Ground Segment

To optimize science feedback from the mission, a special organization was set up for Cluster, dedicated to the processing and rapid circulation of the science data: the CSDS (Cluster Science Data System), forming a geographically distributed database.

JSOC (the Joint Science Operations Centre) located at RAL (Rutherford Appleton Laboratory, UK), is the centre responsible for co-ordinating Cluster science operations.

To give users access to the parameters resulting from measurements by the instruments on-board the four satellites (Primary and Summary parameters), a data management system is scheduled with a user friendly interface, called the CDMS (Cluster Data Management System).

ESOC European Space Operations Centre This ESA centre, located in Darmstadt, Germany, is in charge of all project operations (satellites and payload), the acquisition of functional and scientific telemetry signals via the ground station in Villafranca (Spain), and the distribution of scientific data to the national centres. JSOC Joint Science Operation Centre This centre is located at RAL (Rutherford Appleton Laboratory, United Kingdom) and is in charge of co-ordinating Cluster science operations. SDC Sweden Data Centre (Stockholm, Sweden). HDC Hungarian Data Centre (Budapest, Hungary). GDC German Data Centre (Berlin, Germany). UKDC United Kingdom Data Centre This centre, located at the RAL, makes Cluster data available for the US centre. US_CDC  United States Cluster Data Centre (GSFC Greenbelt, USA). CFC French Cluster Centre (Toulouse, France). CCDC Chinese Cluster Data Centre (Beijing, China). ADC Austrian Data Centre (Graz, Austria). This centre makes Cluster data available for the Chinese centre.

The four Cluster satellites are controlled from ESOC which is tasked with grouping all collected data on the same media (CD-ROM).

The volume of data is approximately one CD-ROM a day for the four satellites. Each contains the sorted unprocessed data from all experiments at full resolution.

CD-ROMs are dispatched to participating laboratories and to the National Data Centres (NDCs).

For the CSDS, the NDCs are in charge of producing parameters with reduced physical values (Primary and Summary parameters) from the measurements of instruments under their responsibility, exchanging these parameters and making them available to the national scientific community.

CNES, in association with the French PI laboratories (CETP for STAFF, LPCE for WHISPER and CESR for CIS) is in charge of developing and operating the French Cluster Centre (CFC).

Decommutation software and processing software is written under the responsibility of the laboratories using specifications defined by the national centres.

The CSDS consequently formalizes close collaboration between the ESA operations centre (ESOC), national agencies and the laboratories, each of which contribute to the edifice thus built.

As soon as the data has been validated by the PIs, each Cluster CoI simultaneously has at its disposal detailed (full-resolution) data on CD-ROM and electronic access to a full set of data averaged over 4 seconds from all on-board experiments.