Titan was a moon of Saturn, the seventh planet of the Sol system. Its (Galifreyan-style) coordinates were "quadrant 62 WHI 12 12 9990 EX 41"
It was the homeworld of notorious criminal Dirk Slipstream. (NSA: Night of the Humans)
A small base existed on the surface of Titan. In the year 5000, the Fourth Doctor destroyed the moon when the base was infected by The Swarm. He ignited fuel tanks in the titan base, amplified by the methane in the air the surface errupted. (DW: The Invisible Enemy)