Japan's previous main space science institute. ISAS was established in 1981 by the reorganization of the former Institute of Space and Aeronautical Science at the University of Tokyo, the centre of Japanese space science since 1964. Although the development of launch vehicles and satellites has been led by the National Space Development Agency (NASDA), ISAS conducted space science research by using its own launch vehicles, scientific satellites, planetary probes, and balloons. On 1 October 2003 it was merged with NASDA and the National Aerospace Laboratory of Japan (NAL) to form the Japan Aerospace Exploration Agency. ISAS retains its original function within JAXA and carries great responsibility for Japan’s space science development, focusing on astronomical observations from outer space to study the structure and origin of the universe, Solar System science, utilization of space environment for microgravity experiments of various kinds, and space engineering to support these activities and pave the way for new possibilities in space. Current ISAS satellite missions: Geotail (1992), Reimei (2005), Hinode (2006), Akatsuki (2010), Ikaros (2010), Hisaki (2013), Hayabusa 2 (2014), and Arase (2016).

ISAS remains a university institute, with its main campus in Sagamihara, about 40 km west of Tokyo. Studies of rockets and space science began in the 1950s, under Japanese rocket engineer Hideo Itokawa.