Greek CubeSat ERMIS-3 sends first laser link to the ground

A shoebox-sized satellite has just shown that laser communications can work on very small spacecraft. ERMIS-3, an 8U CubeSat built by the National and Kapodistrian University of Athens, has established an optical link with a ground station in Greece, the European Space Agency announced on 2 November. ESA calls it Greece's first optical link with a satellite in low Earth orbit.

Why a laser link is hard

Most satellites talk to Earth by radio. Optical links use a narrow laser beam instead, which can carry far more data, but the beam has to be aimed precisely at a receiver while the satellite races across the sky at several kilometres per second. Both ends must find each other and keep tracking for the short window of each pass, and clouds can block the beam completely while turbulence degrades it.

ERMIS-3 carries the ATLAS-1 optical terminal from Lithuanian company Astrolight, which also supplied the receiving and beacon equipment at the Holomondas optical ground station (HolOGS-1), developed by the Aristotle University of Thessaloniki. The link proved the mission's key goal: precise pointing, acquisition and tracking.

Fast from first light to routine

According to ESA, the two terminals made first contact on the satellite's first active pass after commissioning, despite cloud cover, and reached routine operation within a week. The system now works autonomously, making two links a day, day and night, with margins for up to 10 Gbps. ESA notes the link was achieved earlier in the satellite's life than on previous CubeSat-class missions.

ERMIS-3 launched on 30 March 2026 together with ERMIS-1 and ERMIS-2 as part of Greece's National Space Programme, which ESA runs on behalf of the Greek government. ESA supported the project with environmental testing and optical alignment at its ESTEC centre in the Netherlands.

Why it matters

Earth-observation satellites produce ever larger volumes of high-resolution and hyperspectral images, and radio downlinks are becoming a bottleneck. Proving that a small, cheap satellite can use laser links opens the door to faster and harder-to-intercept connections for whole constellations. It's part of the same shift that is bringing space connectivity closer to everyday devices, from satellite texting on phones to navigation systems such as India's NavIC (our report on NVS-03).