would use solar power in the day to flap and gain height. At night it would glide until the Sun appears again. It could be used to explore Venus, Earth and Mars. The aircraft would have a 10-metre-wingspan. This study was funded in 2002 (Phase I) and 2004-5 (Phase II).