This flag is a replica of the one put in place by the astronauts on one of the later Apollo moon-landing missions (Apollo 14,15,16 and 17). The flag was constructed of nylon, and the flag pole had a crossbar to extend the flag (necessary without an atmosphere and wind).
It was transferred from NASA to the Smithsonian in 1974 along with a large shipment of equipment used by astronauts in training.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.