"Well, I'm not telling, 'Acting Captain'."
The position of acting captain or captain pro tem was a position bestowed upon an officer or another individual aboard a starship when the ship's regular commanding officer was unable to command for an extended period of time. The first person eligible was generally the first officer, with the line continuing down the ranks until someone was both physically and psychologically able to command.
History[]
22nd century[]
In 2151, when Captain Jonathan Archer lost consciousness after a fight between the Cabal and Sarin's group of renegade Suliban, T'Pol became the acting captain of Enterprise. (ENT: "Broken Bow")
In 2152, when Captain Archer was on a classified mission with T'Pol, Trip Tucker was the acting captain of Enterprise. (ENT: "The Seventh")
Later that year, Paul Mayweather, temporary captain of the ECS Horizon, joked with his brother Travis Mayweather, citing that "An ensign ought to salute before addressing a captain." Ensign Mayweather laughed it off, reminding him that he was only that "acting captain" and not to "let it go to your head." (ENT: "Horizon")
In 2154, when Captain Archer became obsessed with protecting a Xindi-Insectoid hatchery due to a chemical from the hatchery's eggs, Trip Tucker led a mutiny in order to bring Captain Archer back to Enterprise so that they would be able to continue their mission to stop the Xindi from destroying Earth. During the time that Archer was recovering, T'Pol was the acting captain of the Enterprise. (ENT: "Hatchery")
23rd century[]
After the capture of Captain Christopher Pike and Number One by the Talosians in 2254, Spock became the acting captain of the USS Enterprise. (TOS: "The Cage")
In 2256, Commander Saru became acting captain of the USS Discovery after Captain Gabriel Lorca had been captured by the Klingons. (DIS: "Choose Your Pain")
Later on, after the Discovery jumped into a parallel universe, Commander Saru again became acting captain of the ship due to Captain Lorca leaving to act on his plan to be brought before Philippa Georgiou. (DIS: "Despite Yourself") The crew was ultimately faced with the revelation that the Lorca they knew had been from the mirror universe all along, leaving Saru as acting captain indefinitely. (DIS: "What's Past Is Prologue").
Saru again became acting captain of the Discovery at the conclusion of the Federation-Klingon War of 2256-57, and was in command when the Discovery left Earth for Vulcan to pick up Discovery's new permanent captain. (DIS: "Will You Take My Hand?")
In 2259, Lieutenant Erica Ortegas was made acting captain when Pike, Spock and Lieutenant La'an Noonien-Singh had went down to the surface of Kiley 279 to find out the fate of Number One and others on a botched first contact mission. When a captured Kiley awoke and ran off, forcing Nurse Christine Chapel to hunt him down and re-tranquilize him, Ortegas groaned "Always when I'm in the Captain's chair" suggesting incidents like this happened all the time when she takes the conn. (SNW: "Strange New Worlds")
Later that year, Lieutenant Spock was made acting captain when Pike went on a mission to find a lawyer to defend Commander Una Chin-Riley during her upcoming Court martial. (SNW: "The Broken Circle")
In 2266, with Captain James T. Kirk being detained by the staff on Tantalus V, Spock was the acting captain of the Enterprise and referred to himself as such in the ship's log. (TOS: "Dagger of the Mind")
In 2269, with Kirk, Spock and Doctor Leonard McCoy on Planet Two of the Taurean system, Chief engineering officer Montgomery Scott was acting captain, as noted on his ship's log. However, when he and the male crew of the Enterprise fell under the "siren's song" that brought them there, Lieutenant Nyota Uhura took command. (TAS: "The Lorelei Signal")
24th century[]
While under the influence of the polywater intoxication, Wesley Crusher deemed himself "acting captain" of the USS Enterprise-D in 2364 after commandeering the ship from engineering. (TNG: "The Naked Now")
Later that same year, while the Enterprise-D was on Minos, Lieutenant Geordi La Forge was made acting captain when Captain Jean-Luc Picard and Doctor Beverly Crusher beam down to aid in the rescue of other crew members trapped on the planet. Chief Engineer Lieutenant Logan attempted to pull rank and give command ship to him, but rebuffs him and later requests his help in Saucer separation. When the danger passed, Picard allowed Geordi to remain in command until the saucer was returned (TNG: "The Arsenal of Freedom")
Lieutenant Commander Data became acting captain of the Enterprise in 2367 when Captain Picard was incapacitated due to a lack of REM sleep. (TNG: "Night Terrors")
Three years later, Data again became acting captain when both Captain Picard and Commander Riker were held captive by Arctus Baran. (TNG: "Gambit, Part I", "Gambit, Part II")
On several occasions from 2372 until 2375, Lieutenant Commanders Worf and Jadzia Dax were made acting captain of the USS Defiant for missions in the Gamma Quadrant and during the Dominion War. Captain Benjamin Sisko was the commander of Deep Space 9, which during the war was the headquarters for the Federation Alliance, and would often demand his close attention. As such he would entrust to his most senior Starfleet officers command of the ship and its crew. (DS9: "Rejoined", "Paradise Lost", "Call to Arms", "Behind the Lines")
Several members of Red Squad were promoted to acting officers. (DS9: "Valiant")
Aboard the Silver Blood USS Voyager, its copy of Ensign Harry Kim assumed command of the starship as the highest ranking surviving officer, after his own senior officers had dissolved. (VOY: "Course: Oblivion")
In 2381, Lieutenant junior grade Brad Boimler was briefly promoted to acting captain of the USS Cerritos during the conflict with Nova Fleet while Captain Carol Freeman was off of the ship rescuing Lieutenant Beckett Mariner. (LD: "Old Friends, New Planets")
In 2383, Dal R'El appointed himself acting captain of the USS Protostar, (PRO: "Lost and Found", "Starstruck", "Kobayashi") which lasted through the ship's destruction in 2384. (PRO: "Supernova, Part 2")
In 2384, Dal -- who had been serving as acting first officer -- briefly served as acting captain on the temporally-displaced Protostar as Captain Chakotay was preparing himself for the ship's rendezvous with the USS Voyager-A. (PRO: "Cracked Mirror")
In 2385, when the former Protostar crew was assigned to the USS Prodigy, Dal chose to serve as acting first officer instead and made Gwyndala the ship's acting captain. (PRO: "Ouroboros, Part II")
In 2399, William Riker identified himself as acting captain of the USS Zheng He after briefly returning to active service to help Admiral Jean-Luc Picard against the Romulans. (PIC: "Et in Arcadia Ego, Part 2")
25th century[]
In 2401, Seven of Nine was given a field promotion to acting captain by Admiral Jean-Luc Picard. (PIC: "Farewell")
Later that year, William Riker identified himself as acting captain of the USS Titan-A after the ship's commanding officer, Captain Liam Shaw was injured and transferred command of the Titan to Riker. (PIC: "Seventeen Seconds", "No Win Scenario") When Shaw was later mortally wounded, he transferred command to Seven of Nine. (PIC: "Vox") Following the destruction of the Borg, Seven was officially promoted to Captain of the rechristened USS Enterprise-G by Tuvok on behalf of Stafleet Command. (PIC: "The Last Generation")
Alternate reality[]
In the alternate reality 2233, Lieutenant George Kirk, first officer of the USS Kelvin, became acting captain of that vessel after Captain Richard Robau was forced to leave the ship and was subsequently killed. Captain Christopher Pike, who later wrote a dissertation on the incident noted that Kirk was captain of a starship for a mere twelve minutes but saved the lives of the eight hundred crewmembers aboard the ship. (Star Trek)
In 2258 in the same reality, Captain Pike of the USS Enterprise appointed Commander Spock acting captain and George Kirk's son, Lieutenant Kirk, as first officer when Pike left the ship to confront Nero. Subsequently, Kirk proved that Spock was unable to perform his duties and then Kirk himself was made acting captain. After everything was over, Kirk was promoted to the rank of captain and given regular command of the ship. (Star Trek)
Later, in 2259, Kirk placed Hikaru Sulu in charge when he and other members of his crew flew a K'normian trading ship to Qo'noS to apprehend John Harrison, a move which Leonard McCoy questioned, saying, "You just sat that man down at a high-stakes poker game with no cards and told him to bluff." Kirk rebuffed his concerns. (Star Trek Into Darkness)
As acting captain, Sulu ordered the refueling and preparation of the K'normian ship for Kirk and his team. He also delivered an ultimatum to Harrison that impressed McCoy and caused the doctor to revise his earlier opinion. (Star Trek Into Darkness)
When Kirk was aboard the USS Vengeance and the Enterprise was falling towards Earth, Spock, in the role of acting captain, ordered the entire crew to evacuate the ship while he remained behind to ensure their safety until they did. Sulu and the rest of the bridge crew declined, strapping themselves in. (Star Trek Into Darkness)
32nd century[]
In 3189, Saru identified himself as acting captain of Discovery to Philippa Georgiou. (DIS: "Far From Home")
In 3191, Lieutenant Commander Gen Rhys briefly served as acting captain of Discovery while both Captain Michael Burnham and Commander Rayner were onboard the Eternal Gallery and Archive. (DIS: "Labyrinths")