THE CLUSTER DATA-PROCESSING SYSTEM - A DISTRIBUTED SYSTEM IN SUPPORT OF A CHALLENGING SCIENTIFIC MISSION

The Cluster mission is aimed at the study of small-scale structures th at are believed to be fundamental in determining the behaviour of key interactive processes of cosmic plasma. The mission will be controlled from the European Space Operations Centre (ESOC). ESOC is also in cha rge of the commanding of the scientific payloads on-board the four Clu ster spacecraft after negotiation with the Cluster Principal Investiga tors (PIs) and of collecting and distributing the mission's scientific results to the Cluster community. This paper describes the process of translating the scientific requirements of the Cluster mission into a data-processing system supporting the mission via the definition of a n appropriate operational scenario. In particular, the process of nego tiation between the PIs and ESOC to command the spacecraft is mediated by the Joint Science Operations Centre (JSOC) and finalised by the Cl uster Mission Planning System (CMPS) while the return of the data to t he Cluster community is actuated by the Cluster Data Disposition Syste m (CDDS). The Cluster Mission Control System (CMCS) provides the inter face between these two systems and the spacecraft. These elements cons titute the Cluster Data-Processing System (CDPS).