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27 December 2001 Final results of the Subscale Beryllium Mirror Demonstrator (SBMD) program
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The Subscale Beryllium Mirror Demonstrator (SBMD) has been fabricated and tested, successfully demonstrating some of the necessary enabling technologies for the Next Generation Space Telescope (NGST) and other lightweight cryogenic space mirror applications. The SBMD is a 0.532-meter diameter concave spherical mirror with a 20-meter radius of curvature fabricated from a single billet of consolidated spherical powder beryllium. The mirror is lightweighted by 90% through the use of open back triangular cells and a thin facesheet. The mirror is mounted to a rigid backplane with titanium bipod flexures. Surface figure requirements at 35K of 1/4 wave p-v (full aperture) and 1/10 wave p-v (1-10 cm spatial frequency) required initial vacuum cryogenic characterization of the mirror. Cryogenic deformation and repeatability were characterized using the Optical Testing System (OTS) at the X-Ray Calibration Facility (XRCF) at Marshall Space Flight Center (MSFC). The mirror underwent cryofiguring to optimize performance and was subsequently tested to verify final performance requirements of surface figure, radius of curvature, and microroughness. Presented here are the final results of the SBMD program, showing that all requirements have been met.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Timothy Reed, Stephen E. Kendrick, Robert J. Brown, James B. Hadaway, and Donald A. Byrd "Final results of the Subscale Beryllium Mirror Demonstrator (SBMD) program", Proc. SPIE 4451, Optical Manufacturing and Testing IV, (27 December 2001);

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