This is an unflown Mark 4 reentry vehicle (RV) used on U.S. Air Force Titan I and Atlas E/F intercontinental ballistic missiles that were deployed in the early 1960s. It carried a W-38 nuclear warhead. The size and weight of nuclear warheads had to be reduced before they could be carried by long-range missiles. The nuclear warhead for the Titan I ICBM yielded a blast 250 times more powerful than the one that destroyed Hiroshima on August 6, 1945.