Engineering - Nebula Class - Information
Canon Facts Backstage Info Speculation
The Nebula class was fielded in the 2350's to provide a smaller, more numerous counterpart to the Galaxy class then under construction. The design was intended to parallel that of the Galaxy class as closely as possible in order to allow for many identical systems to be installed in both classes; this has resulted in significant improvements in the design and construction processes for the Nebula class and thus allowed comparatively high numbers to be fielded. Compared to the Galaxy class the Nebula has a more compact shape - the engineering hull is mounted directly to the underside of the saucer section, a measure which saves some 200 metres in length.
The major difference in capability is the addition of a prominent housing aft of the saucer section of the Nebula class. This enables the vessel to carry any one of a variety of special equipment pods - current models include a high capacity sensor pod, an enhanced weapons pod, a colony transport pod, an emergency field hospital unit, or a science laboratory pod. Although the basic Nebula design has approximately 80% of the capability of a Galaxy class vessel in most areas, the addition of the mission pod brings that figure up to 95% or more in that specific area. This flexibility actually allows the Nebula design to accomplish almost identical missions despite its smaller size.
In service the Nebula class has proved highly satisfactory, and in many ways these ships form the backbone of Starfleets exploratory and scientific programmes. Like the Galaxy class they have received regular upgrades to their systems, most notably a new Warp Core design. With the advent of the threats from the Romulan, Dominion and Borg, Starfleet invested in sixty seven new enhanced weapon pods for the Nebula class; most of the vessels now carry this as a standard item. the pod carries eight standard torpedo tubes and a stock of 300 casings, approximately doubling the ships overall rate of fire.
As part of Starfleets war effort many of its ships have been upgraded to increase their combat capabilities. The uprated Nebula design has a maximum warp speed of Warp 9.9 and incorporates improvements to the weapons and targeting systems, a high level structural integrity field, and various other classified changes. All Nebulas now being produced are of the uprated model, and all of these are launched with the enhanced weapons pod as standard.
The Nebula-class is unique in that it has a large interchangeable equipment module located at the rear of the ship. The 'pod' as it is sometimes called, can be replaced with another - sometimes within a few days - when performed at a starbase. Changing pods is a very involved process, and frequent module changes can cause undue stress on the ship. As such, procedure dictates that the ship must not change modules more often than every 6 months without due reason. Such reasons could include damage to the previous module, special missions from Starfleet, or testing new equipment.
The original Nebula-class vessels utilized an elliptical module, which was connected to the engineering section by two reinforced struts. Revisions to the structure later changed the connecting pylon to a singular connection strut. This revision also included a new module design, in the form of a triangular module. This design officially replaced the elliptical module in 2370, and ships are being upgraded as time and resources allow. Completion of the upgrade is expected fleet-wide by 2380.
With the adaptability given to it by use of the swappable pod-module, the Nebula-class is one of the most versatile starships ever seen in Star Trek. While some of the pods (Shuttlebay, Hospital) may not be considered canon, it should be noted that the sensor and weapons modules have not been specifically mentioned by name either. In the early TNG episodes, an elliptical dome was featured on the NCS, yet later it was a triangular pod. Different modules all-together, or simply an upgraded design? Until we learn from canon sources otherwise, I'm going to make the assumption that the elliptical dome was/is the older, original module, and the triangular pod is the newest module.
There are several different pods available, some of which are outlined below.
Sensor pod: The majority of the first Nebula-class ships were outfitted with this pod, which greatly extended the ship's sensor range. With this pod the Nebula-class ship is virtually unmatched in regards to sensor capability. Ships with this pod module were routinely assigned to deep-space exploration, hostile border patrols or long-range reconnaissance.
Weapons pod: With the recent Borg invasions and Dominion War, Starfleet quickly mobilized to deploy the weapons pod, which contains 8 forward-facing torpedo launchers, and 3 Type X point-defense phaser emitters. The launchers are fed by an additional 200 photon torpedoes stored in the pod itself. While equipped with eight launchers, each launcher is a smaller type similar to that used by Intrepid-class ships, and as such can only fire up to 3 torpedoes at once, with a reload time of 6 seconds. Later versions of the pod are also equipped with a limited number of quantum torpedoes. The weapons pod is also equipped with two shield generators (one main, one backup), since it was realized that the pod would be an easy target. The shield generators are the same type used through-out the rest of the ship, and draw power directly from the auxiliary energy reserves during Red Alert situations.
Tactical pod: This is a recent addition to the Nebula-class fleet, and is quickly becoming the default module for all new Nebulas being built. The design combines the scanning capabilities of the sensor pod and the offensive capabilities of the weapons pod into one module. There are disadvantages to this design. The tactical pod contains 75 less torpedoes (125), in order to make room for the sensor pallets. Also, the scanners are primarily designed to aid in targeting for the torpedoes and phasers, and as such are not optimized for long-range usage.
Hospital pod: This specialty pod, while not found in wide-spread use, includes the same medical facilities found in large starbases and is equipped to handle several hundred casualties at once.
Habitation/Colony pod: This pod contains a large number of residential quarters, and is sometimes used on long-term missions, or on missions focusing on populating a colony. Depending on configuration, up to 6,000 people can be ferried in the habitation module. With slight modifications, this module can be configured to act as a troop transport, enabling the ship to carry several thousand troops. During the offensive on Cardassia Prime at the end of the Dominion War, several habitation pod-equipped ships were used with great efficacy to transport Marines to the front lines. This module also contains a dozen dedicated transporters, allowing the roughly 5,000 troops to be beamed out within a relatively short amount of time.
Shuttlebay/Hangar pod: This experimental pod includes a large shuttle hangar with the space to hold over two dozen runabouts and fighters. Further information regarding maximum capacity and capabilities is classified pending review by Starfleet Command.
Skid pod: This pod, while rarely used, can be used to tow a smaller ship at high warp for extended distances. The pod consists of two elongated pylons, which are then connected to another ship with reinforced bolts. By not using tractor beams, the Nebula-class ship is able to divert more power to the structural integrity field, and thus travel at a higher velocity for a longer period of time.
Miniature Warp Nacelles: This type of pod is still considered experimental, and most likely will not be approved for fleet-wide use. The design features two nacelles, each approximately one-third scale, positioned directly above the main nacelles. While not giving the ship a higher warp speed, it does allow the ship to maintain high warp for a longer period of time. Given the amount of work that must be put into properly connecting the mini-nacelles, they are likely to remain in the experimental phase for some time. At this time, only four Nebula-class starships are equipped with this "module".
Most Nebula-class ships are assigned two main modules (one sensor and one weapons module), though some ships are also given a specialty module (hospital/habitation/skid). Some ships are making the tactical pod their main module, since it combines the abilities of the two main pods. At this time, the Hangar Pod is found on only a select number of ships. In order to exchange pods, the ship must be docked at a certified facility for a minimum of two days, to give suitable time to perform diagnostics on all connections and systems. The exchange must be approved by both the ship's captain and the station commander. An upgrade recently approved by Starfleet Command allows a Nebula-class ship to have ablative armor installed over critical points on the ship, mostly centered on the points connecting the pod-module to the ship itself. This upgrade is currently limited to ships serving on the out-skirts of the Federation border, or near hostile borders, due to limited resources.
Many of the above modules contain habitable decks, and are referred to by letters; Deck A would be the top-most deck, deck B would be below it, and so on. Access to these decks is normally restricted, due to the sensitivity of the surrounding areas.