Method of Manufacture for a Lightweight, High-Precision Silicon Carbide Mirror Assembly

Abstract

An aerospace mirror having a reaction bonded (RB) silicon carbide (SiC) mirror substrate, and a SiC cladding on the RB SiC mirror substrate forming an optical surface on a front side of the aerospace mirror. A method for manufacturing an aerospace mirror comprising obtaining a green mirror preform comprising porous carbon, silicon carbide (SiC), or both, the green mirror preform defining a front side of the aerospace mirror and a back side of the aerospace mirror opposite the front side; removing material from the green mirror preform to form support ribs on the back side; infiltrating the green mirror preform with silicon to create a reaction bonded (RB) SiC mirror substrate from the green mirror preform; forming a mounting interface surface on the back side of the aerospace mirror from the RB SiC mirror substrate, and forming a reflector surface of the RB SiC mirror substrate on the front side of the aerospace mirror. Additionally, the method can comprise cladding the reflector surface of the RB SiC mirror substrate with SiC to form an optical surface of the aerospace mirror.

What is claimed is: 
     
         1 . A method for preparing an optical surface of an aerospace mirror, comprising:
 obtaining an aerospace mirror having an optical surface on a front side and a mounting interface surface on a back side, the mounting interface surface facilitating mounting of the aerospace mirror to an external support structure in a final installation by coupling with a final installation mounting structure;   assembling the aerospace mirror to a test support base by coupling a test mounting structure to the mounting interface surface, wherein the test mounting structure corresponds to the final installation mounting structure;   measuring the optical surface; and   machining the optical surface.   
     
     
         2 . The method of  claim 1 , wherein measuring the optical surface and machining the optical surface are repeated until the optical surface is within a tolerance. 
     
     
         3 . The method of  claim 1 , wherein measuring the optical surface comprises optical testing of the optical surface. 
     
     
         4 . The method of  claim 1 , wherein machining the optical surface comprises polishing, grinding, lapping, or a combination thereof. 
     
     
         5 . The method of  claim 1 , wherein the test mounting structure comprises a strut with an adjustable length. 
     
     
         6 . An aerospace mirror, comprising:
 a reaction bonded (RB) silicon carbide (SiC) mirror substrate; and   a SiC cladding on the RB SiC mirror substrate forming an optical surface on a front side of the aerospace mirror.   
     
     
         7 . The mirror of  claim 6 , wherein SiC cladding comprises a chemical vapor deposition (CVD) SiC. 
     
     
         8 . The mirror of  claim 6 , wherein the SiC mirror substrate comprises a plurality of ribs on a back side of the aerospace mirror opposite the front side. 
     
     
         9 . The mirror of  claim 6 , further comprising an optical coating on the optical surface. 
     
     
         10 . An aerospace mirror manufacturing assembly, comprising:
 a test support base;   a test mounting structure; and   an aerospace mirror mounted to the test support base via the test mounting structure, the aerospace mirror having an optical surface on a front side and a mounting interface surface on a back side coupled to the test mounting structure,   wherein the mounting interface surface is operable to mount the aerospace mirror to an external support structure in a final installation by coupling with a final installation mounting structure, and the test mounting structure corresponds to the final installation mounting structure.   
     
     
         11 . The manufacturing assembly of  claim 10 , wherein the test mounting structure comprises a strut with an adjustable length. 
     
     
         12 . The manufacturing assembly of  claim 11 , wherein the strut has a negative coefficient of thermal expansion (CTE). 
     
     
         13 . The manufacturing assembly of  claim 11 , wherein the strut comprises six struts.