Early in the morning of May 9, 1972, four A-6 Intruders and six A-7 Corsairs launched off the aircraft carrier USS Coral Sea steaming in the Pacific far off the coast of North Vietnam. The aircraft headed west and dove down low, keeping under five hundred feet. Underneath the planes’ wings were naval mines, barrel-shaped devices that when dropped in the water would sink to the bottom and once activated could detonate upon detecting a passing ship. But the Coral Sea only had enough nosecones for about half the large Mk-52 magnetic mines carried by the Intruders, thus the mines created a lot of drag and slowed the aircraft down, making them vulnerable.
Applied witchcraft: American communications intelligence satellites during the 1960s