Description: Trex Enterprises Corporation (Trex) proposes technology development to manufacture monolithic, lightweight silicon carbide corrugated mirrors (SCCM) suitable for NASA space telescopes. The manufacturing process for SCCM integrates Trex's patented CVC SiC process technology with ITT's corrugated mirror design. The former technology CVC SiC has been shown to yield an excellent, highly mechanically and thermally stable mirror substrate material, while the latter corrugated mirror concept has been utilized to rapidly and inexpensively fabricate glass mirrors. The SCCM process forms a hollow, closed back corrugated mirror blank by sequentially depositing thin (1-3mm thick) CVC SiC layers onto appropriately designed sacrificial graphite mandrels, which are removed subsequently by burnout in an oxidizing high temperature furnace. Nominally, the hollow SCCM then consists of mirror facesheet layer, a corrugated interior layer and a backsheet layer, each intimately chemically bonded with each other by the CVC SiC layer-on-layer deposition process. The result is a monolithic, highly stiff, mechanically and thermally stable mirror substrate suitable for visible, UV, EUV, x-ray and infrared telescopes. Furthermore, because of the unique fabrication process, minimal after deposition grinding is required, resulting in a cost-effective, rapid deposition process.

Benefits: Lightweight SCCM substrates would have utility in space and airborne telescopes, especially defense-oriented applications (surveillance, tracking, directed energy, etc.). Ground based astronomical observatories utilizing a large aperture segmented primary mirror could also employ SCCM. There may also be utility for the technology in commercial optics for lithography.

Potential NASA applications include UV/optical telescopes such as ATLAST and IR telescopes such as SAFIR/CALISTO, which would benefit from reduced cost of meter-class SiC mirror blanks. The monolithic SCCM substrate will be polishable to visible/UV quality, with surface figure better than 25nm RMS and surface roughness less than 10 Å RMS. Furthermore, cryogenic IR missions will benefit from CVC SiC highly uniform and near zero CTE at cryogenic temperatures, which is expected to outperform any composite, two-phase material solution.