This is an unflown Mark 2 reentry vehicle (RV) that carried the nuclear warhead atop the U.S. Air Force Thor intermediate-range ballistic missiles and early test versions of the Atlas intercontinental ballistic missile in the late 1950s and early 1960s. Made by General Electric, the blunt nose is copper and the rest of the metal is stainless steel. It is the only operational "heat sink" RV the United States employed and was designed to protect the warhead from the tremendous heat generated during reentry into the Earth's atmosphere by absorbtion. This artifact was transferred by the U.S. Air Force Museum to the Museum in 1975.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.