Future large aperture space telescopes may use lightweight correctable active mirrors. The Naval Postgraduate School’s Segmented Mirror Telescope (SMT) test bed uses 1-meter silicon carbide (SiC) active mirror segments to form a sixsegment deployable 3-meter telescope. The active segments suffer from residual surface errors after a correction is applied. A deformable mirror is added at the SMT pupil plane to improve this residual error. The large active SMT segment represents the woofer, and a small continuous micro-electro-mechanical system (MEMS) deformable mirror represents the tweeter. A global influence matrix and closed loop constrained least squares controller command the active segment and additional deformable mirror as a single device. An interferometer measures the surface error and provides feedback to the controller. Simulation and experimental results demonstrate a significant improvement in wavefront error compared to a 2-step sequential woofer-tweeter constrained least squares control approach.

Date Published: 22 May 2015
PDF: 10 pages
Proc. SPIE 9469, Sensors and Systems for Space Applications VIII, 946902 (22 May 2015);

Published in SPIE Proceedings Vol. 9469:
Sensors and Systems for Space Applications VIII
Khanh D. Pham; Genshe Chen, Editor(s)