Titan, the largest moon of Saturn, has a denser atmosphere than Earth and a surface where rain, rivers, and seas are made of liquid hydrocarbons rather than water. And NASA is building a rotorcraft to explore it, because Titan’s physical conditions genuinely favour flight in a way no other body in the solar system does. […] Titan, the largest moon of Saturn, has a denser atmosphere than Earth and a surface where rain, rivers, and seas are made of liquid hydrocarbons rather than water. And NASA is building a rotorcraft to explore it, because Titan’s physical conditions g... [5164 chars]