Constitution class
The Constitution-class was a Federation , Class I Heavy Cruiser. They were the premier frontline Starfleet vessels in the latter half of the 23rd century2. 

They were designed for long duration exploration and patrol missions with minimal outside support and were best known for their celebrated missions of galactic exploration and diplomacy and were capable of operating on five-year mission cycles.

 History 
 2240s-2260s 
2245 to 2250 Initial class construction, late 2240s

During the mid-23rd century, at least twelve Constitution-class starships were commissioned by Starfleet.3 Construction of the starships occurred at Earth's San Francisco Navy Yards, and Luna's Tranquility Base by 2245. (; ; ; ) 

Constitution-class starships were usually charged with carrying out five-year missions of exploration. (; ; )  

One of the class's designers was Lawrence Marvick, whose work included designing the controls for engineering. () Doctor Richard Daystrom was responsible for the basic design of the computers used aboard this class. ()

Future  captain, Robert April, was present when the ship's unit components were built. () 

Early 2250s

The Constitution-class starship, the USS Enterprise, was the first ship to make official first contact with the Talosians on Talos 4. 

All Constitution-class vessels saw a major refitting sometime between 2254 and 2258. The impulse and warp engines of each ship were upgraded and replaced, with angled pylons for the warp nacelles, however most of the hull plating that was undamaged was not replaced (On the USS Enterprise it was common for crewmembers to sign the oldest piece of the Enterprises hull when playing Enterprise Bingo). The interior of all Constitution-class ships was also heavily modified with the bridge of each ship being replaced. The iconic red-orange accents were added to the interior of each ship. (; ); )  

During the , Constitution-class ships were kept off the front lines, as a unit of last resort.4 At the time, the  was assigned to patrol Sector 006, while the  was ordered to continue its then five-year mission under Captain Christopher Pike. This order took a toll on their crews. () Also during this time, the ships were not Starfleet's priority to keep refitted, as there were more advanced warships to keep the Klingons from taking Federation Space, such as the  and its spore drive. (STD: Season 1 )

The mission parameters for the class meant that its vessels usually operated widely dispersed on their own and that encounters with class sisters were few and far between.  The year 2267, however, saw a gathering of the class when a large group was assembled at Starbase 11 for refitting and repairs. ()

Aboard the Enterprise at least, new colorful Starfleet uniforms were adopted before some other ships. They were seen in use shortly after the Federation-Klingon War. ()

Late 2250s

Constitution-class starships (along with their  counterparts) had a small refit project in 2259, updating the interiors of the ships. The main AI and transporters of each ship were also upgraded. Externally, the ships remained mostly the same; however, the bridge observation deck in front of the bridge was replaced and the external bridge window made of transparent aluminum was made smaller. Windows on the saucer section were also replaced, mostly being moved to the top of the ship. ()

Uniforms on the Constitution-class starships were again updated (SNW: "Strange New Worlds" )

Early 2260s

All Constitution-class starships had another major refit program around 2265, where the main structure of each ship and exterior was radically changed, somewhat back to their original design and appearance from when the class was first launched. The interior of each ship was also heavily modified, with the main bridges of the ships replaced. ()

Late 2260s

In 2266, Constitution-class ships received a small refit, most notably the USS Enterprise when it received critical damage after going through the galactic barrier and had to be repaired. Changes included the replacement of the deflector dish, bridge and impulse and warp nacelles. This refit also brought the class up to date on all the latest technology. ()

Despite the successes of the class, exemplified by the performance of the Enterprise, under Captain James T. Kirk, the mission parameters for the Constitution class also meant that the vessels of the class operated under highly dangerous circumstances, resulting in a relatively high loss rate, and that being assigned to one was hazardous at best. 

In 2267 for example, the USS Constellation under the command of Commodore Matt Decker fell victim to what has become known as the "doomsday machine" when it was on a routine survey mission near system L-374, and both the ship and crew were lost. () Likewise, and less than a year later in 2268, the Vulcan-manned USS Intrepid was lost with its entire crew in a fatal encounter with a huge simple cellular being in star system Gamma 7A of Sector 39J. () Later that year, the USS Exeter became infected with an unknown virus, a residue from biological warfare which had raged on Omega IV and which the ship was orbiting, again killing her entire crew, save for its captain, Ronald Tracey. While undamaged, the contaminated ship was for the time being left adrift. ()

In late-2268, the starships Excalibur, Hood, Lexington, and Potemkin all took part in the disastrous testing of the M-5 multitronic unit, which had been placed in control of the Enterprise. The Excalibur was severely damaged, with all hands lost. The Lexington also was brutally assaulted by the M-5 computer when the unit became unstable. () 

Later that year, the Defiant responded to a distress call from an unexplored sector of space, claimed by the Tholian Assembly. Shortly upon entering the region, the Defiant crew began experiencing sensory distortion, and insanity quickly spread throughout the ship. The ship's surgeon was unable to determine what was happening, and eventually, the insanity induced by the phenomenon led the crew to kill each other.

Three weeks later, Starfleet ordered the Enterprise to mount a search mission to locate the Defiant. On Stardate 5693.2, the Enterprise located her adrift, lost between universes in a space warp. As a result of a later phaser exchange between the Enterprise and two s, a hole was created through the spatial interphase, pushing the Defiant into the mirror universe. ()

The Defiant emerged in the 22nd century mirror universe, where the Tholians of that universe had created the interphase rift by detonating a tricobalt warhead within the gravity well of a dead star. The Defiant was initially captured by the Tholians, but later taken over by the Terran Empire with control of the ship finally passing to . ()

In 2267, the  was a Constitution-class starship of the Imperial  identical in configuration to the prime Enterprise. ()

 2270s to 2290s 

During the early 2270s, Constitution-class starships underwent another major refit program. The actual refitting took eighteen months of work and essentially a new vessel was built onto the bones of the old, replacing virtually every major system, allowing the aging ships to continue to serve with upgraded technology. The USS Enterprise continued to serve in its prominent role following the refit. In the early 2270s, the Enterprise was critical in defending the Federation from several external threats, including the V'Ger probe, after the probe returned home to find its creator, and Khan Noonien Singh. (; ; )

In 2293, a Task force consisting of the Constitution-class , , , , and  was assembled to assist with rescuing of James T. Kirk, and Leonard McCoy from Klingon captivity as part of Operation Retrieve. ()

2360s

At least a few Constitution-class ships remained in service through the 24th century, with at least one ship having engaged the Borg at Battle of Wolf 359. ()

Another ship was preserved in the Fleet Museum in its original configuration. ()

 Technical data 
 Physical arrangement 
The Constitution class featured the saucer section-engineering section-warp nacelle layout common to most Starfleet vessels. All ships of the class of the same level of refit appeared to be identical at first glance, but closer inspection revealed minor detail differences on certain vessels. (; ; etc.)

Various science labs, numbering fourteen in all, () were located in the primary hull in the class's configuration in the 2260s. An officers' lounge and dining area would be located in the aft superstructure beneath the bridge after the 2270s refit.  () There were at least seven turbolifts that serviced the primary and secondary hulls. () The Constitution-class had at least two briefing rooms, one of which was located on Deck 14. () The modular design of the Constitution-class allowed for component separation in times of crisis. The primary and secondary hulls could separate where the connecting "neck" joined the saucer, allowing either section to serve as a lifeboat if the other was too badly damaged.  If an emergency was confined to the warp engine nacelles, it was theoretically possible to disengage and jettison the secondary hull while keeping the bulk of the vessel's main section intact. Any hull separation was considered a dangerous procedure and not always an option. ()

Though not an aerodynamic craft, in emergencies, Constitution-class vessels were able to break orbit and enter a class M planet's upper atmosphere (and maintain altitude control while passing through it) for a limited period of time, conditional on the ship's ability to re-achieve escape velocity. ()

A model of a refit version of this ship present in a holographic simulation of Drafting Room 5 at Utopia Planitia Fleet Yards had the warp nacelles rotated 90 degrees and included additional hatches along both sides of the saucer. ()

 Propulsion systems 

The Constitution-class of starships has been fitted with both lithium and dilithium reactor circuits in the warp drive assembly over its service lifetime. The vessel's standard cruising speed was warp 6, while its maximum cruising speed was warp 8. Warp 9 was also possible for this class of starship, although it was highly discouraged because it was an unsafe velocity. 

The Enterprise was twice modified to achieve a speed of warp 11. The probe Nomad increased the ship's engine efficiency by 57% in 2267 and allowed the ship to reach warp 11, but Kirk persuaded Nomad to reverse its "repairs" because the ship's structure could not stand the stress of that much power, and it would eventually destroy the ship. ()

More extensive modifications were made to the ship by the Kelvans in 2268, who were able to produce velocities that were far beyond the reach of Federation science, allowing the Enterprise to safely maintain a cruising speed of warp 11 while traveling through the intergalactic void. ()

The maximum warp speed recorded for this class by itself was warp 14.1, achieved by the Enterprise due to sabotage to the vessel's warp drive system. While the ship itself was not structured to take that speed for any length of time, the Enterprise was able to maintain that velocity for nearly fifteen minutes. ()

The Enterprise also maintained stability at warp 22 while tractored to a ship going warp 32. ()

Warp Engines

From when the class was commissioned to the 2270s refit, the ship was powered by a horizontal dilithium controlled matter/antimatter reactor. Following the 2270s refit of the class, Constitution-class ships were equipped with a linear dilithium-controlled matter/antimatter reactor assembly, and a pulse dilithium-controlled assembly was installed by the mid-2290s aboard the USS Enterprise. (; ) 

The resulting reaction from the warp core resulted in a high energy plasma, also called warp plasma that was directed from the warp core though pipes (plasma conduits) to the warp nacelles. The warp nacelles contained the warp coils and warp field generator at the back that, when fed sufficient power only a warp core could create, created a bubble around the ship that bended and expanded the fabric of space time in the back of the ship and compressed it in front of the ship, allowing Constitution=class ships to move at speeds faster than light. The warp nacelles of the class were replaced as upgrades were made to the ships, allowing them to go faster because they had better warp coils and field generators. (DIS: Season2, SNW, TOS: Season 1, 2 and 3, TMP)

Impulse Engines
The main sub light drive on Constitution-class starships was an impulse drive, located at the back of the saucer/primary hull section of the ship. The impulse drive consisted of about six engine ports, where fusion exhaust propelled the ship. From the late 2260s onward, the Constitution class' impulse drive system was a twin-port engine, capable of velocities at least warp factor 0.8. () A fusion explosion equivalent to at least 97.835 megatons would result if the impulse engines were overloaded in 2267. ()

Constitution-class starships also had standard maneuvering thrusters, which were essentially cold gas thrusters. The thrusters were mainly located on the saucer section and had a few on the warp nacelles and secondary hull. Thrusters would typically be used when entering/departing drydocks or space docks, as it was within Starfleet regulations for ships to disengage engines and operate on maneuvering thrusters only. Both the saucer and secondary hull were equipped with maneuvering thrusters. (; )

The secondary hull of a Constitution class lacked impulse engines and could only run under thrusters or warp drive if separated from the primary hull.

 Tactical systems 
While the Constitution class was never meant as a warship, the vessel was adequately well-armed for dealing with various threats. Exercising Federation defense policy and if need be sustained conflict was built into them. Thus they carried an array of weapons thus allowing them to hold their own against even dedicated warships of its day.

 Directed beam batteries 

During the early 2250s, Constitution-class heavy cruisers were armed with a complement of directed energy weapons, that possessed enough  to destroy half a continent in a concentrated bombardment. In addition, these vessels carried on board laser cannons, capable of operating on energy fed remotely from the ship. ()

Constitution-class starships typically had three dual-emitter energy weapon banks on the ventral and three on dorsal faces of the saucer. They covered the forward, port, and starboard flanks. Two single emitter aft banks were above the shuttlebay and four midship single emitter banks were located on the ventral surface of the engineering hull.

 Laser cannons 
From 2254 to 2257, Constitution-class vessels were fitted with laser cannons. These were an upgrade to the phase cannons on previous ships in Starfleet, however the laser cannons were quickly replaced by phaser banks once the technology was developed. (; DIS: Season 1 ; SNW: Season 1 ; )

 Phaser banks 
By 2257, phaser banks were standard complement aboard this class of ship. A bank actually consisted of a single emitter and its power supply, though it was common practice to fire two banks at a time and refer to it as a single firing. (; )

Ship-mounted phaser banks had a range of approximately 90,000 kilometers. Like hand phasers, they were capable of being adjusted to stun, heat, or disintegrate targets, including objects or beings in space or on a planet's surface. The focus could be adjusted from a narrow to a wide beam. When only motion sensor readings were available, the ship's phasers could be set for proximity blast and bracket the approximate coordinates of the target. (, )

In the original configuration, a battery of several forward phaser emitters was located on the lower part of the ventral side of the saucer section. Aft firing banks were located above and below the shuttlebay on the secondary hull. There were also port, starboard, and midship phasers. (; ; )

After the refit of the 2270s, Constitution-class ships, phaser power was increased by drawing energy directly from the warp drive. This increase in firepower had a drawback, in that the phasers would be cut off if the main reactor was off-line. This problem hampered the USS Enterprise on at least two occasions, one in the 2270s and again in 2285. (; )

 Torpedo systems 

Early configuration Constitution-class ships originally mounted two forward torpedo tubes on the underside of the saucer section,  and one aft mounted tube at the end of the secondary hull. The number on both the top and bottom of the saucer was later increased to six in the late 2260s. This combined arsenal was powerful enough to destroy the entire surface of a planet. (; ; )

Constitution class vessels in the 2270s and onward had two forward firing torpedo launchers located on the base of the neck on the primary hull, though each tube could fire at least two torpedoes before reloading. (; )

 Deflector shields 

The Constitution-class starship had a powerful deflector shield grid. The shield grid was divided into four segments, referred to as "number one shield", "number two shield", etc. () At full power, with the warp reactor tied into the shield system, it was capable of absorbing and repulsing a bombardment of energy impacts equal to the detonation of 360 photon torpedoes of the type the Enterprise was equipped with at the time, before the shielding power was completely lost. In 2267, for example, the Enterprise survived an attack from the Nomad probe. Nomad fired four powerful bolts of energy, each with the equivalent force of ninety photon torpedoes. The first hit reduced shielding power only by twenty percent. After being hit with the equal force of 270 photon torpedoes, warp maneuvering power was lost. Shields were lost with the fourth hit. ()

The deflector shield grid was much more vulnerable to intense standard phaser bombardment. In 2268, an Orion scout ship was able to cause buckling in some of the shields of the Enterprise after it had made just five attack runs on the ship. On the seventh run, the Enterprise lost one of its four shields. () Other more powerful weaponry could take the shields down even more easily, the planet killer for example could completely deplete a Constitution-class starship's shielding power with only three hits with its antiproton beam. ()

The diversion of all but emergency maintenance power to the shields had the adverse effect of reducing phaser power by fifty percent. () A single detonation of a nuclear warhead less than a hundred meters away could cause internal overloads on the ship and leak radiation through the shields to the outer regions of the ship. () Without the warp reactor to power the shields, the system was not very effective in protecting the ship. With only the impulse reactors powering the shields, a  Klingon battle cruiser could deplete a Constitution-class starship's shielding power with only few passes of disruptor fire. ()

In the 2280s, a Constitution-class starship needed 13.5 seconds to lower and raise their shields when taking a shuttlecraft on board via its tractor beam. Piloting the shuttle manually reduced this time significantly. () During yellow alerts, defense fields were activated to offer basic protection to the main bridge. ()

 Navigational deflector 

The navigational deflector dish on Constitution class vessels was mounted at the front of the secondary hull. The deflector dish was mainly used to deflect/repel debris and other microscopic particles that posed a threat to the ship's and its space time bubble at warp. 

 Bussard ramscoop collectors 

The Constitution class was equipped with Bussard ramscoop collectors that could be used to collect interstellar hydrogen (deuterium) and other particles, however they were not used much beyond that. On the oldest version of the Constitution class, ships such as the USS Enterprise had orange opaque Bussard collectors with spikes on the front; however, when the Constitution class got its first major refit, the new Bussard collectors were transparent. This remained till the Constitution class got its third and final major refit, in which the Bussard collectors were no longer dome shaped and orange, instead being grey. (; ; )

 Transporter systems 
Extravehicular transporter to and from the ship could be accomplished by a number of transporter systems besides the airlocks, which allowed personnel or equipment to be transported over large ranges. The transporter platform featured six small pads, which were numbered clockwise, beginning with the right front. A large section in the middle of the transporter could be used to transport large cargo. A redesigned field generator matrix was mounted into the rear wall of the chamber aboard the refit configuration Constitution-class starships. (SNW: Season 1, TOS: Seasons 1, 2, and 3 )

Aboard the Constitution-class vessels of the 2270s and beyond, the transporter operator stood within an enclosed control pod, which had a floor-to-ceiling transparent aluminum panel through which he or she could view the transport platform. This panel served to shield the operator from the effects of any cumulative radiations emitted by the new transporter machinery, a side effect of the more powerful system. 

A door in the standard transporter room wall led to a staging area where landing parties prepared for transporter. 

 Crew support systems 
 Medical systems 

On the Constitution-class starships in the late 2260s, a sickbay facility was located on Deck 6, which featured an examination room, a nursery, the chief medical officer's office and a medical lab. At least one other medical lab was located elsewhere on the vessel, and was used for biopsy, among other things. Sickbay was considered the safest place to be on the ship during combat. () Many of the tools used in the Sickbay aboard the USS Enterprise, following her launch, were designed by her first medical officer, Doctor Sarah April, as life aboard required frequent improvisation. ()

With the class refit of the 2270s, the medical facilities of the Constitution-class starship were considerably updated. New micro-diagnostic tables were capable of fully analyzing the humanoid body at the sub-cellular level, offering the physician a total understanding of the patient's status.

Another new addition was a medical stasis unit, in which patients whose conditions were considered immediately life-threatening could be placed into suspended animation until the proper cure or surgical procedure could be established.  ()

 Interior design 

The color scheme implemented aboard Constitution-class ships was predominantly red-orange accents alongside dark gray or light gray paneling. These colors were accented with soft white light or multicolored lights installed in floor and wall paneling, and later, in the ceiling. This color scheme was put in and kept from the Constitution-class refit of the mid-2250s to the early 2270s. ( ; ; ; )

In the 2270s, the color scheme varied on ships, changing from a beige tone, with red accents to a predominate overall gray/dark gray toward the 2280s. (; ; ; ; ; )

 Main bridge 

As is typical for Starfleet vessels, the main bridge of the Constitution class was located on Deck 1 of the primary hull.

The command chair was located in the recessed area at the center of the room, in a direct line with the main viewer. This position was equidistant from all the control consoles that operated specific areas of the ship. Consequently, the captain could be immediately updated on the condition of the vessel or its crew during missions, and orders could be given clearly with a minimum of effort. The chair was mounted on a circular pillar, attached to a rectangular footplate that was directly anchored to the deck, giving it considerable support during an attack. It was designed to swivel on the support so that the captain could turn to any member of the bridge crew.

Piloting and navigation functions were carried out at the helm console, located in the center of the room, positioned in front of the command chair. This panel consisted of three main sections.

On the left was a compartment which opened automatically to permit operation of the targeting scanner. Next to this was the main control panel, which operated maneuvering thrusters, impulse engines, and fired the ship's weapons. Directly below this panel was a row of eight flip-switches provided to set warp flight speeds.

The central section of the conn panel was fitted with a number of sensor monitor lights and was dominated by two main features: the alert indicator and the astrogator, which was used for long-range course plotting. The navigator's station had a control panel for entering the course and heading data and the flight path indicator and supplied information on any deviations or course corrections in progress. It also had controls for the weapons systems.

Other stations on the bridge were provided for communications, engineering, weapons control, gravity control, damage control, environmental engineering, science and library computer, and internal security. All stations were normally manned at all times. 

Mounted into the room's forward bulkhead was the main viewscreen. Visual sensor pickups located at various points on the Constitution class' outer hull were capable of image magnification and allowed a varied choice of viewing angles. 

The captain's briefing/ready room was typically located on Deck 2 for easy acess, through on Constitution-class ships that were refitted in the 2250s, since the bridge was removed and replaced on Deck 2, the briefing room was located at the back of the bridge. In the late 2260s when the bridge was again moved from Deck 2 to Deck 1, the briefing room remained on Deck 2, even after the 2270s. 

The computer systems aboard the Constitution-class starship were duotronic based. (; )

 Upgrades 

Only one turbolift serviced the bridge of the original configuration Constitution-class ship. In the late 2260s, some were refit with a second lift on the port forward section of the bridge. () After the major refit in the early 2270s, the bridge aboard Constitution-class vessels would continue to utilize two turbolifts, but both would be located behind the command chair. ()

The bridge of the Constitution-class starships were subject to many minor and major cosmetic changes over their many years of service. In particular, the main bridge of the USS Enterprise seems to have undergone considerable changes in appearance. In the late 2260s, along with the added turbolift, the bridge design changed from a segmented flat-panel peripheral station configuration to a completely circular design, including curved overhead view screens, and railings and steps which matched the arc of the circumference. At the same time, an automatic bridge defense system was also installed that obscured the translucent overhead dome, which did not return until the Galaxy-class bridge. () This marked the beginning of major changes to come which would utilize the updated substructure and, most notably, its systems were fully upgraded along with the refit of the early 2270s. ()

The bridge underwent only a few minor modifications from that point until the destruction of the ship in 2285. The bridge of the , commissioned one year later (in 2286), had mainly cosmetic differences at launch, but by 2287, it had been drastically upgraded to reflect the advances made in computer control technology.  The bridge module had again been replaced by 2293.  The lighter color scheme of the original Enterprise-A bridges had made room for a darker, more militaristic look. (; ; ; )

 Crew lounge and Recreation facilities 

The crew/officers lounge on Constitution-class starships offered an officers' lounge, adored by multiple viewpoints and with tables and a seating area.  

In the late 2260s, the crew lounge was located at the front of the saucer section, just above the three windows below it. (SNW: Season 1 )   

In the 2270s, the crew lounge was located at the stern of Deck 2. It also was also an officers' lounge. Here, four huge view ports afforded a spectacular view of the ship's warp nacelles and space beyond. To the sides, small plant areas held flora from several worlds and a small pool featured freshwater tropical fish. Just forward of this section of the lounge were two privacy areas. In each privacy area, a view screen was mounted into the wall, providing a full exterior tour of the vessel.  ()

In the 2280s, the crew crew lounge was again in the middle front of the saucer and an additional lounge was still at the back of deck 2. ()

In the late 2260s, there were at least six recreation rooms, which included three-dimensional chess and card game tables. There was also a holographic rec room, which was the predecessor of the holodeck. Also aboard were an arboretum, galley, gymnasium, a bowling alley, a theater, and a chapel. (; )

On the Constitution-class vessels of the 2270s, recreational facilities were not just limited to the crew/officer's lounge on Deck 2. One large room in the aft section of the starship's saucer section furnished off-duty personnel with a wide variety of recreational games and entertainment. At the front of the room was an immense, wall-mounted viewing screen. Beneath this was an information display alcove; five small screens exhibited a history of selected vessels called Enterprise. A raised platform in the center of the lower-level floor featured a diversity of electronic entertainment. ()

Crew quarters

Crew quarters were located throughout the saucer section – keeping with Starfleet tradition, Deck 5 housed the senior officers' quarters. On the 2270s refit-configuration vessels, these staterooms were quite similar to the VIP units on Deck 4, with only a few differences.

For most of a Constitution-class starship's life (2240s to early 2270s), the officers' quarters featured two areas, separated partly by a wall fragment. One area was allocated as sleeping area, featuring a comfortable bed, and another as work area, including a desk and computer terminal. Entrance to a bathroom was provided through the quarter's sleeping area. Both areas could be configured to personal preference. (; ) 

From the 2250s to at least 2265, officers' quarters on a Constitution class were larger than in latter half of the 2260s and later due to an increase in a Constitution class' crew compliment size from 203 to 450. (; DIS: Season 2 ; SNW: Season 1 ; )

On Constitution-class vessels in the 2270s, rooms of the senior officers were composed of two areas which were separated by a retractable, transparent aluminum  partition. The room's entrance opened into the living area. A library computer terminal and work desk were provided here. The room's corner circular nook, normally occupied by a dining booth, could be modified at the officer's request. 

The other half of the stateroom was a sleeping area, which held a single large bed that could double as a sofa during off-duty relaxation. A transparent door led into the bathroom area. ()

By the 2290s, the size of officers' quarters was reduced to one large room and crewmen were housed in dormitories with bunk beds due to an increased crew compliment in Constitution-class starships. ()

Landing bay and cargo facilities

Deck 17 was the main access level of the engineering hull. The aft landing bay provided personnel in small craft with a means of entering or exiting the vessel, as did docking port on either side of the level. 

The 2260s configuration of the Constitution class carried a standard complement of 4 shuttlecraft, some of which were Class F. ()

The refit configuration of the 2270s Constitution-class starship featured a new landing bay design. A wide range of Starfleet and Federation craft could utilize this state-of-the-art landing facility. Alcoves on either side of the landing bay provided storage for up to six standard Work Bees, and furnished all necessary recharging and refueling equipment. Additional space was available for the storage of non-ship shuttlecraft. 

Just within the landing bay doors was a force field generator unit, which was built into the main bulkheads on either side of the entry area. This field allowed craft to enter the ship, while at the same time retaining the atmosphere and temperature within the landing bay. 

Deck 18 was the shuttlecraft hanger bay level in the 2270s. It was situated at the widest point of the engineering hull. Much of the deck consisted of open space, as it was the mid-level of the cargo facility; thirty-two cargo pod modules could be stored in the alcoves lining the forward, port, and starboard sides of the bay. 

The shuttle hangar had sufficient room for the storage of four craft at any given time. During normal storage situations, these shuttlecrafts faced aft. 

This deck also housed the vessel's lifeboat facilities. These one-man craft, which escaped through blow-away panels in the side of the secondary hull, were provided for those persons were unable to reach the primary hull in case of an emergency.  ()

Airlocks

Constitution-class starships possessed a number of airlocks permitting direct physical access to the ship. On the ship configuration from the 2270s, one airlock was located at the aft of Deck 1 on top of the saucer section. ()

Yet another airlock was located on the ventral port-side saucer section, concealed by sliding hull plates. It was accessed through a staging area. () Four spacesuit lockers lined one wall, each containing one suit, providing enough to clothe a standard party of four. A small, locked arms cabinet held phasers; communicators, tricorders, translators, and outerwear were contained in a separate cabinet on another wall. 

The next set of airlocks were located on the port and starboard sides of the torpedo bays. The final set were located on the port and starboard sides of the secondary hull at the midline. (; ) These airlocks opened into the ship's main cargo bay. There was also a "gangway"-style airlock on the port edge of the saucer section. ()

Located on the upper surface of the saucer section of the refitted Enterprise were numerous small hatches used for entrance and egress during extra-vehicular activities. (Kirk, Spock, Decker, McCoy, and the Ilia probe used one of these hatches to leave the ship when they arrived at V'Gers "core".) ()

Main engineering

Main engineering was from where the ship's warp was controlled. All thrust and power systems were primarily controlled from this site, and it is also where the main dilithium crystal reactor/warp core was located for most of the ship's life. Life support was controlled separately from Deck 6. (, )

In 2259, the warp core was located in main engineering. The matter and antimatter were directed down into the reaction chamber where the dilithium crystals were and then the resulting electro-plasma was directed through unseen conduits into the warp conduits on the walls in the back of the engineering room to the warp nacelles. ()

In 2266, the warp core was moved to a separate room called the dilithium crystal energizer room, where the main warp reaction occurred horizontally. The warp plasma conduits to the nacelles remained in main engineering but were secured being a grate. () In 2268, the warp core was moved back to Engineering, with the dilithium crystals and main reaction occurring in a dilithium crystal converter. The matter anti-matter reaction still happened horizontally at this time and was still directed into unseen conduits beneath the engineering deck. In late 2269, a new vertical component of the warp core was added to the dilithium crystal converter. ( )

During the 2270s, the interior design of the engineering section was drastically upgraded on constitution class starships, featuring a vertical warp core and the horizontal warp plasma conduits to the nacelle conduits nor being below the warp core. (; )

Main engineering was typically lodged on Decks 14 and 15. Deck 14 was the uppermost level of the engineering hull and was the anchoring framework for the connecting dorsal and the warp nacelle pylons. 

On the forward end of the deck was the engineering computer monitoring room, which encircled the cortical intermix shaft and opens, to the rear, into the engineering computer bay. 

In the 2270s, Deck 15 housed the main engineering room. Located in the center of the room and extending for many levels both above and below the deck, was the warp core. This complex, radically new design in intermix technology, provided operational power for the impulse drive system and furnished enough additional energy to power all other shipboard systems. ()

Both matter and antimatter for this chamber were contained in a series of magnetic bottles, which were housed in pods at the base of the intermix shaft.  ()

Ships commissioned

Appendices
See also 
 Constitution-class decks
 

Appearances
The Constitution-class Enterprise appeared in every episode of SNW, TOS, and TAS (except for ). Episodes featuring other Constitution-class vessels, or the Enterprise for other series, are listed below.
 
 

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Background information
For information on the origin of the Constitution-class designation, please see .

 Interiors
For information on the Constitution-class interior sets, please see Constitution-class sets.

 Registry number
Apart from designing the ship, Art Director Matt Jefferies was also responsible for conceiving its original, famous registry number "NCC-1701". As he explained, "Since the 1920's [sic], N has indicated the United States in Navy terms, and C means 'commercial' vessel. I added an extra C just for fun. Interestingly, Russia's designation is CCC. So The N and C together made it kind of international. After that, I had to pick some numbers. They had to be easily identifiable from a distance, so that eliminated 3, 8 , 6, 9 and 4-none of which is that clear from a distance, That didn't leave much! So 1701 was as good a choice as any. The reason we gave for the choice afterwards was that the "Enterprise" was the 17th major design of the Federation, and the first in the series. 17-01!" (Star Trek: The Original Series Sketchbook, p. 62), "(…) which, incidentally and coincidentally, happens to be very close to the license number on my airplane – NC-17740. But I have never really stepped out and squashed the rumor that the number on the "Enterprise" came off my airplane." ()

 Saucer separation
A saucer separation capability for the Constitution-class was suggested as early as the second season of the Original Series in the original script of its episode , but was never produced as no Original Series script has ever actually called for one. The capability was however envisioned by the producers, "Designed to operate separately from the rest of the ship, the saucer therefore contains all elements necessary for independent operation." (The Making of Star Trek, p. 171) The intent made it even into the official series' internal writer's guide, The Star Trek Guide (third revision, page 15 of the supplement and generally dubbed the "Writer's Bible"), where the saucer section was described to be "in fact a completely self-sustaining unit which can detach itself from the galaxy drive units and operate on atomic impulse power for short range solar system exploration." 

The original saucer separation intent was reconfirmed years later on two occasions, when efforts were underway to revitalize the live-action franchise. Production Illustrator for Star Trek: Planet of Titans, Ralph McQuarrie, stated on several of the concept drawings he had created for a newly conceived Enterprise, "The saucer of the Enterprise (which was detachable) ends up in the shroud. They meet the aliens and had a dramatic finale. These two images are of the Enterprise saucer in the shroud. (…) The disc of the Enterprise would separate from the rest of the ship to land on the surface of planets."  The sketches McQuarrie referred to, of the independently operating saucer section, were published in The Art of Ralph McQuarrie (pp. 124-129). The second occasion occurred when Star Trek: Phase II Producer Robert Goodwin reported in a progress memo dated , "Meanwhile we're having a new model of the Enterprise constructed, with the added bonus of a saucer section which can separate from the engine nacelles, should such a maneuver be a necessary part of some story. This capacity of the Enterprise was described in The Making of Star Trek, although it was never utilized in the first series." (, issue 11, p. 39)

Yet another saucer separation sequence was envisioned by Andrew Probert in 1979 when script treatments for Phase IIs successor, The Motion Picture, were in flux. During a lull in script development Probert came up with an alternative scene in which V'Ger releases a Klingon  battle cruiser. Upon re-materialization the Klingons true to their nature immediately attack the Enterprise. During the battle Kirk is forced to perform a maneuver akin to that of William T. Riker in . Douglas Trumbull liked the idea and had Probert draw up color storyboards to show the sequence. Some of the storyboards were published in , and in The Art of Star Trek, pages 198-199. Probert's concept was not entirely a flight of fancy as the actual studio model, in line with Goodwin's prior memo annotation, was constructed in such a way that a saucer separation could easily be filmed if the need arose – contrary to the Original Series filming model, which was not. () Probert himself remarked in this regard, "The Enterprise was always designed to separate from the Engineering section. I knew about this when I did Star Trek: The Motion Picture. And if you look at the bottom of Kirk's Enterprise[note: original configuration], you'll notice two triangular items, which are two of the landing feet for the saucer. Regardless of whether it was Matt Jefferies' original intention or not, it's sort of the way that "Trekdom" or "Star Trek lore" has labeled those features. So taking my cue from that for Star Trek: The Motion Picture, I placed four landing legs in the bottom of the Enterprise and created a very specific separation line on the dorsal." (Star Trek: The Next Generation USS Enterprise NCC-1701-D Blueprints, booklet, p. 8)

Size

The dimensions of the Constitution-class, 947 feet (289 meters) long for the original configuration and 1,000 feet (305 meters) for the refit-configuration, are the ones that are universally accepted by production staff and fans alike, and propagated in virtually all reference works dealing with the subject, starting with the very first one, The Making of Star Trek, published in 1968. That being said and oddly enough, neither dimension has actually ever been canonically confirmed, as neither dimension was ever seen or referred to in any of the live-action Star Trek productions until 2019.

The original configuration length of 947 feet was first derived from Stephen Edward Poe's reference book, The Making of Star Trek, p. 178, and that dimension has been propagated in every subsequent reference work ever since. However, what Poe did not mention was that designer Matt Jefferies had originally produced that graphic in 1967 as a reference for Poe's employer, model kit company Aluminum Metal Toys for their 1968 second edition retooled USS Enterprise model kit, No. S951 – where the graphic was displayed on the side of the box prior to its publication in the book – and not for the actual Original Series production. Remarkably, the dimension of the starship had been in flux until that time as producer Gene Roddenberry's memo of 24 August 1964 evidenced, "We anticipate a final design might see the ship as 200 feet in length, and thus even a 1½-inch scale would give us quite a huge miniature." This figure, initially accompanied with a crew complement of 203 would actually more or less stand until Jefferies, utilizing his engineering background, recalculated the figures for his design three years later. (The Making of Star Trek, pp. 89, 134)

The original configuration Constitution-class length came closest to canon, when two ship size comparison graphics were featured in the Original Series third season episode . The two computer console graphics, also created by Jefferies, showed a Constitution-class vessel in comparison with a Romulan  battle cruiser and an in the episode barely discernible yardstick. Yet, careful measurement of the production art of the graphic, using the featured yardstick, measured the Constitution-class vessel actually at exactly 900 feet (274 meters). Jefferies later sold his original plan view design art, including that for AMT, in the Profiles in History The Star Trek Auction of 12 December 2001, in order to raise funding for the  charity.

Likewise, the 1,000 feet length of the refit-Constitution-class was never canonically established on screen either, instead generally gleaned from the 1991 reference book, Star Trek: The Next Generation Technical Manual, where it was propagated to the public at large. The Manual itself was based on the internal document Star Trek: The Next Generation Writers' Technical Manual in which Andrew Probert had provided dimensions for most of the more prominent Starfleet vessels until then established in the live-action franchise. In fact, it was Probert himself who took the initiative to introduce the new dimension when he co-designed the refit-Enterprise for The Motion Picture, "I wanted to actually go larger on the size of the ship, not realizing at the time that the Enterprise was originally in drydock for a refitting. Richard felt we should stay with the proportions that we had inherited from Matt Jefferies and Joe Jennings, when they'd designed it for Star Trek: Phase II. So with that as our starting basis. I lengthened the ship to a thousand feet, just a few feet longer than it was, and enlarged the saucer, eventually adding an updated superstructure to the top and bottom of it." 

In turn, Visual Effects Art Director Nilo Rodis adopted Probert's dimension as a yardstick for the multitude of newly-introduced starships designs on the size comparison production art, he had created for , published in a Cinefantastique article (Vol 17 #3/4, 1987, p. 77) almost a decade later, and where the size was actually disclosed to the general public for the very first time. This was not a whimsical act on Rodis' part; since studio models were almost never build in scale to each other, visual effects compositors at Industrial Light & Magic needed some sort of a reference dimensional framework in order for them to take the relative sizes of the newly designed ships into account, when editing their ship effects footage if more that one appeared in a shot, for the interior Earth Spacedock scenes in particular. Rodis' dimensions for the new ships (and spacedock) were reciprocally adopted by Probert for the later Writer's Technical Manual.

Studio models
For information on the Constitution-class studio models, please see:
Constitution-class model (original)
Constitution-class model (refit)
Constitution-class model (retcon)

 Footnotes
1 In  (set in 2254), Pike claims to be responsible for 203 lives. In  (set in 2257), scans show 203 crew members which is explicitly called the vessel's entire complement. However, a display graphic featured in the same episode specifically states that the crew complement is 430 (43 officers, 387 enlisted). This is the implied number of personnel of the ship in  (set in 2268, during a later five-year mission). The 203 crew count originated from Gene Roddenberry's original March 1964 Star Trek is... pitch (p. 9), whereas he had revised the number upwards to 430, "approximately one-third of them female", in the 17 April 1967 third draft of what was now the The Star Trek Guide (p. 7), famed in later Star Trek-lore as the "The Writer's Bible". The latter number was adopted by Franz Joseph for his 1975 Technical Manual, whose "Class I Heavy Cruiser – Constitution Class Starships" specifications in turn became the source for most of these seen on the "Brother" graphic display, thereby de facto elevating the hiterto conjectural specifications to canon.

2 The launch date of the class (for the Starship vs. Constitution-class dichotomy, please refer to: Starship-class background information) has never been established, but the reference book The Making of Star Trek stated on page 203 that the producer's intent was that the "Enterprise-class starships have been in existence for about forty years." Its author Stephen Whitfield, who had full access to production sources, wrote the book during the production of season two, narrowing the class launch window down to the mid-2220s. Interestingly, this meant that the Enterprise was a relative latecomer into the class, as its launch year was generally understood, but not firmly established, to be 2245 by production staffers and as was propagated in numerous reference books afterwards. Greg Jein in his influential "The Case of Jonathan Doe Starship" article also proceeded from this understanding and, taking his cue from the "MK IX/01" annotation on the technical journal graphic Montgomery Scott was reading in , postulated the ship to be of a newer "MK IX" subclass, with the USS Constitution (NCC-1700) as its (sub-)class vessel, in the process trying to make sense of the lower registry numbers by postulating them to belong to older subclasses. Jein postulated the Enterprise as the second MK IX subclass member, hence the justification of the "01" addition to both the registry "NCC-17" and the technical journal graphic as seen, the reasoning adopted by the original registry designer, Matt Jefferies, as he himself had stated above.  It was not until the Discovery episode "Brother" that the launch year of Enterprise was confirmed in canon on a graphic display.

3 There may only be twelve Constitution-class ships as of the first season episode , but the line this was drawn from ("there are only twelve like it in the fleet") has given rise to speculation that the Enterprise should be excluded from the count, meaning there could be thirteen Constitution-class ships as of that date. The twelve-ship assertion was actually supported by production sources, as The Making of Star Trek (pp. 163, 203) clearly stated that, as far as the production staff was concerned, the intent was that there were twelve operational ships of the class foreseen for the second season by the time of its production, the Enterprise included and taking into account the two ships,  and , already established as being destroyed in the first season episode , and already foreseen as mentioned destroyed in the second season episode , respectively. Kirk's statement then neatly corresponded with the twelve-ship assumption; two, the Farragut and Valiant, presumed destroyed before the remark, with the  (in "The Doomsday Machine", and already accounted for by D.C. Fontana in her memo version, though it was still in operation at the time of "Tomorrow is Yesterday" canonically) and  (in "The Immunity Syndrome") being destroyed after the remark. It should be noted that the inclusion of the Valiant was a late addition and that it was not even considered in the first two proposals. This, canonically speaking at least, constituted somewhat of a conundrum, an observation not lost on Greg Jein, as he had noted that the ship in question was already destroyed in 2217, whereas the Constitution-class only became operational a decade later as far as was established by the producers.  While another, new ship would have made more sense, the intent of the producers was clear, the class was retro-applied to the lost ship. Yet, the twelve-ship statement only held true under the supposition that the Defiant – not foreseen by the producers – had not yet been commissioned, which is open to debate; otherwise, and this was implied by the fact that the ship was already fully operational less than a year later, the thirteen-ship number became valid. And indeed, this only became firmly established – and thus canon – when Defiant was in dialog mentioned operational as early as 2256 in the 2018 Discovery episode , meaning that Defiant was not even a recent class addition, but actually one of the older class vessels, its highest onscreen established Original Series-era registry, as devised by Jein, notwithstanding. The teleplay writers for  on the other hand, had already adopted Jein's reasoning with the inclusion of a script note in the final draft script which read, "We'll suggest the Defiant is a slightly newer vessel than Kirk’s ship; the exterior shows slightly more detail...".

After some corresponding with suggestions to and fro, the definitive name list of vessels belonging to the, then still called Starship-class, was agreed upon by the producers (dutifully carried over to the decal sheet of AMT's 1968 re-issue USS Enterprise model kit) at the start of the series' second season, and comprised the following vessels (The Making of Star Trek, pp. 164-165):

Remarks:

4 While the Discovery series has shied away from explaining in canon the in-universe visual configuration differences of Enterprise between "The Cage" and the Original Series, an attempt was made to do so in the 2019 officially licensed in-universe reference book Star Trek: The USS Enterprise NCC-1701 & 1701-A Illustrated Handbook, were it was implied that the upgrades were a temporary measure to meet the crisis situation if the ship was called upon to perform as a "last resort" in the war. Page 34 had it stated that "[m]any of the Enterprises systems had been augmented and enhanced for the mission, to ensure the ship was capable of withstanding any exceptional and extreme conditions in the extreme regions it was exploring," continuing to explain the alterations. Page 54 further implied – rather implausibly, as Kirk's mission was every bit as "exceptional" and "extreme" as Pike's had been – that these alterations were no longer deemed necessary for the subsequent five-year mission under Kirk, and that the ship was therefore returned to the "The Cage"-era configuration, though some upgrades under Pike were "retained", which included the dispensing with of the "spikes" on the Bussard collector caps and the smaller deflector dish.

5 Even though the hologram appearance of the Discovery redesign in the lobby of Starfleet Headquarters can easily be construed as a homage to Pike's ship in that particular era, there had been indications that the latter-day Star Trek producers, responsible for all on-screen Star Trek from Discovery onward, consider it the canon replacement for Jefferies' classic design – that is, in their minds at least. Shortly before its introduction in the season one closing episode , Executive Producer Alex Kurtzman indicated,
"Obviously [Discovery] looks more modern than The Original Series, because we are in a modern world now and if we made the show look that way people would not feel that it was worth the money. That being said, every prop and costume design is filtered through what existed at the time. And do we create the new version of it or do we augment the original design in very subtle ways or do we just leave it alone? And when I say every prop and design choice I mean every [note: "every" emphasized] prop and design choice. So, I think you will see a lot of tips of the hat to devices to The Original Series and the timeline. But, obviously we wanted to create a more modern experience and that necessitated certain adjustments." 
Shortly after the introduction Production Designer Tamara Deverell has added more specifically, "For the Enterprise, we based it initially off of The Original Series. We were really drawing a lot of our materials from that. And then we particularly went to more of the Star Trek movies, which is a little bit fatter, a little bit bigger. Overall, I think we expanded the length of it to be within the world of our Discovery, which is bigger, so we did cheat it as a larger ship."  The implied intent had already accrued credence when the redesign appeared as Kirk's Original Series ship in the  episode  shortly before its holographic reappearance, for all intent and purposes the first actual retconning of the ship in canon – which, incidentally, was all the more remarkable as the interiors shown in that episode adhered more closely to the ones as seen in The Original Series. 

6 Certain ships: While most of these ships were already confirmed as class member in the Original Series, even more emphatically reaffirmed in its 2006-2008 remastered version, the classification of others was more tentatively derived. The Eagle, Korolev, Emden, Endeavour, and Ahwahnee, with their respective registry numbers, were all derived from the Operation Retrieve mission charts artwork, seen in the  DVD, where they were represented by Constitution-class icons. Michael Okuda, who created the mission charts, indicated they were intended to be of this class,
"If I recall correctly, the charts visible on film/video listed only ship names and registry numbers. One can probably glean some class designations from the ship icons in the diagrams. I don't have the original art handy (I think it's archived on Syquest disks, which I don't have the ability to read, even if I could find the disks themselves), but I recall giving the info to Bjo Trimble, and I'm pretty sure she used most of it in her revised Star Trek Concordance. I might note that some of the ship registry numbers came from Greg Jein's interpretation of the starship chart in Commodore Stone's office in "Shore Leave" (TOS). Other registry numbers came from Franz Joseph's Star Fleet Technical Manual or his Starship blueprints. In still other cases, the ships and/or numbers did not come from either source, but were consistent with some fleet status charts I did elsewhere on the Enterprise-A in Star Trek VI. (In other words, there's something that just about everyone will disagree with, but I also hoped that there would be at least something that almost everyone would agree with.) I should also point out that I prepared several charts for the rescue briefing scene, and that not all of them ended up in the final cut of the film. I don't recall which ones were used, or which ones ended up unseen. I do seem to recall that there was at least one chart that had quite a number of registries – mostly, I recall, from FJ's work – that ended up unused." 

7 The Star Fleet Technical Manual lists the Defiant as NCC-1717, though the reference book has since then been considered non-canon and treated as apocryphal by the franchise. On-screen the ship was endowed with the registry number NCC-1764, though it was not discernible in its original appearance in "The Tholian Web".Registry numbers: Although the  and other reference works provided complete registry numbers for many Constitution-class ships, these numbers were until 2006 at best conjecture. Many of the Encyclopedias numbers were derived from Greg Jein's above-mentioned "The Case of Jonathan Doe Starship" article, which assumed that the list seen on the wall at Starbase 11 in  were all Constitutions. Yet, once the 2006 remastered version of the series came along, Michael Okuda made use of the opportunity to marry Jein's conjectural registry numbers, where applicable, to their respective ship names, thereby elevating conjecture to canon for those registry numbers, including that of the Defiant, which actually became the first of Jein's registries to be elevated to canon as it had already appeared in "In a Mirror, Darkly", one year before the remastered version came along. Incidentally, the USS Intrepid (NCC-1631) has only been referenced to in dialog in the original version of The Original Series, but was especially visually retconned into the remastered episode , along with its Jein registry, where it was seen orbiting planet M-11.

8 An USS Intrepid (NCC-1707) has nearly made the list as well as it was slated to make an appearance in The Voyage Home. The name was established in dialog whereas registry and class were established in two with dialog corresponding LCARS graphics that later turned up at . This Intrepid was mentioned in Diane Duane's 1984 novel My Enemy, My Ally as the original configuration replacement for the one lost in "The Immunity Syndrome", whereas FASA's 1985 Federation Ship Recognition Manual (second edition, p. 11) lists the ship in its refit-configuration.  wherein this was to be established was however deleted from the film as ultimately released, along with the corresponding graphics which went unused. For further details, see: "NCC-1707" and "".

9 Uncertain ships: These ships have been listed in various reference works as Constitution-class, but were never canonically established on screen as such, and are therefore of uncertain class. There was another factor to consider – in the Original Series-era, ships that were identified as starships were automatically considered to be of the Starship-class ship, or in later reference works, the Constitution-type starship. This would account for the inclusion of the USS Carolina in this list, plus the unnamed ships from the Starbase 11 chart. The Farragut, Kongo, Republic, Valiant, and Yorktown were from The Making of Star Trek, as discussed above.

10 USS Yorktown: Gene Roddenberry suggested that the  was first designated as , and later recommissioned as USS Enterprise-A, probably because Yorktown was the original name used in Roddenberry's 1964 proposal pitch to NBC. Roddenberry felt that it was very unlikely that a brand-new ship would have been constructed so fast after the destruction of the original Enterprise. () Had this became canon, the Yorktown would have definitively been established as a Constitution-class vessel, which had been the intent of the Original Series producers in the first place. It would have also served as a convenient rationale why Scotty had so much trouble getting the ship into operational order in  after the debilitating effects the Whale Probe inflicted on the ship in the previous outing. The notion of the re-naming was flat-out stated by Michael Okuda as being the case in his Star Trek: The Next Generation Writers' Technical Manuals (2nd edition, p. 6), somewhat toned down in his later published reference works, but emphatically reaffirmed in the even later officially licensed Star Trek Fact Files and the 2010 reference book USS Enterprise Owners' Workshop Manual (p. 38 and on which Okuda served as the technical consultant). The Starfleet practice of renaming a vessel for a very deserving previous vessel was later canonically established in , when the  was rechristened USS Defiant when the original latter was destroyed in the Dominion War. ()
 On a side note; The World War II aircraft carrier  (CV-6), after which Roddenberry named the NCC-1701, was a sister ship of the USS Yorktown (CV-5), belonging to the same Yorktown-class, the other one being the USS Hornet (CV-8), a name also considered by the aforementioned staff in an earlier draft of the names list. (The Making of Star Trek, p. 164) The three class sisters had their finest hour at the  in 1942, where they operated together, but where the Yorktown was lost. The Hornet and the Wasp (CV-18, a scaled down variant of the Yorktown-class and another name considered by the producers) were lost later in the war, leaving the Enterprise the sole class survivor. Like its fictional counterpart, the historical Enterprise has become one of history's most celebrated vessels. Incidentally, the Starfleet renaming practice was carried over from the United States Navy, who introduced the tradition in World War II for its lost in battle aircraft carriers by renaming the later Essex-class carriers after the lost predecessors, and which included Enterprises lost Yorktown-class sisters. Enterprise herself survived the war, but efforts to preserve her as a museum ship failed and she was scrapped in 1958.

Apocrypha

Constitution-class registry

Although not considered canon, several sources have produced a long list of Constitution-class starships. The main source was Franz Joseph's aforementioned Star Fleet Technical Manual, which listed over one hundred Constitution-class ships divided into subclasses: Constitution, Bonhomme Richard, Achernar, and Tikopai. Ships of the class were later expanded by other publications such as Ships of the Star Fleet which included the Endeavour, Enterprise, and Enterprise (II) subclasses. It should be noted that Joseph incorporated all the ship names the Original Series producers had originally proposed at the start of the second season, and had only these listed in his Star Trek Blueprints companion publication.

Ships of the Star Fleet substitutes the following for Star Fleet Technical Manual's "replacement vessels."
USS Truxton (NCC-1728)
USS Confiance (NCC-1729)
USS Bunker Hill (NCC-1730)
USS La Vengeance (NCC-1731)

Apocryphal appearances 
The Constitution-class was present in the alternate Star Fleet Universe, where it served as the backbone of Starfleet from its inception in the Y120s to the advent of the General War and the related deployment of the Chicago-class New Heavy Cruiser. In the Star Fleet Universe, the Constitution design is descended from the Republic-class cruiser, the first in that universe's Federation fleet to possess the saucer and nacelle configuration. (Some of the older ships were refitted into Constitution-class ships over time, while others became part of the Federation National Guard, protecting the major member worlds.) In time, the advent of more advanced technology resurrected the ship design through the Vincennes-class vessels, a parallel evolution to that seen in the change from the TOS-era Enterprise to the TMP ship design. Notably, a number of the ships referred to in the original series (such as the Hood and the Excalibur) or listed in the Technical Manual (such as the Kongo) are expanded upon in the Star Fleet Universe – but due to the licensing restrictions under which ADB operates, the Enterprise herself is not detailed, though her registry is included.

A saucer separation has been depicted in the DC Comics Star Trek: Debt of Honor. Here Kirk used "explosive bolts" to sever the connection between the saucer module and the engineering section of the USS Farragut. The same trick was used again in the DC Comics Star Trek: The Mirror Universe Saga, where Kirk and his crew escaped the self-destruction of the ISS Enterprises engineering section in a last-minute separation. Another Constitution-class ship, the , was shown operating without its saucer section in Marvel Comics  Issue 4; after the crew abandoned the engineering hull via saucer separation due to a failure in an experimental propulsion system upgrade. In the early drafts of Star Trek: The Motion Picture, the Enterprise was to separate the saucer. The 2006 Star Trek: Ships of the Line calendar includes a picture of a separated Constitution-class ship, engaging Klingons – or possibly a Klingon ship flown by the Romulans – in battle.

Constitution-class vessels are prominently featured in fan film productions like Star Trek: Phase II, Starship Exeter (where the USS Kongo has actually performed a saucer separation in its second episode), Starship Farragut, and Of Gods and Men.

The refit version of the Constitution-class was still in service in 2409 as a cruiser in the video game Star Trek Online (though the TOS configuration can be purchased into the game as well). The class has also inspired three 24th/25th century successors: the , , and  classes. The TOS configuration comes with retrofit fore and aft phasers, which are the TV-correct blue phasers. The Exeter-class, which also can be purchased, comes with the ability to fire photon torpedoes which can hunt down cloaked targets. The Discovery configuration, available through "Infinity Promotions", is classified as a "flight deck carrier" with two full squadrons of tactical flyers.

External links

 – article on Matt Jefferies' design of the Enterprise for The Original Series

 – article on the design of the refit Enterprise for The Motion Picture

 – analysis of the several modifications performed on the Constitution-class

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Federation starship classes
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