Antireflecting–passivating TiO2–SiO2 double layers on crystalline silicon (Si) were optimized and characterized for space solar cells applications. In the numeric optimization, the MgF2–glass–adhesive–TiO2–SiO2–Si structure was considered. In order to fabricate the TiO2–SiO2 double layer, titanium films were deposited on Si wafers in a vacuum chamber, and then, the sample was annealed in oxygen at high temperatures. Glasses with evaporated MgF2 thin films were bonded to the TiO2–SiO2–Si samples so as to obtain the complete structure. A gain of up to 23.5% in the maximum power is demonstrated for simulated c-Si solar cells using the optimized structure. Characterization of the TiO2–SiO2–Si structure using transmission electron microscopy (TEM) and X-ray reflectivity (XRR) as well as optical characterization are presented.