ERMIS-3, an 8U CubeSat built by the National and Kapodistrian University of Athens, established a laser communication link with an optical ground station in Greece weeks after its launch on 30 March 2026. The satellite connected with the Holomondas Optical Ground Station (HolOGS-1) operated by Aristotle University of Thessaloniki using the ATLAS-1 optical terminal developed by Lithuanian company Astrolight.
This marks Greece's first optical link with a low Earth orbit satellite. The achievement validated precise pointing, acquisition and tracking (PAT), one of the mission's core objectives.
Optical communications use narrow laser beams to transmit data at high rates, but require exact beam direction toward a moving receiver traveling at several kilometres per second. Both terminals must acquire and continuously track the signal during limited communication windows. Atmospheric conditions compound the challenge. Clouds can block the link entirely, and turbulence degrades signal quality.
ERMIS-3 launched alongside ERMIS-1 and ERMIS-2 as part of an in-orbit demonstration programme testing communications technologies for small satellites. The European Space Agency provided technical expertise including environmental testing and optical alignment at its ESTEC facility in the Netherlands.
Optical links could address growing data volumes from missions such as Earth observation, where high-resolution and hyperspectral imagery must transfer to ground stations. The mission is part of Greece's National Space Programme, implemented by ESA on behalf of the Greek government.