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Installation 00

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Installation 00 / The Ark
Background information


262,144 light years from galactic center




Severely damaged by Installation 04B's premature activation

Firing Record



127,530 kilometers (79,244 miles)

[Source]   [Talk]

“Where would someone go to activate the other rings?”
“...Why, the Ark, of course.”

Installation 00, also known as The Ark, or The Lesser Ark via Halo: Primordium, is an enigmatic Forerunner installation from which all the Halo Installations across the galaxy can be activated[1] simultaneously. In addition, it functions as a safe haven from the Halo network's strategic pulse, as well as a facility to construct and repair any of the Halo Array. It was first mentioned by 343 Guilty Spark at the Battle of Installation 05 (in its control room), where he explains the fail-safe protocol of the Installation and the standby modes of the seven rings after its unexpected shutdown. The Ark is about 218 (exactly 262,144) light years from the galactic center (For range comparison Earth is 25,000 light years from the galactic center).[2]



The Ark sending the Halo Array through Slipspace during the Forerunner-Flood War

Installation 00 is a part of the Forerunner construct designed to wipe the Flood from the Galaxy. Located about 262,144 light years from the galactic center, Installation 00 is located outside the galaxy and is thus safe from the Halo effect (as it is referred to by the Forerunners in the terminal transcripts) that kills all organic sentient lifeforms; the main Forerunner behind its use was the Iso-Didact. The commission of this installation is to remotely activate the seven Halo rings then in existence, from outside the pulse radius of the array. This is a fail-safe system, and is only activated by an aborted firing such as the one that occurred at the end of the Battle of Installation 05 (Delta Halo). In addition, Installation 00 can also function as an automated factory to construct replacement Halo installations, thereby ensuring that the Halo array is always ready to fire, should the array be needed.

“Every vessel we can fill, we send to the Ark. I dare not cease the mission. Not now, not until I've done all I can. Each one of these souls is finite and precious.”
— --Transcript of a message from the Librarian to Ur-Didact, interpreted post-cataclysm and retrieved from the first Terminal on the level "The Ark"

During the construction of the Halo Array, while the rest of the Forerunners civilian and military presence attempted to defeat the Flood through any way they knew possible, a plan B was also approved by the Ecumene Council, which included the construction of the Shield Worlds like Onyx, and The Arks (as seen in Halo 3).

With this final push, a last ditch plan for the defeat of the Flood, The Librarian was to index every sentient species in the Galaxy, and bring many of the more intelligent species to the Arks, and then presumably key Forerunners would take refuge within the Ark's secret location, until the Flood were starved and they could go return to the Milky Way Galaxy.

However, things did not go as planned, as the Forerunner military AI 032 Mendicant Bias turned on the Forerunners after considerable convincing from a Gravemind, and began assisting the Flood. Mendicant Bias knew of the Ark, how to access it through Forerunner Key Ships (only Lifeworkers had slipspace privilges at the time due to indexing requirements), but did not know of its exact location outside of the Milky Way Galaxy. The Ecumene Council then commissioned another military AI, Offensive Bias, in order to devise the best possible defense against Mendicant Bias, his fleet, and the impending attack against the Maginot Line. The Librarian scuttled all of the Key Ships under her command.

Long after the firing of the Halo Array, Installation 00 would be host to the final battle of the Human-Covenant war and decisive victory over the Flood.

After the war, the UNSC sent an investigative group to Installation 00. After launching probes, the group recieved a Forerunner signal coming from the surface of the Ark. After the team determined the dense debris field to be stable for further activity in the region, the UNSC Rubicon was deployed from Luna to conduct a more thorough investigation of the installation's ravaged surface. Due to the damage dealt to the Ark's life support systems and its artificial sun, heavily inclement weather have became common.

The Rubicon had several remote contact teams, who landed on the Ark and attempted to find the source of the mysterious signal. After nearly eight days, all contact with the teams was lost; only one team, RCT-06, returned, having sustained heavy casualties and carrying with them an unknown device. The armature's origin was subjected to debate, but it was believed by the team to be the source of the beacon picked up by the initial investigative group. The device turned out to a broken, barely active monitor which began to relate its past life as a human: Chakas. Though the ship's ONI attachment initially doubted the accuracy of the monitor's account, the science team leader noticed that it was consistent with the Bornstellar Relation found on Onyx.

Eventually, the monitor revealed that it was 343 Guilty Spark. Claiming that he knew the location of the Librarian, whom he believed to be alive, Spark incorporated the ship's AI, incapacitated the crew via the life support systems, and hijacked the ship. Communications with the Rubicon stopped within 48 hours after last report. Search and rescue teams were then sent to the site, but have, so far, reported no findings.

Layout and FunctionEdit


A Holographic representation of the Ark.


The Ark compared to the planet Earth and Halo. (Courtesy of Stephen Loftus)

Installation 00 resembles a massive wheel with a series of eight curved arms retreating from its centre, similar to a sea star and bearing similarities to a sun. The Ark Core is the stripped remnant of a material-rich planetoid, asteroid, or other celestial body used for the construction of the Halos, which the Ark constructs. The entire upper surface is terraformed, with oceans, forests and even a large desert, where John-117 first makes landfall. At the time of construction, the Ark lacked its core and a livable surface with no land or water. The structure is the second largest known Forerunner construct, only dwarfed by the Micro Dyson Sphere (such as Shield 0006) which has a diameter of 300 million kilometers. A simple inspection of the holographic representation reveals the Ark to be anywhere from 90,000 to 100,000 kilometers (55,890 to 62,100 miles) in diameter.[3]

The three shown primary functions of Installation 00 are to act as a remote for activating the entire Halo Array network while safely out of the Halos' range, as an automated construction facility for the creation of replacement Halo installations (ensuring that the network continues to operate even if any rings are destroyed), and it has also been confirmed that the Ark was meant to be used to reseed the galaxy in the event of the Halo Arrays being fired. Held deep within its mysteries was a collection of every species the Forerunners had studied and governed over. How this plan was to be initiated is still unknown, although, gleaning information from how the Milky Way Galaxy was reseeded eventually, the same conventions and constructs would have most likely been used, such as automated data logs for the retrieval and reseeding of the galaxy through means of Forerunner Key ships which were found on several planets in the galaxy such as Earth and the San'Shyuum home world of Janjur Qom.

Most interestingly, the Ark is not actually in the Milky Way as noted by a stunned ODST soldier at the start of the level The Ark. The Ark is in the void in between galaxies, known as intergalactic space. As such, it's outside the believed range of any Halo installation. The Ark also has an artificial sun floating above it. An observer can see this more clearly on the level "Halo" when looking up at the sky.


A view of Installation 00's Artificial Sun.

The FoundryEdit

Main article: Strip Mining Moon

The Strip Mining Moon is the open area at the heart of Installation 00, which is surrounded by a void, and is the automated factory for replacement Halo installations. This void conceals the Halo Foundry, which constructs the Halo Rings and sends them to their orbital destinations. Raw materials for the process are supplied by a planetoid roughly 1/3 the size of Earth. The moon is large enough to make several replacement installations, as seen in Halo 3 when it produced a replacement ring for Installation 04 in a matter of months.

Cooling SystemsEdit


A view of a cooling system.

The intense heat generated by the Ark's Foundry, where the Halo Rings are constructed, heats the Ark up so much that multiple cooling stations are needed. At least two systems span a snowy gorge at one point or it could be that the massive cooling systems are causing this icy climate due to their nature. The systems are long, and they curve up, retreating from the Foundry of the Ark. Above the systems are small bridges, as well as two stations on each side. An example of a cooling system are the two on the Halo 3 multiplayer map Narrows.[4]


Ark surface 3

A view of the Ark's arms from the surface. The Ark's artificial sun can be seen in the sky.

Along with most Forerunner constructs, the Ark consists of an atmosphere similar to Earth, comprised of mostly oxygen and nitrogen. This makes all Human and Covenant able to live on this planet (excluding Grunts who depend on methane tanks to sustain life) and the Flood as well. Also, like Earth and the other Installations, weather can radically change on the Ark.

The Ark has a habitable surface on each of its spokes and on the majority of the inner circle just outside of the Foundry. The landscapes and biomes are as diverse as those of Earth and even of the Halos; consisting of deserts, taiga and forest as seen on The Covenant, and deciduous forests as seen in Isolation. Several bodies of water are dotted around the area as well. As such, the Ark can sustain its own ecosystem, providing a variety of habitation for many kinds of life. If the Halos were fired, all forms of life could thrive and reproduce in the Ark's highly varied ecosystem, eventually being able to return to the Milky Way to recreate a full food chain on each planet. The diverse locations may also assist in the studies of the Flood in a natural, but isolated, environment.

As the Ark is outside of the galaxy, isolated in a black void of space, there are no nearby natural sources of light to power the Installation and facilitate the survival of biological organisms on its surface. To counter this problem, the Ark is equipped with an artificial structure consisting of a bright, sun-like light, with several metal arms jutting from its center.[5] From aerial pictures of the Installation, it seems the light source "scans" over certain areas to generate day/night cycles, further contributing to the growth of vegetation and controlling weather patterns.


Main article: The Artifact

An important component of the Ark which serves as a medium of transportation, the Artifact is a Forerunner creation which is designed to open a Slipspace portal to enable access to Installation 00.  In Halo: Silentium, this portal is shown to be created from a Gargantua class ship, at the Librarian's request to allow humanity to 'reclaim' their rightful position in the galaxy sooner.

As first seen in the Halo 3 Announcement Trailer and numerous other promotional materials, this construct was originally thought to be the Ark itself; however, this was disproved with the release of Halo 3. The Artifact was partially uncovered when Regret's carrier destroyed a portion of Mombasa during the Battle of Earth, and completely excavated by Covenant Loyalist forces during the weeks that followed.

By the time of Halo 3, Covenant Loyalists had excavated the Artifact from the crater and were able to completely uncover it. The Prophet of Truth activated it at the conclusion of the level The Storm. It formed a massive portal, in which the Forerunner ship immediately entered (presumably carrying Truth), followed immediately by the Covenant Loyalist ships. At the end of the level Floodgate, human and Swords of Sanghelios forces resolved to follow Truth's ships through the portal, and ended up at Installation 00. At the end of the game, the damage caused to the Installation caused the portal to collapse, severing the Dawn in half as it passed back through. The forward section, in which Thel 'Vadam had been inside of, made it back to Earth, plunging into an unspecified body of water. Humans soon rescued Thel. The other section of the Forward Unto Dawn, containing John-117 and Cortana, did not make it through the portal, and were left stranded in an unknown location of deep space, drifting towards Requiem.

Guilty Spark meets Mendicant BiasEdit

This transcript is taken from the third Terminal which is found in the game. It basically tells that 343 Guilty Spark is being warned for accessing Installation 00's systems and is warned that even though he is the Monitor of Installation 04, he has no right to be accessing systems on the Ark. He also learns that Installation 00 has the capability of constructing another Halo Installation.

Warning: Your intrusion has been logged.

04-343 (errant): Excuse me?

Your intrusion has been logged. And now it has been halted.

04-343 (errant): On whose authority?

Advice: Any further attempt to access [insects under stone] will result in your immediate addition to local Sentinels' targeting ledger.

04-343 (errant): Vexation! I am the Monitor of --

Judgment: Your authority means nothing here.

04-343 (errant): Impatience!

04-343 (errant): I have told you who I am. Who are you?

All our makers once held dear. [Alexandria before the Fire]

04-343 (errant): Sincere apology. But how --

Explanation: This facility is host to the [Librarians'] final --

04-343 (errant): The archive is intact?! Then our makers' plan --

But also maintains [bellows, crucible, castings]

04-343 (errant): A what?

[bellows, crucible] --

04-343 (errant): A Foundry?

04-343 (errant): For what purpose?!

Warning: Your intrusion has been logged.

Advice: Any further attempt to access will result --

04-343 (errant): Indignant!

-- immediate addition to local sentinels' targeting ledger.

{Terminal gets overridden by 032 Mendicant Bias}



  • There are actually two "Arks," as described in Halo: Primordium. The Lesser Ark is Installation 00, which is presumably is the Ark that created all of the Halos that are 10,000 km in diameter, while the Greater Ark ("Installation 0"?) is the installation that more than likely created the Halo installations that are 30,000 km in diameter. 
  • Within the Halo Graphic Novel, in the short comic Second Sunrise Over New Mombasa, a transmission is intercepted between the Covenant assault forces stating that once the humans were dealt with in the Battle of Mombasa, they would start uncovering the Ark. There is also, of course, the strongly supported theory that human life originated in East Africa, usually associated with the Great Rift Valley.
  • In the fifth server of the Iris VMC it was stated that the Ark was built to protect humanity from the Flood and the activation of the Halos.
  • In the real world, the Ark of the Covenant, which according to the old Testament contains the stone tablets of the ten commandments, the holiest object of the Jewish faith, and important to Christianity, is said to have brought victory to the Israelites when it was placed at the head of their army during battle. The Ark of the Covenant is popularly believed to lie somewhere in East Africa, albeit in Ethiopia rather than Kenya.
  • During the level The Ark, 343 Guilty Spark mentions that the Ark is 218 (262,144) light years away from the center of the Milky Way. As the Milky Way is around 100,000-120,000 light years in diameter, the installation is beyond the reaches of galactic space, thereby keeping anyone who is on it safe from the firing of the Halos.
  • The Ark is located at the far estimated edge of what is called the Milky Way's spheroidal halo, adding another level to the series' title.
  • A member of HBO estimated the size of the Ark by comparing its size to a Halo installation and Earth and estimated its size to be approximately 90,000 to 100,000 kilometers in diameter.[6]
  • In the Art of Halo 3, it showed a picture of a giant firestorm sweeping across the entire Ark as the replacement Halo fired, thus doing "a number on the Ark", though this outcome is unconfirmed as the Ark's final fate was not seen in Halo 3.
  • The entirety of the Ark is never seen in game; only petals or the center of the Installation are seen. This contrasts the Halo Installations, which were usually given full-bodied debuts for their entrances.
  • The Ark is a Biblical reference; "The Ark" saves the species cataloged by the Forerunners from around the galaxy from "The Flood", similar to how Noah's Ark saved the world's animals from the great flood, and then allowed them to reseed Earth.
  • The Ark has some similarity to the concept of an Alderson Disk. However, an Alderson disk is much larger and has a star in the center.
  • Six Multiplayer maps are based on locations of the Ark; Construct, Isolation, Narrows, Valhalla, Epitaph and Citadel.
  • In Halo Legends, the Installation is depicted as having no land on its surface.
  • In the last mission of Halo 3, 343 Guilty Spark mentions that a premature firing will destroy The Ark, meaning that The Ark could have been destroyed more than been extremely damaged. However, he spoke as if the firing would certainly destroy it, in which case he was incorrect.
  • In Halo: Escalation, Petra Janecek theorized that Installation 00 has doomsday capabilities beyond just replacing Halo rings.




  1. Halo 2, The Great Journey, Final cinematic.
  2. Halo 3, The Ark
  4. Halo 3's Multiplayer Level Narrows's description. "Without cooling systems such as these, excess heat from the Ark's forges would render the construct uninhabitable."
  5. [1]
  6. [2]

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