.A submarine to explore in 2040 the largest ocean in the northern hemisphere of Titan, Saturn's largest moon, is among a dozen futuristic proposals of the National Aeronautics and space Administration (NASA) of the United States. Titan, the second largest moon in the solar system after Ganymede, highlighted by the presence of lakes and seas on its surface, although these are not composed of water and earth, they are seas of liquid hydrocarbons.
