Horizontal free-space optical link with CubeISL over 143 km

Recent advancements in free-space optical (FSO) communications are enabling a breakthrough in satellite miniaturization and data transfer rates. The CubeISL laser communication terminal (LCT), a development of the German Aerospace Center (DLR), is set to showcase inter-satellite links at 100 Mbps and downlinks at 1 Gbps once it launches in 2025. This technology aims to establish itself as the cutting-edge solution for efficient CubeSat communications, delivering high data rates. To validate its capabilities, the terminal underwent rigorous testing in a 143 km FSO link between the astronomical sites of La Palma and Tenerife in the Canary Islands. The European Space Agency’s Optical Ground Station emulated downlinks, while the communication between two LCTs simulated inter-satellite links. This paper outlines the current developmental stage of the CubeISL LCT and presents the outcomes of its horizontal link demonstration.