posted
Article by Bernd. As far as I know, there are no diagrams for this one.
The first decades of the 24th century had brought many advances in starship technology, especially warp field dynamics, power generation, and sensor systems. Most of them were not yet implemented in the current starship generation that included the Ambassador class and Renaissance class. Therefore it was deemed useful to begin work on a new family of starships of different sizes sooner than originally scheduled. In 2340, the Advanced Starship Design Bureau (ASDB) issued a "Master Plan for the Renewal of the Fleet" which outlined basic specs and mission profiles for the starships that should later become the Galaxy class, New Orleans class, Springfield class, and Cheyenne class. At that time the Galaxy class was supposed to be the only replacement for the Ambassador class as the capital ship type of Starfleet, beginning in the 2360s. The Galaxy class development at Utopia Planitia officially started in 2343. First simulations of the overall performance of the the future starship came to the conclusion that the intended mass and volume would require a revision of the design principles that had been derived for smaller ships. Two basic plans were worked out. The first one featured warp nacelles in the rear half of the ship, with a vertical position between the saucer and the engineering hull, close to the center of mass. The second design was a much more compact arrangement, with only two thirds the length of the first one, the nacelles being mounted underneath the saucer and engineering hull. The ASDB voted in favor of the first solution which, among other benefits, promised a better peak performance of the propulsion system. Although it was never officially confirmed, it may have played a role too that this approach was sleeker and therefore considered better suited for representation of Starfleet and the Federation. Since 2345, the design group focused entirely on this design whose outside appearance changed only insignificantly until the actual construction started at Utopia Planitia in 2350. Although it had been dropped in the first attempt, the second Galaxy design variant became an option again some time later. The Galaxy was planned as an explorer-type starship, fully equipped with a dozen scientific departments, more than a hundred laboratories, and a crew complement of 1000. The mission profile of most starships, however, was supposed to be more specialized and wouldn't require the permanent presence of exactly this equipment and personnel. Upon checking the design specs of the Galaxy class, Starfleet Command approved of it, but didn't sign contracts for more than six ships of this class, with an option for six more to be built in the 2370's. At this point the ASDB revived the second design variant whose construction and operation was regarded less complex. The ASDB further simplified the design, and came up with a proposal for the Nebula class. The new starship was almost equal in volume to the Galaxy, but had a smaller scientific department and a crew of only 750. A mission-specific sensor or laboratory pod was proposed as a further option. Offensive and defensive capabilities were designed to be equal to the Galaxy. First calculations showed that construction of one unit, still without the pod, would be possible at 70% of the cost of a Galaxy class, and only 60% of the time. Now being the true and urgently needed successor of the Ambassador class, the Nebula class quickly found supporters within Starfleet Command, and the development was approved in 2347. Starfleet Command already asigned names and registry numbers for the first two ships to be built, the prototype being the U.S.S. Nebula NCC-60204. To speed up the project, it was decided to perform the early stage of the development at Utopia Planitia where the Nebula could easily profit from the work already done for the Galaxy class. The detail work and the construction were to take place at San Francisco Fleet Yards so that the expected increased efforts at this stage would be shared. It was deemed useful to employ largely the same primary hull as the Galaxy, but relocate several labs and crew quarter sections to provide more room for cargo and mission-specific modules, especially in the decks six throughout nine. The ship would have different maneuvering thrusters, and a smaller number of sensor pallets. The engineering hull would be heavily reworked for the specific needs of the Nebula. The propulsion system was planned to be largely identical, with according changes to the locations of the warp core and PTC's, and slight modifications to the design of the warp nacelles. The construction of the U.S.S. Nebula at San Francisco Fleet Yards started in 2351. Work proceeded very fast, and soon it became clear that the Nebula would be launched prior to the Galaxy. In 2350, however, it became clear that the new warp nacelles wouldn't be completed until 2356, two years too late, since the coils were still being developed at Utopia Planitia, complying with the schedule for the Galaxy class. Since the U.S.S. Nebula was supposed to be an experimental ship anyway, an quick solution for this particular ship was found. It was decided to remove the Galaxy/Nebula prototype nacelles from their testbed and test them directly on the U.S.S. Nebula. The only problem was that simulations showed that the prototype warp nacelles were 20% less efficient than specified for the final version due to high impurity concentrations in the verterium cortenide crystal structure. This is why they wouldn't succed in generating a stable warp field also in the region above the wide saucer. Natural subspace inhomogenities within the specified tolerance for normal ship operation would easily collapse the warp field. The solution to this problem was unusual. Two nacelles from the New Orleans class were shortened by two coils, making them work like smaller copies of the main nacelles with a synchronous ignition sequence, and were mounted directly behind the saucer to close and stabilize the warp field. In 2355, the Nebula was completed, and launched from San Francisco Fleet Yards for a flight around the Earth and to the Moon with maneuvering thrusters. One year later, the impulse and warp drive were operational too, the ship was officially commissioned and underwent several test series outside the solar system. The Nebula kept the two aditional nacelles until the ship was destroyed in the battle against the Borg at Wolf 359 in 2367. Owing to the fact that the Nebula was rushed into service, the construction of the three other ships, now with the final, more powerful nacelle design, was delayed, until the components and methods for an efficient series production were found. The U.S.S. Honshu NCC-60205 was launched in 2360, the U.S.S. Gujarat NCC-60596 and U.S.S. Farragut NCC-60597 followed in 2361. Three more batches of eleven ships altogether were commisioned until 2365. None of these ships originally had the typical triangular mission pod that wouldn't become available until 2367. The U.S.S. Phoenix NCC-65420 was the only ship to be equipped with a special sensor pod for monitoring the Cardassian border after the cease-fire. This task was later transferred to newly built fixed sensor platforms. The first starship to receive the triangular pod was the U.S.S. Prometheus NCC-71201. Subsequently all other ships of the class were equipped likewise, now giving them the same internal volume as a Galaxy-class ship. Among other design variations, some of these newer ships have the same RCS as the Galaxy class, or they have crew quarters instead of cargo bays in the decks six to nine, with several additional windows. A total of 46 Nebula-class ships was built so far, construction is going on. 13 ships are irretrievably lost, were heavily damaged in the recent Dominion War and are undergoing extensive repairs.
SPECIFICATIONS: Category: Explorer Dimensions: length 441m, width 467m, height 128m Decks: 27 (w/o pod) Crew: 750 officer & crew, plus 700 visiting scientists Maximum Capacity: 20,000 General structure: saucer, engineering hull, warp nacelles underneath the saucer, mission pod Shuttlebays: main shuttle bay on deck 4, auxiliary bay in the stern Armament: 2x2 photon torpedo tubes; 7 Type 10 phaser arrays Warp propulsion: M/ARA, two warp nacelles mounted on pylons, 2x18 YSTC-2019 split-toroid warp coils Impulse propulsion: 2 KPS-2320-A saucer impulse engines, 1 YPS-8030 impulse engine in the stern Mass: 3,900,000 metric tons (complete), 3,309,000 metric tons (w/o pod) Computer System: LCARS Expected Duration: 100 years Time Between Resupply: 10 years Time Between Refit: 20 years
-------------------- "Kirito? I killed a thing and now it says I have XPs! Is that bad? Am I dying?"
-Asuna, Episode 2, Sword Art Online Abridged
Registered: Mar 1999
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posted
Good article and some nice explanations for the four-nacelled oddity from BOBW (though it leaves out why the secondary hull configuration would be shortened and the deflector re-designed on the production run ships).
A couple of issues though-
The Nebula was shown to have the Galaxy's ventral torpedo launcher in FC, so the ship should have at least three torpedo launchers...though their performance might be less than the ones on a Galaxy, I suppose.
The notion that all Nebulas after a point were built with the silly triangular, shuttlebay-blocking module kind of defeats the whole "specialty pod" notion (not that I ever cared for the concept of swapping millions of tonnes of starship from mission to mission, mind you). The Phoenix's pod works so much better from a design POV- we just never saw it do anything.
If either the Phoenix or Southerland-style pods hold labs (and they certainly should), then the Nebula would actually have a greater internal volume than the Galaxy.
-------------------- Justice inclines her scales so that wisdom comes at the price of suffering. -Aeschylus, Agamemnon
Registered: Aug 2002
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