These are hold-down arms for the Saturn 1. The Saturn 1 was an uncrewed launch vehicle used to test the propulsion and aerodynamics of what would become the Saturn V, the launch vehicle for the Apollo lunar missions. The first Saturn 1 launch took place at Kennedy Space Center, Florida, in October 1961. Its last three flights placed Pegasus meteroid satellites into orbit. The final Saturn 1 launch took place in July 1965.
Hold-down arms were used to restrain the giant Saturn 1 for nearly four seconds after ignition, until sufficient thrust had been developed for lift-off. The Saturn 1 used eight arms, which were spread equally around the top of the launch pad pedestal. The arms here are likely early developmental models.
The arms were transferred to the Smithsonian in 1974 from NASA's Marshall Space Flight Center.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.