Fabrication of strongly curved aspheric silicon carbide mirrors

TNO Science and Industry has designed and is currently developing the Basic Angle Monitoring Opto-Mechanical Assembly (BAM OMA) [1], which is part of the GAIA spacecraft. In GAIA two telescopes mounted on a slowly spinning satellite will measure the position of the stars with an accuracy much higher as ever done before. Crucial in the system is that the relative angle between the two telescopes should remain stable in the μrad range. The GAIA BAM-OMA system is equipped with two off-axis parabolic mirrors that have to be polished to a high shape accuracy.