File Based Operations - Architectures and the EUCLID Example

Euclid will be launched in 2020 to explore dark energy and dark matter in order to understand the evolution of the Universe since the Big Bang and, in particular, its present accelerating expansion. It will have an operational orbit around Sun-Earth-Liberation-Point 2 and will generate about 100 GB of science data per day. To transfer these data to ground a high telemetry rate via K-band is required. The weather depending quality of a K-band link requires a failure detecting downlink protocol with automatic retransmissions of corrupted or missing data segments. For this purpose the Consultative Committee for Space data Systems (CCSDS) File Delivery Protocol (CFDP) has been selected. The operations concept for Euclid is that it will be an “offline” mission, i.e. there is a high level of on-board autonomy for routine operations and failure discovery, isolation and recovery, scientific data will be generated as files and housekeeping telemetry (instruments and service module) will be stored in files on a file system hosted by the Mass Memory Unit (MMU). Daily ground contact will be of the order of 4 hours. Data will be downlinked as files from the MMU. OBCPs and software images will be uplinked as files to the MMU.