Surface accuracy measurements of a foldable composite reflector

One of the most important points in design of foldable reflectors is surface accuracy tests. Electronic performance depends on surface accuracy of reflective surface. Sufficient surface accuracy can be provided when the reflector is designed correctly and its material is chosen accordingly. This research presents surface accuracy measurements of foldable reflector, which is made of the ultra-thin composite materials, for space applications. The reflector has a flexible shell structure and the reflective surface is supported by a skirt to maintain the structural integrity of the reflector which surrounds the surface. Prototypes of the full-scale reflector with a diameter of 1.5 m and also 2 m were manufactured using carbon/epoxy composite and the accuracy of surfaces were measured. Photogrammetry technique and PhotoModeler software are used for measuring of surface accuracy. Root Mean Square (RMS) error of reflective surfaces at different boundary types is investigated to estimate the gravity-induced structural deformation in the reflector surface. As a result of studies, the RMS error of 1.5 m diameter reflector was found 0.49 mm. Effect of gravity on the RMS error is found to be important due to the structure?s flexibility.