Structures, Pointing, and Control Engineering, A Segmented Reflector Testbed

D. Mirmirani, H.R. Boussalis, and D. Florakis (USA)


Space Telescope, Decentralized Control, Modeling, FEA,


Because of the weight and volume constraints of space borne astronomical instruments, segmented reflectors have become the only practical choice for future astrophysical missions. While a monolithic reflector depends on the mechanical properties of its material to provide the dimensional stability required for good optical performance, a segmented reflector requires an active segment-alignment control system to maintain the alignment of the reflecting surfaces to have the optical performance of a monolithic unit. This paper describes an experimental testbed developed at the Structures, Pointing, and Control Engineering (SPACE) Laboratory at California State University, Los Angeles. The SPACE testbed is a 2.4 m focal length Cassegrain optical configuration consisting of a 2.66 m actively controlled segmented primary, an active secondary and is fitted with a complete ensemble of sensors, actuators, and electronics. The testbed capabilities include figure maintenance of the primary mirror to within 1 micron RMS distortion, a high level of disturbance rejection (100:1), a unique open architecture to support implementation of a variety of control algorithms, self homing, and an optical scoring system enabling pointing with an accuracy of 2 arc seconds

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