An improved structure and method for building large-aperture lightweight deformable mirrors uses a hinged substrate. In addition to reduced weight, the approach provides rigidity to the mirror, which is necessary for the accurate response to actuator commands and tolerance to disturbances. No stresses are induced in the substrate due to the commanded deformation of the substrate, regardless of the magnitude of the deformation. Any stresses in the substrate structure are those induced due to forces in the face sheet, which are likely to be small using advanced nano-laminate and membrane face sheet technologies. The magnitude of the deformation (dynamic range) is limited only by the actuator stroke, and not by the stresses induced in the substrate. The design therefore accommodates small-force, large-stroke actuators, as opposed to the current designs that use large-force, small-stroke actuators. The invention finds utility in numerous applications, including lightweight large aperture mirror substrate and RF reflector structures.