1962: Operation DOMINIC. From Johnston Island, a Thor IRBM carried a megaton-plus hydrogen bomb above 200 miles in altitude. The detonation marked the highest thermonuclear blast by a US bomb, and perhaps the highest of any nation. It also provided the U.S. public with the first display of the major EMP effects of a high-alt nuclear burst. Operation Dominic was a series of 31 nuclear test explosions (“shots”) with a 38.1 Mt (159 PJ) total yield conducted in 1962 by the United States in the Pacific. (DOMINIC Sunset, USAF Image)
