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The mechanical properties of ceramic materials make them very well suited for space applications where thermal and dynamic stability requirements are demanding. However, their brittle fracture behaviour requires that stringent mechanical design and verification approaches are followed.
Complete Gaia torus
Therefore, for all ceramic components, specific design and verification guidelines are followed. These include probabilistic derivation of strength properties based on dedicated batch sample testing, detailed analyses of critically stressed areas, proof testing of all components and thorough inspections before and after assembly, integration and testing activities. The analytical verification is currently accomplished by a classical deterministic approach using a large safety factor of 2,4. The trend is that a probabilistic approach, consistent with the probabilistic derivation of strength will be implemented for future verifications.
Monolithic ceramic materials as SiC100®, Cesic® or ZERODUR® have been used in European Space programs for more than twenty years now. They are used for mirrors (e.g. Pléiades and Herschel), focal planes (e.g. GAIA), optical benches (e.g. NIRspec and GAIA) or full ceramic structures as in GAIA torus shown in the picture. New ceramic materials are currently being considered for future missions as is the case, for instance, of new grades of Silicon Nitride.
Additionally, ceramic matrix composites (CMC’s) are being used for refractory applications. Although, these are mainly applied for high temperature applications, their suitability for other structural applications is currently under research.
Last update: 8 January 2013