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GOCE (the Gravity Field and Steady State Ocean Circulation Explorer) is the first Earth Explorer Core Mission of the Earth Observation Envelope Program of the European Space Agency (ESA). The Satellite is planned to be launched in June 2008 on a Rockot launcher into a near-circular sun-synchronous orbit for Earth's gravity field measurements. The objective of the mission is to produce high-accuracy, high-resolution, global measurements of the Earth's gravity by satellite, leading to improved gravity field and geoid models for use in a wide range of applications (geodesy, solid-Earth physics, oceanography, climate, ice topography). In particular, the goal is to produce a map of the gravity anomaly field with an accuracy better than 1mGal (1 mGal=10-5 m s-2), and of the geoid height with accuracy better than 1 cm, all over the Earth's surface with a resolution at sea level of at least 100 km.

High accuracy measurements of the earth’s gravitational field by satellites are affected by noise due to micro-vibrations caused by the environment and internal sources. In order to derive the best possible gravity field model the effects of non-gravitational accelerations have to be avoided and, where this is not possible, compensated or minimized. Among many other sources of those undesired disturbances are also classical thermal hardware items. This paper describes the development test programme established within the GOCE project to characterize the performance of MLI blankets, which were identified as potential micro-disturbance sources. The outcome of these tests is briefly discussed and the resulting selection of the flight thermal hardware is presented.

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.

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.