City-ship

"Flying city."

- Jack O'Neill

A city-ship is a mobile city used by the Ancients. With roughly the same internal space as is found on Manhattan island, it is among the largest vessels in the known universe.

Overview
The Ancients were already using city-ships several million years ago, when they departed Antarctica for the Pegasus galaxy aboard the city-ship Atlantis. At least one other Ancient built city-ship is known to exist in Pegasus; whether it was constructed there or was part of the Ancients' original migration is unknown. A city-ship's design much more closely resembles a that of modern city than a spacecraft, with systems and living quarters distributed throughout several towers that extend away from the drive system; while in flight, the top of a city-ship would be considered the "front."

All known city-ships are capable of planetary landing; and indeed, they do not seem to have been designed primarily to function in space. Their hulls are not airtight, requiring the use of a shield to maintain atmosphere. As they are typically powered by three ZPMs, the shields are exceptionally powerful; though probably as a result of this, the hull itself is quite fragile.

As evidenced by Atlantis, city-ships are inherently buoyant, capable of floating on the surface of a large body of water without any apparent technological aid; they can also rest on the bottom of an ocean, though again the shield is needed to prevent flooding. Some city-ships, such as Atlantis, contain their own Stargates, located near the top of the central tower so that it may be easily accessed by puddle jumpers. On other city-ships, however, this location instead houses the control chair, which in Atlantis is located in another tower altogether. City-ships carry a large number of drone weapons, which are apparently their only armament as the ships were origionally built at a time when the Ancients had no enemies and could rely on ships for defence. (The Atlantis Expedition did, however, install Railguns on Atlantis for use as point-defense weapons against the Wraith darts attacking the city, but these were unnecessary for the Ancients as Dart blasts were nothing to the power of a shield with 3 ZPMs, and thousands of drones.)

In addition, city-ships can host a myriad of other systems, many of which can be run without the need for a ZPM. However, most of the offensive systems, such as the drones, can be run off a pair of Mark II Naquadah generators, in a state of barely controlled overload. They require a ZPM for extended operations however, including the shield. The stardrive is designed to function with three ZPMs, but it is possible (if inadvisable) to fly the city with less. The Atlantis Expedition managed to do so with only one ZPM, albeit using additional energy supplied by an Ancient geothermal drilling platform.

Command and Control Systems
These vessels also contained internal sensors which allowed for the detection of individuals or objects inside the city. However, if power was shut down in a certain area then the sensors in that grid were offline and incapable of providing information to the control room. Another aspect of this sensor grid was the biometric sensor which was capable of detecting irregularities in biometric rhytm and reported tem to the system. This made it similar to a Life signs detector though this more powerful city based sensor allowed it to detect alien organisms inside the ship and alerted the crew of its finds. However, it required a significant amount of power to operate though it was possible to focus the scanning field to certain parts of the city.

In addition to this, the city ships possessed powerful Long range sensors capable of detecting distant ships moving through space and even allowed for the detection of such vessels through hyperspace. The data collected by these sensors was capable of being displayed through the mind of a user of the city-ships control chair who was capable of forming a holographic image of what the sensors percieved. This allowed for the remote viewing of locations on a planet's surface.

Offensive and Defensive Systems
A City-ship contained a powerful shield which was powered up by it's ZPM Hub with even a single power module being capable of projecting a defensive barrier capable of resisting an orbital siege. This shield was only capable of resisting the assault as long as the power source remained. It was possible to alter the shield generator in order to create a Anti-Replicator field allowing it to destroy all Replicator or Asurans inside the city. The shield was a vital component during space travel as the vessel lacked a hull in a traditional sense and required the protective barrier produced by the shield generator to retain at atmosphere in the city. The lack of a shield means that the crew are exposed to the vacuum of space and will die as a result.

The only armaments of these Ancient vessels were a stockpile of drone weapons, as the city was built to be able to rely on ships for defence at a time of peace. These were stored within the city itself where it was capable of being launched from launching portals located at the edges of the city. These weapons provided a high level of protection and were quite capable of resisting fighter based assaults on the City, and destroying any orbiting ships. The drone weapons were controlled through the City's chair room where they were mentally controlled by someone using the Control chair. This required a great deal of energy to charge the drones which was easily managable the ZPMs powering the city but secondary external power sources were only capable of maintaining it enough to launch about a dozen drones.

Stardrive
The great city-ships of the Ancients are starships capable of traveling across space, despite their apperence as cities. They contained both a sublight engine allowing for slower-than-light travel and a hyperdrive allowing it to travel between solar systems. This even allowed it to cross galaxies and was known as the Star drive. The powering of the sublight enough to life the city weighing millions of tons was far beyond a Naquadah generator, and required a ZPM. Allthough there was easily enough power in a ZPM, it could not channel enough out at one time, so if only one is installed, another power source must be used as well such as the Mobile drilling platform.

List of City-ships

 * Atlantis
 * The Tower
 * Asuran city-ship(s)

Gate Room
This served as the central point in the City-ship as it served as a connection to the vast galaxy spanning Stargate network. Near the Stargate itself resided the hidden overide controls that can be activated by a Lantean giving them control of the City-ship. This chamber inside the city contained a doorway in the ceiling allowing for a Puddle Jumper to drop down and enter the Stargate. The Stargate itself was secured by a force field protecting it thus preventing enemies from entering the city. It was possible to disable the Stargate's DHD by removing the control crystal.

Not all city-ships contain a Stargate in their Gate room.

Operations Centre
Located directly opposite the Stargate was the main operations center which was used as a central command point for the city. This position allowed the occupants of the city-ship to monitor every aspect of the city's technologies and sensors as well as control its defensive shield (allthough drones were controlled from the Control chair in the chair room.

The destruction of the operations center can have a crippling affect on the management of the city-ship as some systems (such as internal sensors) would go offline as they can only be accessed via the OC for security reasons.

Auxiliary Control Room
City-ships contained an Auxiliary Control room similar to their Aurora class warships. It was capable of accessing the city's internal communication system and it was able to determine the status of the ZPM's power level. In addition, it was capable of activating enough systems within the City to deplete its power source.

This made it a vital location within the vessel and was capable of monitoring many of the systems on the vessel similar to the Operations Center. As such, it was capable of activating the City-ships Stardrive, allthough the Control chair is neccessary to navigate.

Hologram Room
The hologram room was a specific chamber inside the City ship which served as an archive where information was capable of being conveyed to visitors of the room. A single computer display was present which was capable of activating the holographic display itself. This display took the form of a Lantean avatar that detailed various pieces of information depending on the program.

Most, if not all, programs were interactive to a certain extent (voice) and can mimic certain behaviours making it seem like a real person. The room took some power to activate which was why it was a burden to use compared to database terminals if the City-ship was low on power.


 * Presumably, all City-ships contain similar facilities.

ZPM Hub
Zero Point Modules were created to power a city-ship in a group of three and can be used to power a city for thousands of years. It took on the appearance of a triangular shaped structure with three ports at the three corners of the machine that contained entry holes where a ZPM fit. The power modules required to be in a set position after which a control activated which retracted the ZPM into the hub whereupon it begins powering the City-ship.

It was possible to alternate the power between the three modules allowing them to keep the City-ship powered for thousands of years thus increasing their lifespan but this required constant adjustment over the centuries.

Gateship Bay
City-ships contained a hanger bay which contained a large number of Gateships and was also known as the Puddle Jumper Bay. The Jumpers are located in compartment rows and were located in a location that allowed for easy deployment throughout the city by allowing entry into the Gate Room itself or exit the City through external portals allowing them to travel around the City-ship.

The city also contained a secondary Gateship Bay which had the danger of being flooded when it landed on the water though this made it typically underwater allowing for a potential second entrance into the city-ship. There were outer doors which were capable of being remotely controlled allowing for a jumper to enter the city after which they required to be closed in order to pressurize the bay. There was the danger that these door were capable of jamming over thousands of years making it a potential threat.

Gateship Bay Control Room
This was located on the other side of the Gateship Bay and was a means of controlling the water flow as well as doors of the bay room. The control room was located in the next level with entry possible through a hatch that led into the chamber. It was located directly below this point where the manual override was present serving as an emergency control mechanism in the center of the console though there were actually dozens of controls on the platform.

The manual override required to be kept down constantly in order for it to activate the Gateship Bay room.

Drone Storage Chamber
Deep inside the vessel resided a chamber which contained a stockpile of drone weapons which were capable of being deployed at a moment's notice. The room contained numerous drones that were held in hexagonal containers where they waited for deployment into the launching chambers inside the vessel. It was possible for an individual to take a single drone and control it manually though this was dangerous.

There can be hundreds of drone storage racks present in the chamber but constant use can deplete a city-ships supply of drones which necessitates replacement weapons in the future.

Stasis Chambers
The city was equipped with an unknown number of stasis chambers where crewmen were capable of being placed within booths whereupon they entered a state of protective stasis where they were covered by an icy cube that filled the booth. This allowed personnel to survive for countless millenia in the city but unfortunately did not halt the rate of aging entirely but merely slowed it down by a massive amount (ten-thousand years in a chamber ages someone about 60 years.) Ultimately, an individual within the chamber will age and become older over a period of thousands of years.

They also served as a method of keeping terminally ill individuals alive virtually indefinatly until a cure can be discovered. There appeared to be a number of computer terminals on the sides of the chamber.

Holding room
The holding chamber was a large room containing a cubical prison cell where prisoners are detained. The cell itself was of an unusual design which had bars and slided open. It made use of shield technology to trap occupants inside the cell preventing their escape.

The shield had to be deactivated in order to allow entry into the cell if the crew wished to interrogate a prisoner. A control for the cell doors and shield are located in the external corner of the cell itself allowing for it to be shut down as long as the right sequence of commands were entered into it (and a valid access code.)

Grounding Station
City-ships were apparently equipped with a number of rods that can number up to four and were called Grounding stations which were used to channel lightning strikes away from the fragile hull of the city itself. The energy itself was redirected into the surrounding water where the city-ship was floating in preventing any damage to the vessel. Two were located in the central part of the city while another two were located on its outskirts, near the edge of the piers. It was possible to disable the station by entering a code in Ancient which separated the grounding station from the rest of the city and causing a lightning strike to run rampantly within the corridors of the city-ship.