Over the summer 2025, ESA successfully completed a series of four increasingly complex deep-space optical communication links with NASA’s Deep Space Optical Communications (DSOC) experiment aboard the Psyche spacecraft – currently flying at over 300 million kilometres from Earth.
From the Kryoneri Observatory, located in southern Greece, a powerful laser beacon was directed toward NASA’s Psyche spacecraft. Though it carries no data, the beacon is designed to be so precisely targeted that the DSOC experiment onboard Psyche can lock onto it and send a return signal back to Earth. That return signal is then captured by the Helmos Observatory, situated 37 km away on a neighbouring mountain peak.
The Ground Laser Transmitter integrates five high-power lasers with ultra-precise steering controllers into a special 20-foot-long container with a lifting platform. This allowed to protect the sensitive equipment from sunlight during the day and lift it into the open after sunset.