July 26, 2016


The Merlin system architecture is based on following elements:

  • a Space Segment, namely the Merlin satellite, encompassing:
    • a platform, based on Myriade Evolutions concept,
    • a payload (IPDA lidar),

  • a Control Ground Segment (CGS) function, including components shared with other missions:
    • a Command and Control Centre (CCC) based on the new ISIS (Initiative for Space Innovative Standards) standard,
    • an S-band and X-band communication system using the CNES 2 GHz and 8 GHz multi-mission network of Earth terminals,
    • additional support functions implementing CNES multi-mission services. These include the debris management service, the COO orbital computation centre and the main control room,
    • a numerical simulator of the system used for tests and qualification,

  • a Payload Ground Segment (PLGS), encompassing:
    • a payload management function, in charge of instrument monitoring and control (PLOC),
    • a mission data management function (PLDP), in charge of generating and disseminating mission products,
    • a product expert appraisal function (SPEX) for monitoring the quality of products,

  • a position aboard a launch vehicle, featuring:
    • a physical place for Merlin on a launcher,
    • appropriate support from launch services.

These components are interfaced and operated in order to fulfil the following two main System functions:

  • Mission programming (based mainly on S-band activities) which consists in:
    • planning routine mission activities,
    • monitoring and controlling the space segment (sending of commands, monitoring telemetry),

  • the Science collecting line (based mainly on X-band activities) consisting in:
    • retrieving, processing and disseminating science data,
    • performing expert appraisals on scientific quality (product quality check).


 Merlin system architecture


The launch vehicle will be chosen from Europe’s own portfolio. Both Soyuz and Vega are eligible.
From a technical viewpoint, the satellite is compatible with launchers from outside Europe, such as PSLV.
The project remains compatible with two local times of the ascending node: 06:00 and 18:00