Minimally Machined HoneySiC Mirrors for Low Areal Cost and Density

A problem perceived for Trex Enterprises chemical vapor composite silicon carbide CVC SiCTM mirrors is the cost associated with machining and lightweighting the mirrors. Indeed these processes are labor, schedule, risk and cost drivers for our exceptional, high performance variety of silicon carbide material. Although we have made significant strides in improving our baseline CVC SiCTM manufacturing processes, the product is still substantially higher priced than the goals of the NASA project. In Phase I, we created and demonstrated a manufacturing process for the new ceramic matrix composite honeycomb panel silicon carbide (HoneySiC or H-SiC) which nearly eliminates the machining and lightweighting process steps for mirrors and opto-mechanical structures. The new material achieves lightweighting of 92% relative to bulk material and net production cost on the order of $38K per square meter (unpolished), less than half of NASA's goal of $100K per square meter. Web thickness, core geometries (pocket depth, pocket size), and mirror shape are easily tailored since H-SiC starts as a molded precursor material. The Phase II project will start at Technology Readiness Level 3 (TRL 3, experimental critical function and characteristic proof of concept) and end at TRL 5 (breadboard in a relevant environment). More »