HORYU-VI. International cubesat mission to investigate lunar horizon glow

The smallest component of the lunar regolith that is called lunar dust is a significant risk factor on the surface activities of any manned and robotic missions. Interaction with the solar wind and UV/X-ray irradiation can cause these particles to be electrostatically charged and mobilized all around the Moon, and light scattering by these dust cloud can be observed over the boundary between dayside and night side of the Moon. This phenomenon, which has also been called the lunar horizon glow (LHG), still remains unexplained. The LHG observations using conventional lunar probes have limited observation opportunities and do not cover varying space weather conditions in cislunar environment such as strong upstream plasma flow and micrometeoroid flux that could enhance the lunar dust presence in the exosphere. The nanosatellite “HORYU-6” specialized in LHG observations will be put into lunar orbit to detect the light scattering above the lunar terminator. The proposed payload will perform multi-spectral imaging to monitor the lunar horizon several minutes before orbital sunrise or after orbital sunset for light scattering analysis. Therefore, it will improve our understanding of the lunar dust presence in various altitudes, which could have an impact on near-surface activities. We show that we can obtain scientific results of lunar and planetary exploration using CubeSat at low cost and in a short period of time, and contribute to the development of lunar and planetary exploration in the future. The spacecraft will be developed jointly with universities in Singapore, the United States and Italy under the supervision of Kyushu Institute of Technology, with the aim of launching the SLS-2 rocket in the second half of 2022. Together with its own scientific objectives, the HORYU-6 mission will demonstrate the low thrust trajectory optimization by utilizing electric propulsion system together with other novel embedded technology demonstrations such as atomic clock, deep space navigation and communication with CubeSats.