Achievements and Future Plan of JAXA’s Interplanetary CubeSats and Micro-sats

The University of Tokyo and Japan Aerospace Exploration Agency (JAXA) developed the world’s first deep space micro-spacecraft PROCYON. Its mission objective is to demonstrate a micro-spacecraft bus technology for deep space exploration and proximity flyby to asteroids performing optical measurements. PROCYON was launched into the Earth departure trajectory on December 3, 2014, together with Japanese asteroid sample return mission Hayabusa-2. PROCYON completed the bus system demonstration mission in its interplanetary flight.

Currently, Japan is not only pursuing the improvement and utilization of the demonstrated micro-sat deep space bus system with a weight of tens of kg or more, but also trying to develop smaller spacecraft with a weight of less than tens of kg, namely CubeSats, for deep space exploration. We are developing two self-contained 6U CubeSats for the rideshare opportunity on the USA’s SLS EM-1 mission, one of which (EQUULEUS) will fly to a libration orbit around Earth—Moon L2 point and perform scientific observations of the Earth and the Moon, and the other (OMOTENASHI) is planning to perform "semi-hard" landing on the moon by using a solid rocket motor onboard.

We are also seeking the possibility of CubeSats which is carried by a larger spacecraft to the destination and supports the mission by taking advantage of its low-cost and risk-tolerable feature. We are studying several other CubeSat and Mirco-sat deep space missions in Japan, and this paper overviews the Japanese achievements and future plans of CubeSats and Micro-Sats for deep space exploration.