Type:

Enhanced Scientific/Diplomatic Explorer

Unit Run:

U.S.S. Ahwahnee, NCC-71260
U.S.S. Cheyenne plus 78 vessels built since 2345.
62 remain in service

Commissioned

2345 - 2352

Dimensions

Length 326 m
Width 250 m
Height 134 m
Decks 16, excluding nacelle engineering spaces
Mass 900,000 tons

Crew

245

Warp Speeds

Normal Cruise Warp 6
Maximum Cruise Warp 9
Maximum Rated Warp 9.4 for twelve hours

Armament

4 x Type VIII Phaser arrays, total output 7,500 TeraWatts
2 x Type 2 burst fire photon torpedo tubes + 50 torpedoes

Defense Systems

Shield system, total capacity 337,500 teraJoules
Standard Duranium single hull
Standard level Structural Integrity Field
Strength Indices (Galaxy Class=1,000)
Beam Firepower 300
Torpedo Firepower 700
Weapon Range & Accuracy 105
Shield Strength 80
Hull Armour 75
Speed 890
Combat Manoeuvrability 1,100
Overall Strength Index 370

Diplomatic Capability

Grade 4

Expected Lifetime

60 years

Refit Cycle

Minor 1 year
Standard 5 years
Major 25 years

General Information

The Cheyenne project was approved in 2338 as a scoutship to counterpart the New Orleans class Frigate and the upcoming Galaxy and Nebula class Explorers.
As with most scouts the Cheyenne was intended to be somewhat faster than its contemporaries in order to allow it to travel out ahead of the main body of a fleet. In order to accomplish this, the Cheyenne was fitted with four nacelles in the pattern established by the much earlier Constitution class.
Initially, all did not go well with the Cheyenne. Starfleet has relatively limited experience with four nacelle designs, and a good deal of difficulty was experienced with the warp field geometry. Eventually these problems where overcome and the USS Cheyenne, launched in 2344, achieved a maximum speed of Warp 9.4 in trials. However, in December of 2344 the Galaxy project received new specifications calling for a top speed of Warp 9.6.
With the prototype about to enter service and five more ships under construction, it was already too late to make any serious attempt to improve the top speed of the Cheyenne, so Starfleet was forced to bring a scout into service which was some 10% slower than the vessels it was supposed to work with. Over the succeeding years several attempts where made to bring the speed of the Cheyenne up to Warp 9.7, but problems with the field geometry began to re-surface with alarming regularity.
This culminated with a test on board the USS Ahwahnee; when a new computer control system was tried out the ship created a wormhole effect on its first test flight. Although the Ahwahnee survived and there where no casualties, the subspace stress caused severe cracking in the hull structure of all four nacelle struts. The ship was in spacedock for over a year while the struts where replaced. Starfleet suspended production of the class in 2352 after twenty five had been commissioned, mothballing the six ships under construction.
The Cheyenne has proved less than successful in service. Her relatively low speed has restricted her performance in her designed role, and she has been forced to operate in the role of a Frigate. She is not especially suited to this task - certainly not when compared to the New Orleans class which was purpose designed for the role. As a result the Cheyenne's have been given a very low priority for refits and upgrades, and have fallen considerably behind the rest of Starfleet in this respect.