The GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) spacecraft is one of the ESA’s Earth Explorer Core missions. The GOCE mission science, due for launch in 2007, will provide data sets required to determine global models of Earth’s gravity field, the geoid, ocean circulation and sea level change.
The GOCE Gradiometer, the Core of the Spacecraft, consists of 3 pairs of 3 axes servo controlled accelerometers. In order to comply with the scientific objectives, the instrument shall provide a very stringent mechanical stability between accelerometers. This stability requirement implies the use of very low expansion structures (carbon/carbon sandwich panels), and a high level of stability performance for the thermal control subsystem ≈5μK/√Hz in the [0.005Hz;0.1Hz] measurement bandwidth (MBW). The temperature stability of the Core is done by a very stable active thermal control system and the passive use of the thermal heat capacity.
A second part is the Electronic Subsystem with the Front End Electronic Units (FEEU) and the Interface Unit Electronic (IUE). This second part of the Gradiometer is also thermally controlled by an active thermal control associated to a radiator. The stability requirement of Front End Electronic Units is less severe than the Core (≈10mK/√Hz in the [0.005; 0.1 Hz] bandwidth).
All the GOCE activities were done under contract for the European Space Agency. This paper focuses on the thermal control concept and design, including the characteristics of the active thermal control subsystem, and the computation of the thermal and mechanical stabilities in order to meet the technical requirements. The exploitation results of the thermal test performed on the structural thermal model will also be presented and discussed.