High Precision Large Deployable Space Reflector Based On Pillow-Effect-Free Technology

Abstract

Existing large deployable reflectors use metal meshes as a reflecting surface (RS) and are characterized by a pillow effect, which in turn reduces the precision of the RS, evaluated numerically in this paper. The paper focuses on results of extensive numerical and experimental investigations in SMART (Shell Membrane Antenna Reflector Technology) for thermo-mechanical and radio-frequency (RF) characterization. The developed SMART reflector concept includes a pillow-effect-free RS made of carbon fibre reinforced silicone composite material (CFRS). The removal of the pillow effect is achieved by giving a slight bending stiffness to the RS material and eliminating the need of tensioning completely. The bending stiffness helps to acquire a double curved parabolic shape while remaining easily foldable. A backside structure of the reflector uses a membrane system, deployed and tensed by radial pantographs. Manufacturing and thermal deformation accuracy of the RS is assessed using nonlinear FEM analyses and photogrammetry measurements of the lab model. Reflectivity and losses of the RS were measured as well. The backside structure of the SMART has been analyzed numerically and stiffness, buckling, and orbital behaviour have been studied using an optimized FEM model. According to the obtained results the SMART with chosen materials and established technologies can be used up to Ku-band frequencies successfully. SMART scaled model building is in progress.