Qualification of Inter-Satellite Link Laser Communication Terminals on CubeSats - CubeISL

Abstract

Free Space Optical (FSO) communications on the rise to replace classic Radio-Frequency (RF) systems in many sectors of satellite communication. DLR has a long heritage in developing Laser Communication Terminals (LCTs) for LEO satellites. Major requirement for the design of the terminals is the optical characterization. Beside the verification in the laboratory, the terminals must withstand the harsh conditions of launch and space and fulfil all functionalities. To characterize the LCTs optical properties, DLR developed and built an Optical Ground Support Equipment (OGSE) which mirrors the functionalities of an Optical Ground Station (OGS), in a small scale, to test and adjust the LCTs. This paper describes the setup of the OGSE and its capabilities. The success of the New Space move is based on short qualification and development times. Thus, DLR tailors common standards to the needs of the final mission. The paper describes the qualification approach with the example of the worlds smallest LCT OSIRIS4CubeSat (O4C). The next step is to transfer the technology from Direct-To-Earth (DTE) into the Inter-Satellite Link (ISL) domain in the CubeISL project. To reduce time and cost efforts for development and qualification, subsystems and processes were reused from O4C.