The CLUSTER Mission Control System: A distributed architecture for a 
real-time critical and multiple spacecraft Control System

Erik M. Soerensen, Gianpiero Di Girolamo, Richard Corkill
 
ESA/ESOC, CRAY Systems Ltd. at ESOC

Abstract:
The Cluster mission is aimed at studying small scale structures that 
are believed to be fundamental in determining the behaviour of key 
interaction processes of cosmic plasma. The mission will be 
controlled from the European Space Operations Centre (ESOC). ESOC is 
also in charge of the commanding of the scientific payloads on board 
the four Cluster spacecraft after negotiation with the Cluster 
Principal Investigators (PI) and of collecting and distributing the 
scientific mission results to the scientific community.

This article describes the architecture of the CLUSTER Mission 
Control System (CMCS). The CMCS is a software system developed in 
ESOC in order to support the CLUSTER Mission Operations activities 
related to the on-line monitoring and control of the 4 spacecraft. In 
particular, the architectural layout and the system main components 
will be presented: the system gateway (NCTRS) to/from the GS 
equipment in charge of receiving the TM from the GS and to dispatch 
it to the each Dedicated Control System, and in charge of collecting 
the TC as generated by each Dedicated System and to forward them to 
the GS, the Cluster Dedicated Control System (CDCSnn=1,2,3,4) where 
on for each Spacecraft the on-line TM monitoring and the TC 
preparation and control is performed, the Cluster Data Base 
Maintenance System (CDBM) for the creation and maintenance  of the 
TM/TC Database, and the On-Board Software Maintenance Facility 
(OBSM).

Key Words: Ground Segment, Mission Control System