The USS Tranquillity Base (NCC-19585) was a Federation starship that was in service with Starfleet in the mid-24th century. In 2364, this starship was commanded by Rick Sternbach.
In that year, prior to stardate 41775, this ship patrolled the Neutral Zone. While on patrol, the ship received an order from Commodore Joshua Jae of Starfleet Mission Operations Division. According to that order, the Tranquillity Base was to modify its defensive coverage of the zone by increasing sensor drone surveillance in the sectors 045 to 052 while decreasing it in sectors 004 to 010. In these latter sectors, active patrol duty required approval by the Commodore’s office.
At the end of that year, Data read orders received by the Tranquillity Base and several others to investigate claims of a conspiracy among the highest members of Starfleet Command. (TNG: "Conspiracy")