Hinged substrate for large-aperture lightweight deformable mirrors: a novel concept

Sarma N. Gullapalli; Thomas Joseph Duffy; Carl D. Crane III; Neil L. White; Harvey Lipkin

doi:10.1117/12.460773

18 December 2002 Hinged substrate for large-aperture lightweight deformable mirrors: a novel concept

Sarma N. Gullapalli, Thomas Joseph Duffy, Carl D. Crane III, Neil L. White, Harvey Lipkin

Proceedings Volume 4849, Highly Innovative Space Telescope Concepts; (2002) https://doi.org/10.1117/12.460773
Event: Astronomical Telescopes and Instrumentation, 2002, Waikoloa, Hawai'i, United States

Abstract

A novel concept for large aperture lightweight deformable mirrors is presented. This new concept is based on using a flexure-hinged truss substrate as opposed to monolithic substrates used in all past and current deformable mirror technologies. With its ability to deform in tangential as well as normal directions, this new concept solves the problem of coefficient of thermal expansion (CTE) mismatch between face sheet and substrate. It takes advantage of the newly emerging face sheet technologies such as nanolaminates that produce extremely lightweight optical quality face sheets and require very small forces to deform them. It also provides rigidity to the thin face sheet mirror, necessary for the uniqueness of response to actuator commands and for tolerance to disturbances. Any stresses in substrate structure are mainly limited to those induced by the forces in the face sheet itself, which are small in the new lightweight face sheets. The dynamic range of deformation is limited only by the actuator stroke, and not by the stresses induced in the substrate. Therefore it drives the actuator design to small force large stroke actuators, as opposed to the current designs that use large force small stroke moment actuators.

Citation Download Citation

Sarma N. Gullapalli, Thomas Joseph Duffy, Carl D. Crane III, Neil L. White, and Harvey Lipkin "Hinged substrate for large-aperture lightweight deformable mirrors: a novel concept", Proc. SPIE 4849, Highly Innovative Space Telescope Concepts, (18 December 2002); https://doi.org/10.1117/12.460773

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