Constitution Upgrades   7-05-2009

Constitution Upgrades and Refit Timeline
XON Gaming Item; Researched, Compiled and Written by Mark_XON

(from the Voyager First Season Technical Manual (draft))


This page shows that the (TOS) Enterprise has always been upgraded over the years. Much of the other material presented here was used to help establish technological levels during different periods, also to provide some small 'correct?' speculations. If you have any comments about this Timeline let me know.

A FASA Group has converted all the dates over to canon with a three column chart, and James Dixon has also converted the dates. I use those converted dates and chart they produced.

About USS Enterprise 1701 Images:
I found it very hard to find the correct images of the USS Enterprise in its various forms of Refit and unfortunately the views are limited. Common problems where finding authentic movie stills. The colors of the images I have here match as closely as possible. I have resized many of these images and poorer quality than the originals. If you want good copies of them they are available on the internet somewhere in a larger and more detail size. Checks the links on the bottom of this page, you may find them there.

The use of the "Enterprise Show"
 in this timeline is with great hesitation. I found during my research that the Show has often moved events to suite there needs, one means is they slightly altered wording of events to establish them occurring at different times. They have even invented MAJOR events that completely altered the overall original feel and ideas of a pre-TOS Star Trek and they keep on doing it, and wrong.

in-particular moving Cochrane's Warp 1 flight (instead of unmanned flight) to an earlier date to explain why Warp 5 is so common so soon. (The top speed of Warp during the ENT time is incredibly high for what has previously been solidly established as much slower)

Technology is an area they have moved dates back to explain why the series has more 'advanced technology' then previously established.

Transporters in ENT where already working, and they 'just' where calibrated for BIO transfers. (something that doesn't occur until much latter, not to mention even existing for cargo use) Another thing with the Transporter is that they where able to beam up a person running, thats not suppose to be able to happen until sometime in TNG era, and any beaming prior to STIII/STIV a person had to be still to get beamed up, then by STIII/STIV the person getting beamed can have some limited movement and except post-start additional 'objects'. The Klingon BoP from STIII had those type of transporters.

Also in ENT they 'just' abandoned Lasers for Phase Pistols, this doesn't realy happen until much later given that lasers are still in use during 2254 on Starfleet Ships.

I could name things they got right but how productive is that? Okay how about grappling hooks...they got that one right.

As far as history-current existence of the well know TOS Alien Worlds and Races.... hmmm not to sure, I didn't imagine the Andorians that way based on events in TOS, and the Vulcans I didn't expect so much emotion or the general feeling that I'm visiting Bajor. Some of the Vulcan stuff is good though.

Oh here's a good one, They had a dead Borg in there sickbay in one episode,  totally giving the show the wrong feel not to mention screwing up canon events. I'm sure in the TNG era they would still have the memory banks from ENT, and in TNG era they wouldn't have had a problem figuring out what a BORG basically was once Q "re"-introduced them.

KLINGON "Bird of Prey" and Cloak?
They had Klingons with "Bird of Prey" Style ships with cloak, when we know Klingons didn't have cloak until after the TOS/TAS/TMP series and the "Bird of Prey" was a Romulan Design traded to the Klingons some time before STIII.

The final episodes in the Mirror Universe that didn't even look like the Pirate Mirror Universe at all. They had a chance to redeem themselves with these episodes but they just didn't do it. The computer generated Gorn was more like something from Jurrasic Park than the TOS Gorn, the voice was okay but it lacked the 1960's reverb effects.

Overall its much too active of a universe, they treat about everything as if its routine and practical, more like a TNG era universe than a mysterious, unknown, and cautious universe. Where's the planets they discover and investigate, where's the common people of these planets, Why is the show rushing the timeline?

Can you have a "Star Trek Series" without Transporters, weapons that are worded to sound like phasers, photons, ... YES you can but they didn't do it that way. Without Transporters there would be more shuttles in the universe, no phasers or photons but variation of lasers and accelerated cannons.  I would enjoy a  bunch of ENT seasons with the TOS flavor of exploring before they make the highly crowed episodes that would be expectable in a -TV Movie- series of episodes. I just hope before they release the videos/DVDs that the effects people go back and fix all the blunders and inconsistencies in the series.



  • Cochrane's Warp Flight. Warp 1 Reached (ENT: Broken Bow)




  • Zefram Cochrane takes his last interstellar voyage. [TOS: Metamorphosis, Star Trek Maps]


  • First contact with Tellarites (61 Cygni) (ref - Fandom)


  • First contact with Andorians (ref - Fandom)


  • A warp-driven Earth colony ship departs Earth.


  • Zephram Cochrane disappears and is presumed dead at age 87 (TOS: Metamorphosis)


  • The Warp 5 Complex is established. (ENT: Broken Bow)




August 2143

  • The Warp 2 barrier is broken twice. (Warp 2.5 reached)


April 2145

  • Warp 3 is reached.


  • April 14: First warp 5 Starfleet Starship, the Enterprise NX-01, is launched. (ENT: Broken Bow)
  • Introduced the Matter/Antimatter powered drive system
  • Maximum of Warp 5 is still a barrier. (Warp 4.4 was reach) (ENT: Broken Bow)
  • Plasma Rifles and Blaster Pistols still in use. (ENT: Broken Bow)
  • Phase Pistols entering service to replace Blaster Pistols. (ENT: Broken Bow)
  • Transporter has been improved for Bio transport. (ENT: Broken Bow)
    (um why did they have transporters at this time? Stupid)


  • Photonic torpedo is developed [ENT: ?] (um photon torpedoes where not made until the TOS, why are they made now?)


  • Enterprise NX-01 returns from its five year mission.


  • Romulan War Starts


  • Transporter invented.


  • Romulan War Ends


  • The Federation is established- UFP founded (TNG Outcast)


  • Warp 6 Engine


  • The Bonaventure was the first Federation Designed Warp Powered ship


  • Subspace radio is still not invented.


  • Early Impulse engine


  • Grahd of Tellar invents the first transporter. The device is unfit for living beings.


  • The 1st Medical Tricorder is invented.


  • The Transporter is perfected for use with living beings.


  • ?Transporters officially incorporated into ship designs?

(2209? or 2206?)

  • The first case of transporter psychosis is diagnosed on Delinia II. (2206 year given in "Realm of Fear", (TNG))


  • Starfleet begins development of the first Photon Torpedo


  • First contact with the Klingon Empire by the Federation (TNG: First Contact episode)


  • The first experiments toward a Quantum torpedo take place [STDS9:TM]
  • Sometime after this a threshold of velocity known as the "time barrier" is broken - which had been preventing high speed warp travel.


  • Starfleet is deeply involved in choosing a heavy cruiser design that will represent Federation interests across known space. The contenders are narrowed down to the Constitution   and Neihardt  classes. The Constitution is adopted, being almost 30% cheaper to fabricate than Neihardt  class components. Only 3 ships comprise this class. [Biraktes Shipyards (Internet)]
  • Pathfinder Constitution  Class, under construction?


  • Warp 6+ reached.
  • Dr. Richard Daystrom invents the Duotronic computer system. (or is it 2242?)
    (25 years prior to TOS: "Ultimate Computer:")


  • The Pathfinder is launched, Constitution  Class

Appearance: Enterprise NCC 1701 Out of Dry Dock: New
Captain Robert April

  • Warp 8 Engine
  • It incorporates a new generation warp drive providing much higher speeds and no time dilation.
  • USS Enterprise, NCC-1701, Starship  class, commissioned (STTNG:TM)
  • Briefing Room [TOS: Where No Man Has Gone Before]
  • Ship chapel
  • Ship theatre
  • Six Recreation Rooms; Tri-Chess and Card Games, Gymnasium-separate rooms for combat sports, such as judo and karate, bowling alley.
  • Crew quarters are located throughout the ship's saucer section; Senior officers usually have larger quarters then junior officers and crewman.
  • Transporter Rooms [TOS: Where No Man Has Gone Before] They are located in the ship's saucer section. The transporter platform has six pads, being able to transport six people at the time. There are additional cargo transporters in the engineering section of the ship.
  • The Sickbay; features an examination room, office, and a medical lab. [TOS: Where No Man Has Gone Before]
  • 14 science labs [TOS: "Operation__Annihilate!]
  • The original starship Enterprise was launched at the San Francisco Fleet Yards orbiting Earth for its first (and April's first) five year mission.
  • I never seen any early photos or drawings of the ship.

Stardate 83759.7, 24 February

  • Montgomery Scott temporarily serves as a senior engineer at the San Francisco Ship Yards, overseeing the refitting of the Enterprise  and three of her sister ships. [TOS: The Galactic Whirlpool]


  • The Enterprise  is re-commissioned following the promotion of Captain April to Commodore.


  • Christopher Pike assumes command of the USS Enterprise, NCC-1701. (TOS: The Menagerie)


  • Enterprise enters refit, see 2254 for closes final appearance.
  • Motion activated control systems, doors and lights existed or added
  • (Phased) laser systems existed
  • Gooseneck intercom units existed or added


  • The phaser and photon torpedo replace the phase cannon and accelerator cannon as the Federation's primary shipboard weapons systems.

Captain Christopher Pike

  • The USS Enterprise, NCC-1701, Starship  class begins its second (and Pike's first) 5 year mission.



  • The Four Years War Officially Starts [FASA]


  • Spock transfers to Enterprise (2252?)


Image Source: ?

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Upgraded Appearance: The Constitution Class from the first pilot (The Cage) (2254)
Designed by Matt Jefferies's The First Pilot version
Captain Christopher Pike

  • The rear nacelle end caps didn't feature round vents or the large balls that were added to the series version. It had a silver vertical rectangle, plain looking.
  • Spikes on nacelle Bussard Ram scoops.
  • Lack of screening inboard on warp nacelle and on the nacelle struts
  • The navigational deflector dish and mount are much larger diameter.
  • The ships appearance is a glossy finish and 'covers the grid pattern on the saucer.
  • Bussard Ram scoops where a deep red.
  • The bridge module is Tall and has a big window instead of using a view screen.
  • Additional markings on top saucer surface, they use a slightly different font than the Series version.
  • Additional paint on the primary hull.
  • Orientation of NCC-1701 markings on bottom saucer surface
  • There were no lights shown.
  • Hull windows. Both pilot models had slightly different patterns.
  • The forward top saucer has only two windows.
  • A row of five rectangular windows with round ones fore and aft along with a  singular rectangular one up near the base of the hull pylon.

Captain Christopher Pike

  • Enterprise returns from its second (and Pike's first) 5 year mission.
  • Enterprise enters refit in (earth?) space dock for about a year of refit work.


  • The Four Years War Ends

Captain Christopher Pike

  • Enterprise starts its third (and Pike's second) 5 year mission.

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  • Enterprise returns from its third (and Pike's second) 5 year mission and enters for a major refit(2261-2264) at space dock lasting for about two years. See 2265 for closes appearance of the ship

Constitution Class Refit (2261-2264)

  • Major bridge upgrade
  • The bridge module undergoes several more minor upgrades.
  • A direct scanner scope (type: SP-HCA/RVS-1) is incorporated onto the Engineering Station.
  • A hardcopy plotter output slot is added to the Science Station.
  • The Helm/Navigation console's warp factor readout and astrogator function monitor boards (of 10 lights each) are replaced with ship's sensors activity monitors (9 lights each).
  • The Helmsman's Station's status board and control panels are replaced with a retractable weapon targeting scope and an all-new helm function panel (a 6x6 board of buttons/indicators with 6 operating modes/overlays).
  • Bridge overhead cove lighting colors are also altered (Communications Station from yellow to green, Science Station from blue to yellow, Engineering Station from red to blue etc.)
  • Engines updated. Engines use four "lithium crystals"
  • Enterprise new systems include two retractable phaser banks (note the upgrade from phased lasers.)
  • Experimental photon torpedo system
  • Turbo lift alterations
  • Transporter upgrades
  • Many of the interior rooms are altered
  • Ship wide elimination of gooseneck intercom units
  • Motion activated control systems are replaced by switches and toggles
  • Ships population is substantially enlarged, rising from 203 to 430.

Captain Kirk

  • James Kirk becomes Capt. of the USS Enterprise, NCC-1701, Constitution   class
  • Refit Continues

Captain Kirk

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  • The Enterprise, under the command of Captain Kirk embarks on its fourth (and Kirk's first) five-year mission.

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Upgraded Appearance: The Constitution Class from the second pilot (Where No Man Has Gone Before, Stardate 1312.4 )
(in ST3, it's mentioned that the Enterprise is 20 years old, but this is not the source of the date)
Designed by Matt Jefferies's, Second Pilot version
Captain James Tiberius Kirk

  • Bussard Ram Scoops no longer feature a protruding pipe or spike.
  • The is no surface detail, including the windows, screens on the pylons and inboard recess' of the engine nacelles and the intercoolers.
  • The most obvious difference between the Production version and the Pilot versions are the number of  windows. Now look at the hull windows. Both pilot models had slightly different patterns. This picture has a row of five rectangular windows with round ones fore and aft along with a   singular rectangular one up near the base of the hull pylon.
  • The Production was slightly weathered while the pilot versions were not. The Pilot version also has a glossy finish.
  • The aft ends of the warp engines had seven rows of black holes and two black horizontal vents, one above the holes, one below.
  • Still no screening inboard on warp nacelle and on the nacelle struts
  • The impulse deck has a pattern of 9 square exhaust holes and the surface is flat and smooth.
  • There is no screening on the intercoolers,  inboard on the warp nacelles and on the nacelle pylons. There was some raised surfaces.
  • The underside of the saucer didn't have a dear drop shape, it was staright, flat.
  • The Bridge Module replaced: some instruments on the main bridge and the colors of the bridge were changed
  • These are of five little numbers that run along the lower hull. The one at the fantail is 1837 with a small vertical line above it. The one up by the warp pylon is 1364, the next lower one is 1300 then 705 and 102 up at the forward end.

Stardate 1329.1 

  • Enterprise has burned out one of its "lithium" crystals from maintaining high warp speed.
  • Shortly after TOS episode #2 "Mudd's Women" Dilithium was introduced.


  • Enterprise Enters Refit

Constitution Class TOS Refit (2266-late 2266)

  • The Enterprise gets a minor refit  See (late 2266) for Appearance
  • Engines Updated- White ball added to aft of Warp Engine.
  • The navigational deflector dish and mount are upgraded to a more powerful and smaller versions
  • Impulse engines up rated.
  • Shuttle Bay up rated with new doors and an observation dome.
  • Paint job changed.
  • Crew rotation
  • The Sickbay underwent several changes, making the room considerably larger by adding a nursery.
  • During the second season: The Enterprise’s Engine room and warp nacelles are overhauled at least once.

Image Source: by Bernd Schneider, based on Charles Casimiro's work

(late 2266)

Upgraded Appearance: Series Updates
Designed by Matt Jefferies's Production version

  • Slightly weathered looking paint.
  • New Screening on the intercoolers,  inboard on warp nacelle and on the nacelle struts.
  • The rear nacelle end caps feature the white large balls.
  • The navigational deflector dish and mount are smaller versions.
  • The upper saucer featured the infamous grid pattern.
  • The impulse engine raised details were slightly different as well.
  • Shuttle bay observation dome.
  • Bussard Ram Scoops where lightened and the black rings where made the color of the ship
  • The B-C deck teardrop shape changed slightly
  • Bridge module was made small and lower to the saucer
  • All the surface detail was  the windows, screens on the pylons and inboard recess' of the engine nacelles and the intercoolers
  • Leading edge of neck support is a darker color
  • Grey area behind the bussard collectors on the under side of the warp engine

Stardate 3087.6 

  • Enterprise in for general repair and maintenance at Cygnet XIV
  • Enterprise receives a temporally computer 'personality' update.

(2267) (Star Trek: Season 1)

  • 12 Constitutions Remain [TOS: "Tomorrow is Yesterday"]
  • Enterprise arrived at Starbase 11 for repairs after being damaged in an ion storm. [TOS: "Court Martial"]

Stardate 3451.9 

  • USS Enterprise is modified by Nomad and reaches WF 14.1

Stardate 3715.3

  • Saucer Separation: Its mentioned the Saucer section can be separated from the engineering and warp drive section. (TOS: The Apple) The method used is explosive bolts. The Saucer can not be reconnected to the secondary hull without construction. The saucer can not "land" on a planet. Its unclear if this was possible since this ships original construction, however there's no refit or upgrade that's mentions anything about this part of the ship..its currently assumed that this ability to separate was in the original design plans.

Stardate ?

  • The first Warp 8.5 engine is built.
  • In (when?) Season 2: engineering room was modified and a dilithium chamber was added. overall dimensions remained identical. (engineering may have also been relocated.)

Stardate (none given)

  • The Enterprise reached warp 14.1 in 2268(or is it 2267?) when sabotaged by an alien name 'Losira' (That Which Survives [TOS])

Stardate 4729.4

  • Enterprise is temporally fitted with the M-5 multitronic unit. M5 computer on Enterprise destroys USS Excalibur.

(2268) (Star Trek:Season 2)

  • Starfleet Photon Torpedoes are fully developed (STDS9:TM).
  • Work Bee goes into production.

Stardate 5031

  • Enterprise  captured by Romulans.  They escape, stealing a cloaking device. (Enterprise Incident[TOS])

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Constitution Class Major Refit Overhaul (2268-227?)
Designed by Matt Jefferies / Mike Minor

  • Complete Refit Overhaul of the Constitution Class Begins.

(2269) (Star Trek:Season 3)

  • Yorktown enters Complete Refit Overhaul [Speculation]
  • - Romulans form alliance with Klingons; Klingons get cloak, Romulans get improved warp drive and improved ship designs. Klingons got the bad end of the deal. Romulans start using Klingon ship designs and quickly phase out their older Bird-of-Prey ship designs.
  • - Kirk acts insane and steals Romulan cloaking device, which Scotty installs on the Enterprise, and the Enterprise cloaks for the first time ever.

(Star Trek:Animated series:Season 1) (Star Trek:Animated series:Season 2)
Upgrade Enterprise Animated: April 2269
Captain James Tiberius Kirk

  • The U.S.S. Enterprise  has a minor refit layover at Starbase 2.
  • Crew rotation.
  • New holographic recreation room
  • Ship's bridge received a secondary exit located just to the left of the main view screen.

(Later in 2269)

  • The Enterprise returns from its fourth (and Kirk's first) 5 year mission. (In Voyager they state this happened in 2270, but late 2269 is close enough considering how people refer to dates and times in casual terms.[VOY"Q2"])

The only shipyard available to do the Enterprise refit was finishing up the refit of the USS Kitty Hawk, Constitution-Class (Refit), San Francisco orbital drydock.
Once final construction was completed, Kitty Hawk was moved to Space dock (Starbase One) for final tests and preparations for launch, while the Enterprise was brought in to begin refit.

  • First experimentation with Single Nacelle Warp Drive. Experimental work with single warp drive nacelles and more than two nacelles yields quick confirmation that two is the optimum number for power generation and vehicle control. [STTNG:TM]
  • U.S.S. Enterprise  in for refit preparations.

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Upgrade: Enterprise, Constitution Class under Refit. (2269-2271)
Designed by Andrew Probert, partly based on Mike Minor's design sketches for Star Trek: Phase II
Other Designers: Joe Jennings, Douglas Trumbull, and Harald Michelson, based on the concepts of Matt Jefferies.

12 May

  • The remaining 4 heavy cruisers to be up rated to "Constitution (II)" specs from "Achernar" configuration are approved. [Ships of the Starfleet (Vol. 1)]

11 September

  • The USS "Excalibur" (NCC-1705) heavy cruiser is re-launched after being converted to "Enterprise" specs. [Ships of the Starfleet (Vol. 1), USS Enterprise Heavy Cruiser Evolution Blueprints, Federation Reference Series]

12 September

  • The USS "Hood" (NCC-1707) heavy cruiser is dry-docked at Starfleet Division, San Francisco Yards, Earth for conversion to "Enterprise" specs.
    [Ships of the Starfleet (Vol. 1), USS Enterprise Heavy Cruiser Evolution Blueprints, Federation Reference Series]

27 October

  • The USS "Exeter" (NCC-1706) heavy cruiser is re-launched after conversion to the "Enterprise" configuration.
    [Ships of the Starfleet (Vol. 1), USS Enterprise Heavy Cruiser Evolution Blueprints, Federation Reference Series]

03 November

  • The USS "Farragut" (NCC-1702) heavy cruiser is re-launched after con- version to the "Enterprise" class configuration.
    [Ships of the Starfleet (Vol. 1), USS Enterprise Heavy Cruiser Evolution Blueprints, Federation Reference Series]

24 November

  • The USS "Constitution" (NCC-1700) heavy cruiser is dry-docked at Star Fleet Division, San Francisco Yards, Earth for major upgrading.
    [Ships of the Starfleet (Vol. 1), USS Enterprise Heavy Cruiser Evolution Blueprints]

Willard Decker

  • Major refitting process
  • The U.S.S. Enterprise  undergoing an extensive rebuild and upgrade while in dry-dock orbiting Earth

Stage 1

  • New engines mounted same haul and saucer. (ST: Phase II)
  • Main Engineering was redesigned, Interior design was drastically changed, now featuring the vertical warp core and the horizontal intermix area. (ST: Phase II)
  • Holographic recreation room updated. (or was completely removed) (ST: Phase II)
  • The Bridge was redesigned, Navigation had a globe to project holographic star maps (ST: Phase II)
  • Interior nearly identical to the original Constitution at this point (ST: Phase II)

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Stage 2
Hull is redesigned.

  • Engineering hull was extended
  • the windows are all new
  • shuttle bay was significantly enlarged (The cargo deck and shuttle bay still are unfinished in 2271)
  • shuttle bay platform and door is new too
  • Ship's engineering systems updated
  • power transfer conduits inside the engineering hull has changed
  • the location of the warp core and main engineering changed
  • double photon torpedo launcher with its rectangular housing
  • internal equipment like wall, floor and ceiling panels and doors is new
  • The deflector dish is not sticking out any more
  • Recreation Room Updated; features a diversity of electronic entertainment
  • complete outer surface is new

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Stage 3
Saucer is redesigned.

  • Saucer and recently updated Bridge where last added
  • New bridge module, again two decks tall. Consoles and stations were updated with new technology, and the chairs were replaced. Features a secondary turbo lift like in the April 2269 minor refit.
  • saucer diameter was extended
  • old engine room doesn't exist any longer
  • the sensor dome and the impulse engines.
  • interior partition has noticeably changed
  • The deflector grid, phaser emitters and windows are entirely new.
  • Medical facilities updated
  • Transporter Room Updated.
  • Saucer Separation updated: Its mentioned the Saucer section can be separated from the engineering and warp drive section. (TOS: The Apple) (TMP Pre-production) The method used is explosive bolts. The Saucer can not be reconnected to the secondary hull without construction. Its possible that the updated refit saucer can land on a planet with the four landing pads on the underside of the saucer.

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  • U.S.S. Enterprise  is still in major Refit.

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Stardate 7400?  or 7412.6

  • Star Trek: The Motion Picture (18 months after the ship's return)


  • In the wake of the success of the linear warp drive and the heavy cruiser refit, Starfleet initiates a large-scale refit and shipbuilding program.

Image Source: Unknown Custom Model (not movie model)

Image Source: Unknown Custom Model (not movie model)

Upgrade: Final Stage, USS Enterprise Constitution Class Refit. (2271)
Willard Decker

  • Warp 9 Engine
  • New Photon Torpedoes developed [STTNG:TM]
  • Final Work and Systems where being tested on the Enterprise.

(late 2271)
Admiral James Tiberius Kirk

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  • USS Enterprise, NCC-1701, Enterprise  class, commissioned. (Enterprise   class may have been referring to a refitted Constitution Class, or may have been just established for the USS Enterprise  itself, which is more likely. The original designers( Andrew Probert) of this refitted model of the Enterprise gave the class name as "Enterprise  class." STII gave evidence on a wall label. Which makes me believe that this class was established for the USS Enterprise   only, either in honor of or perhaps it was fitted with experimental equipment that wasn't yet used in any other Consitution  Class Refit. In all respects the USS Enterprise  is essentially a Major refit, an upgraded Constitution   Class.
  • Enterprise embarks on its fifth (and Kirk's second) 5 year mission.


  • The USS Yorktown Constitution Refit ended and returned to service. External appearance differs slightly than the USS Enterprise. Paint color and details??? [STIV] (I'm uncertain if the external appearance change now or in (2286) in Star Trek IV when the Yorktown was repaired and prepared to be re-commissioned as the USS Enterprise.)


  • The first Warp 9.5 engine is built.


  • Enterprise returns from its fifth (and Kirk's second) 5 year mission. (or is this 2275?)

Captain Spock

  • Commander Spock was promoted to captain of the Enterprise


  • The first Warp 10 Engine is built

Captain Spock

  • Enterprise returns from its sixth (and Captain Spock's first) 5 year mission.
  • Enterprise was retired from exploratory duty and was assigned to Starfleet Academy as a cadet training ship


Kirk Meets Antonia and retires from Starfleet (ref - ST7:Gen)

Upgrade: Constitution Class minor update .(Between STI and STII)

  • Bridge Module Up rated: The bridge stations where moved back to a configuration similar to the TOS style.


  • Transwarp testing bed launched; USS Excelsior.
  • The first Warp 10.5 Engine is built.
  • USS Yorktown enters for another refit


Kirk tells Antonia he's going back to Starfleet (ST7:Gen)

The 2285 date was cannon finalized after years of not knowing when STII took place.  This of course left a huge gap between the first movie and the second and has provided a larger area on the timeline to help explain some inconstancies.

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Stardate 8130.4  Star Trek II: The Wrath of Khan

  • Enterprise is damaged in a sub-light low impulse battle with a Miranda Class Ship



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Stardate 8201.3 (8210.3?)  Star Trek III:  The Search for Spock

  • Improved Transporter Modules introduced; movement paralysis and time suspension is no longer any issue.
  • Enterprise enters space dock for repairs, during repairs some systems where updated.

Upgrade: Constitution Class minor repair and system updates.

  • Bridge Module: The bridge stations received some system updates. (Only a slight variation of the STII Bridge)
  • Repairs where halted, Starfleet decided to scrap the ship, thinking that the age of the ship wouldn't make a repair worthwhile.
  • The unfinished Enterprise is stolen then destroyed



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Stardate: 8390.0 Star Trek IV: The Voyage Home (3 months after [STIII]) (78 years before TNG)

  • The USS Yorktown  is disabled by the "whale" probe near the beginning of the movie. (this event isn't shown on screen)
  • Dilithium Re-crystallization Techniques first discovered.
  • The USS Yorktown  is damaged but is able to enter for repairs.

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  • The USS Yorktown Bridge seen in STIV at the beginning of the movie is not clear if the bridge scene was intended to be a Constitution bridge or not. Apparently AFTER the filming of STIV Gene Roddenberry suggested the Yorktown to be a Constitution Class Ship. The graphical displays behind this Captain somewhat indicate this bridge was of a STII/STIII era design.


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  • At the end of the movie the Yorktown bridge now as the Enterprise-A is that of some up rated variation of the Bridge seen in STII/STIII. Unfortunately this particular bridge design has only been seen briefly at the end of STIV and is replaced yet again sometime before STV.

Upgrade: The USS Yorktown Constitution Class Repair Refit. (It is unclear when all these updates where made, some may have occurred in STIII era and some must have occurred during the repair/minor refit of the Yorktown prior to the end of the STIV movie.)

  • USS Enterprise -A  Bridge module had a major update. [STIV]
  • USS Enterprise -A  Systems and Consoles throughout the ship including Engineering where updated to touch sensitive smooth surfaces [STIV]
  • USS Enterprise -A  Graphic Displays where up rated. [STIV]
  • USS Enterprise -A  Cosmetic changes in bulkhead and flooring design.
  • USS Enterprise -A  Deck layout was changed very slightly.
  • USS Enterprise -A  Outward appearance was altered slightly. [STIV] ( ILM  redid the paintjob on the -A variant)
  • USS Enterprise -A  "core ejection" and "antimatter refill" hatchs on the underside of the secoundary hull are now visually added.
  • USS Yorktown  Re-launced at Earth Space dock as USS Enterprise -A   Variant, "NCC-1701 Alpha". (Specs are that of an up rated Constitution Class Refit of the [TMP])


refits-stiv-enterprise-a.jpg (30228 bytes)

  • USS Enterprise -A  Variant outward appearance changed slightly. Both images from [STIV]. This may have been Yard Changes done to the Yorktown in the early refit operations of pre-TMP, may have been a custom refit or done during the damage repair and minor refit during [STIV] prior to becoming the Enterprise-A.
  • refits-stiv-enterprise-a2.jpg (35480 bytes)

(later 2286 through 2287)

Upgrade: The USS Enterprise-A Constitution Class Refit. (Between STIV and STV)

  • USS Enterprise -A  Experimental systems where installed.
  • USS Enterprise -A  Interiors were redesigned and sections updated,   including a briefing room/formal dinning
  • USS Enterprise -A  A new Bridge module added. (This is the second bridge the Enterprise-A had/ would have been Yorktowns third bridge)
  • USS Enterprise -A  Engineering Section updated.
  • USS Enterprise -A  Transporter Room updated.


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Stardate: 8454.1  Star Trek V: The Final Frontier (2287)

  • USS Enterprise -A  was still in for refit and final testing.
  • USS Enterprise -A  goes on a problematic shakedown cruise and returns.
  • Transwarp testing projects completely abandoned.

refits-stv-enterprise-a.jpg (18812 bytes)

  • USS Enterprise -A  Variant. [STV Image] - Notice that the Contrast and Gamma is a bit high in the film image. This was due to the effects peoples limited dedication to finishing/perfecting there work for the movie.  I'm not sure if there was even any filming light effects done by the movie crew. The ship is pretty much washed out, note the black on the nacelle is 'misty' white, instead of a rich black. If they could have 'raised' the details and keep the 'whitish hull' it would have been a nice change for for a ST movie...perhaps the quadrant they where in had different -lighting- than other areas the ship has been in.


  • The first Warp 11 engine is built.


Upgrade: The USS Enterprise-A Constitution Class Refit. (Between STV and STVI)

  • USS Enterprise -A  Bridge module had a major update. (This is the second bridge the Enterprise-A had)
  • USS Enterprise -A  Interiors were redesigned, including a briefing room/formal dinning
  • USS Enterprise -A  Transporter Room updated.
  • USS Enterprise -A  is outfitted with improved sensors [STVI]


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Stardate: 9521.6 Star Trek VI: The Undiscovered Country

  • The first Warp 11.5 engine is built.
  • USS Enterprise -A  Suffered major structural damage, Enterprise -A  is decommissioned.
  • The remaining Constitutions where decommissioned over the next five years
    one vessel, the USS Constitution, remains officially commissioned, though in service as a museum ship

refits-stvi-enterprise-a.jpg (24591 bytes)

  • USS Enterprise -A  Variant [STVI Image.] This is one of the cleanest shots I ever recall seeing this ship. Notice the various blue tint paint and perhaps some grays. Okay some green too!


(Late 2293) 

refits-stg.jpg (9014 bytes)

Stardate: 9500.0?   Star Trek VII: Generations (TMP era; first 18mins)

The New Updated and Refitted Excelsior Class U.S.S. Enterprise-B  is commissioned, Captain John Harriman commanding. The TMP era Starfleet technology at this point has made the next big leap towards the TNG era.

History records that James Kirk died in 2293, but in fact, Kirk has been pulled into the nexus re-experiencing events of 2284("...9 years ago..."). Then in 2371, Kirk will emerge from the nexus to assist Captain Jean-Luc Picard to save Veridian IV.


  • Captain Scott retires, is missing en route to the Norpin Colony aboard USS Jenolen.


  • The first Warp 12 engine is built.


  • The last Constitution Class starship is removed from active duty. One is retained in the Starfleet Museum.

2311 - No further contact with Romulans for next 53 years


  • The new Modified Cochrane Unit (MCU) warp scale is adopted. (TNG era Scale). All ships now use the new scale, even the ships from the TMPs when they appear on TNG era.


  • Last reported case of transporter psychosis. Federation replaces Active Feed Pattern Buffers with Multiplex Pattern Buffers

2333 - Picard begins serving on Stargazer












  • Class D-12 Bird Of Prey Decommissioned (STVII); Retired from Service because of Defective Plasma Coils; part of the cloaking device. Ionic Pulse directed here will engage the ships cloaking device. Required The Galaxy Class ships bridge console compartment to be manually accessed to target, set modulation and to initiate the pulse. (IN ST7 why didn't the Klingon Ship de-cloak and re-raise shields? or better yet Warp-Out?)


  • USS Enterprise Galaxy Class Launched

(2364) (Star Trek:TNG:Season 1)

  • TNG Series Starts - Started "78 years after" ST4 (2286)  as suggested in its early press reports.

2365 - (Star Trek:TNG:Season 2)

(2366) (Star Trek:TNG:Season 3)

  • A model of a modified Constitution Starship is shown. Among noticeable changes where the Warp engines rotated 90 degrees. (TNG: Booby Trap)
  • On the model the saucer has some black or darkened segmented sections. (TNG: Booby Trap)
  • Constitutions In reserve fleet.(Wolf985) [TNG: "Best of Both Worlds"] 2367?

2367 - (Star Trek:TNG:Season 4)

2368 - (Star Trek:TNG:Season 5)

2369 - (Star Trek:TNG:Season 6)

2370 - (Star Trek:TNG:Season 7) (Star Trek:DS9:Season 2)


  • Star Trek 7: Generations (The TNG Era half of the movie. "78 Years Later (than ST7   2293?)" prompted on screen.) Of course it should read '122 years later'. (78 years after the Enterprise-B was commissioned)
  • Kirk Emerges from the nexus.


  • Starfleet issues plans for the TNG Constitutions Refit.


  • USS Prometheus (NX-59650) (Warp 9.99 Engine (TNG Scale)) launched.

Upgrade: Constitution Class DS9 variants under Emergency Refit. 24th Century Constitution Refit (2374-2377+)

  • Constitutions are removed from Mothball / Reserve fleets and up rated to cover the huge losses incurred while fighting against the Borg and Dominion.
  • 20 Months of Refit
  • Old Equipment is removed


  • New outer Hall
  • Upgraded Warp Core
  • Upgraded Computer Core
  • Nacelles Changed.
  • Ship Systems Updated


  • Saucer Section Changed
  • Improved Sensor Arrays
  • Torpedo Launchers updated
  • Type IX Phaser Array added
  • Crew Accommodations Installed
  • New Bridge Module
  • Shielding Updated
  • Improved Navigational Deflector

(late 2376)

  • Aft Torpedo Launcher Added to TNG Constitution Class


  • Major systems tested
  • Hull painting and markings applied
  • Crew is assigned.


  • Four Constitutions still in service.


Background Sources:

James Dixon's Fandom Chronology
Star Trek Chronology(1993) by Michael Okuda and Denise Okuda
Mr. Scott's Guide to the Enterprise( ) by Shane Johnson - TMP Refit Details and -A variant at the time of STIV