The Navy launched the first submarine with a radioactive fuel source in 1954. In 1958, a submarine by the name US Nautilus became the first vessel to reach the North Pole. Submarines back then had diesel engines and needed to dock to refuel. Submarines powered by nuclear energy may operate for around 20 years without refueling. The only constraint on a nuclear submarine’s stay at sea became food supplies. Since then, aircraft carriers powering ᴍᴇᴛʜods have also been developed.