Search Results

The Polar Platform is a multi-mission platform designed to operate from low earth polar orbits. Its purpose is to accommodate and support various instrument complements dedicated to meteorology, earth observation and science. In its first mission configuration, ENVISAT-1, dedicated to earth observation, the lower three sections of the Payload Module represent the Payload Equipment Bay (PEB), which houses the payload support subsystem units and various payload instrument electronics equipment. All units are mounted on to the internal faces of the PEB CFRP honeycomb side panels. The PEB thermal design is basically passive, assisted by heaters and in general uses conventional techniques. However, thermal doublers, used to spread high heat fluxes over a greater area are made for the first time from carbon/carbon. This material matches the low coefficient of thermal expansion of the CFRP panels and at the same time provides the high thermal conductivity required for this application.

Thermal design features of the ESA European Polar Platform are described. Due to the low conductivity of the CFRP/aluminium honeycomb sandwich panels of the Payload Equipment Bay, carbon/carbon thermal doublers are used as heat spreaders for high dissipating units. The main challenge for the thermal design of the Data Relay Satellite Terminal Outboard Assembly are the motor gears and the rotary joints. High RF dissipation combined with low thermal capacitances result in extreme orbital temperature variations. The temperature limits are met by a proper selection of thermooptical properties and thermostatically controlled heaters.