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 Starfleets exploration capacity. At this point further production is expected to be terminated in favour of the new Sovereign class.