Tbc, if the structure is at the same temperature as its surroundings (which is the point of these proposals -- no refrigeration required), then this radiation c

Tbc, if the structure is at the same temperature as its surroundings (which is the point of these proposals -- no refrigeration required), then this radiation cannot be used to visually distinguish the structure from its surroundings. The reason is that all blackbody radiation is the same, regardless of the surface it's coming off of. The inside of every closed and equilibrated oven looks identical, regardless of shape and contents: a uniform glow in all directions. In other words, if there was a human down on the surface who could somehow survive and look around from a nuclear-powered refrigerated spacesuit, they would only be able to distinguish the robot structure by the radiation it was reflecting/emitting other than the blackbody radiation associated with the ambient temperature.