Northern Fleet Project 42 and 50 ASW vessels). On 1 April 1961, the division was renamed the 2nd Anti-Submarine Warfare Division. On 1 July 1958, the Northern Fleet raised the Soviet Navy ensign over the first Soviet nuclear submarine, K-3 Leninsky Komsomol. Following the 1958 voyage of USS "Nautilus", the "Leninsky Komsomol" (named for Vladimir Lenin’s Komsomol) traveled under the Arctic ice and surfaced at the North Pole on 17 July 1962. Russian submarines have visited the North Pole region more than 300 times since then. Two nuclear submarines of the Northern Fleet made a journey under the Arctic ice cap and
Ice Station Zebra (novel) under the North Pole), , and . MacLean may have been anticipating the excitement of his British readers regarding the upcoming commissioning of the , the Royal Navy's first nuclear submarine. Also, MacLean may have been influenced by press reports about the nuclear-powered submarine USS "Skate" visiting Ice Station "Alpha", located on Ice Island T-3 in the Arctic, on 14 August 1958, as part of the International Geophysical Year (IGY)". At the time that the novel was published, under-the-ice operations by US Navy nuclear-powered submarines were prohibited until SUBSAFE measures had been implemented following the loss of the . "Ice