The S-3 Viking was first conceived in 1960s to serve as a next-generation submarine hunter. In the event of a war between NATO and the Warsaw Pact, the U.S. Navy’s most important mission would have been combating the Soviet Union’s large submarine fleet. If the war went nuclear, Soviet ballistic-missile submarines could have wreaked terrible devastation on U.S. cities. And if the conflict remained conventional, then attack submarines would have done their best to sink convoys of American troop ships reinforcing NATO forces in Europe.
During World War II, carrier-based aircraft such as the TBF Avenger torpedo bomber played a major role in sinking Axis submarines. However, the diesel-electric submarines of that era needed to surface frequently to recharge their batteries, exposing themselves to air attack. By the late 1950s, the Soviet Union had begun to deploy its first nuclear submarines, which could remain submerged for weeks, and later months, at a time, and the current S-2 submarine hunters were no adequate for chasing them down.