On December 19, 2016 the Exploration of Energisation and Radiation in Geospace (ERG) mission, operated by the Japan Aerospace Exploration Agency (JAXA), studying Earth’s magnetosphere was successfully launched. Also known as SPRINT-B, ERG aims at elucidating how highly charged electrons have been born while they generate and vanish repeatedly along with space storms caused by the disturbance of solar wind caused by space storms, and how space storms are developed.