The USS Triton made the first circumnavigation underwater voyage on 25th April 1960. What was the code name of this voyage?

Operation Sandblast was the code name for the first submerged circumnavigation of the world, executed by the United States Navy nuclear-powered radar picket submarine USS Triton (SSRN-586) in 1960 under the command of Captain Edward L. Beach. The New York Times described Triton's submerged circumnavigation of the Earth as "a triumph of human prowess and engineering skill, a feat which the United States Navy can rank as one of its bright victories in man's ultimate conquest of the seas."

The circumnavigation took place between 24 February and 25 April 1960, covering 26,723 nautical miles (49,491 km; 30,752 mi) over 60 days and 21 hours. The route began and ended at the St. Peter and Paul Rocks in the middle of the Atlantic Ocean near the Equator. During the voyage, Triton crossed the Equator four times while maintaining an average speed of 18 knots (33 km/h; 21 mph). Triton's overall navigational track during Operation Sandblast generally followed that of the first circumnavigation of the world, led by Portuguese explorer Ferdinand Magellan from 1519 to 1522.