The goal of deformable mirrors (DMs) is to correct aberrated optical wavefronts in spaceborne electro-optical (EO) payloads. It is used as part of an active/adaptive optics system. A continuous-surface, metal-based DM is highly reliable and less complex to assemble, has better stability of the active surface, is less expensive, and can be manufactured quickly. In addition, metal DM with actuation away from the active surface makes the overall configuration scalable. Continuing our previous work on deformable metal mirrors, this work presents the design, validation, and qualification of an aluminum DM using 25 piezoelectric actuators, which include an actuator in the center of the mirror, to improve the spherical aberration correction accuracy. The optomechanical design and analysis of the deformable mirror assembly (DMA) are also presented for performance and survival loads. Later, a qualification model (QM) was built with vacuum-compatible closed-loop piezoelectric actuators. The correction accuracy was demonstrated at the QM by correcting aberrations in the mirror itself. The QM was successfully tested in the space environment in the ThermoVac for operating temperature limits of 20°C±5°C and demonstrated survivability for storage temperature limits of 20°C±40°C. Likewise, the survivability of QM for launch environments such as sinusoidal and random vibration loads is demonstrated. The successful completion of all these tests has improved the maturity of this technology to the technology readiness level of 7 and is now ready to be configured for the appropriate spaceborne EO payload.
Deformable mirrors (DM) are critical components of active optics systems that are used to compensate for wavefront correction in spaceborne electro-optical (EO) payloads. In comparison to glass mirrors, a metal-based mirror is lighter in weight, has more compact design, is less expensive, and can be manufactured quickly. Furthermore, aluminum has higher yield strength than glass, which is advantageous in the event of mirror deformation. We present finite element (FE) optimization of an aluminum mirror’s active surface for the contradictory requirements of flexibility for mirror deformation and stiffness for mirror fabrication. The active surface thickness considered for optimization is 1 to 6 mm for varied mirror diameters ranging from 80 to 100 mm. Aspects related to mirror fabrication on single point diamond turning (SPDT) machine have been considered during the design stage. We compare correction accuracy targeting more than 95%, peak to peak actuator stroke, and root mean square error for various diameters and thicknesses. The optimized mirror was fabricated using SPDT and tested using an interferometer. Later, a DM prototype was built using commercially available piezoelectric actuators, and targeted aberrations/shapes were generated to demonstrate the accuracy of correction.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.