Excelsior class

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The Excelsior-class was a type of battleship and explorer that was first built in the 2280s and went on to be used by Starfleet throughout the late 23rd and the 24th centuries. 

The prototype of this class was the USS Excelsior (NCC-2000) was initially fitted with an experimental transwarp drive and was proclaimed as "the Great Experiment". 

The last ship constructed of this class was the USS Dallas (NCC-2019). 

Although this may have been indented to be the final ship it seams this decision was reversed since in 2409 Starfleet has ship of the Excelsior class and the Enterprise-B refit in service 125 and 116 years after the first ships were commissioned respectfully.

History
The "great experiment" of transwarp drive was meant to revolutionize faster-than-light transport by capturing the warp envelope in a transporter field and beaming it ahead of the ship and increasing the speed in which it could travel. However, the Excelsior's first test of the transwarp drive to apprehend the stolen USS Enterprise (NCC-1701) in 2285, was thwarted when the drive was sabotaged by Montgomery Scott. 

Despite the ignoble start, tests continued to be ran on the Excelsior but the transwarp drive continued to prove unreliable and was declared a failure. However, the Excelsior's spaceframe proved to be very stable and reliable and it was decided to replace the transwarp engines with standard warp drive and continued with production of further starships. A further Mark I Excelsior-class starship, the USS Proxima (NCC-2001) was built and she underwent shakedown trials in 2288 (reference stardate 2/2400).

Two Mark II Excelsior-class vessels, the USS Columbia (NCC-2002) and USS Galacta were also launched in the same year for shakedown trials. 

Several years later, a new variant of the Excelsior-class design entered service with added modifications to the basic hull design. The first ship to be constructed to these specifications was the USS Enterprise (NCC-1701-B) which was launched in 2293. 

Although some Excelsior-class vessels were built to these specifications, many new vessels used the original design. (Star Trek: The Next Generation; Star Trek: Deep Space Nine; ; )

The production run of the Excelsior-class ran well into the 24th century which highlighted the adaptability and soundness of the basic design. However by the early 2330s, construction on new Excelsior-class vessels was down to just two a year, as new starship classes such as the came into service. Although the Excelsior's were often relegated to secondary duties by the 2360s, large numbers remained in service. (SS ST (Hour of Fire); ; ; )

During the 2370s, the Excelsior's served in the bulk of engagements against the Borg and the Dominion, although there was a high attrition rate in combat missions. Due to this, at least one Excelsior-class, the USS Lakota (NCC-42768), was refitted with more advanced weaponry, such as quantum torpedoes.

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. 

Armaments
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. 

Defenses
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. 

Saucer separation
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 and  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 (NCC-2000) 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 (NCC-2000), USS Yorktown (NCC-2033) and USS Hood (NCC-42296) were equipped with the same ability to separate the saucer. 

Apocrypha

 * The RPG The Dominion War Sourcebook: The Fires of Armageddon, published by Last Unicorn Games after they had lost their Star Trek licence listed several other Excelsior-class starships: USS Caldos (NCC-32628), USS Kolno (NCC-41069), USS Carpathia (NCC-43118), USS Blackeagle (NCC-46200), USS Vasidrun (NCC-47936), USS Apache (NCC-57924), USS Tyr (NCC-58314), USS Sunchaser (NCC-63185) and the USS Bolsetu (NCC-63744).


 * The RPG Ship Recognition Manual, Volume 2: Starships of The Original Series Era, published by Last Unicorn Games after they had lost their Star Trek licence listed two other Excelsior-class starships: USS Valorous (NCC-2053) and USS Retribution (NCC-2017).