CNES projects library

January 4, 2021


The CSO satellites (for Composante Spatiale Optique) of the MUSIS programme (Multinational Space-based Imaging System) are reconnaissance sensors for the French military forces and their partners. Overseen by CNES for DGA, the French defence procurement agency, they are set to succeed the Helios 2 system and help to strengthen force capabilities in space-based intelligence and in support and execution of in-theatre operations.

The CSO system is part of the MUSIS multi-sensor programme, conducted by the DGA and designed to ensure the continuity and improvement of the spatial imaging services currently available to French Defense.

The CSO constellation will comprise three optical polar-orbiting satellites at different altitudes to fulfil a dual mission: a reconnaissance mission at 800 km geared towards providing coverage, acquisition over theatres of operations and revisit capability; and an identification mission at 480 km to supply imagery at the highest possible level of resolution, quality and analytical precision.

The satellites’ payloads will enable day/night acquisition of very-high-resolution visible and infrared imagery with a range of viewing modes tailored to meet a broad spectrum of requirements. All three satellites are highly manoeuvrable and built around the same bus architecture that draws partly on the heritage of Pleiades, affording great autonomy and agility despite a mass of 3.5 tonnes. The CSO satellites will keep station thanks to their unique autonomous orbit control capability.

The overall system is designed—mission operations timing and a ground station network with a dedicated polar station—to assure fast turnaround between tasking requests and acquisition of intelligence combined with rapid delivery of data to the point of need.

The French defence procurement agency DGA has delegated oversight of the satellites and mission ground segment to CNES, which is also co-system architect and in charge of satellite launch, in-orbit checkout and positioning operations.

Airbus Defence & Space France is responsible for designing and building the satellites, to be assembled at its Toulouse facility, while Thales Alenia Space will supply the optical instrument. Airbus Defence & Space France is also prime contractor for the user ground segment, under contract to DGA. Development of the mission ground segment and the mission programming and image processing workflows will involve a number of industry firms including Thales Services, Cap Gemini and CS-SI.