Despite the limited time available for contact with the spacecraft, engineers on the ground have to handle various time-critical orbit changes, and provide continuous support and co-ordination for spacecraft operations. The Cluster ground segment is used to monitor and control the four satellites, and to receive, archive and distribute the science data. It is composed of:
Diagram of Cluster operations
- an Operations Control Centre (OCC)
- ESA's Ground Stations and Communications Network (ESTRACK)
- the Cluster Science Data System (CSDS)
Operations Control Centre
The core of the Operations Control Centre (OCC) facilities is the Cluster Mission Control System. This handles:
- real-time/near real-time data-processing tasks essential for controlling the mission
- acquisition and interim storage of raw scientific data
- payload command requests, together with the planning and scheduling of satellite operations
The Mission Control System is supplemented by the Flight Dynamics System, which handles all satellite activities related to orbit, attitude determination and control.
The Cluster communications networks plays a vital part in the mission. Information is relayed between team members by means of the public internet and via ISDN lines which are leased from national telecommunications companies.
In this way, the Cluster team is able to retrieve raw science, 'housekeeping' and auxiliary data stored at the OCC; to submit requests (via the Joint Science Operations Centre in the UK) to the OCC for commands to be sent to the spacecraft; and to electronically exchange processed science data and related software between the national data centres.
||Communications & Tracking
Last Update: 24 Aug 2006