European Optical Nucleus Network (EONN) - Robotic optical link acquisition, tracking and data reception for optical ground stations network

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The goal is to robotize the entire operations so that the Nucleus Stations can be controlled from TNOC like any other RF antenna controlled from there today. Software interfaces will be used to connect different Site Controllers with a single Reservation system in an automated fashion. Each station’s Site Controller will receive schedules booked through TNOC and provide monitoring feedback during and after a spacecraft contact. A common ICD with common command language (syntax), interface transport layer and update rate are to be implemented.


The lack of an operational optical ground segment is the reason that there are so few optical payloads. The lack of optical spacecraft makes it hard to invest into optical ground systems.

Heterogeneous partner booking and reservation systems are to be integrated in a single booking and reservation system. This single schedule simple interface can be applied for all future potential partners.

The lack of available laser terminals in space for testing represents a major challenge. Different space laser terminal missions are under discussion. 


With a single Reservation system, the user will be able to access all OGS’s in the nucleus network.
Once the optical market gets enough traction the network can easily be extended around the world and become a high data rate complement to RF networks.  The network can also be used for future lunar communications.


The optical stations of DLR, ESA and KSAT are all different. The Nucleus network is realized by software that interfaces between these heterogenous station towards the KSAT Network Operations Centre. Each partner connected to the network is integrated similarly, even KSAT’s own OGS. This is to ensure conformity and make growing the network easier in the future.

System Architecture

Each partner operates their own OGS and accompanying Site Controller software. All reservations are handled by TNOC. This architecture assumes that each station has software capable of automatically retrieving schedules and trajectory information over interfaces described in the ICD elaborated during the project.

eonn system architecture


The project activities cover a Definition Phase, Technology Phase and a Demonstration Phase. The Definition Phase was kicked off in June 2021 starting with the analysis and understanding of the interfaces. This phase ends by the definition of the architecture and the completion of the common network ICD.    During the Development Phase the software is written and installed at the sites. The KSAT station at Nemea will be connected to TNOC by Q2/2022. The other partner stations will be connected in 2022.  During the Demonstration Phase in 2023 (Q1/Q2), the full network capability is tested and demonstrated.

Current status

The first milestone (Definition Mid Term Review) is successfully completed with the preliminary definition of the booking and reservation architecture and ICD in collaboration between ESA-ESOC and DLR-GSOC. The KSAT optical station in Greece has been tested. The stations of DLR and ESA are under construction.

The EONN has been presented at SpaceOps 2021 and IAC 2021.

Work in progress.

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