| The development of lightweight optics through material and structural design has been under investigation over the past several decades: of this work, the greatest achievements have been realized in primary mirror design. A wide variety of mirror materials and structural layouts have been proposed for a range of applications. This thesis describes in detail the major trends in optical light-weighting. Materials and structural designs are discussed such that a database outlining advantages and disadvantages of current approaches has been established. Using this data, materials have been chosen that are best suited for production-scale airborne optical systems: these include aluminum, Zerodur, and a proprietary CANMET metal matrix composite. A test case for traditional mirror configurations has been established using finite element analyses and compared to interferometric data. Peak-to-valley error predicted theoretically was found to deviate less than 1.0 μm from experimental data for the Zerodur mirror, falling within acceptable limits. Using this model, structural light-weighting of the Zerodur mirror was analyzed using circular pockets. It was found that a multiple-pocket design that focused on mass reduction through pocket depth was most advantageous. |
