SUDDEN STRESS RELEASE TESTS PERFORMED ON GOCE SPACECRAFT COMPONENT SAMPLES

摘要

Gravity Field and Steady State Ocean Circulation Explorer (hereafter GOCE) is an ESA mission, in the frame of Earth Exploration, devoted to provide a unique reference solution for the Earth's gravity field. This will forward a new and fundamental insight to wide range research application areas including oceanography (for global and regional ocean circulation studies), Solid Earth's physics (for studies of the continental lithosphere and plate tectonics) and geodesy (for the unification of height systems and navigation).The main instrument of the spacecraft is the Gradiometer. It is comprised by three pairs of accelerometers, that are arranged two per axis. They will measure on-board spatial gradient components of the Earth's gravity field. Taking into account the distance between accelerometers in each axis (0.5 m), it can be easily guessed the very high sensitivity of such accelerometers.The range of use of the instrument accelerometers, in terms of electronic saturation, is very tight. In the mission frame, only very 'calm' periods in the seasonal range are suited for the measurement phase. The key for the mission success is to keep these 'calm' conditions during those phases.In the case of GOCE, is was determined that shocks above 10-5 g reaching the Gradiometer base, would cause instrument saturation and therefore interruption of the measurement, loosing the precious 'calm' period for several hours, which is the time needed to resume the measurement phase.