Designing and testing a highly stable ceramic sensor platform for challenging thermoelastic requirements

摘要

The Meteosat Third Generation's extreme pointing requirements call for a highly stable bracket for mounting the Star Trackers. HB-Cesic?, a chopped fibre reinforced silicon carbide, was selected as a base material for the sensor bracket. The high thermal conductivity and low thermal expansion of HB-Cesic? were the key properties to fulfil the demanding thermo-elastic pointing requirements of below lμrad/K for the Star Trackers mounting interfaces. Dominated by thermoelastic stability requirements, the design and analysis of the Bracket required a multidisciplinary approach with the focus on thermal and thermo-elastic analyses. Dedicated modal and thermal post-processing strategies have been applied in the scope of the light weighting process. The experimental verification of this thermo-elastic stable system has been a challenging task of its own. A thermo-elastic distortion measurement rig was developed with a stability of <0. lμrad/K in all three rotational degrees of freedom.