Lightweight meter class optics for deployable optical arrays

Next generation space-based imaging systems (>4 meters) will require high resolution, timely imagery without substantially adding to system mass or cost. Locating tactical targets from high orbits that provide synoptic coverage requires large aperture imaging. The need for large aperture imaging systems pushes fairing volumetric constraints and launch mass constraints. To satisfy this need for large aperture optics, deployable lightweight optical arrays are required. The Space Vehicles Directorate of the Air Force Research Laboratory (AFRL/VS) has pooled its resources in an effort to enable space-based imaging systems at a reduced payload mass. Currently, AFRL/VS is working on a ground demonstration of lightweight meter class optics (UltraLITE program). The ground demonstration test bed includes a full scale deployable precision structure integrated with an optical-mechanical control system. A lightweight optical array flight experiment is being proposed as a follow-on. To support this initiative, AFRL is investing in two high payoff structures technologies: lightweight support structure for deployed optics and ultralight composite mirrors. The goal of the composite mirror program is to develop subscale lightweight (area densities: 5-8 kg/m/sup 2/) mirrors with residual figure errors of /spl lambda//40 r.m.s. and wavefront errors of /spl lambda//20 r.m.s. These subscale ground demonstration mirrors are to operate in the visible spectrum (650 nm). A composite fixed third surface mirror and a Continuous Fiber Reinforced Ceramic (CFRC) Silicon Carbide (SiC) mirror are being considered as possible candidates for future ground and flight demonstrations of lightweight mirrors.