Army fires the smallest U.S. nuclear device at Nevada; Robert Kennedy watches from the line

By the summer of 1962, the United States and Soviet Union had detonated hundreds of megatons in open air, and Congress and scientists alike worried about fallout drifting across the globe. On July 17, at the Nevada National Security Site, the Army fired a Davy Crockett round tipped with a W54 warhead, the smallest nuclear device the U.S. had built, from a stationary 155 millimeter launcher. It detonated roughly 1.7 miles downrange, 20 to 40 feet above the ground, yielding 18 tons of TNT. Attorney General Robert Kennedy and General Maxwell Taylor watched from the observer line. It was the last near-ground atmospheric nuclear detonation by the United States, though high-altitude Fishbowl tests continued into November 1962…