The USS Nautilus, the world's first nuclear-powered vessel, is commissioned by the United States Navy. The 325-foot sub, designed by Russian-born American engineer Hyman George Rickover, could remain submerged for almost unlimited periods because its atomic engine needed no air. It could also fire missiles at enemy targets on land or sea from its submerged position. With a speed of over 20 knots, the sub could move faster under water than most vessels could travel on the surface. In 1958, the Nautilus made the first undersea crossing of the North Pole.