Low-Cost Manufacturing of Composite Hybrid Isogrid Mirror (CHIM)

The DoD requires lightweight, stiff and stable mirrors for use in high quality, space-based optical observation and energy projection systems. Current technology uses various types of honeycomb core material with optical and composite face sheets. Thehoneycomb material, while excellent in compression, does not transfer the bending shear loads efficiently enough for truly lightweight optical systems. Honeycomb mirrors also are slow and costly to manufacture.During the Phase I program, Foster-Miller developed a novel mirror system that uses highly efficient truss structures to provide bending stiffness for a thin meniscus mirror face sheet. The Composite Hybrid Isogrid Mirror (CHIM) uses axially oriented,high-modulus fibers to provide an efficient, dimensionally stable, support structure. This structure supported the face sheet using truss elements rather than honeycomb plates and reduced the mirror density to 2.7 kg/m2. The manufacturing techniques reduceand simplify the steps required and thus reduce production cost and schedule.In Phase II, Foster-Miller will develop the CHIM system through a careful plan of design, modeling, and prototype manufacture and testing. Complete development of this technology will provide a mirror system that will enable better, lighter, and lessexpensive optical instruments with an ultimate density goal of 1.2 kg/m2. (P-030064)