History of submarines few years before the US, and paralleled subsequent US development in this area. In the 1950s, nuclear power partially replaced diesel-electric propulsion. The sailing of the first nuclear-powered submarine, the USN ""Nautilus"" in 1955 was soon followed by similar British, French and Russian boats. Equipment was also developed to extract oxygen from sea water. These two innovations, together with inertial navigation systems, gave submarines the ability to remain submerged for weeks or months, and enabled previously impossible voyages such as the crossing of the North Pole beneath the Arctic ice cap by the USS "Nautilus" in 1958. Most of the
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