LUCAS: The second-generation GEO satellite-based space data-relay system using optical link

After 13 years successful operation of Japanese first data relay satellite “KODAMA” (DRTS), JAXA launched a new data relay satellite which adopts optical inter-satellite communication technology in 2020 successfully. The first user satellite, named as ALOS-3 is planned to be launch in 2022 Japanese fiscal year. First demonstrations of optical data-relay satellite system are planned between these two satellites In this paper, the authors outline the plan of the program and its technology.