Hisaki, also known as the Spectroscopic Planet Observatory for Recognition of Interaction of Atmosphere (SPRINT-A) is a Japanese ultraviolet astronomy satellite operated by the Japan Aerospace Exploration Agency (JAXA). The first mission of the Small Scientific Satellite programme, it was launched in September 2013 on the maiden flight of the Epsilon rocket.
Hisaki remains operational as of 2017, and is performing joint observations with Juno orbiter.
Hisaki was named after a cape Hisaki (火崎, literally Cape Fire) used by local fishermen to pray for safe travels in the eastern part of Kimotsuki, Kagoshima near the Uchinoura Space Center, but has the additional meaning of "beyond the Sun". An old name for the mission was EXCEED (Extreme Ultraviolet Spectroscope for Exospheric Dynamics).
Hisaki carries an extreme ultraviolet spectrometer which will be used to study the composition of the atmospheres and the behavior of the magnetospheres of the planets of the Solar System. Designed for a one-year mission, Hisaki will be operated in a low Earth orbit with a perigee of 950 km (590 mi), an apogee of 1,150 km (710 mi), 31 degrees of inclination and a period of 106 minutes.
An Epsilon was used to launch Hisaki. Making its first flight, the four-stage Epsilon rocket flew from the Mu rocket launch complex at the Uchinoura Space Centre. The launch occurred at 05:00 UTC on 14 September 2013, following a scrubbed launch attempt on 27 August 2013. Following its successful insertion into orbit and deployment of its solar arrays, the satellite was renamed Hisaki, having been designated SPRINT-A until that point.