Dimensional stability of Hexoloy SA silicon carbide and Zerodur glass using hydroxide-catalysis bonding for optical systems in space

Optical systems made for space-based interferometric missions like LISA or SIM must be made of materials that can endure significant accelerations and temperature fluctuations while staying dimensionally stable. Temperature-induced effects can be reduced with thermal shielding techniques and estimated using the thermal expansion coefficient. However, the stability is often limited by virtually unquantified material internal relaxation processes. In this paper we describe the experimental layout and present the status of our experiments to measure the dimensional stability of Zerodur and Hexoloy SA^® silicon carbide using hydroxide-bonding and discuss its feasibility for the LISA mission.