A Deterministic Approach to the Demonstration of Dimensionally Stable and Survivable VIS/IR CVC-SiC Mirrors for the Space Tracking and Surveillance Sy

MDA, Air Force, and Raytheon require dimensionally stable and survivable SiC substrates and coatings for the Space and Precision Tracking and Surveillance System (STSS/PTSS) Track Sensor Telescope(s). System requirements include: operation in Low Earth Orbit (LEO), surviving a nuclear event, optical performance across the 0.6-12 microns wavebands (VIS/MWIR/LWIR), and operational temperatures from 70-130 K. In Phase I Trex demonstrated a deterministic “RadHard by Design” approach to produce dimensionally stable and space/nuclear survivable CVC-SiC™ mirrors. The coated mirror dimensional stability was proven for 20 cryo-cycles of immersion in liquid nitrogen and warming to ambient temperature; the average figure error of 0.0414 waves HeNe P-V (<< less than &lambda;/10 P-V requirement) changed by less than ±1.3 nm RMS HeNe. The average mirror surface roughness was 1 Angstrom RMS, 10X lower than the goal. The mirrors survived (without damage) a total dose of 300 krad(Si) from high energy protons, and high energy x-ray testing at the National Ignition Facility. Meetings with the COTR, STSS representatives and Raytheon resulted in a Phase II plan to produce improved LWIR coatings and optimized prototype silicon carbide mirrors for a Next Generation STSS-like silicon carbide space sensor telescope.