Ultra-lightweight and high-accuracy CFRP (carbon fiber reinforced plastics) mirrors for space telescopes were fabricated and their feasibility for low temperature applications was demonstrated. The CFRP mirrors were composed of sandwich panels with CFRP skins and CFRP honeycomb cores. Surface was deposited with epoxy thin layers by using a replica technique. The surface accuracy of the demonstrate mirrors of 150 mm in diameter was 0.8 μm RMS and the surface smoothness was improved to 5 nm RMS. Surface accuracy degradation was 0.6μm RMS (root mean square) from ambient temperature to liquid nitrogen. Surface asperity was classified with respect of their wave intervals and measurement areas. Surface accuracy and dimensional stability were strictly affected by raw materials and manufacturing conditions. Surface accuracy was measured at each process on the way of mirror forming. Manufacturing conditions to depress asperity were discussed.

Date Published: 13 September 2012
PDF: 7 pages
Proc. SPIE 8450, Modern Technologies in Space- and Ground-based Telescopes and Instrumentation II, 84502R (13 September 2012); doi: 10.1117/12.926133

Published in SPIE Proceedings Vol. 8450:
Modern Technologies in Space- and Ground-based Telescopes and Instrumentation II
Ramón Navarro; Colin R. Cunningham; Eric Prieto, Editor(s)