Prior to Star Wars, friendly robots had already appeared in sci-fi stories such as Tobor the Great (1954), in which robot Tobor befriends a scientist’s child and joins the scientist in adventures ;Forbidden Planet (1956), in which a space crew is rescued by Robby the Robot ; and Silent Running (1972), wherefriendly robots Huey, Dewey, and Louieassist the hero in his adventure, one of them sustaining injury. Hypothetically, Fox might have argueda copyright in the specific combination of a friendly robot allied with democratic heroes fighting a totalitarian regime; but this argument is at least made more difficult by the presence of these characters and ideas in pre-1977 sci-fi.
Additionally, Fox asserted copyright in spaceships which “are made to look used and old, contrary to the stereo-typical sleek, new appearance of space age equipment.”