The Japan Aerospace Exploration Agency Spectroscopic Planet Observatory for Recognition of Interaction of Atmosphere (SPRINT-A), nicknamed HISAKI, is a planetary-science program launched on 14 September 2013. Its extreme-ultraviolet imaging spectrograph observes planetary exospheres and the Io plasma torus, including Jupiter’s aurora and magnetosphere, to study how solar-wind energy interacts with planetary atmospheres; JAXA describes the mission within its in-operation space-science portfolio and its international research cooperation.