Commodore was often mentioned in [[Star Trek: The Original Series]] (TOS) and messages with this rank can be heard in the background at the beginning of [[Star Trek: The Motion Picture]]; however, the rank fell into disuse in subsequent feature films and series. During TOS, a total of six characters appeared on camera as Starfleet Commodores:
The third season of the TOS portrayed no Commodores and a Starfleet Commodore is not seen again until only briefly in the Federation Council Chambers of [[Star Trek IV: The Voyage Home]]. Later Star Trek television series have never had a Commodore appear on camera.
A first season episode of Star Trek: The Next Generation (TNG), entitled "Coming of Age", gave indication that Commodore might no longer be a Starfleet rank in the late 24th century. This is taken from a line of dialogue where CaptainJean-Luc Picard is told that he is to be promoted directly to the rank of Admiral and assume duties as Commandant of Starfleet Academy. Since promotion to Commodore is not mentioned, it may be assumed that the rank was no longer in use. However, in real life, many officers in the BritishRoyal Navy were also promoted directly from Captain to Rear-Admiral (since Commodore was only an appointment of Captain and not a true rank), so this is not necessarily the case.
The FASArole-playing game manual Star Trek: The Next Generation Officer's Manual (which is not considered canon) indicates that Commodore may still have existed during the timeframe of TNG, with the insignia conjectured to appear as five pips worn on a uniform collar.Star Trek: The Next Generation Officer's Manual, p. 8The Star Trek Encyclopedia would later indicate that the rank of Commodore may have been denoted as a single rank pip insignia, enclosed within an Admiral 'rank box' worn on both collars of a uniform.Star Trek: The Next Generation Technical Journal, p. 38
This, however, is contradicted in The Star Trek Encyclopedia where the one pip insignia is indicated as an Admiral (possibly a Rear Admiral (lower half)). It can therefore be assumed that, after the first season of TNG, the rank of Commodore was renamed Rear Admiral (lower half) as it was in the United States Navy after which the rank system in Starfleet is largely based.
In the third season episode of TNG "The Enemy", Lt. CmdrGeordi La Forge – while investigating a Romulan incursion on the planet Galorndon Core in Federation territory – whimsically refers to a Romulan with whom he is trapped as "Commodore"; the Romulan later identifies himself as Centurion Bochra.
In the most recent Star Trek series, [[Star Trek: Enterprise]], the only appearance of a Commodore was in a flashback sequence during the episode "First Flight". In the episode, Vice Admiral Forrest is seen as a Commodore, establishing that the rank existed in Starfleet as early as the mid 2150s.
Junior rank:
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Addendum: Star Trek creator Gene Wesley Roddenberry saw action in WWII, during which the term Commodore was widely used, influencing Roddenberry. Starfleet (TOS) used both Fleet Captain (Whom Gods Destroy) and Commodore to describe Senior Captains, typically in command of a supply base or as captain of a ship (Dekker). Official publications from the 1968/1971 era indicate Starfleet was a young organization with only 14 "star" ships, and express a wild west frontier mentality. In such a situation, flag officers would remain with the home fleet, and senior captains would command expeditionary forces. See the Franz Joseph book.
