The Galaxy class was developed to replace the ageing Ambassador and Oberth class starships as Starfleet's primary exploration vessel. The design was initiated in 2343 with a highly challenging specification which called for a ship based on the Nebula design then being developed, but equally capable of scientific, exploration, diplomatic, cultural, and combat roles all within a single multi-mission hull. In fact, many came to regard the requirement as too challenging; the project suffered from numerous delays due to a wide range of design, manufacturing, and construction problems. The first of the class, the USS Galaxy, was launched in 2357 and commissioned in 2362, nearly two decades after initial approval.

The USS Galaxy which emerged from the Utopia Planitia shipyard had very similar lines to the Nebula class. The Galaxy is slightly larger in volume, although its less compact design gives it considerably greater length than the smaller vessel. The major change between the two is the lack of a mission specific pod on the Galaxy class, the increased volume allowing sections within the hull to be mission customized. This combined with a more advanced systems level to allow all functions to be performed by the single design. In addition the saucer and engineering hulls are separated by an eleven deck connecting neck section. This separation between the two hulls allows the nacelles to be located outboard and above the engineering hull, a position which increases the efficiency of the warp drive field slightly. This gives the Galaxy class warp coils an efficiency of 88% at speeds of up to Warp 7 and 52% through Warp 9.1 - the comparable figures for the Nebula class are 84% and 47% respectively.

The increased internal volume allowed for 800,000 square metres of mission adaptable facilities. This allows the Galaxy class to support a wide range of ongoing research projects independently of the vessels primary mission. Although not a new idea in Starfleet vessels, the Galaxy class is unique in the extent to which this is possible. These ships are capable of supporting up to 5,000 mission specialists, while the decentralized nature of the secondary power grids allows laboratories to function effectively even during combat operations.

The combat capability of the Galaxy class was also significantly greater than that of the Nebulas. The three burst fire torpedo tubes are each capable of launching ten photon torpedoes every six seconds, while there are no less than twelve Type X phaser arrays. As with many recent Federation designs, the use of long phaser arrays rather than banks gives the main phasers of the Galaxy class a great capability for sustained firing and rapid recharge/cool down time. The Galaxy class is the first on which all segments of every phaser array are supplied by a separate power system; although this increases the complexity of the system tremendously, it gives the phaser arrays a tremendous survivability in the face of combat damage.

In service the Galaxy class at first proved exemplary, but by 2371 no less than three of the initial six ships had been lost, one with her entire complement of crew and families. This alarming record led to many changes being introduced during refits of the remaining three vessels, and also to the construction of six new Galaxy class ships from space frames held in reserve against future need. The unfortunate history of the Galaxy class vessels combined with the recent escalation's in tensions within the alpha quadrant has led to all six vessels being subsequently completed, and all are now on active service against the Dominion.

Major changes to the Galaxy class have included a new more powerful warp core, a redesigned shield system intended to perform far better against phased polaron beam weapons, various changes to the ships computer systems, plus many minor changes to the ships systems. There are currently nine galaxy class vessels in service. Production of these vessels continues today; five Galaxy class ships took part in the recent operation to retake Deep Space Nine from the Dominion and the class has gained a fearsome reputation during the war, so far operating without loss. Though new Galaxy class ships are being produced without any science or diplomatic facilities included in order to reduce the vessel mass and so enhance combat performance during the Dominion war. These ships will be "filled out" after the war, considerably enhancing Starfleet's exploration capacity. At this point further production is expected to be terminated in favour of the new Sovereign class.

The up-rated Galaxy class has been fielded by Starfleet in order to increase the combat capability of the class for service in the Dominion war. The improvements include an extra pair of phaser arrays mounted on the nacelles, an increase in the maximum speed to Warp 9.9, and various other enhancements. As with the Nebula class, Starfleet refuses to comment on which Galaxies are enhanced and which are not.

The origins of the Sovereign class date back as far as 2338. At this time relationships between the Federation and the Klingon empire had degraded significantly, to the point where war was considered by many to be imminent. The President ordered Starfleet to place a design proposal for a new class of starship with very much greater military capability than current designs. This project was in the advanced planning stage when the loss of the Enterprise-C during the Narendra III incident eased tensions considerably. The warship project was initially to be scrapped, but Starfleet was instead asked to continue the project on a research basis only. Dubbed the Sovereign project it became a theoretical starfleet battle cruiser designed only as a computer model, with specimen hardware occasionally produced to test the design principles. The intention was to create a design that could be put into production with no delay, should a future crisis present itself.

The basic design was to be updated every five years so as to incorporate technology advances as they occurred. Initially the Sovereign design was a simple re-working of the Ambassador class, emphasizing weapons rather than exploratory and diplomatic capabilities. In the design updates of 2350, 55 and 60 much of the technology being developed for the Galaxy class project was incorporated, especially in the nacelle and warp core design. The re-establishing of relations with the Romulans in 2364 led to a major revision in the 2365 update, and many elements of the Sovereign went into low rate production in order to establish a stockpile ready for rapid assembly.

In mid 2365 first contact was also made with the Borg. The Sovereign project was activated and construction began on the first four ships of the class. However, it was apparent that much of the Sovereigns weaponry was based on that of the Galaxy class - a vessel which had proven ineffective against the Borg during that first encounter. New weapons were in preparation for the next design update due in 2370, but these were not going to be available in the immediate future. It was clear that despite the engineers best intentions, the Sovereign project was not going to meet it's primary goal - to get a warship into service fast enough to meet the crisis now looming.

The answer Starfleet settled on was to continue construction of the hull, propulsion, computer, and sensor systems of the ships already under construction but to suspend work on the shield, phaser and photon torpedo systems for three years. Instead, a crash development project was begun to field a small, very easily produced warship incorporating the new weapons - essentially a replay of the Sovereign project in miniature. To cut size - and therefore design and build time - to a minimum the new vessel would only be capable of short duration missions. The vessel would be very maintenance intensive, but would carry only limited stocks of non-replicatable spares. Combined with limited accommodation standards and small fuel reserves the new class would be capable of maintaining full readiness for only six to eight weeks during independent operations, far less than had been envisaged for the Sovereign. An important secondary role of this Defiant class was as a development test bed for the technology which would be worked into the Sovereign project as soon as it was ready.

Construction continued on the Sovereigns throughout the late 2360's. With the destruction of the Borg cube in 2366, Starfleet deemed that the threat had reduced to a level which would allow the Sovereigns to enter service before any renewed offensive. The Defiant class was therefore suspended, although the prototype was put into storage rather than scrapped. The lessons learned with the Defiant were incorporated into the Sovereign when work resumed on her weapons, a process which continued after the USS Defiant was reactivated for use at DS9. The switch from photon to quantum torpedoes and the inclusion of ablative armour are prime examples of this process. In addition, the bio-neural computer system pioneered by the Intrepid class was also included. The first of the class was was launched in 2371 as the USS Sovereign, with the USS Honorious due to follow six months later. The loss of the USS Enterprise in that year led to a last minute re-christening of another ship as the USS Enterprise, NCC 1701-E.

The Sovereign class has emerged from the dockyards as Starfleet's most sophisticated and comprehensively armed vessel. The vessel is equipped with a new variant of the Type XII phaser array - formerly known as the 'Type X+' for security reasons - which equips the Federations most powerful Starbases and deep space facilities. The type twelve has a raw beam power output some 60% more powerful than the Type ten arrays installed on the Galaxy class. In addition the type twelve has a shorter recharge time and can fire a longer sustained burst, giving each bank a combat effectiveness 79.4% greater than a type ten array. Since the Sovereign carries fourteen arrays compared to Galaxies twelve, this gives the ship an overall 92.6% increase in phaser capability.
The torpedo armament is similarly impressive. The large quantum torpedo turret forward of the deflector dish is capable of firing five rounds per second, a greater overall rate of fire than the two main ten round burst photon torpedo tubes of the Galaxy class combined. Backup to the quantum torpedoes is provided by five photon tubes; these are located at the base of the engineering section in pairs which face forward and aft, and above the aft hangar bay. Each is capable of firing twelve round bursts. This gives the Sovereign class the most powerful torpedo armament of any vessel in Starfleet service.

The shield system of the Sovereign class is similarly the most powerful of any Starfleet ship; the design was modified just prior to installation in order to increase effectiveness against both high energy tractor beams and phased polaron particles, measures clearly aimed at the Borg and Dominion respectively. Under normal operation the shield modulation frequencies are under the control of the ships computer system, which continually evaluates incoming weapons fire and automatically re-modulates the shields to give the most effective possible defence. It is thought - hoped - that this system will also enable the Sovereign class shield system to prevent beam-through by Borg transporter technology.

The warp engines of the Sovereign are of a new design which eliminates subspace distortion effects inherent to standard warp drives, a feature now becoming common on most Starfleet ships. The Sovereign class is currently the fastest vessel in Starfleet, with a maximum cruise speed of Warp 9.9 and a top speed of Warp 9.99 for up to twenty four hours. The very high cruise speed is intended to allow the ship to deploy as rapidly as possible to potential trouble spots. Her Impulse drive system is the most sophisticated model in production, giving the Sovereign class a manoeuvrability equal to that of a vessel one quarter its size.
The Sovereigns baptism of fire came in 2373 when a Borg vessel again attacked the Federation. The USS Sovereign herself was too far away to participate and the USS Enterprise - the only other Sovereign in service - was ordered to patrol the Romulan Neutral Zone rather than join the fleet engaging the Borg, a curious decision since engaging the Borg is what the ship was specifically designed for. Captain Picard disobeyed this order and joined the battle in Earth orbit, co-ordinating a mass strike on a weak point on the cube and destroying it. The Enterprise was subsequently pulled into the past by the Borg and almost assimilated. The crew were successful in defeating the Borg and returning to 2373. Captain Picard was subsequently ruled to have been justified in disobeying his orders, and continues in command of the Enterprise.

The Ambassador class was developed during the 2320's as a replacement for the ageing Excelsior and Constellation classes as Starfleet's front line Explorer type vessel. Several innovative new features were included in the new design, most notably for the diplomatic and scientific missions. The USS Ambassador included high quality guest quarters and was equipped with elaborate conference facilities. Many of these areas were capable of maintaining a wide range of environments, a vital prerequisite for a vessel which would spend a great deal of its life dealing with non standard life forms. These facilities allowed her to host a much wider range of diplomatic functions than the more cramped Excelsior class, although it did lead to the class being dubbed "space hotels" in some quarters.

The scientific facilities of the Ambassador class were equally well equipped. The ships contained the most powerful space borne sensor arrays of their time, including eighteen modular sensor pallets for mission specific equipment. Twenty eight large dedicated laboratory facilities are included in the ship, along with facilities to convert three of the cargo bays to hold extra scientific equipment if necessary. This gave the Ambassador an estimated 450% increase in research capabilities over an Excelsior class vessel.

While the primary purpose of a starship is exploratory and scientific, the Ambassadors also have teeth. The class introduced phaser arrays to Starfleet in place of the ball turret phasers carried by previous designs. This measure greatly increased the ability of the Ambassador class to fire sustained bursts, and greatly reduced the recharge and cool down times. The use of an independent power system for every group of ten emitter segments in the array triples the survivability of the array compared to a ball turret, while there are also benefits to the reaction time, greater control of thermal effects, field halos and target impact. Overall the phaser arrays of the Ambassador are over 65% more effective than ball turrets of similar power. The concept of burst firing photon torpedoes was another first; although fitted with the same number of torpedo tubes as the Excelsior class, the Ambassadors ability to fire five torpedoes at a time from each tube effectively gave her ten tubes in place of two.

After the first batch of Ambassadors was delivered, Starfleet requested a series of modifications for the second batch. The USS Yamaguchi pioneered these changes. The engineering hulls aft end was widened to allow the shuttle bay to be enlarged, and a third shuttle bay was added to the underside of the engineering hull. This allowed the Yamaguchi to handle over 30% more shuttle craft than the standard Ambassador, making the ship more effective in colony establishment and support operations or emergency evacuation scenarios.

The sitting of the Ambassadors saucer forward on the neck had led to some structural problems with early members of the class. Although these had largely been fixed by modifications to the structural integrity field, the changes had led to considerable complication of the layout of the ships connecting neck structures. Starfleet took the opportunity to shift the Yamaguchis saucer section back by six metres, allowing them to eliminate return to the original SIF modification without further difficulties. The nacelles were also shifted back in order to keep them at minimum safe distance from the saucer. The bussard collectors are a different model on the Yamaguchi, with a cap on the top and bottom of the inlet system which allows a less turbulent flow into the collectors, so increasing their efficiency by 12%.

The deflector dish was modified to allow more sensor systems to be installed, and to provide additional protection at high warp speeds. Additional sensor systems were installed in the main sensor dome on the saucer section, necessitating a housing to be installed between the dome and the hull to hold the extra equipment. This allowed the sensor range and sensitivity to be increased by over 20% compared to the original Ambassador. The layout of lifeboats within the saucer section was also modified to allow increased evacuation speed in an emergency.

Perhaps the most important change was the installation of a new model of impulse engine. The original Ambassadors had always been considered to have low speed and agility at impulse and the new engines provided almost 30% greater thrust, largely correcting this problem. The only exterior change caused by this alteration is that the engine exhaust is red rather than blue.

The Yamaguchi subtype proved highly successful in service, and all existing vessels began to upgrade to this standard from 2350. The only ship which was not so refitted was the USS Enterprise-C, which was destroyed in 2346 while defending a Klingon outpost from attack by the Romulans. The action secured peace between the Federation and the Klingon Empire. The ships destruction came some six months before it was due to return to Spacedock for modification.

The USS Ambassador was launched in 2330 and commissioned in 2332. Series production continued at a slow but steady pace until 2357, when the sixty eighth vessel was launched. Production was then suspended in favour of the new Galaxy class.

The USS Akira is one of the very few Starfleet vessels which is heavily biased toward the combat role. The ships carry an extremely heavy torpedo armament of no less than 15 photon torpedo tubes. Seven of these are mounted in the large roll bar pod, all facing forwards; the remaining eight are located in the saucer section, two of which face directly out to port and starboard - an unusual feature in a Starfleet vessel.

Another unusual feature of the Akira class is the hangar bay arrangements. There are two large shuttle bays in the saucer section, one at the forward edge of the saucer section and one at the rear. These are linked together through the centre of the ship, allowing large numbers of launch and landing operations to be handled simultaneously. During peacetime this allows the Akira to evacuate large numbers of small survey craft, or ferry evacuees on board at a high rate. During the Dominion war the ships often serve as fighter carriers; in this role they can carry up to one hundred attack fighters, although a load of thirty six fighters and a dozen utility craft is more usual.

The USS Akira entered service in 2363, and a rapid production run put nearly a hundred others into the fleet over the next twelve years. Most were assigned to units on the outer Federation territories, performing patrol and presence missions as well as the normal mapping and exploration duties which any Starfleet vessel is expected to handle.

More recently the escalation of tensions at the Federations core over the last few years has led to almost all of the Akiras being recalled to operate nearer to Earth; thirty five where assigned to the Typhon Sector Fleet in 2370, the remainder being assigned to the areas adjacent to the Cardassian, Klingon and Romulan borders. Akira class vessels featured prominently in the 2372 Borg attack on Earth; the Typhon Fleet, together with several reinforcement squadrons, fought a running battle with the Borg vessel from the Typhon sector to Earth. Many of the ships were destroyed during this battle. A notable participant was the USS Thunderchild, NCC 63549, which participated in the final assault which destroyed the Borg cube.

The Akiras had been due to cease production in 2373, but with the disastrous contact with the Dominion Starfleet decided to continue production at an increased rate. When the Dominion war began, production of the Akira was boosted to eighteen per year as the Federation converted its economy to a war footing. The Akiras have now become a common sight on the front lines, participating in most of the major battles.

Nebula Class

The Nebula class was fielded in the 2350's to provide a smaller, more numerous counterpart to the Galaxy class then under construction. The design was intended to parallel that of the Galaxy class as closely as possible in order to allow for many identical systems to be installed in both classes; this has resulted in significant improvements in the design and construction processes for the Nebula class and thus allowed comparatively high numbers to be fielded. Compared to the Galaxy class the Nebula has a more compact shape - the engineering hull is mounted directly to the underside of the saucer section, a measure which saves some 200 metres in length.

The major difference in capability is the addition of a prominent housing aft of the saucer section of the Nebula class. This enables the vessel to carry any one of a variety of special equipment pods - current models include a high capacity sensor pod, an enhanced weapons pod, a colony transport pod, an emergency field hospital unit, or a science laboratory pod. Although the basic Nebula design has approximately 80% of the capability of a Galaxy class vessel in most areas, the addition of the mission pod brings that figure up to 95% or more in that specific area. This flexibility actually allows the Nebula design to accomplish almost identical missions despite its smaller size.

In service the Nebula class has proved highly satisfactory, and in many ways these ships form the backbone of Starfleet's exploratory and scientific programmes. Like the Galaxy class they have received regular upgrades to their systems, most notably a new Warp Core design. With the advent of the threats from the Romulan, Dominion and Borg, Starfleet invested in sixty seven new enhanced weapon pods for the Nebula class; most of the vessels now carry this as a standard item. the pod carries eight standard torpedo tubes and a stock of 300 casings, approximately doubling the ships overall rate of fire.

As part of Starfleet's war effort many of its ships have been upgraded to increase their combat capabilities. The up-rated Nebula design has a maximum warp speed of Warp 9.9 and incorporates improvements to the weapons and targeting systems, a high level structural integrity field, and various other classified changes. All Nebulas now being produced are of the up-rated model, and all of these are launched with the enhanced weapons pod as standard.

This information is courtesy of the Daystrom Institute Technical Library and copyright Graham Kennedy