DLR's Optical Communication Terminals for CubeSats

Free space optical communication (FSO) overcomes the challenges of traditional RF-communication in space. With its high data-rates, robustness against electromagnetic influences and being free from organizational regulations, FSO provides solutions for high-rated Direct to Earth (DTE) and Intersatellite (ISL) communication. With the raising CubeSat market and the increasing number of satellite constellations, the request for compact and efficient designs increases as well. Thus, German Aerospace Center (DLR) developed the world's smallest laser communication terminal for CubeSats (OSIRIS4CubeSat, O4C). O4C is flying on the CubeL satellite in the PIXL-1 mission. The payload itself has a modular design which allows to transfer the technology into other fields of satellite communication. The basic payload can be adapted and/or extended by different subsystems to provide solutions for intersatellite communication or Quantum Key Distribution (QKD). This paper gives an overview of the first results of the PIXL-1 mission. After the Launch and Early Orbit Phase (LEOP) the first contact between the laser terminal and DLR's Transportable Optical Ground Station (TOGS) could be established. Afterwards, further experiments were done to demonstrate the performance of the O4C terminal. Furthermore, this paper shows the ongoing and upcoming developments. Based in the O4C dedicated terminals towards higher data rates, optical intersatellite links and QKD on CubeSats are and will be developed.