A modern nuclear submarine is one of the only machines on Earth that can vanish for months and come back fine. Its nuclear reactor makes electricity for years on end without refueling. Electric machines split seawater to create breathable oxygen and pure drinking water. Carbon dioxide gets scrubbed from the air the crew breathes.
The world’s first nuclear sub, the USS Nautilus, launched in 1954 and changed naval warfare overnight. Earlier diesel-electric submarines had to surface every day or so to recharge their batteries. Nuclear subs don’t. They can patrol deep beneath the ocean for 90 days or more, and the only real limit is how much food the crew can stuff into the kitchen.
Living on a sub is strange. There are no windows, no sunlight, and very little space. Crews sometimes share beds in shifts, sleeping when their replacements wake up. Some subs even run on 18-hour daily schedules instead of 24. Despite all that, hundreds of crew compete fiercely for assignments under the sea.
