Silicon Carbide (SiC) Cryogenic Optics Technology Advancement

The objective of the All SiC Telescope Cryo-Test program (ASTCT) is to validate the optical performance of the Silicon Carbide Telescope for STSS (SCATS) near 120K. The off-axis, relayed, afocal telescope has an F/0.5 primary mirror and is equivalent to the current beryllium STSS fore optics. The SiC mirrors and structure are made by the Chemical Vapor Conversion process (CVC) process that allows very low stress monolithic SiC structures to be fabricated by fusing complex parts together. The technology for making the mirrors and structure and integrating them into a telescope have been demonstrated by POCO graphite on previous SBIR programs. This program will validate the technology at operating temperature, readying it for insertion to STSS and other cryogenic space sensors. The proposed phase 1 program will 1) establish the best of three potential facilities at which to conduct the cryo-test; 2) verify the ambient wavefront quality of the telescope to solidify the baseline for cryogenic test and test accuracy; 3) establish the test configuration and the conceptual design of needed fixturing plus instrumentation; and 4) develop the test plan. These tasks will form the basis for implementing the test plan and conducting the test on phase 2.