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USS Enterprise in spacedock

The Enterprise undergoing a refit

"I know engineers, they love to change things!"

Refit, retrofit, or maintenance overhaul was the processes by which a piece of technology (such as a starship or any of its components) was overhauled and re-outfitted with newer technology.


A refit was the installation of new or updated equipment aboard a starship, such as new nacelles, nacelle pylons, impulse engine, phaser banks, shields, or hull plating to replace damaged or outdated components. A refit is a more in-depth change to a vessel than a retrofit but stops short of being a complete transformation of the vessel's overall structure. A refit required some form of spacedock in which the work to be done. (Star Trek: The Motion Picture; Star Trek V: The Final Frontier; Star Trek VI: The Undiscovered Country)

During the mid-22nd century, the Romulans modified one of their warbirds into a drone ship. (ENT: "The Aenar")

The Enterprise NX-01 underwent several refits over the course of ten years. the first refit occurred in 2153 when the Enterprise was retrofitted with photonic torpedoes. Sometime after January 2155, the Enterprise underwent a massive refit that which saw the addition of an underslung secondary hull, as well as a larger deflector dish. (ENT: "The Expanse"; PIC: "The Bounty")

The original USS Enterprise underwent at least 5 major refits over the course of its life, usually during downtime between five-year missions. The last major refit of the ship began in 2270 and required eighteen months in Spacedock. It involved replacement or reconstruction of a majority of the ship's systems, including the weapons systems and warp drive. Most noticeable of the changes in this refit were new nacelles and nacelle pylons. (TOS: "The Cage", "Where No Man Has Gone Before", "The Corbomite Maneuver"; DIS: "Will You Take My Hand?"; SNW: "Strange New Worlds"; Star Trek: The Motion Picture Star Trek IV: The Voyage Home)

In 2260 of the alternate reality, the USS Enterprise was repaired and refit with a new, wider impulse engine as well as new warp drive components on the fins of the warp nacelles for her first five-year mission. By 2263, the nacelles were replaced with slightly smaller units and the nacelle pylons were swept back away from the primary hull. (Star Trek Into Darkness; Star Trek Beyond)

Following the Enterprise's battle with the USS Reliant, Montgomery Scott informed Admiral James T. Kirk that the refit time required until the ship could be taken out again would be eight weeks, but that he could do it in two. Kirk then noted Scotty's propensity to multiply his repair estimates by a factor of four, to which Scotty replied, "How else can I keep my reputation as a miracle worker?" However, Admiral Morrow stated that there would be no refit of the Enterprise, choosing instead to decommission her and reassign Mr. Scott to the USS Excelsior. (Star Trek III: The Search for Spock)

The USS Enterprise-D underwent a computer refit during its first year (TNG: "Datalore") as well as a very extensive refit after the Borg incursion in 2367. (TNG: "The Best of Both Worlds, Part II", "Family")

The USS Lakota was refit in 2372, just before Benteen took command. The refit included upgrades to the weapons systems beyond the norm for an Excelsior-class ship, including quantum torpedoes. (DS9: "Paradise Lost")

In 3189, the time-displaced USS Discovery received several upgrades as part of a refit to make her suitable for the era, this included detached nacelles, a modified navigational deflector, programmable matter control surfaces, and an enhanced Spore Hub Drive control system. Her registry was also changed by adding a hyphenated letter: A. (DIS: "Scavengers") The vessel was also equipped with a cloaking device. (DIS: "Su'Kal")


A retrofit was the installation of updated equipment aboard a starship. It differs from a refit in that the vessel's overall structure remained unchanged in the process – the components in question were simply swapped out. A retrofit did not always require a spacedock.

A common type of retrofit was to switch out the bridge module of a starship. Bridge modules might appear radically different from previous versions, while the structure of the starship remains the same. (Star Trek: The Motion Picture; Star Trek V: The Final Frontier; Star Trek VI: The Undiscovered Country; Star Trek Generations)

The concept of replaceable bridge modules was developed to explain why the bridge of the Enterprise and USS Enterprise-A appeared completely different over the course of various films, or the USS Enterprise-D between Seasons 1, 2 and 7 and Generations.

In 2369 Deep Space 9's airlocks were being retrofitted, as nearly all of them had been damaged. (DS9: "Emissary")

In late-2370, Captain Keogh asked Chief O'Brien to retrofit Deep Space 9's Danube-class runabouts with an extra complement of photon torpedoes prior to joining the USS Odyssey on a rescue mission to the Gamma Quadrant. (DS9: "The Jem'Hadar")

In early 2372, Benjamin Sisko told Kasidy Yates that Deep Space 9 was being retrofitted with upgraded weapons systems. (DS9: "The Way of the Warrior")

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