The aggressive space environment requires high performance materials with excellent thermal, physical, proton, electron, and UV radiation resistance properties. Space solar cells must also maintain excellent transparency over long service lifetimes. Hyperbranched polycarbosiloxanes (HB-PCSOX) and polysiloxanes (HB-PSOX) with octafunctional polyhedral oligomeric silsesquioxane (POSS) branchpoints are formulated with linear polysiloxanes to fabricate high-transmission and robust nanostructured POSS materials that could be tailored to give adhesives, or rigid or flexible coatings as desired. This study by Nita Xu et al. on page 3849 was performed at Michigan Molecular Institute and EMCORE Photovoltaics, and funded by the US Air Force.