Editing Installation 04

{{Status|Canon}}
{{Center|'''''Installation 04''' redirects here. For other uses, see [[Installation 04 (disambiguation)]]''.}}
{{Megastructure infobox
|image=[[File:H2A-AlphaHaloDiscovery.jpg|300px]]
|description=
|location=[[Soell|Soell system]], in orbit around [[Threshold]],<ref name="VIS">'''[[Halo: The Essential Visual Guide]]''', ''page 6''</ref> [[Orion Arm]],<ref name="warfleet">''[[Halo: Warfleet]]'', p. 12</ref> [[Milky Way]]
|anchor=Threshold/[[Basis]]{{Ref/Reuse|VIS}}
|type=[[Halo Array|Halo Installation]]
|function=*Galactic sterilization<ref name="halo array">[https://www.halowaypoint.com/en-us/universe/tech/halo-array '''Halo Waypoint''': ''Halo Array'']</ref>
*[[Flood]] containment and research{{Ref/Reuse|halo array}}
|caretaker=[[Monitor]] [[343 Guilty Spark]]
|constructed=[[97,445 BCE]]{{Ref/Reuse|halo array}}
|destroyed=[[2552#September|September 22, 2552]]
|diameter={{Convert|10000|km|mi|sp=us|sigfig=4}}{{Ref/Reuse|VIS}}
|surface width={{Convert|318|km|mi|sp=us|sigfig=3}}{{Ref/Reuse|VIS}}
|gravity=0.992 G (approx){{Ref/Reuse|VIS}}
|surface temperature=-23°C to 40°C (-9°F to 104°F) (controlled){{Ref/Reuse|VIS}}
|atmosphere=1 ([[Wikipedia:Nitrogen|N<sub>2</sub>]], [[Oxygen|O<sub>2</sub>]]){{Ref/Reuse|VIS}}
}}
{{Quote|Whoever controls Halo controls the fate of the universe.|[[Captain (Navy)|Captain]] [[Jacob Keyes]]}}
'''Installation 04''', also known as '''Alpha Halo''', or simply '''Halo''',<ref>'''[[Halo: Combat Evolved]]''', campaign level, ''[[Truth and Reconciliation (level)|Truth and Reconciliation]]'' - Captain Keyes: "''They call it, Halo''"</ref> was one of [[seven]] ring-shaped superweapons that comprised the [[Forerunner]]s' [[Halo Array]]. It was located in the [[Soell system]] in the [[Orion Arm]] and was the closest Halo ring to the [[human sphere]].{{Ref/Reuse|warfleet}}

The [[Covenant]] reverentially described Installation 04 as either the '''First Holy Ring''' or the '''First Sacred Ring'''. After its destruction at the end of the [[Battle of Installation 04]], [[Installation 00|the Ark]] started to construct [[Installation 08|a replacement for Installation 04]]. After the replacement was destroyed, the Ark constructed [[Installation 09|yet another replacement]].

==Overview==
[[File:HCE-AlphaHalo-RingDetail.jpg|thumb|250px|left|Installation 04.]]
The purpose of Installation 04, along with its brethren, was to preclude and thwart the parasite forms known as the [[Flood]] from consuming all sentient life in the galaxy by destroying all sentient life to prevent eventual consumption. In the event of a Flood outbreak, one of the seven installations could be triggered (in turn triggering the remaining Halos) to annihilate all sentient life within a radius of 25,000 light years. In the event of an unexpected shutdown, all remaining rings would go into a "standby state", in which they could be fired at once from the Ark if need be.

Installation 04, until its destruction by John-117, was controlled by the [[Forerunner]] artificial intelligence construct ([[Monitor]]), [[343 Guilty Spark]].

The climate of Installation 04 was very similar to [[Earth]]'s climate. There have been hurricanes over the oceans on the ring.<ref>'''[[Halo: The Flood]]''', ''page 14''</ref> The weather was, however, extremely unpredictable - rain and snowfall could occur at random, leading [[Cortana]] to wonder if the weather was intentionally irregular, or if it followed a pattern such as snow being deliberately made at the control room to slow the Flood.<ref>'''Halo: The Flood''', ''page 107''</ref><ref>'''Halo: Combat Evolved''', campaign level ''[[Assault on the Control Room]]''</ref> The ring boasted a diverse ecosystem, which included colonies of [[Thanolekgolo]].<ref>'''Halo: Nightfall''', ''Chapter 3''</ref>

Installation 04 orbited the massive gas giant [[Threshold]], and was suspended in the [[Lagrange point]] between Threshold and its largest [[natural satellite]], [[Basis]]. The installation had a 24-degree axial tilt from Threshold's orbital plane. Due to this, any given point on the surface of the ring received sunlight from the star [[Soell]] for half of the time it was on the sunny side of Threshold, and none when was on the dark side. This created a somewhat unusual day-night cycle for the ring, in which it was dark three-fourths of the time and had no sunrise or sunset similar to those of a planet.<ref>'''[[Halo: Combat Evolved: Sybex Official Strategies & Secrets]]''', ''page 64''</ref>

With a diameter of 10,000&nbsp;km and a surface width of 318&nbsp;km, the ring has a surface area of 9,990,000&nbsp;km<sup>2</sup>.

==History==
===Construction and early history===
[[File:HaloConstructionCEA.jpg|thumb|250px|Sentinels finalizing Installation 04's construction process.]]
The [[Forerunner]]s had Installation 04 constructed by the [[Foundry (location)|Foundry]] of [[Installation 00]]<ref name="p371">'''[[Halo: Primordium]]''', ''page 371''</ref> approximately around the same time as the rest of the [[Halo Array]], circa [[97,445 BCE]] during the [[Forerunner-Flood war]].{{Ref/Reuse|halo array}}<ref>[https://www.halowaypoint.com/en-us/news/canon-fodder-array-with-words '''Halo Waypoint''': ''Canon Fodder - Array With Words'']</ref> The array was designed by the Forerunner [[Builder]]s to combat the parasitic [[Flood]] by eradicating them and all [[Sentience|sentient]] life in the [[Milky Way]]. After the rings were built, Installation 04 and its fellow Halos were distributed from Installation 00 to positions across the galaxy through [[slipstream space]] [[Slipspace portal|portals]].{{Ref/Reuse|halo array}}<ref>'''[[Halo Legends]]''', ''[[Origins]]''</ref>

When the [[IsoDidact]] activated the Array at the [[Forerunner-Flood war]]'s conclusion, ending the centuries-long conflict, Installation 04 was the first to fire,<ref>'''Halo: Silentium''', ''String 38''</ref> followed shortly after by the other six Halo rings. Installation 04 lay dormant for a hundred thousand years, with [[343 Guilty Spark]] and his [[Sentinel]]s ready to keep the [[Flood]] confined in the [[Flood containment facility|Flood containment facilities]] and keeping the infrastructure of the Halo in perfect working order.

===Intermediate period===
After eons of uneventful existence on Installation 04, 343 Guilty Spark eventually found himself bored. For his own amusement, Spark began an experiment in which he evacuated entire sections of the Installation into space; according to Spark, these were experiments to measure the geologic effects of exposure to the vacuum of space and the eventual biological recovery of the evacuated sections, in order to gain insight into emergency response scenarios.<ref>'''Halo: Combat Evolved Anniversary''' - ''[[Terminal (Halo: Combat Evolved Anniversary)#Terminal 4|Terminal 4]]''</ref>

Around [[40,000 BCE]], an [[unidentified alien vessel]] crash landed in [[Sector 1215]]. Sometime prior to the crash the ship started broadcasting a distress signal.<ref name="terminal5">'''Halo: Combat Evolved Anniversary''' - ''[[Terminal (Halo: Combat Evolved Anniversary)#Terminal 5|Terminal 5]]''</ref><ref name="time">'''Halo: Combat Evolved Anniversary''' - ''[[Terminal (Halo: Combat Evolved Anniversary)#Terminal 6|Terminal 6]]'' (343 Guilty Spark: ''"I have now endured 60,000 years without word from outside the Array."'')</ref> After attempting to translate it, [[343 Guilty Spark]] blocked the signal, as no communication revealing the location of any of the Halos was allowed.{{Ref/Reuse|terminal5}} After no lifeforms exited for several days, Spark had a large sarcophagus constructed around the vessel.{{Ref/Reuse|time}}

Between the activation of the Array and the arrival of the UNSC and the Covenant, a number of space-faring species stumbled across the installation. Although they reportedly explored the facility and recorded their findings, all of these species eventually left without breaking containment.<ref>'''[[Conversations from the Universe]]''', 343 Guilty Spark's Log</ref>

===Discovery and destruction===
{{Main|Battle of Installation 04}}
{{quote|Halo... It's finished."<br/>"No, I think we're just getting started.|Cortana and John-117 after the destruction of Installation 04.}}

[[File:Autumn Arrival.png|thumb|right|250px|The {{UNSCShip|Pillar of Autumn}} arrives at Installation 04.]]

The Covenant discovered the location of Installation 04 after the Covenant [[Fleet of Particular Justice]] followed the {{UNSCShip|Pillar of Autumn}}, which was fleeing from the [[Fall of Reach]] through [[slipspace]]. The Halos are deeply ingrained into the Covenant's [[Covenant religion|religious dogma]], but prior to this discovery they had never actually found one. Due to the Covenant's faster slipspace capabilities, they arrived before the ''Pillar of Autumn''.

The ''Pillar of Autumn'' arrived around September 19, 2552 and was promptly shot down by the warding Covenant ships. Shortly thereafter, the Covenant ground forces on Installation 04 accidentally unleashed the Flood from captivity. [[Human]]s, [[Flood]], and the Covenant fought massive battles against one another as the Forerunner constructs tried to control the outbreak by activating Halo. The ring's monitor, [[343 Guilty Spark]], tried to convince the [[John-117|Master Chief]] to activate Halo. Not knowing the truth of what it did, he attempted to light the ring but was stopped by his AI friend and companion Cortana who was in [[the Core]]. She informed the Master Chief of Halo's true purpose and stashed the [[Activation Index]] in her memory banks. The Monitor betrayed the two and tried to kill the Master Chief and retrieve Cortana, but the two escaped and started plotting against him.

[[File:H2A-AlphaHaloDestruction.jpg|thumb|left|250px|The destruction of Halo.]]
In the conclusion of the battle, John-117 detonated the ''Pillar of Autumn''{{'}}s [[Fusion drive|fusion reactors]] in order to destroy the ring. The explosion critically damaged the superstructure below it; the resulting shockwave and damage to the ring's systems destabilized the ring, shattering it into pieces.<ref>'''Halo: Combat Evolved''', campaign level ''[[The Maw]]''</ref>{{Ref/Note|The particulars of Installation 04's destruction differ throughout its various depictions. In ''Halo: Combat Evolved'', ''Combat Evolved Anniversary'' and most [[terminal]] depictions, a portion of the ring next to the ''Autumn''{{'}}s explosion is sent flying to the other side where it bisects the ring, further splintering the superstructure. The most noticeable change is in the flashback portion of the level ''[[The Heretic]]'' in ''Halo 2: Anniversary'', where the fragment is no longer propelled to the other side and the ring simply shatters, with the explosions spreading in both directions of the epicenter in a chain reaction. The blue lights on the outer surface are also seen going out in this version. The [[Terminal (Halo 2: Anniversary)|''Halo 2: Anniversary'' terminals]] give two versions of the ring's destruction, the first (in Terminal 4) being identical to ''Halo: Combat Evolved Anniversary''{{'}}s [[Terminal (Halo: Combat Evolved Anniversary)|Terminal 11]], which is closer to the original ''Halo: Combat Evolved'' mechanics, although the ring's shattering is more violent. The second version, shown in Terminal 12, is closer in line with the depiction in ''Halo 2: Anniversary'' version of the flashback in ''The Heretic'' and lacks the shard being blasted to the opposite side.}}

Only a handful of humans and Covenant survived the battle. 343 Guilty Spark floated through space to a [[Threshold gas mine|gas mining platform]] over Threshold, where he stumbled upon a Covenant expeditionary force. Inspired by his words, they began a [[Sesa 'Refumee's heretic faction|heretical]] rebellion against the greater Covenant. Installation 04's destruction is seen as the first step in the chain of events that led to the [[Great Schism]]. The Heretics were quelled by [[Arbiter]] [[Thel 'Vadam]] who silenced their leader, but the seeds of a rebellion were planted. The Monitor was then captured by the loyal Covenant and later defected to the humans' side until he was destroyed on the replacement Alpha Halo by SPARTAN-117 with the help of Sergeant Johnson.

Installation 04 was the first Halo installation encountered by humanity, as well as first to be destroyed. Its attempted firing triggered the activation of a portal leading to [[Sarcophagus|Shield World 006]] within [[Onyx]],{{Ref/Novel|GoO|Page=175|Quote=Halsey: That timing coincides with the activation of an alien weapon world - before John thankfully destroyed it. It is no coincidence that the Sentinels appeared then. It must be part of a larger Forerunner plan.}} and also caused [[Installation 00|the Ark]] to start constructing a [[Installation 08|replacement ring]].

===Debris field===
[[File:H2A - Alpha Halo remains.jpg|thumb|right|250px|The burning wreckage of Installation 04, surrounded by vessels of the Covenant armada in the aftermath of the battle.]]
Installation 04's destruction left behind a large field of debris, with a few large chunks of the ring remaining.<ref>'''[[Halo 2]]''', campaign level ''[[The Heretic]]''</ref> Some smaller pieces of Installation 04 have landed on Basis, while others have burned up in Threshold's atmosphere upon entry.<ref>'''[[Halo 2]]''', multiplayer map ''[[Burial Mounds]]''</ref> [[Alpha Shard|One damaged fragment]] notably made a slipspace jump as a safety measure, and ended up in a distant system.{{Ref/Reuse|wp shard}}

====The ''Mona Lisa''====
{{Main|Skirmish on Mona Lisa}}
[[File:TML - broken Halo.png|thumb|250px|A segment of the broken ring.]]
Following the return of the survivors from the battle, the Office of Naval Intelligence learned of the Flood lifeform. Section III sought to establish a research laboratory in order to control the Flood parasite and possibly weaponize it against the Covenant. A science team headed by Major [[John Smith]] was authorized to take command of the [[prison ship|prison vessel]] ''[[Mona Lisa]]''. After bringing a group of Covenant prisoners aboard, they jumped to the wreckage of Alpha Halo in the Soell system. Some Flood specimens had survived the ringworld's destruction and were recovered to be experimented on both human and Covenant prisoners. However, the Flood soon broke quarantine and infected the ship. ONI later dispatched a [[prowler]], the {{UNSCShip|Red Horse}}, to assess the status of the ''Mona Lisa'' under the pretenses of investigating Halo's debris field. On October 25, 2552, the prowler was forced to destroy the overrun vessel with a [[Shiva-class nuclear missile]].<ref>'''Halo: Evolution - Essential Tales of the Halo Universe''', ''The Mona Lisa''</ref>

===First replacement===
{{Main|Installation 08}}
Shortly after the destruction of the Halo, [[Installation 00]] began to automatically construct a new Halo to replace Installation 04. This exact copy of the first Halo ring was nearing completion only a few months after the first ring was destroyed, but was also subsequently [[Raid on Installation 08|destroyed]] when it was fired before it was ready by John-117 and Cortana. 343 Guilty Spark attempted to prevent this, but was finally destroyed by the Master Chief with the help of Sergeant Johnson in the new ring's [[Control Room]].<ref>'''[[Halo 3]]''', campaign level, ''[[Halo (Halo 3 level)|Halo]]''</ref>

===Post-war===
The UNSC's [[Treaty of 2552|peace treaty]] with the [[Swords of Sanghelios]] forbids either party from landing on the remains of Installation 04.{{Ref/Reuse|nf1}} There is a 500-[[Wikipedia:Light-second|light-second]] exclusion zone surrounding the former site of the ring. In [[2556]], [[Spartan-IV]] [[Fireteam Apollo]] was [[Operation: SHELL GAME|deployed to the exclusion zone]] in direct violation of the treaty; there they recovered some items of value, including a "black box" from the Covenant cruiser ''[[Undiminished Entelechy]]''.<ref name="lc">'''[[Halo Legendary Crate]]''', ''[[Halo Legendary Crate/Data Drops|Data Drop 3]]''</ref>

At some point after the war, a Spartan-IV reconnaissance team was deployed to [[Basis]]. Wearing [[VECTOR-class Mjolnir]] armor, a variant designed for artifact retrieval, their mission was to assess the debris of Alpha Halo scattered on the moon's surface.<ref>'''Halo 5: Guardians''', ''[[VECTOR-class Mjolnir]] armor description''</ref>

====Lost fragment====
{{Main|Alpha Shard}}
When the ''Pillar of Autumn''{{'}}s reactors went critical, Installation 04 attempted to activate a safety measure and make a slipspace jump. However, this self-preservation protocol was only partly successful, and only a small portion of the ring managed to enter slipspace before the ''Autumn''{{'}}s reactors overloaded and destroyed the ring. The surviving fragment of the Halo reentered normal space in the vicinity of [[Thotael system|a red giant star]] some distance away from the [[Orrichon system]] and was caught in the giant star's orbit.<ref name="wp shard">[https://www.halowaypoint.com/en-us/universe/locations/halo-ring-fragment '''Halo Waypoint - Universe''': ''Alpha Shard'']</ref> This fragment was home to a unique element apparently created by the heat of the ring's explosion and not found elsewhere in the universe. The element was later refined and used in a [[bioweapon]] unleashed in a [[terrorist]] attack on [[Sedra City]].<ref name="nf1">'''Halo: Nightfall''' - ''Chapter One''</ref> [[Mission to Alpha Shard|A joint classified mission]] was launched to Alpha Shard by an [[Locke's team|ONI team]] and members of the [[Sedran Colonial Guard]]. Though most of the team was killed during the mission, [[Colonel]] [[Randall Aiken]] sacrificed himself to destroy the deposits with a [[HAVOK tactical nuclear weapon]].<ref>'''Halo: Nightfall''' - ''Chapter Five''</ref>

===Second replacement===
{{Main|Installation 09}}
During the {{UNSCShip|Spirit of Fire}}'s [[Second Ark Conflict|battle]] with the [[Banished]] at the Ark in [[2559#March|March 2559]], Captain [[James Cutter]], Professor [[Ellen Anders]], and logistics AI [[Isabel]] formed a plan to deploy the second replacement for Alpha Halo, Installation 09, to the Soell system in an attempt to send a [[distress beacon|distress signal]] to [[Human colonies|human space]].{{Ref/Level|HW2|[[Hold the Line]]}} On the way to the original site of Installation 04 however, a Forerunner [[Guardian|Guardian construct]] controlled by Cortana's [[Created]] intercepted the ring.{{Ref/Level|HW2|[[Last Stand (Halo Wars 2 level)|Last Stand]]}}

==Non-canon and dubious canon appearances==
===Silver Timeline===
{{Status|Silver}}
[[Makee]] discovered the location of the Halo ring from her and [[John-117/Silver|John-117]]'s visions, which proves to be Installation 04 in the center of the [[Soell system]]. By tracking Makee's ship, the UNSC was able to locate the ring as well.{{Ref/Film|Id=Thermopylae|TV|Episode=[[Thermopylae (TV Series)|Thermopylae]]}}

When John arrived in ''[[Condor 325]]'', he found the Covenant [[First Fleet of Solemn Accord]] chasing Makee and [[Arbiter]] [[Var 'Gatanai]] towards the Halo ring while the [[SPARTAN-III program/Silver|SPARTAN-IIIs]] prepare to launch a possible suicide mission that would destroy both the UNSC and Covenant fleets as well as the star system and the Halo ring.{{Ref/Reuse|Thermopylae}}

==Trivia==
[[File:Inst04detail.png|thumb|250px|Detail of the outer surface of the ring in ''Anniversary''.]]
===Redesigns===
While the design of the Halos has stayed largely consistent across all post-''[[Halo: Combat Evolved]]'' media, Installation 04 underwent a significant visual overhaul in ''[[Halo: Combat Evolved Anniversary]]''. The entire superstructure of the ring has been redesigned. To wit, the surface features are completely different and much more pronounced, including additions such as rows of prominent prongs lining the ring's edges and large-scale patterns of bluish light. This redesign has not been carried over to post-''Anniversary'' media: the prongs are absent from [[Installation 03]] in ''[[Halo 4]]'', and [[:File:FUD-HaloRing.jpg|a visual allusion]] to the Halos in ''[[Halo 4: Forward Unto Dawn]]'' follows the original design. However, the "prong" design does make a subtle appearance on the outer shells of the arcade machines for ''[[Halo: Fireteam Raven]]''.

Installation 04 also underwent a number of visual changes in ''[[Halo 2: Anniversary]]'', including the addition of blue lighting in the circular patterns on the ring's outer surface. Curiously, [[Installation 05]] in the same game uses a distinct model, which bears different surface patterning more closely modeled after that in [[Bungie]]'s games but is noticeably wider than either the Installation 04 model in ''Halo 2 Anniversary'' or the Halos in prior media. Furthermore, [[Blur Studio]] used Installation 05's model, rather than that of the original Installation 04, from ''Halo 2 Anniversary'' for [[Installation 09]] in ''[[Halo Wars 2]]''.<ref>'''Halo 2 Anniversary''', [[:File:H2A - DeltaHalo.jpg|''Delta Halo model'']]</ref><ref>'''Halo Wars 2''', [[:File:HW2 I04C.png|''Installation 09 model'']]</ref>

===Miscellaneous===
*Sergeant Johnson humorously describes Installation 04 as "God's own anti-son-of-a-bitch-machine" and a "giant hula-hoop".
**The former is surprisingly accurate as to the ring's actual function, since the Forerunners were worshiped as gods by the Covenant, the Flood could quite accurately be referred to as a "son of a bitch", and the ring's purpose is to fight the Flood.
*Except for [[Boarding Action]] and [[Chiron TL-34]], all ''Halo: Combat Evolved'' multiplayer maps are set on Installation 04.
*It is possible to see falling debris from Installation 04 on the Halo 2 multiplayer map [[Burial Mounds]].

==Gallery==
===Concept art===
<gallery>
File:MarcusLehto_PreCE_Halo_sketch.jpg|An early sketch for Installation 04's layout and mechanics by [[Marcus Lehto]].
File:H2_RingDestruction_Concept.jpg|''Halo 2'' concept art of the destroyed Installation 04.
File:HCEA_Installation04Menu_Concept_1.jpg|Concept art of Installation 04 in ''[[Halo: Combat Evolved Anniversary]]''.
</gallery>

===Regular gallery===
<gallery>
File:Installation04S.png|The symbol representing Installation 04.
File:HCE Ringworld Concept.jpg|Concept art of Installation 04.
File:HCE-AlphaHalo-OrbitingThreshold.jpg|Installation 04 orbiting Threshold, as seen in ''[[Halo: Combat Evolved]]''.
File:HCE-AlphaHalo-SurfaceDetail.jpg|A close-up view of Installation 04's exterior surface.
File:OneRing.jpg|Installation 04's surface.
File:HCE-HaloRingLoadingScreen.jpg|Installation 04 as the loading screen for the PC and Mac version of ''Halo: Combat Evolved''.
File:HCE - Halo.jpg|The surface of Halo.
File:HCE Halo Sky.png|The sky of Halo.
File:HCE Halo Island.jpg|An island in Halo.
File:AlphaHaloview2.jpg|''Pillar of Autumn''{{'}}s engines detonate, destroying Installation 04.
File:HCE-AlphaHalo-Destruction-screen.jpg|Installation 04 breaking apart.
File:Broken Ring.jpg|A section of the broken ring.
File:FoR - Halo.png|The ring in ''[[Halo: Fall of Reach]]''.
File:HCE Halo Surface.png|The surface as depicted in ''Halo: Combat Evolved''.
File:HCEA Halo Surface.jpg|The surface as depicted in ''Halo: Combat Evolved Anniversary''.
File:HCE Halo Exterior Surface.png|The exterior surface as depicted in ''Halo: Combat Evolved''.
File:Halo ring.jpg|Installation 04, as depicted in ''Halo: Combat Evolved Anniversary''.
File:GuiltySparkAnniversary.png|[[343 Guilty Spark]], [[Monitor]] of Installation 04.
File:AssaultonControlRoom.png|The Forerunner "temple" housing Halo's control room.
File:PhasePulseAnniversary.png|One of Installation 04's three [[phase pulse generator]]s.
File:Inst04 vista.jpg|A rocky shoreline on Installation 04.
File:Installation 04 Terminal.jpg|Installation 04, as seen in a [[Terminal (Halo: Combat Evolved Anniversary)|Terminal]].
File:HCEA-Terminal-AtmoEjection.jpg|343 Guilty Spark exposing a section of Installation 04 to hard vacuum.
File:Installation04destroyed.png|The destruction of Installation 04.
File:HaloDestructionCEA.png|Installation 04 being destroyed in ''Halo: Combat Evolved Anniversary''.
File:H5G-Alpha Halo.png|Installation 04's surface as seen in the ''[[Halo 5: Guardians]]'' [[Forge]] map [[Parallax]].
File:LC 003 Cov1.png|Covenant readout of Installation 04.
File:LC 003 Cov2.png|Another Covenant readout.
</gallery>
{{Linkbox|gallery=yes}}
{{Clear}}

==List of appearances==
*''[[Halo: The Fall of Reach]]'' {{1st}}
*''[[Halo: Combat Evolved]]''
*''[[Halo: The Flood]]''
*''[[Halo: First Strike]]''
*''[[Halo 2]]'' {{C|Flashback}}
**''[[Conversations from the Universe]]''
*''[[Halo Graphic Novel]]''
**''[[The Last Voyage of the Infinite Succor]]''
**''[[Breaking Quarantine]]''
*''[[Halo: Ghosts of Onyx]]'' {{Mo}}
*''[[Halo 3]]'' {{Mo}}
*''[[Halo Legends]]''
**''[[Origins]]''
*''[[Halo: Evolutions - Essential Tales of the Halo Universe]]''
**''[[The Mona Lisa]]''
*''[[Halo: Reach]]
*''[[Halo: Fall of Reach]]''
**''[[Halo: Fall of Reach - Invasion|Invasion]]''
*''[[Halo: Combat Evolved Anniversary]]''
**''[[Terminal (Halo: Combat Evolved Anniversary)|Terminals]]''
*''[[Halo 4]]'' {{Mo}}
*''[[Halo: Silentium]]''
*''[[Halo: Escalation]]''
*''[[Halo: Broken Circle]]'' {{Mo}}
*''[[Halo: Nightfall]]''
*''[[Halo 2: Anniversary]]'' {{C|Flashback}}
**''[[Terminal (Halo 2: Anniversary)|Terminals]]''
*''[[Halo: Hunters in the Dark]]'' {{Mo}}
*''[[Halo 5: Guardians]]''
*''[[Halo Mythos]]''
*''[[Halo: Tales from Slipspace]]''
**''[[Dominion Splinter]]'' {{C|Flashback}}
*''[[Halo Wars 2]]'' {{Mo}}
*''[[Halo: Envoy]]'' {{Mo}}
*''[[Halo: Fireteam Raven]]''
*''[[Halo: Official Spartan Field Manual]]''
*''[[Halo: Renegades]]'' {{Mo}}
*''[[Halo: Shadows of Reach]]'' {{Mo}}
*''[[Halo: Point of Light]]'' {{Mo}}
*''[[Halo: Divine Wind]]'' {{Mo}}
*''[[Halo Infinite]]'' {{Mo}}
*''[[Halo Infinite: Memory Agent]]'' {{Mo}}
*''[[Halo: Outcasts]]'' {{Mo}}
*''[[Halo: Battle for the Blood-Moon]]'' {{Mo}}
*''[[Halo: The Television Series Season Two]]''
**''[[Thermopylae (TV Series)|Thermopylae]]''
**''[[Halo (TV Series)|Halo]]''

==Notes==
{{Ref/Notes}}

==Sources==
{{Ref/Sources}}

{{Forerunner|array|category=no}}

[[Category:Installation 04 locations| ]]
[[Category:Halo Array]]