March 21, 2019



For the Argos-4 project:

  • CNES is the system prime contractor and has oversight responsibility for the ground and space components. As such, it is responsible for defining the space and ground segments, and in particular for supplying the instrument to the satellite prime contractor.
  • CLS is the system operator on behalf of CNES. It is responsible for distributing data collected by transmitters to users and for sending directives or messages to transmitters. It is tasked with the routine operation of the spaceborne instruments.

CNES is responsible for the spaceborne systems up to the in-orbit commissioning phase, with CLS providing technical support. Handover to CLS is effective once CNES has declared the spaceborne systems operational.

From that point on, CLS is responsible for orbital tracking and for monitoring the spaceborne instrument with technical assistance from CNES.


The Argos mission is governed by several cooperation agreements between CNES and its three current partners: NOAA (National Oceanic and Atmospheric Administration) for the USA, Eumetsat for Europe and ISRO (Indian Space and Research Organisation) for India.

These agreements are applicable for the Argos-3 instruments planned to fly on the POES, Metop and SARAL satellites. For Argos-4, agreements are being formalized with NOAA and Eumetsat to fly the CNES instruments on NOAA’s Polar Free Flyer satellite and Eumetsat’s Metop-SG satellite.

As a general rule, for Argos:

  • CNES has technical responsibility for developing the spaceborne instrument and for supporting its integration on satellites and post-launch operations.
  • CLS is responsible on behalf of CNES for development of the Argos-4 ground segment. There is no exchange of funds for this activity for the Argos-4 project; CNES's responsibility is therefore limited to validating the interfaces between the space and ground segments.
  • The partner is responsible for spacecraft bus development, integration of the Argos instrument on the bus, launch, the satellite's command/control ground segment, and data distribution to the Argos mission ground segment.

Operations Committee

The Argos Operations Committee (OPSCOM) is designed to:

  • oversee development and operation of the Argos data collection system
  • review and approve requests for applications from potential platform operators to use the Argos system
  • review and approve pricing for processing of science data by the Argos processing system
  • resolve any issues arising out of the implementation and operation of the Argos system

Agencies contributing to the space segment of the Argos data collection system are considered "Participating Agencies"—currently, CNES, NOAA, Eumetsat and ISRO—and each appoint a co-chair of the Argos Operations Committee. Agencies preparing a future contribution to the space segment of the Argos system are considered observer members, as was the case for ISRO until the launch of SARAL.

OPSCOM decisions are recorded in its consolidated report.