Syracuse (SYstème de RAdioCommunication Utilisant un SatellitE; English: Satellite-based radio communication system) is a series of French military communications satellite constellations.
The Syracuse program is intended to enable safe and secure permanent communications between headquarters in mainland France and units deployed in theaters of operation around the world at all times (peace, crisis, major disaster...) as well as between the units themselves. It contributes to command, intelligence and logistics operations. Four generations of Syracuse constellations were deployed between 1984 and 2023.