Editing Installation 05

{{Status|Canon}}
{{disambig header|the Halo installation|the campaign level|Delta Halo}}
{{Megastructure infobox
|image=[[File:H2A - DeltaHalo.jpg|300px]]
|description=
|location=Orbiting [[Substance]], [[Coelest system]],<ref name="VIS">'''[[Halo: The Essential Visual Guide]]''', ''page 46''</ref> [[Norma Arm]]<ref name="warfleet">''[[Halo: Warfleet]]'', p. 13</ref>
|anchor=Substance/[[Opusculus]]{{Ref/Reuse|VIS}}
|type=[[Halo Array|Halo installation]]
|function=Galactic sterilization/[[Flood]] containment and research
|caretaker=[[2401 Penitent Tangent]]<ref name="universe">[https://www.halowaypoint.com/en-us/universe/locations/delta-halo '''Halo Waypoint''': ''Delta Halo'']</ref>
|constructed=c. [[97,445 BCE]]
|destroyed=*Surface [[Glassing|glassed]] by the [[Fleet of Retribution]] to prevent further Flood outbreak<ref name="GoO glassed">'''[[Halo: Ghosts of Onyx]]''', pages 195-197</ref><ref name="ENC glassed">'''[[Halo Encyclopedia (2009 edition)]]''', ''page 186'' (''"Having been cauterized and quarantined by the [[Sangheili]] fleets, 05 now sits dormant."'')</ref>
*Deactivated from [[Installation 00]] as of December 11, 2552{{Ref/Reuse|ENC glassed}}
|destroyed-title=Status
|diameter={{Convert|10000|km|mi|sp=us}}{{Ref/Reuse|VIS}}
|surface width={{Convert|318|km|mi|sp=us}}{{Ref/Reuse|VIS}}
|gravity=1.04 G{{Ref/Reuse|VIS}}
|surface temperature=-19°C to 42°C (-2.2°F to 107.6°F){{Ref/Reuse|VIS}}
|atmosphere=1.01 ([[Wikipedia:Nitrogen|N<sub>2</sub>]], [[Oxygen|O<sub>2</sub>]]){{Ref/Reuse|VIS}}
}}
{{Quote|This installation has a successful utilization record of 1.2 trillion simulated and one actual. It is ready to fire on demand.|[[2401 Penitent Tangent]]<ref name="h2grave">'''[[Halo 2]]''', campaign level ''[[Gravemind (level)|Gravemind]]''</ref>}}

'''Installation 05''', also known as '''Delta Halo''',<ref name="deltahalo">'''Halo 2''', campaign level ''[[Delta Halo]]''</ref> is one of the massive [[Halo Array|Halo fortress worlds]] built by the [[Forerunner]]s. The ring was formerly maintained by [[monitor]] [[2401 Penitent Tangent]], until his lax oversight led to the [[Flood]]'s escape from their [[Flood containment facility|containment facilities]].{{Ref/Reuse|ENC glassed}} The Halo orbits [[Substance]], an ice giant and the fourth planet in orbit in the [[Coelest system]],{{Ref/Reuse|VIS}} located in the [[Norma Arm]] of the [[Milky Way]] galaxy.{{Ref/Reuse|warfleet}}

The purpose of Installation 05, along with its brethren, was to preclude and thwart the parasitic Flood from consuming all [[Sentience|sentient]] life in the [[Milky Way|galaxy]]. In the event of a Flood outbreak, one of the seven installations could be triggered to annihilate all sentient life within 25,000 light-years. Once one ring is set off, all remaining rings would activate. All seven rings could be fired at once if need be.{{Ref/Reuse|ENC glassed}}

Installation 05 was the third Halo discovered by [[human]]ity<ref name="11th">'''[[Eleventh Hour reports]]''', ''#5''</ref> and the second found by the [[Covenant]].{{Ref/Reuse|deltahalo}} The ring became a battleground near the end of the [[Human-Covenant War]]; more importantly, it was at Installation 05 that the [[Great Schism]], the civil war that sundered the Covenant, began. The installation was ultimately partially [[Glassing|glassed]] by the [[Sangheili]] in order to prevent the Flood from escaping in the wake of the [[Battle of Installation 05]].{{Ref/Reuse|GoO glassed}}{{Ref/Reuse|ENC glassed}}

==History==
===Early history===
{{Quote|Those who built this place knew what they wrought. Do not mistake their intent, or all will perish as they did before.|The [[Gravemind]]{{Ref/Reuse|h2grave}}}}
Installation 05 was built by [[Installation 00]]'s [[Foundry (location)|Foundry]]<ref name="p371">'''[[Halo: Primordium]]''', ''page 371''</ref> approximately around the same time as the rest of the [[Halo Array]], circa [[97,445 BCE]].<ref>[https://www.halowaypoint.com/en-us/news/canon-fodder-array-with-words '''Halo Waypoint''': ''Canon Fodder - Array With Words'']</ref><ref>[https://www.halowaypoint.com/en-us/universe/tech/halo-array '''Halo Waypoint''': ''Halo Array'']</ref> [[Human]] analysts of the 26th century believe that an extensive collection of species were brought to the installation to be studied by the [[Lifeworker]]s, as part of the [[Conservation Measure]].{{Ref/Reuse|universe}} Installation 05 was activated shortly after by the [[Forerunner]]s at the conclusion of the [[Forerunner-Flood war]], eradicating all [[Sentience|sentient]] life in the galaxy and, presumably, destroying the [[Flood]] as well, with the exception of those specimens kept in the Halos for research. After the Array was fired, the installation was hardly peaceful, with over 32,967 simulated test firing a day. As of [[2552]], it had a record of 1.2 trillion simulated firings and one actual activation.{{Ref/Reuse|h2grave}}

===Flood outbreak===
[[File:HTMCC-H2A 2401PenitentTangent.png|thumb|250px|2401 Penitent Tangent, Installation 05's monitor.]]
At some point, the Flood on Installation 05 escaped and evaded containment due to negligence on the part of the installation's [[monitor]], [[2401 Penitent Tangent]].<ref>'''[[Halo 3]]''', multiplayer level ''[[Cold Storage]]''</ref><ref name="containmentfail">'''[[Containment failure report]]'''</ref> It is believed that the Flood's escape was either the result of a system malfunction that was not properly addressed by Penitent Tangent or due to the meddling of visiting species.{{Ref/Reuse|universe}} The Flood quickly grew out of control around the area of the installation's [[Library]];{{Ref/Reuse|containmentfail}} the Flood were kept contained by a [[Sentinel wall]] built around the Library. Somehow, the Flood on the ring were able to amass enough biomass to create a [[Gravemind]]. 2401 Penitent Tangent attempted to control the situation, but he was captured by the recently formed Gravemind.{{Ref/Reuse|ENC glassed}} Without the monitor, the [[Sentinels]] of the Halo lacked a controlling intelligence and so many of the structures around Installation 05 fell into disrepair, and most of the installation came to look like a jungle strewn with ruins.{{Ref/Reuse|containmentfail}}

Even with the addition of Forerunner [[Aggressor Sentinel]]s and [[Enforcers]], the Flood were able to remain loose, albeit contained within the [[Quarantine Zone]] by the Sentinel wall.{{Ref/Reuse|zone}} This stalemate is believed to be the cause of the slow decline into the deteriorated condition of the structures of the installation. The Gravemind itself resided in the chamber directly below the [[index chamber]] in the center of the Library.{{Ref/Reuse|h2grave}} The use of the Quarantine Zone was not a standard [[containment protocol]], but the lack of a monitor forced Installation 05's Sentinels and other [[ancilla]] to employ unique countermeasures.{{Ref/Reuse|universe}}

===Discovery and conflict===
{{Quote|no=two|1=Miranda Keyes|q1=Cortana, what exactly am I looking at?|2=Cortana|q2=That... is another Halo.|3=Commander Miranda Keyes and Cortana upon discovering the installation{{Ref/Reuse|deltahalo}}}}
[[File:H2A - In Amber Clad approaches Halo.png|thumb|250px|left|The discovery of Installation 05.]]
In [[2551]], following the [[Battle of Meridian]] during the [[Human-Covenant War]], [[Steward]]s of the [[Covenant]]'s [[High Prophet of Regret]] studied a [[Luminary]] found on [[Meridian|the world]]. The Luminary revealed the location of the [[Portal at Voi|portal]] that led to Installation 00, as well as the location of each ring of the Halo Array.<ref name="beholden">'''[[Halo 2: Anniversary]]''', ''[[Terminal (Halo 2: Anniversary)|Terminal 14]]''</ref><ref>''Halo: Mythos'', page 104</ref> Regret traveled to the portal's location, unaware that his destination was [[Earth]], humanity's homeworld. Arriving on [[2552#October|October 20, 2552]], the High Prophet of Regret ultimately fled the [[Battle of Earth]] to Installation 05 aboard his [[flagship]], ''[[Solemn Penance]]''. The [[CAS-class assault carrier|carrier]] was pursued by {{UNSCShip|In Amber Clad}}, captained by [[Commander]] [[Miranda Keyes]].<ref name="metro">'''Halo 2''', campaign level ''[[Metropolis]]''</ref> ''In Amber Clad'' exited [[slipstream space]] near the installation on [[2552#November|November 2, 2552]]; [[UNSC]] forces were deployed to the ringworld to [[Battle of Installation 05|engage]] Covenant forces, while [[Spartan-II]] [[John-117]] was ordered to assassinate Regret.{{Ref/Reuse|deltahalo}} While Commander Keyes took ''In Amber Clad'' to the installation's Library to procure the [[activation index]] before the Covenant, John-117 located Regret at a [[Temple (Installation 05)|temple]] on the ring. After eliminating the [[Hierarch]], ''[[High Charity]]'' and its [[High Charity defense fleet|defense fleet]]—having been contacted earlier by Regret who sought assistance—arrived over the installation. ''Solemn Penance'' attempted to destroy the Spartan alongside the temple, though John-117 escaped by jumping into a nearby lake where he was captured by the Gravemind.<ref name="regret">'''Halo 2''', campaign level ''[[Regret (Halo 2 level)|Regret]]''</ref>

[[File:H2A - Great Schism.jpg|thumb|250px|Jiralhanae and Sangheili vessels battle around the Halo.]]
Meanwhile, [[Arbiter]] [[Thel 'Vadam]]ee was charged with retrieving the activation index from the installation to begin the [[Great Journey]]. Following the orders of [[Jiralhanae]] [[Chieftain of the Jiralhanae|Chieftain]] [[Tartarus]], the Arbiter infiltrated the Sentinel wall and deactivated its [[containment shield]] to allow Covenant infantry deployment in the area. Inadvertently, this allowed the Flood to escape the Quarantine Zone.<ref name="icon">'''Halo 2''', campaign level ''[[Sacred Icon]]''</ref> Journeying to the Library, the Arbiter encountered Commander Keyes and Sergeant Major [[Avery Johnson]] who had just retrieved the index. While engaging them, the index was taken by Tartarus and the humans were captured by his Jiralhanae forces. Following the orders of the [[Prophet of Truth|High Prophet of Truth]], Tartarus betrayed the Arbiter and cast him into the depths of the [[index chamber]], initiating the [[Great Schism]].<ref name="zone">'''Halo 2''', campaign level ''[[Quarantine Zone]]''</ref> The Arbiter was also captured by the Gravemind, and brought to the chamber where the Flood intelligence resided. Within the chamber, the Gravemind informed the Arbiter and John-117 of the Halo's true purpose. Using Installation 05's [[teleportation grid]], the Gravemind sent John-117 to the orbiting ''High Charity'' and the Arbiter to the installation's [[Control Room (Installation 05)|Control Room]] to search for the index and prevent the Covenant from activating the Halo. The Flood managed to board ''In Amber Clad'' and made a slipspace jump inside of ''High Charity'' to infect the holy city. While John-117 pursued the Hierarchs and Tartarus to retrieve the index, they were able to escape with their human captives—though the [[Prophet of Mercy|High Prophet of Mercy]] was killed by a [[Pod infector]].{{Ref/Reuse|h2grave}}

[[File:H2A - Battle of Delta Halo.jpg|thumb|250px|left|The firing of the installation is averted.]]
While Tartarus took the index and the humans to the Control Room to activate the installation, Truth abandoned ''High Charity'' aboard the city's [[Forerunner Dreadnought]] and fled to Earth to seek out the Ark. In the event that Tartarus was successful in activating the Halo, [[Artificial intelligence|AI]] [[Cortana]] decided to remain on ''High Charity'', where she could detonate the engines of ''In Amber Clad'' to destroy the installation; John-117 boarded Truth's Dreadnought just as it exited the system to eliminate the High Prophet.<ref name="charity">'''Halo 2''', campaign level, ''[[High Charity (level)|High Charity]]''</ref> Meanwhile, the Great Schism resulted in the Sangheili completely abandoning the Covenant and a civil war ensuing throughout the system. Sangheili and Jiralhanae ships of the ''High Charity'' defense fleet battled each other over the installation, with both sides focusing a small number of their ships to prevent Flood-infected vessels from trying to escape the system.<ref>'''Halo: Ghosts of Onyx''', ''pages 193-198''</ref> On the Halo, the Arbiter regrouped with [[Special Operations Commander|Commander]] [[Rtas 'Vadum]], and the two led Sangheili forces towards the Control Room.<ref name="uprising">'''Halo 2''', campaign level, ''[[Uprising]]''</ref> While Tartarus entered the Control Room with the index and the captured Keyes and [[343 Guilty Spark]], the Sangheili unintentionally rescued Johnson from his Jiralhanae captors. With Johnson operating a {{Pattern|Protos|Scarab}}, the Arbiter agreed to work with him to stop Tartarus from activating the Halo. Johnson used the Scarab to destroy the Control Room's entrance and he entered the chamber, along with the Arbiter and a handful of Sangheili warriors.<ref name="journey">'''Halo 2''', campaign level ''[[The Great Journey]]''</ref>

Tartarus activated the Halo when Johnson and the Sangheili arrived to intervene. While the chieftain battled the Arbiter and Johnson, Keyes and Guilty Spark worked to retrieve the index and stop the activation process. The Arbiter and Johnson managed to kill Tartarus, while Keyes retrieved the index out of its chamber and the firing sequence was put on standby mode, ready for remote activation through the Ark.{{Ref/Reuse|journey}} The battle soon ended when the Sangheili ships proved victorious over the Jiralhanae. Under the command of 'Vadum, the remnants of the Sangheili fleet sterilized the installation by [[glassing]] the Flood-infected portions of its surface, thereby preventing the parasite from leaving the [[Coelest system]]. According to [[000 Tragic Solitude]], the surface of Installation 05 was "scorched to char and ash" by the Sangheili ships. Now allied, the Sangheili and humans eventually returned to Earth to assist with finishing off the Covenant.{{Ref/Reuse|GoO glassed}}{{Ref/Reuse|ENC glassed}}<ref>'''[[Halo 3]]''', campaign level ''[[The Covenant]]''</ref><ref name="HITD272">'''[[Halo: Hunters in the Dark]]''', ''page 272''</ref>

===Post-Covenant War===
After the end of the Human-Covenant War, the [[Office of Naval Intelligence]] established [[Lisbon Station]]{{Ref/Reuse|11th}} in orbit of Installation 05; beyond the range of the ring's automated defenses.{{Ref/Reuse|universe}} The station's purpose was to study the Halo prior to its decommissioning.<ref>'''[[Halo 4]]''', campaign level ''[[Infinity (Halo 4 level)|Infinity]]''</ref> Lisbon Station is located in orbit around the ring, as the surface is considered too dangerous to house permanent settlements. The station is used as a staging point for UNSC research and artifact retrieval units. Numerous scans of the installation captured by {{UNSCShip|Coral Sea}} and ''In Amber Clad'' during the Battle of Installation 05 are now the basis of several [[War Games]] simulations utilized by the [[SPARTAN-IV program]].{{Ref/Reuse|universe}}

In [[2555#March|March 2555]], [[monitor]] [[000 Tragic Solitude]] used the contamination and later sterilization of Installation 05 as part of his justification for wiping out all life in the galaxy along with the destruction of [[Installation 04]], the damage done to [[Installation 00|the Ark]] and the destruction wrought by the firing of [[Installation 08]].{{Ref/Reuse|HITD272}}

Both the ring and the Coelest system at large were quarantined after the war, and as of [[2558]], UNSC and [[Swords of Sanghelios]] ships patrol the region.<ref name="HOSFM84">''[[Halo: Official Spartan Field Manual]]'', ''page 99''</ref>

At some point, unusual activity on the ring was investigated by ONI through remote surveying technology. The intelligence agency discovered strange structures that suddenly appeared on the installation's surface at key power and data junctions. ONI created War Games simulations [[Orion]] and [[Pegasus]] based off of these structures for Spartan-IVs to train in, with the intent to send these Spartans to Installation 05 to examine the structures. The Spartans were trained to deal with any possible threat from [[Aggressor Sentinel]]s, [[Promethean]] constructs, or [[Covenant remnants]] that would interfere with the investigation. It was later discovered that, around these structures, the local Aggressor Sentinels suddenly became actively hostile and organized.<ref name="canonfodder">[https://www.halowaypoint.com/en-us/news/canon-fodder-beta-late-than-never '''Halo Waypoint''': ''Canon Fodder - Beta Late Than Never'']</ref>

==Topography==
===Environment===
[[File:H2A - ZenithRing.jpg|thumb|250px|The surface of the Halo.]]
Installation 05 has a gravity of 1.04 Gs, and an average surface temperature of -19&nbsp;°C to 42&nbsp;°C (-2.2&nbsp;°F to 107.6&nbsp;°F). The ring's atmospheric composition is 1.01 and is largely made up of [[oxygen]] and [[Wikipedia:Nitrogen|nitrogen]] gas.{{Ref/Reuse|VIS}} The controlled climate of Installation 05 is similar to that of [[Installation 04]], with varying weather conditions in different areas. Its terrain includes lakes, jungles, hills, canyons, and valleys,<ref>'''[[Halo: Broken Circle]]''', ''pages 216-218'' (Google Play edition)</ref> as well as the ice and snow-filled [[Quarantine Zone]].{{Ref/Reuse|zone}} Several hundred years prior to [[2552]], the [[Flood]] escaped the their containment on the ring. As the Flood began to spread throughout the installation, the Halo's surface was heavily altered. While the Flood was eventually contained within the Quarantine Zone, the capture of [[2401 Penitent Tangent]] prevented Installation 05's environment from being properly maintained and its flora became overgrown on numerous Forerunner facilities throughout the installation. The installation was partially [[Glassing|glassed]] by the [[Sangheili]] during the [[Battle of Installation 05]].{{Ref/Reuse|ENC glassed}}

The Halo's numerous dense jungles were also home to several [[Forerunner]] facilities. At least one dry desert exists on Installation 05; the desert featured a small canyon home to Forerunner outposts on either side.<ref>'''Halo 2''', multiplayer map ''[[Coagulation]]''</ref> Human scientists have theorized that the canyon was likely used by young Forerunner [[Warrior-Servant]]s that sought to demonstrate their prowess in combat arenas. During the Battle of Installation 05, [[UNSC]] surveillance unit [[RECON 127]] discovered a dormant Forerunner vessel buried beneath an island on the ring's surface which had been carefully hidden by the Forerunners.{{Ref/Reuse|universe}}

===Structure and systems===
[[File:H2A - Library.jpg|thumb|250px|left|The Library of Installation 05.]]
Installation 05 is 10,000 kilometers (6,200 miles) in diameter and has a surface width of 318 kilometers (198 miles).{{Ref/Reuse|VIS}} Orbiting [[Substance]], it is likely the installation's location over the large ice giant is a safety measure; the Halo can be plunged into the planet's high-pressure interior if deemed necessary.<ref>'''Halo Encyclopedia: The Definitive Guide to the Halo Universe''', ''page 310'' (2011)</ref> Installation 05's orbit over Substance is maintained by energy nodes. These power conduits are used to delicately control the direction and movement of the ring over the ice giant. Until his capture by the [[Gravemind]], the installation's [[monitor]] was 2401 Penitent Tangent.{{Ref/Reuse|universe}} The [[Control Room (Installation 05)|Control Room]] of Installation 05 is the site that controls many of the installation's operations. The Control Room is used to activate the installation's firing sequence. Housing vast archive complexes and research facilities,<ref>'''Halo: The Essential Visual Guide''', ''page 108''</ref> the installation's [[Library]] also contains the local [[activation index]] in the [[index chamber]].{{Ref/Reuse|zone}} As a result of the Flood's spread, the [[Quarantine Zone]] was a perimeter established on the Halo to prevent the Flood from spreading further. The zone was surrounded by a [[Sentinel wall]], an encompassing structure that manufactured [[Sentinel]]s to either repair the facility or engage the Flood. The entire Quarantine Zone was enclosed by a [[containment shield]] projected by the Sentinel wall.{{Ref/Reuse|icon}} Additionally, Installation 05 maintains an automated defense system that partially extends to the Halo's orbit.{{Ref/Reuse|universe}}

[[File:H2A - Delta Halo activated.jpg|thumb|250px|Installation 05's Control Room is activated]]
Installation 05 maintains a vast [[teleportation grid]] to allow individuals with the proper authority to quickly reach certain areas of the ring. The teleportation grid is sustained by a dense web of telemetry conduits, which are powered by generators buried in steep, narrow canyons throughout the installation.{{Ref/Reuse|universe}}<ref>'''Halo 2''', multiplayer map ''[[Beaver Creek]]''</ref> The surface of Installation 05 is home to numerous [[relay station]]s.{{Ref/Reuse|universe}}<ref>'''Halo 2''', multiplayer map ''[[Ascension]]''</ref> As with the other installations of the [[Halo Array]], Installation 05 hosts several [[Flood containment facility|Flood containment facilities]] scattered across the ring. These facilities were designed to analyze Flood samples kept in various states of development—beyond the firing of the Halo Array. The primary research facilities are located in remote regions of the installation, such as in a series of vast bogs and swamplands. Human analysts believe that the Forerunners placed the facilities in undesirable locations to discourage potential intruders. At least one facility specialized in determining extremophilic thresholds of specimens infected by the Flood;{{Ref/Reuse|universe}} this facility was apparently maintained by [[Unidentified ancilla (Installation 05)|an ancilla]] of its own.<ref>'''Halo 3''', multiplayer map ''[[Cold Storage]]''</ref> Prior to the Halo's activation, Forerunner [[Lifeworker]]s maintained several facilities—located in the ring's dense jungles—that were used to study an extensive collection of catalogued species during the [[Conservation Measure]]; the facilities were abandoned during the [[dark time]] that followed the [[Great Purification]].{{Ref/Reuse|universe}} Installation 05 also possessed numerous [[anti-gravity gondola]]s that allowed individuals to travel long and extensive distances.{{Ref/Reuse|regret}}

===Architecture===
{{Quote|You know, I think the Forerunners built these new structures around the old, to protect them, to honor them.|[[Cortana]], commenting on some of the structures on Delta Halo{{Ref/Reuse|regret}}}}
[[File:Ruins1600.jpg|thumb|left|250px|Ruins on Installation 05.]]
The architecture of structures on Installation 05 follows the general Forerunner aesthetic, but has a clearly distinct style from some other installations such as [[Installation 00]] or [[Installation 04|04]], an example being [[Control Room (Installation 05)|Installation 05's Control Room]] having similarities to [[Control Room (Installation 04)|Installation 04's Control Room]] in purpose, but with a different look—including a spherical shape at the center of the building. In addition, many structures on Installation 05, including the [[Temple (Installation 05)|temple]], appear to be more weathered than those on other installations,{{Ref/Reuse|universe}} having a slightly brown-tinted gray color as opposed to the clean, pristine silver-gray surface material of most Forerunner structures.{{Ref/Reuse|deltahalo}}{{Ref/Reuse|regret}}

Much of the decor within the structures of Installation 05 seems to be less practical and more ostentatious than that of Installation 04. Many of the rooms contain standing tables and basins that seem to serve a purely aesthetic purpose, perhaps at one time serving as lamps or torches. An island on Installation 05 is also home to a towering, weathered megalith, a structure that resembles other artifacts on the ring.{{Ref/Reuse|universe}}

[[File:H2 - Delta Halo towers 7.png|thumb|250px|The newer metal structures built around the older stone structures]]
A curious feature on Installation 05 are the stone ruins encountered on the ring. While clearly consistent with known motifs of Forerunner architecture, the ruins seem clearly older and more primitive than most Forerunner structures, and seemingly predate the construction of the ring.{{Ref/Reuse|VIS}} They are also made of stone, as opposed to the metallic material seen on the majority of Forerunner constructs (although the Forerunners are known to have favored stone as a construction material in a number of other sites as well). This brings up the question of whether these are Forerunner structures at all, or if they were built by an even more ancient civilization or the Forerunners themselves long time before the construction of the Halo installations, and later moved to the ring for unknown reasons.<ref>'''[[Halo Waypoint]]''', ''Memory Lane - [[Sanctuary]]''</ref> Some [[human]] analysts speculate that these structures were not created by the Forerunners, but were transported to the ring for other species that were temporarily housed on Installation 05 during the Conservation Measure. Certain analysts believe that some of the stone structures were intended to fulfill a cultural purpose rather than a practical one, possibly as a memorial or tomb.{{Ref/Reuse|universe}} Only a fraction of the installation's structures represent the older variety, as most of them are in a similar condition as on other known installations. Some of the newer structures were also built around the older ones to support and protect them, which is clearly evident in some of the spires built over the lake near the temple.{{Ref/Reuse|regret}}
{{Clear}}

==Trivia==
{{Linkbox|gallery=yes}}
*There are six ''[[Halo 2]]'' campaign levels that take place on Installation 05: ''[[Delta Halo]]'', ''[[Regret (Halo 2 level)|Regret]]'', ''[[Sacred Icon]]'', ''[[Quarantine Zone]]'', ''[[Uprising]]'', and ''[[The Great Journey]]''.
*The ''Halo 2'' multiplayer maps set on Installation 05 include [[Ascension]], [[Backwash]], [[Desolation]], [[Lockout]], [[Relic]], [[Sanctuary]], [[Uplift]] and [[Warlock]]. The ''[[Halo 3]]'' multiplayer map [[Cold Storage]] is the only one in ''Halo 3'' to be set on Installation 05. The ''[[Halo 5: Guardians]]'' multiplayer maps [[Pegasus]] and [[Orion]] are set on Delta Halo.{{Ref/Reuse|canonfodder}}

==Gallery==
<gallery>
File:H2 DeltaHalo Building Concept.jpg|Concept art for a structure on the installation.
File:H2 Concept DeltaStructures.png|Concept art of another structure on the installation.
File:Installation05S.png|The [[Forerunner symbols|Forerunner symbol]] for Installation 05.
File:Delta Halo.jpg|A view of Installation 05.
File:Halo6.jpg|A Phantom approaches Delta Halo.
File:PT2401.JPG|The [[monitor]] of Installation 05, [[2401 Penitent Tangent]].
File:Sacredicon1600.jpg|The Library of Installation 05.
File:H2 Delta Halo Tank.jpg|A structure and a bridge on Installation 05.
File:H2 Uprising Control room building.jpg|The [[control room]] of Installation 05.
File:H2 - Delta Halo towers 1.png|A pair of towers framing older stone ruins on the lake surrounding the temple.
File:QZ - battle zone 1.png|The dilapidated conditions of the installation's [[Quarantine Zone]].
File:H2-Uprising_Eld.png|An iteration of the ubiquitous [[Forerunner symbols#Eld|Eld]] symbol found on Installation 05.
File:H2-Uprising_mural.png|A mural in a structure on the installation, identical to a design at [[Installation 04]]'s [[Silent Cartographer]].
File:H2 - Delta Halo door 1.png|A baroquely ornamented [[door]] on Delta Halo.
File:H2 ringbirds.jpg|[[Quadwing]]s on Delta Halo.
File:Coldstorage1 inline.jpg|A compromised Flood containment facility deep within Installation 05.
File:43472886-Full.jpg|A section of Installation 05 completely overrun by the Flood.
File:Installation 05.jpg|Installation 05's firing sequence being canceled in ''Halo 2''.
File:Coelest.jpg|A measurement of [[Substance]] and Installation 05 from space.
File:Haloverse-PlanetDistances scaled.jpg|A scaling of the distance between Substance and Installation 05 within Coelest system, along with the [[Soell system]].
File:H2A - DeltaHalo Scenery.jpg|Scenery on Delta Halo from ''Halo 2: Anniversary''.
File:H2A BlurRegretTemple Render 1.jpg|The temple in ''Halo 2: Anniversary''.
File:AerialDelta.png|Aerial view of Delta Halo temple and lake.
File:H2A Cutscene SanctumHaloView.png|Installation 05, as seen from the [[Sanctum of the Hierarchs]] in ''[[High Charity]]''.
File:LC 05 Doc2.png|Covenant readout of Installation 05.
</gallery>

==List of appearances==
*''[[Halo 2]]''  {{1st}}
*''[[Halo: Ghosts of Onyx]]''
*''[[Halo 3]]'' 
*''[[Halo Legends]]''
**''[[Origins]]''
*''[[Halo: Combat Evolved Anniversary]]''
**''[[Terminal (Halo: Combat Evolved Anniversary)|Terminals]]''
*''[[Halo 4]]'' {{Mo}}
*''[[Halo: Broken Circle]]''
*''[[Halo 2: Anniversary]]''
**''[[Terminal (Halo 2: Anniversary)|Terminals]]''
*''[[Halo: Hunters in the Dark]]'' {{Mo}}
*''[[Halo: Last Light]]'' {{Im}}
*''[[Halo 5: Guardians]]''
*''[[Halo Mythos]]''
*''[[Halo: Age of Retribution]]''

==Sources==
{{Ref/Sources|2}}

{{Forerunner|array|category=no}}

[[Category:Installation 05 locations| ]]
[[Category:Halo Array]]