The Excelsior-class was a type of Federation starship used by Starfleet from the late 23rd to the late 24th century. It was the backbone of Starfleet for nearly a century, making it one of the longest serving starship designs, and one of the most recognizable ships in the fleet.
Although the Dallas may have been intended to be the final ship, it seems this decision was reversed, since, in 2409, Starfleet has ships of the Excelsior class and the Enterprise-B refit subclass in service 125 and 116 years after the first ships were commissioned, respectively.
The Excelsior-class was initially constructed during the early 2280s at Starfleet's San Francisco Fleet Yards orbiting Earth, although some, like the USS Gemini-A, were built at Riverside Shipyards in Iowa.
Starfleet had high hopes for the first ship of this class, the prototype, which was equipped with transwarp drive, and was regarded as that century's "Great Experiment."
Despite the failure of the "Great Experiment," Starfleet forged ahead with employing the Excelsior design. After remaining in Earth Spacedock until at least 2287, the prototype Excelsior was subsequently recommissioned for active service by 2290.
In 2293, the fate of the Excelsior design was sealed when Starfleet passed on the name of a legacy. The launch of both the USS Enterprise-B opened the door for the Excelsior-class to become one of the most widely used designs in all of Starfleet, a design lasting well into the late 24th century.
Once fully integrated into the fleet, the Excelsior's sister ships were used for a variety of mission profiles, ranging from deep space exploration and terraforming missions, to patrol duty, to courier and transport runs. The Excelsior-class was also frequently used by the Starfleet flag officers for use as a personal flagship.
The Excelsior-class was present in several major Federation engagements, including the Borg invasion of 2366-2367, where it participated at the Battle of Wolf 359, as well as the engagement against the Borg sphere that entered the Sol system in 2377. They were also present in numerous Dominion War battles, seeing action during Operation Return, the First and Second Battles of Chin'toka, and the Battle of Cardassia. Many Excelsior-class vessels were stationed on the front lines near Deep Space 9 during the war.
Details of this class would be retained well into the 31st century, when Captain Jonathan Archer and Lieutenant Malcolm Reed viewed schematics on the class in the 22nd century while accessing the database belonging to temporal agent Daniels.
The initial Mark I design of the Excelsior-class included 16 phaser banks (8 FH-11's, 8 FH-5's) and 4 photon torpedo launchers. The two varied phaser types was to make sure that all weapons arcs were covered by both long-range and short-range weapons. However, the evaluation teams decided to replace the 8 FH-5 banks and replaced them with two further FH-11 banks, which meant that the Excelsior's only had ten phaser banks, but the field of fire overlapped more effectively.
The improvement in torpedo launchers technology allowed two further launchers to be incorporated into the Mark II design and remained in place through further models.
By the 2370s, the Excelsior design had been outfitted with improved phaser emplacements, quantum torpedoes and other tactical improvements which brought it into line with later starship designs and proved necessary during the conflicts with the Borg and the Dominion. Due to its reliable design, ships of this class could be retrofitted with new technologies and weaponry making them a match to newer vessels in the 25th century.
The deflector shields of the Excelsior-class were an improved version of the quadri-transducer shield that was in use in the late 23rd century, and was found to deliver more deflective power.
By the mid-24th century, Starfleet began to allow civilians to travel aboard Federation starships and allow an officer to have their families with them as they traveled. While the newest starship designs such as the Galaxy class and Nebula class were built to accommodate civilians, the older Excelsior-class ships weren't designed to carry them. In fact, one of the administrative reasons for family accomodations on exploratory vessels was often cited as the attempted disciplinary action against an officer of the USS Excelsior itself, who had to demand a leave for an important family matter.
However, minor refits allowed for some accommodation of families. The presence of civilians also made their safety a top priority, as the larger Galaxy-class vessels were equipped with a facility to separate the saucer section and allow civilians to escape from a field of battle. With this procedure in mind, several Excelsior-class vessels, such as the USS Excelsior, USS Yorktown and USS Hood were equipped with the same ability to separate the saucer.