The Navigation Officer, or Navigator, works very closely with the Conn Officer of a starship. The NO's primary duties are to plot courses taking into account such phenomenon as the effects of quasars, nebulae, tachyon eddies and the gravitational effects of planets. He also must constantly review Starfleet databanks for any hazards to navigation that might exist in the space ahead of the ship. Because of the importance of the position, the Navigation Officer is usually occupied by an officer with the minimum rank of Lieutenant. Years ago the job of starship Navigator and Helmsman (Conn) were held by two different individuals, but by the 2360s Federation starships had become sufficiently automated to allow one highly trained officer to carry out both duties.
With the development of such huge starships as the Invincible-class in the mid 2380s, Starfleet found it more efficient and safer to once more separate the two functions of Conn and Navigation onboard these capital ship types.