A relay platform for communicating telemetry data from one or more moving observation satellite(s) to the ground is provided. The relay platform for communicating from a space observation system, installed on board an aircraft moving above the clouds, comprises a first reception interface for demodulating telemetry data from at least one moving observation satellite, a second transmission interface for modulating and transmitting the data received to at least one destination ground station. The relay platform comprises a first descending two-level decryption/encryption chain for the telemetry data returned from at least one moving observation satellite(s) to the destination ground station(s).