This silver dollar (proof) is one of two commemorative coins issued by the U.S. Mint to celebrate the 150th anniversary of the Smithsonian Institution in 1996. It depicts the Smithsonian Castle and laurel branches (obverse) and an allegorical figure bearing the torch of knowledge (reverse) with anniversary dates and other inscriptions. The commemorative set also includes a gold five dollar coin (proof). Two sets of these coins were flown aboard Space Shuttle "Atlantis" on the STS-79 mission in September 1996 and then presented by the crew in a ceremony at the National Air and Space Museum in December. One set remains in this Museum and the other is held in the Numismatics Collection of the National Museum of American History.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.