Performance of the Thermal Control Subsystem of ECS-Satellites 861830
In June 1983 and August 1984 the European Communications Satellites ECS-F1 and F2, were successfully launched on board ARIANE L 06 and L 10 to provide international trunk telephone circuits, television program and from ECS-F2 onwards specialised business services distribution within Europe. ECS-3 was destroyed during launch due to the ARIANE V15 failure. ECS-4 and 5 are currently being prepared for launch.
This paper summarizes the history associated with the development and testing of the thermal control subsystem (TCS), as well as the initial evaluation of the in-orbit-performance of ECS-F1 and F2. Special features of the TCS include the treatment of the high dissipating Travelling Wave Tube Amplifiers (TWTA), battery thermal control and thermal conditioning of the Reaction Control Subsystem components.
To compensate the effect of changes in the communications channels density utilisation a computerized algorithm heater system was introduced which also assists the TCS by reducing S/C daily temperature variation and gradients.
ECS-F1 carries three units mounted on North/South-Radiators designated Thermal Housekeeping Packages, containing Quartz Crystal Monitors and Calorimeters to provide indication of degradation/contamination on the on-board OSRs.