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 that of a 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, at least not in the majority of the ship, requiring the use of a shield to maintain atmosphere. As they are typically powered by three ZPMs, the shields are exceptionally powerful, withstanding days of constant enemy fire with just one ZPM; 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 originally built at a time when the Ancients had no enemies and could rely on ships for defense. (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


The central nexus of command within the City-ship was the control tower which was the single tall spire in the centre of the vessel. Inside this location was the control room and Stargate Operations where the crew operated the ship. This region contained such locations as the holo room, conference room and the commander's office. The Stargate was typically located here but this was not always the case. From this point, the crew were capable of directing Stargate operations allowing for the dialing of planets or raising the city's shield to prevent attackers from gaining entry. In addition to this, aspects such as the city's shield and cloaking mechanism were capable of being accessed from this point. While this was the primary point of control for the ship, there was the Auxiliary control center located deep inside the city which provided a similar point of command allowing for control over systems such as the stardrive. The control chair can also be used to control and configure some of the city's systems; in theory, the control chair could also be used as a backup command center, although only one person can use the chair at any one time. If Gate Operations was destroyed, it was possible to relocate the command and control systems to another part of the City but the danger in this was that the systems were not designed to handle such a strain in governing the entire city.



An important part of the city ship was the chair room which contained a control chair that responded to the mental input of its user. Through this, a user with the ATA gene was capable of interfacing with the city's systems, allowing them to control the weapon systems of the ship. In addition, it was an important aspect in controlling the navigation system, allowing the city-ship to be piloted to new worlds. It can also be used to reconfigure power systems, and most likely numerous other systems as well.



Another aspect of the command and control systems that the Lanteans installed in these vessels was the override-mechanism. This was hidden in the Gate room and concealed beneath the floor. New occupants of the city unaware of the design specifications were capable of living in ignorance of the mechanism being present. Once a Lantean was present, the fail-safe was capable of being remotely activated after which it was capable of shutting down the entire city and returning it to Lantean control.

A city-ship possessed a highly automated computer system which was linked with the sensors and tasked with defending the city to a certain degree. When detecting a disease or pathogen in areas where the sensors were active, the city-ship engaged an automatic lockdown program which shut out users of the system. This was to prevent the spread of any illness by closing down systems such as the transporters and locking the doors in order to contain its spread. The city's sensors were powerful enough to detect any personnel wearing bio-suits (even those not designed by the Lanteans themselves) and allow those individuals safe passage to treat the infected.



These vessel's internal sensors 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 rhythm and reported them 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, 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 perceived. This allowed for the remote viewing of locations on a planet's surface.

Hanger and transportation systems
Inside the ship lays a number of hanger bays which contain Gateships which are slotted into various alcoves. There existed a primary and a secondary bay with external doors allowing for the gateships to enter and exit the ship. One exit to the ship lies at the peak of the control tower while internal door mechanisms allow a gateship to be dropped into the gate room for easy access to the Stargate. There was also at least one entry point from the underneath of the ship. This point of access was rarely used by the Expedition due to the fact it was flooded, it was used by the team who retook Atlantis from the Asurans.

Internally, city-ships possess a number of transporter booths which allows for access to another booth inside the vessel. This allowed for the quick deployment of personnel through various locations of the ship.

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 literally impenetrable, but it was only capable of resisting an assault as long as enough power was available to keep the shield raised. It was possible to alter the shield generators in order to create an anti-Replicator field, meaning any Replicator or Asuran inside the city would fall apart whenever the shield is activated. 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 an atmosphere in the city. The lack of a shield also meant that the inhabitants of the city would be exposed to the vacuum of space, killing them.



The only armaments these vessels possessed were a stockpile of drone weapons, as the city was built to be able to rely on its inpenetrable shield for defense. These weapons were stored within the city itself, and they were launched from portals located at the edges of three of the city's piers. 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. Drone weapons were controlled through the city's chair room by someone using the control chair. A great deal of energy was required to charge the drones, which was easily manageable when ZPMs were powering the city, but secondary power sources were only capable of providing enough energy to launch around a dozen drones.

Power generation systems
These cities of the Ancients were created to utilize special power modules in groups of three in order to power the ship to its full capacity. This energy distribution system was essential in powering the various aspects of the ship such as weapons, shields and engines. There was a fine level of control over the allocation of power throughout the city and it was possible to stop the flow of energy to certain areas. One of the main power conduits ran beneath the control tower and led directly into the power module hub serving as an express lane. It was possible to shut down other parts of the city but this conduit was required to keep the energy distribution grid moving along. The city included a set of solar powered generators which added to the power grid.

It was possible to add power from other sources to the system though ideally it worked best with a power module.

Stardrive
The great city-ships of the Ancients are starships capable of traveling across space, despite their appearance 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. Although 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.

Structure
From above, a city-ship resembles a giant snowflake with its buildings located on a giant platform. The majority of the taller buildings are located on the central platform, while the smaller ones are situated along the edges of the six piers. The control tower (the largest of the buildings), is located in the exact center of the city, housing several important rooms including the gate room, the control chair (if there is no Stargate), the main jumper bay, and the holo room. Surprisingly, the hull of a city-ship is remarkably fragile in comparison to other space-faring vessels, and so a city-ship requires its powerful shield to protect it from such threats as orbital bombardment, natural weather phenomena, and the hazards of space travel.

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 (although 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, although the Control chair is necessary to navigate.

Chair Room
The chair room was an important location in the ship and contained the control chair itself. From this chamber, a user was capable of controlling the cityships defensive systems such as shields or drones. It was also vital in the navigation of the city through hyperspace.

The chair was not always located in this room as there was one case where it was placed within Gate Operations if the Stargate was not there.


 * It's possible that the chair room was linked to the city's sensors in order to direct the drones as the Asurans were incapable of directing the drones into the water when the control centre was destroyed, but once it was repaired Dr Beckett could.

Laboratories
The large nature of the city-ship allowed for a number of research laboratories to be present within the ship were scientific studies were capable of being conducted. There existed numerous computer panels, displays and other forms of equipment with the rooms themselves varying depending on the form of research being conducted.

The Lanteans created a Nanite lab on Atlantis where they created the Ancient nanovirus that evolved into the Asuran species. In addition to this, they also embarked on research into Ascension with a special Ascension lab. They furthermore embarked on a mission of administering the development of Human civilizations through the Society research lab. They also had a Bio lab which contained facilities to study the life on a planet.


 * Only Atlantis itself has shown to possess research laboratories but presumably other city-ships contained similar such facilities.

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.

Conference Room
There are at least two known conference rooms present within the cityship. A sliding doorway served as the entrance to the room. The first room was small contained a rectangular table which was used for general meetings and discussions with the crew of the cityship. The table itself was not fixed and was capable of being removed.

The second more larger room was used for larger meetings and contained a ringed table which faces towards the multipanel doorway. The Ancients used this room as the base from where their leadership governed their empire. The Asurans similarly used this room to where their Asuran Council sat during meetings with outsiders.

Living Quarters
The large city-ships contained a large number of chambers that serve as living quarters for the crew of the vessel. The doorways into the rooms hold a door sensor that requires an individual to wave their hand across it in order to activate the door mechanism allowing for entry. Inside, there were beds where the crew were capable of resting and sleeping. By the bed was another sensor that, when a hand was waved over it, activated or deactivated the lights for the room.

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 millennia 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 indefinitely until a cure can be discovered. There appeared to be a number of computer terminals on the sides of the chamber.

Transportation Booths
Internally, the city contained a number of transporter booths which allowed individuals to move from one such booth chamber to another in the city thus allowing them to move from one part of the ship to the other with ease. When a person entered into the room, a display opened on the wall which contained a schematic of the city with a tap at one of the glowing dots representing another transporter.

The Atlantis Expedition originally believed the booths were simple storage closets and accidentally discovered their true function. Power and access to the transporters can be regulated by the computer system and power distribution grid.


 * Presumably, the booths were a successor to the ring transporter.

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 slides 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.

History
The most well known of all the city-ships was the capital of the Ancients known as Atlantis which departed Earth and left for the Pegasus galaxy over 10,000 years ago. It served as the centre of their government and was the last bastion of their civilization when the Wraith arose and fought them in the Ancient-Wraith War. The Lanteans were driven from their worlds until only Atlantis was all that was left and eventually they sunk the city and left to Milky Way galaxy.

After discovering information on it, the Atlantis Expedition arrived at the city-ship and began to use it as a base of operations in the Pegasus galaxy. During their explorations, they discovered another city-ship which was partially underground. A further city-ship was discovered on the Asuran homeworld of Asuras who used it as a means of destroying Atlantis but it in turn was destroyed when its ZPM core was set to overload.

Known city-ships

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