Optimal design of cored mirror structures

The design and construction of lightweight mirror substrates has been the subject of considerable study in recent years. A consensus has been reached that the best design approach involves two plates connected by an array of ribs and consisting of a single material throughout. Although a single, rib reinforced plate has some advantage over a solid plate in efficient use of material, the two-plate sandwich is even more efficient, and our attention has been focused there. The consensus has not yet progressed to total agreement on preferred rib configurations, thickness, and spacing or preferred plate thicknesses and total thickness. This article attempts to demonstrate that some preferences can be established in general, although modifications may be appropriate for particular applications.