European Space Agency Modular Ground Segment Infrastructure for Deep Space Optical Communications

This paper provides a detailed insight into the development of the European Space Agency's (ESA) optical ground segment, intended to support National Aeronautics and Space Administration's (NASA) Deep Space Optical Communication (DSOC) experiment. The objective is to demonstrate enhanced ground infrastructure capable of establishing an end-to-end High Photon Efficiency (HPE) optical communication link between Earth and the DSOC payload of NASA's Psyche spacecraft. The implementation involves a modular bistatic ground segment with non-co-located sites, comprising a Ground Laser Receiver (GLR) stationed at Helmos Observatory, Greece, and a Ground Laser Transmitter (GLT) planned for Kryoneri Observatory, Greece, both managed by the National Observatory of Athens. This paper focuses on the detailed implementation of the GLR, which consists of an optical bench, a tracking sensor, and a Superconducting Nanowire Single-Photon Detector (SNSPD). The GLR system interfaces with the 2.28-meter telescope at Helmos Observatory and a specially developed CCSDS-compliant HPE modem within an ESA-initiated activity. On the other hand, the GLT, consisting of multi-beam laser and transmission systems, launches an aggregated high-power kilowatt uplink laser beacon. Beyond demonstrating the high technology readiness level of ESA's optical ground segment and enhanced interoperability between space agencies, the developed infrastructure serves as a stepping stone for future missions, including cis-lunar and Mars communication and navigation infrastructures. Furthermore, it addresses the technological prospects for revolutionizing planetary exploration within ESA's Voyage 2050 vision, which envisages data-return for future missions to the giant planets and beyond.