Editing United Nations Space Command

{{Status|Canon}}
{{Military infobox advanced
|image=[[File:Merch UNSC Logo Black.svg|100px]]<br/>The [[Symbols of the UNSC|UNSC logo]] circa [[2560]].
[[File:HW Cover-Wide.jpg|300px]]<br>[[SPARTAN-II program|SPARTAN-IIs]], [[UNSC Marine Corps|UNSC Marines]], and several UNSC vehicles
|formed=[[2163]]{{Ref/Reuse|waypointuniunsc}}
|allegiance=[[Unified Earth Government]]
|headquarters=*[[HIGHCOM Facility Bravo-6]], [[Sydney]], [[Australia]], [[Earth]] {{C|Primary}}{{Ref/Reuse|waypointuniunsc}}
*[[UNSC Supreme Headquarters]], [[United Republic of North America|URNA]], [[Earth]]<ref>''[[Halo Encyclopedia (2009 edition)]]'', p. 285</ref>
|branch=
|type=*Military, exploratory, and scientific force
*Emergency military government
|role=Military defense of [[Earth]] and [[Human colonies|her colonies]]{{Ref/Site|Id=waypointuniunsc|URL=https://www.halowaypoint.com/en-us/universe/factions/unsc|Site=Halo Waypoint|Section=Universe, Factions|Page=UNSC|D=19|M=1|Y=2021|LocalArchive=https://archives.halopedia.org/waypoint/www.halowaypoint.com/en-us/universe/factions/unsc.html}}
|size-title=Divisions
|size=
*UNSC armed forces
**[[UNSC Naval Command]]
***'''[[UNSC Navy]]'''
****'''[[Office of Naval Intelligence]]'''
**[[Unified Ground Command]]
***'''[[UNSC Army]]'''
***'''[[UNSC Air Force]]'''
***'''[[UNSC Marine Corps]]'''
**'''[[Spartan Operations]]'''
|nicknames=UNSC
|motto=Per Mare, Per Terras, Per Constellatum{{Ref/Reuse|spartan ops}}
|engagements=*[[Mars Campaign]]
*[[Interplanetary War]]
*[[Inner Colony Wars]]
*[[Insurrection]]
*[[Human-Covenant War]]
*[[Post-Covenant War conflicts]]
*[[Created conflict]]
|commander1-title=Judicial branch
|commander1=[[UNSC Judge Advocate General's Corps]]
|commander2-title=Executive branch
|commander2=[[UNSC High Command]]
|commander3-title=Head of military
|commander3=
*[[UNSC Security Council]]<ref name="fs104">''[[Halo: First Strike]]'', p. 104</ref>
**[[Chief of Naval Operations|Commander-in-Chief Fleet/Chief of Naval Operations]]<ref name="GL209">'''[[Halo: Glasslands]]''', ''page 209''</ref>
**[[Commander-in-Chief of the Office of Naval Intelligence]]
**[[Commander-in-Chief of the Spartans]]
***<small>''Represented by:''</small><br> [[Chief of Staff of Spartan Operations]]<ref name="osfm1">''[[Halo: Official Spartan Field Manual]]'', p. 114</ref>
|commander4-title=Chairman
|commander4=[[Fleet Admiral]] [[Lord Terrence Hood]]<ref>[https://www.halowaypoint.com/en-us/universe/characters?page=4 ''Halo Waypoint'', Characters] "Fleet Admiral Terrence Hood is the UNSC Navy’s highest ranking officer and Chairman of the influential UNSC Security Council."</ref> 
}}
{{Quote|Per Mare, Per Terras, Per Constellatum.|Motto <small>([[Latin]] for ''"Through Sea, Through Land, Through the Constellations."'')</small><ref name="spartan ops">'''[[Halo 4]]''', ''[[Spartan Ops]]''</ref><ref>[[:File:Colonial Militia logo.jpg|Colonial Militia emblem from licensed ''Halo'' products]]</ref>}}
The '''United Nations Space Command''' ('''UNSC''') is the military, exploratory, and scientific agency of the [[Unified Earth Government|Unified Earth Government (UEG)]] and has acted as the emergency governing body of the [[human]] race at large for a time.<ref name="McLees">[http://halostory.bungie.org/oconnor_mclees_080508.html '''Halo.bungie.org''': ''Interview with Frank O'Connor and Robert McLees'']</ref> The UNSC was formed in the 22nd century, a time when remnants of old cultural ideologies clashed for supremacy in the [[Sol System]]. The UNSC served mainly as overseer of [[United Nations]] military operations in space. After initiating massive militarization [[propaganda]] throughout its off-world colonies, through the UNSC, the UN defeated [[Frieden]] and [[Koslovic]] insurgent forces in a conflict known as the [[Interplanetary War]], which consisted of several side-battles that took place on [[Mars]], the [[Jovian Moons]] and the [[South America]]n rainforests. Although the Interplanetary War brought a great deal of suffering to both the colonial population and the residents of Earth, it also united most of humanity's military forces by the end of the 22nd century.{{Ref/Site|Id=xbox|URL=http://www.xbox.com/en-US/games/h/halo/storyline.htm|Site=Xbox.com|Page=Halo Storyline|D=24|M=04|Y=2008|LocalArchive=Archive:Xbox.com/Halo/Timeline}}

Prior to the [[Covenant]] [[First Battle of Harvest|attack]] on [[Harvest]] in [[2525]],{{Ref/Reuse|xbox}} the UNSC was stretched across [[Human colonies|human space]]. The most urgent concern was to contain the spread of the [[Insurrectionist]]s, a violent resistance movement consisting of colonists who wanted independence from the Unified Earth Government. The UNSC fought constant battles in a loosely-defined civil war known as the [[Insurrection]]. In an attempt to help end the long-running war, the UEG commissioned the [[ORION Project]] and later the [[SPARTAN-II program]], which created elite supersoldiers to combat the Insurrectionists. When the [[Human-Covenant War]] began and the alien invaders began destroying the [[Outer Colonies]], these Spartans became humanity's best hope against the technological superiority of the hegemony. When the war began, the UNSC, which had been mired in controversy, became humanity's greatest protector. This allowed the UNSC to override civilian rule and establish itself as humanity's primary government. Although the Unified Earth Government was more open to step down, the [[Colonial Administration Authority]], the arm of the UEG ruling over the colonies, resisted the UNSC's rise to power, and was stripped of its influence.{{Ref/Reuse|McLees}}

Near the end of the year [[2552]], Earth was the last remaining major human bastion: it too nearly fell under attack by the Covenant, succumbing to occupation. Near-crippled in the aftermath of the [[Fall of Reach]], the UNSC led by [[United Nations Space Command Security Council|Chairman]] [[Chief of Naval Operations]] [[Fleet Admiral]] [[Lord Terrence Hood]], dedicated most of its remaining assets to the defense of the Sol System. The Human-Covenant War finally came to an end after the UNSC and the [[Sangheili]] [[Fleet of Retribution]] [[Battle of the Citadel|eliminated]] the Covenant [[Prophet of Truth|leadership]] and [[Raid on Installation 08|destroyed]] the Flood threat.

In the aftermath of the war, the UNSC has upheld its [[Treaty of 2552|alliance]] with the [[Swords of Sanghelios]] and eventually ceded political power back to the UEG. The UNSC is now experiencing a resurgence as it rebuilds humanity's war-torn domain and moves to reestablish itself as a major power within the [[Orion Arm]].

==Mission==
[[File:HW2 MarineDeployment Concept.png|thumb|250px|A UNSC unit preparing to conduct a mass-deployment.]]
Though the official UNSC mission statement has been amended since it was established in [[2163]],{{Ref/Book|Id=osfm2|OSFM|Section=8: UNSC Organization}} the UNSC's statement of function can be summarized in two points:

*Uphold and advance the policies of the [[Unified Earth Government]].{{Ref/Reuse|osfm2}}
*Ensure the safety and security of Unified Earth Government territories, possessions, and areas vital to its interests.{{Ref/Reuse|osfm2}}

During the [[Human-Covenant War]], notably during the [[Siege of the Inner Colonies|later years]], the UNSC's purpose was to protect [[humanity]] and ensure the survival of the human species.

==Structure==
Ultimate authority to direct the actions of the UNSC's armed forces lies in the office of the [[President of the Unified Earth Government]]. The authority granted to the President is legally absolute, though the Chairman of the [[UNSC Security Council]] is the principal commander of all UEG military assets and is authorized to act in the president's stead regarding matters of defense.{{Ref/Reuse|Enc22UNSC}} The Security Council acts as the principal staff element of the UNSC and is responsible for policy development, strategic planning, resource management and fiscal evaluations. The Security Council is staffed by the highest-ranking officers from the Navy, Marine Corps, Army, Air Force and Office of Naval Intelligence - with the [[Chief of Staff of Spartan Operations|Chief of Staff]] of the Spartan Operations department granted a non-voting advisory role on the council as of [[2554]].{{Ref/Reuse|Enc22UNSC}} The UEG also maintains a [[Secretary of Defense]] position, though the powers and limitations of this office are unknown.{{Ref/Level|H2|Metropolis}}

Despite the official status of the UNSC as subordinate to the UEG, the [[Massacre of the Outer Colonies]] in the war with the Covenant saw substantial authority handed from the government to the UNSC - with the military granted substantial emergency powers and martial law declared for the duration of the conflict. Civilian governance was formally restored in [[2553]] following the war's end, though this process considerably eroded the institutions of government and as such the UNSC retains a wide latitude of operational freedom regarding interactions with surviving colonies and affairs on Earth. This has led to a mass public sentiment that the UNSC is a military government, with the UEG in practice merely acting as its public relations arm.{{Ref/Reuse|Enc22UNSC}} The UNSC is additionally bound by the laws of the [[UNSC colonial charter]], a document written to provide a set of regulations regarding military colonial governance.{{Ref/Novel|CH|Chapter=15}}

Below the UNSC Security Council is the [[UNSC High Command]], or HIGHCOM - the UNSC's joint staff and executive body. Senior HIGHCOM officers report to the Security Council, but they primarily serve to coordinate joint and inter-agency protocols and objectives. HIGHCOM controls a wide range of sensitive and strategically vital officers and boards including the [[UNSC Inspector General]], [[General Officer Review Board]], [[UNSC Special Topics Committee]] and [[UNSC Ordnance Commission]].{{Ref/Reuse|Enc22UNSC}} HIGHCOM also serves to advise UEG civilian leadership on issues relating to defense, and are based at [[HIGHCOM Facility Bravo-6]] in [[Sydney]], [[Australia]].{{Ref/Book|Id=OSFMOrganisation|OSFM|Page=120-121}} Other organizations included within HIGHCOM are a number of administrative commands, including [[UNSC Personnel Command]] (PERSCOM), the [[UNSC Medical Corps|Medical Corps]], the [[UNSC Engineering Corps|Engineering Corps]], [[UNSC Human Resources|Human Resources]], and [[UNSC Astrophysics|Astrophysics]].{{Ref/Novel|FoR|Chapter=15}} Legal matters such as the issuing and enforcement of [[:Category:UNSC protocols|protocols]] are handled by the [[UNSC Judge Advocate General's Corps]].<ref>''[[Halo: Ghosts of Onyx]]'', p. 123</ref> Research designed to improve the UNSC's operations is carried out by the [[UNSC Internal Audit|Internal Audit]] office.{{Ref/Novel|Gla|Chapter=13}} 

Overall, HIGHCOM ensures that the UNSC's component branches work in close coordination, with very few "turf wars" over resources or responsibilities.{{Ref/Reuse|Enc22UNSC}}

===Combatant commands===
The UNSC is divided into two primary combatant commands - [[UNSC Naval Command|Naval Command]] (NAVCOM) and [[Unified Ground Command]] (UNICOM). The former controls all space-based assets and operations, while the latter focuses on terrestrial and close-orbit missions.{{Ref/Book|Id=OSFMCommands|OSFM|Page=122-123}} NAVCOM has administrative control over the Navy{{Ref/Reuse|Enc22Navy}} and its officers alongside select Marine Corps units.{{Ref/Reuse|Enc22Marines}} UNICOM has operational authority over UNSC Army{{Ref/Reuse|Enc22Army}} and Air Force deployments and some Marine units{{Ref/Reuse|Enc22Marines}}, and work alongside the Navy to coordinate [[Orbital bombardment|orbital fire support]] missions and in-atmosphere support.{{Ref/Reuse|Enc22Navy}}

NAVCOM and UNICOM form joint task forces that are thus then assigned to one of four [[Central Command]]s (CENTCOMs) - responsible for the defense and security of a given region of human space, referred to as CENTCOM Regions. These regions follow well-mapped [[Slipstream space|slipspace]] routes which connect dozens of star systems; forces assigned to one CENTCOM cannot be moved to another without the approval of HIGHCOM, thus meaning each region must carefully marshal their limited resources. UNICOM planetside forces are organized into [[task force]]s that contain ground, air and maritime combat assets.{{Ref/Reuse|OSFMCommands}}

==Military departments==
The UNSC's armed forces are comprised of six major military departments; four of these branches ([[UNSC Navy|Navy]], [[UNSC Marine Corps|Marine Corps]], [[UNSC Army|Army]] and [[UNSC Air Force|Air Force]]) are recognized and defined in UEG law, while the [[Spartan Operations]] division is a "continuing organization" that lacks explicit recognition and instead works directly under the UNSC's [[UNSC High Command|High Command]]. The [[Office of Naval Intelligence]] is a unique case; an organization that is bureaucratically a subordinate service of the Navy and not recognized as an independent service branch, but has enjoyed ''de facto'' autonomy from the Navy for nearly a century.{{Ref/Book|Id=Enc22UNSC|Enc22|Page=52-53}} Despite these technicalities, these six organizations are all on occasion informally referred to as the six branches of the UNSC{{Ref/Book|Id=OSFM120|OSFM|Page=12-121}}{{Ref/Site|Id=WPUNSC|URL=https://www.halowaypoint.com/en-us/universe/factions/unsc|Site=Halo Waypoint|Page=UNSC|D=30|M=04|Y=2021}}

The military departments themselves are broken down into two major groupings; the '''UNSC Defense Force''' (UNSCDF) and the UNSCEF (presumably standing for something akin to '''UNSC Expeditionary Force'''). The former administers defensive assets of the UNSC and encompasses the Army and Air Force{{Ref/Site|URL=http://halostory.bungie.org/oconnor_mclees_080508.html|Site=halo.bungie.org|Page=Frank O'Connor/Robt McLees Interview - August 2008|D=18|M=04|Y=2022}}, while the latter includes Naval and Marine Corps forces. It is unclear whether the UNSCDF and UNSCEF have any relation to NAVCOM and UNICOM.

===Navy===
[[File:UNSC-Navy-logo1.png|thumb|250px|The UNSC Navy's logo.]]
{{Main|UNSC Navy}}
{{Quote|Provide naval forces to ensure freedom of access for aerospace and terrestrial operations.|The Navy's official mission statement.{{Ref/Reuse|OSFMNavy}}}}
The Navy is the senior service of the UNSC{{Ref/Book|Id=Enc22Navy|Enc22|Page=62}}, formed in [[2163]] during the [[Interplanetary War]].{{Ref/Reuse|WPUNSC}} The UNSC Navy is commanded by the [[Chief of Naval Operations]] (CINCNAV){{Ref/Book|Enc22|Page=104}}, with a [[Deputy Chief of Naval Operations]] serving as their deputy.{{Ref/Novel|HFS|Chapter=11}} The Chief of Naval Operations serves as the Navy's representative on the UNSC Security Council.{{Ref/Comic|HE|Issue=1}} The Chief of Naval Operations also serves as the [[Commander-in-Chief Fleet]] (CINCFLEET).{{Ref/Novel|Gla|Chapter=11}}

The UNSC Navy operates, trains, organizes and equips space forces to establish space superiority in deep space and close orbit - primarily signified by the use of its vast fleet of [[UNSC starship|spacecraft]]. This force is used for the purpose of destroying or suppressing enemy space components, in particular those seeking to attack UEG commercial or terrestrial holdings.{{Ref/Book|Id=OSFMNavy|OSFM|Page=124-126}} The Navy ensures the safety of UEG trade and commerce, assists other governmental agencies in agencies of interstellar governance and as such, very little of interstellar consequence happens without the help or oversight of the Navy.{{Ref/Reuse|Enc22Navy}} The UNSC Navy is headquartered at [[Fleet Command Headquarters]] on [[Reach]].{{Ref/Novel|Id=CH2|CH|Chapter=2}}

The Navy's collateral functions include;
*Interstellar transportation of UNSC combat assets.{{Ref/Reuse|OSFMNavy}}
*Development of doctrine, procedures and equipment that are of common interest to the Air Force and Marine Corps.{{Ref/Reuse|OSFMNavy}}
*Providing forces for joint aerospace and terrestrial operations, in accordance with UNSC doctrine.{{Ref/Reuse|OSFMNavy}}
*Coordinating with UEG civil agencies for the establishment and maintenance of naval depots and orbital yards.{{Ref/Reuse|OSFMNavy}}
*Establishment of emergency military government in designated crisis areas.{{Ref/Reuse|OSFMNavy}}
[[File:HM SpaceBattle ColourAdjusted Small.jpg|thumb|250px|UNSC Navy frigates engaging Covenant warships in space.]]
The Navy has a dual chain of command; administratively, Navy personnel report to NAVCOM while operationally they report to their assigned Task Command. There are three Task Commands under NAVCOM;
*[[UNSC Naval Command|UNSC Navy Fleet Command]] (FLEETCOM) - Headed by the Secretary of Fleet Command{{Ref/Site|URL=https://www.halowaypoint.com/en-us/universe/characters/dimah-tchakova|Site=Halo Waypoint|Page=Dimah Tchakova|D=30|M=06|Y=2021}} and directs the movement and tasking of naval squadrons and coordinates with UNICOM. FLEETCOM is responsible for the deployment of Navy warfighting assets and maximizing their combat efficacy.{{Ref/Reuse|Enc22Navy}} Their direct deployment of the UNSC fleet sees them as the largest and most powerful of any NAVCOM grouping.{{Ref/Reuse|OSFMNavy}}
*[[Naval Logistical Operations Command|UNSC Navy Logistical Operations Command]] (NAVLOGCOM) - Oversees the design, contracting and construction of Navy spacecraft alongside ensuring they are spaceworthy and supplied with parts, munitions, food and reaction mass.{{Ref/Reuse|Enc22Navy}}
*[[Naval Special Warfare Command]] (NAVSPECWARCOM) - A smaller, culturally-distinct section of the Navy that trains, equips and oversees [[UNSC Special Forces|special forces]] personnel in support of UNSC space operations.{{Ref/Reuse|Enc22Navy}} Marine Corps special forces units are typically tasked under NAVSPECWARCOM, as were the [[SPARTAN-II program|SPARTAN-II]] and [[SPARTAN-III program|SPARTAN-III]] program personnel prior to the establishment of the Spartan Operations branch.

Navy spacecraft are assigned to [[fleet]]s, which are organized in one of two ways;
*Expeditionary fleets - Numbered fleets (e.g. [[Third Fleet]]) designed for offensive operations in deep space and centered around massive [[UNSC carrier|carriers]].{{Ref/Book|HWF|Page=40-41}} Expeditionary fleets were largely decimated during the early years of the Covenant War, and by the war's end had no appreciable differences with defensive fleets due to being unable to make any major offensives without leaving the Inner Colonies dangerously vulnerable.{{Ref/Book|Id=HFB9|Halo: Fleet Battles|Section=Core Rulebook|Page=9}}
*Defensive fleets - Named fleets (e.g. [[Epsilon Eridani Fleet]]) typically named after the star system in which they are based. Defense fleets were historically considered little more than revenue police, though the onset of the Covenant war saw these units take a valuable role in providing desperately-needed training cadres and battle-ready (if outdated) warships.{{Ref/Reuse|Enc22Navy}}{{Ref/Reuse|HFB9}}
Fleets are assigned to numbered numbered [[Sector]]s such as [[FLEETCOM Sector One]], contextually organized based on low-energy slipspace routes leading away from [[Earth]]. Special [[task force]]s may also be created without being assigned to a sector, and given responsibility for regions outside of these standard routes - designated as "lettered sectors".{{Ref/Reuse|Enc22Navy}} Fleets are comprised of numerous [[battle group]]s, flexible combat elements that can be "plugged together" into ad-hoc fighting forces depending on the immediate situation. [[Squadron]]s serve as administrative groupings of warships for record-keeping and honorific purposes.{{Ref/Reuse|Enc22Navy}}

The UNSC Navy maintains its own [[military police]] force{{Ref/Book|Id=OSFM112|OSFM|Page=112}}

===Marine Corps===
[[File:UNSC-Marines-logo1.png|thumb|250px|The UNSC Marine Corps' logo.]]
{{Main|UNSC Marine Corps}}
{{Quote|Provide combined arms expeditionary forces and security detachments.|The Marine Corps' official mission statement.{{Ref/Reuse|OSFMMarines}}}}
The UNSC Marine Corps is another senior service of the UNSC{{Ref/Reuse|Enc22Marines}}, and was formed alongside the Navy in 2163.{{Ref/Reuse|WPUNSC}}{{Ref/Book|Id=Enc22Marines|Enc22|Page=56-57}} The Marine Corps is the space infantry department of the UNSC, and works closely alongside the Navy to effect military action across human space.{{Ref/Reuse|Enc22Marines}} The administrative head of the Marine Corps is the [[Commandant of the Marine Corps]] (CMC), who serves as the Marine Corps' senior general and service representative on the UNSC Security Council and Unified Ground Command staff. The CMC is responsible for organising, planning and implementing all Marine Corps activities.{{Ref/Reuse|Enc22Marines}} The Marine Corps is headquartered at [[Fleet Command Headquarters]] on Reach.{{Ref/Reuse|CH2}}
The Marine Corps is responsible for maintaining an expeditionary force in readiness, which can seize and defend terrestrial and extraterrestrial strategic sites in advance of a larger main UNSC deployment. As such, the Marine Corps organizes, trains, equips and maintains planetary and space-based combined-arms teams capable of being rapidly deployed by the Air Force and Navy.{{Ref/Book|Id=OSFMMarines|OSFM|Page=130-132}} They are the general-purpose combat force of the UNSC, and employ a wide range of personnel from [[Sniper|sharpshooters]] to [[combat engineer]]s to xenolinguists.{{Ref/Reuse|OSFMMarines}} Marine Corps forces are under administrative control (ADCON) of [[Marine Corps Forces]] (MARFOR), which focuses on the ability to reorganize, train and direct a given unit's long-term activities. Operational control (OPCON) of combat forces is handed to one of two combatant commands; Naval Command (NAVCOM) and Unified Ground Command (UNICOM) - which provides the authority to conduct missions and delegate tasks, but not the ability to alter the internal organization of subordinate units.{{Ref/Reuse|Enc22Marines}}

Marine Corps forces are unusual in that they may transition back and forth between combatant commands in combat zones, synchronized by [[Joint Deconfliction Team]]s. Marine Corps forces assigned to NAVCOM form a unit referred to as Fleet Marine Forces, under the operational control of [[UNSC Fleet Command|FLEETCOM]] command. Fleet Marine Forces include Marines assigned to shipboard and facility security, [[Naval boarding|boarding parties]] and most aerospace assets. Landing parties and expeditionary ground combat elements remain under the jurisdiction of NAVCOM, though this reading of the regulations is vehemently contested by UNICOM. Conversely, Marines conducting long-term planetary security missions, train-and-equip details and force augmentation for UNSC garrisons fall under UNICOM control.{{Ref/Reuse|Enc22Marines}}
[[File:H3ODST Mombasa Marines Concept.png|250px|thumb|Marines and ODSTs on deployment in [[Mombasa]].]]

The Marine Corps' collateral functions include;
*Enforcement of emergency military law in designated crisis areas.{{Ref/Reuse|OSFMMarines}}
*Development of doctrine, procedures and equipment that are of common interest to the Army and Navy.{{Ref/Reuse|OSFMMarines}}
*Furnishing security teams for the protection of UNSC property and high-value personnel.{{Ref/Reuse|OSFMMarines}}
*Deployment of security detachments and organizations for service on Navy ships.{{Ref/Reuse|OSFMMarines}}
*Development of doctrine, tactics, techniques and equipment for the rapid deployment and utilization of interstellar combat power.{{Ref/Reuse|OSFMMarines}}

Marine Corps forces are typically deployed as part of a [[Marine Expeditionary Force]], which may encompass several divisions as subordinate units and is itself subordinate to Fleet Marine Forces.{{Ref/Novel|CH|Chapter=7}}
:xx - [[Division]] - 14,000 Marines led by a [[Major General]] and deployed as a [[Marine Expeditionary Force|Marine Expeditionary Unit]]{{Ref/Reuse|Enc22Marines}}
:x - [[Brigade|Marine Brigade]]/[[Wing|Marine air wing]] - 9,000 Marines led by a [[Brigadier General]] and deployed as a Marine Air Wing{{Ref/Reuse|Enc22Marines}}
:||| - [[Regiment]]/Marine Air Regiment - 3,000 Marines led by a [[Lieutenant Colonel]] or [[Colonel]] and deployed specifically by UNICOM as a Rapid Reaction Force{{Ref/Reuse|Enc22Marines}}
:|| - [[Battalion]] - 900 Marines led by a Lieutenant Colonel or Colonel and deployed as a [[task force]] ground combat element or as a unit assigned to a [[UNSC carrier|carrier]]{{Ref/Reuse|Enc22Marines}}
:| - [[Company]] - 180 Marines led by a [[First Lieutenant]] or [[Captain (UNICOM)|Captain]] and deployed as a special task force or as a unit assigned to a [[cruiser]]{{Ref/Reuse|Enc22Marines}}
:{{*}}{{*}}{{*}} - [[Platoon]] - 40 Marines led by a [[Second Lieutenant]] or [[Staff Sergeant]] and deployed as a unit assigned to a [[UNSC frigate|frigate]]{{Ref/Reuse|Enc22Marines}}
:{{*}}{{*}} - [[Squad]] - Thirteen Marines led by a Corporal or [[Sergeant]]{{Ref/Reuse|Enc22Marines}}
:{{*}} - [[Section]] - Eight Marines led by a Lance Corporal or Corporal{{Ref/Reuse|Enc22Marines}}
:Ø - [[Fireteam]] - Four Marines led by a [[Lance Corporal]] or [[Corporal]]{{Ref/Reuse|Enc22Marines}}

Marine [[Special operations (disambiguation)|special operations]] forces such as the [[Orbital Drop Shock Troopers]] (ODSTs), [[UNSC Marine Corps Force Reconnaissance]] and other Marine special forces are typically deployed under the control of [[Naval Special Warfare Command]] (NAVSPECWARCOM).{{Ref/Reuse|Enc22Marines}} The ODSTs maintain a number of specialized internal divisions to oversee special activities such as the [[ODST Special Purpose Forces]], containing the air assault units nicknamed "[[Bullfrogs]]" and the [[Special Tactics and Equipment Group]] (STEG), who oversee the [[Hellbringers]] - specialized ODST warfighters who oversee the usage and deployment of demolition charges, incendiary weapons, [[nuclear weapon]]s and thermobaric weapons.{{Ref/Book|Id=Enc22ODST|Enc22|Page=58-59}}

===Army===
[[File:UNSC-Army-logo1.png|thumb|250px|The UNSC Army's logo.]]
{{Main|UNSC Army}}
{{Quote|Provide forces for sustained terrestrial combat operations and civil works.|The Army's official mission statement.{{Ref/Reuse|OSFMArmy}}}}
The UNSC Army is the primary terrestrial department of the UNSC, and provides the majority of the logistical support and [[UNSC Army Reserve|reservist soldiers]] who fight in ground campaigns.{{Ref/Book|Id=Enc22Army|Enc22|Page=61}}{{Ref/Book|Id=OSFMArmy|OSFM|Page=133-135}} The Army is responsible for defense of UEG territorial holdings and the long-term occupation of enemy territories, and as such trains, organises, equips and maintains amphibious, land, and airborne forces for this mission.{{Ref/Reuse|OSFMArmy}}{{Ref/Reuse|Enc22UNSC}} As such, while all Army soldiers are trained warfighters, in peacetime they also provide an invaluable force of engineers, technicians, builders and designers who perform public works and improve existing colonial infrastructure to support future UNSC deployments.{{Ref/Reuse|OSFMArmy}}{{Ref/Reuse|Enc22Army}} The Army also maintains its own [[UNSC Army Corps of Engineers|Corps of Engineers]] for performing some of the duties listed above{{Ref/Game|H5G|Edition=Limited Edition|[[Halo 5: Guardians Limited Edition dossiers|Dossier]] - Holly Tanaka}}{{Ref/Comic|HE|Issue=17}}, alongside the [[UNSC Army Security Forces|Army Security Forces]] for the purpose of [[Military police|military policing]] - particularly among the [[Inner Colonies]]. Army Security Forces may be employed for the duties of colonial occupation, reconstruction oversight and even civilian law enforcement, or deployed into the [[Outer Colonies]] to assist [[CAA Marshals]] and UNSC peacekeeping forces in fighting against [[Insurrectionist]] elements, monitoring megacorporate activities and guarding critical infrastructure.{{Ref/Reuse|Enc22Army}}
[[File:HR Campaign Winter Contingency 3 Charlie attacking.jpg|250px|left|thumb|Troopers of [[3 Charlie]] engaging Covenant forces in the [[Visegrád]] region on the morning of [[2552#July|July 24, 2552]].]]
The Army's collateral functions include;
*Conducting civil works that have strategic application, including projects for improvement of navigation and follow-on [[terraforming]].{{Ref/Reuse|OSFMArmy}}
*Development of doctrine, procedures and equipment that are of common interest to the Air Force and Marine Corps.{{Ref/Reuse|OSFMArmy}}
*Organisation and training of civil defense units (colloquially "[[Colonial Militia|militias]]"){{Ref/Reuse|OSFMArmy}}
*Providing forces for joint aerospace and space operations, in accordance with UNSC doctrines.{{Ref/Reuse|OSFMArmy}}

Army forces have been historically administratively organised under the control of specialised local commands ([[Army Component Command]]) based on a particular assigned [[Human colonies|colony]], though the destruction of many of these worlds in the war with the Covenant saw most of these "temporarily" disestablished and replaced by sector working groups on [[Earth]] and [[Reach]]. Operational authority of Army forces is granted to UNICOM.{{Ref/Reuse|Enc22Army}}

The Army operates its own special forces such as the [[UNSC Army airborne|Army airborne]], [[UNSC Army Pathfinders|Pathfinders]] and [[UNSC Army Rangers|Army Rangers]] - who are presumably organised under [[Unified Special Warfare Command]] (USW), or simply Special Warfare Command (SPECWARCOM). SPECWARCOM organises its detachments into "Groups" such as [[Special Warfare Group Three]]. , as well as specialised maritime forces colloquially referred to as the "wet navy". Army submarine arsenal ships and aircraft carriers are vital components in the defense of colony worlds.{{Ref/Reuse|Enc22Army}}

===Air Force===
[[File:UNSC-AirForce-logo1.png|thumb|250px|The UNSC Air Force's logo.]]
{{Main|UNSC Air Force}}
{{Quote|Provide aerospace defense and conduct space control operations.|The Air Force's official mission statement.{{Ref/Reuse|OSFMAirForce}}}}
The UNSC Air Force serves as the primary aerospace combat department of the UNSC. Contrary to their name, the Air Force does not simply operate aircraft within a planetary atmosphere, but instead focus on maintaining aerospace superiority over a given world via the use of unmanned drones, [[Space fighter|crewed aerospacecraft]] and [[orbital weapon platform]]s.{{Ref/Book|Id=Enc22AirForce|Enc22|Page=60}} The Air Force operates a network of quick rapid reaction squadrons on Earth and in the Inner Colonies, which are prepped and ready to deploy atmospheric fighter craft and military spaceplanes at a moment's notice. These strikecraft work alongside surveillance and weapons satellites to attrition an attack and assist Navy elements on station - this task saw the Air Force rack up a considerable kill ratio against Covenant invaders during the Great War despite their disadvantage in numbers and technology.{{Ref/Book|Id=OSFMAirForce|OSFM|Page=136-138}} The Air Force's atmospheric forces are primarily comprised of unmanned drones such as the [[F-99 Wombat]] which are deployed in large numbers, though they are augmented by crewed multi-role craft such as [[GA-TL1 Longsword]] interceptors, [[F-41 Broadsword]] fighters and even [[B-65 Shortsword]] strategic bombers.{{Ref/Reuse|Enc22AirForce}}
[[File:F-99 CAP.jpg|thumb|250px|left|The Air Force operates a number of Unmanned Aerial Vehicles (UAVs) such as the F-99 Wombat (pictured).]]
The Air Force's collateral functions include;
*Deployment and maintenance of UNSC unmanned defense satellites and orbital weapon platforms.{{Ref/Reuse|OSFMAirForce}}
*Monitoring and regulation of military and civilian orbital activites.{{Ref/Reuse|OSFMAirForce}}
*Development of doctrine, procedures and equipment that are of common interest to the Army and Navy{{Ref/Reuse|OSFMAirForce}}
*Furnishing support and space support for the Army and Navy.{{Ref/Reuse|OSFMAirForce}}

Air Force units may be expeditionary or garrison in nature, with the largest overall groupings named [[Group]]s and [[Wing]]s, respectively. A given Group/Wing is a larger organisation within the Air Force that combines several air [[Squadron]]s with non-aircraft units to provide specialised functions such as airbase operation and fuel refining. Squadrons consist of two to six [[Flight]]s plus additional command and technical elements, and are typically named by a number and a mission type (such as the [[980th Intercept Squadron]]), while a Flight consists of three to four individual aircraft and their support personnel. Flights are officially identified by a phonetic letter designation, though most also get an informal nickname.{{Ref/Reuse|Enc22AirForce}} 

Air Force orbital defense platform assets are grouped under the [[Orbital Defense Command]]{{Ref/Level|H4|Midnight}}, while regular air combat operations are conducted under the [[Air Combat Command]].{{Ref/Map|HR|Tempest}} The Air Force also maintains its own [[Wikipedia:Signals intelligence|signals intelligence]] (SIGINT) division{{Ref/Book|Id=OSFM113|OSFM|Page=113}} and the [[Air Mobility Express]] - who work to provide airlift and spacelift capacity for the UNSC.{{Ref/Game|HR|[[AMX-4]] and [[AMX-42]] decals}} The Air Force often employs Army maritime forces as launch platforms for its operations, using roving watercraft and carrier platforms to vector strikes against targets from outside the enemy's sensor horizon before retreating to underwater staging areas.{{Ref/Reuse|Enc22AirForce}}

The Air Force was the first service department to directly collaborate with the newly-established Spartan Operations branch, funding a joint-operations laboratory to test novel ways in which super-soldiers can augment their capabilities and certifying [[SPARTAN-IV program|Spartan-IV]] personnel as [[pilot]]s for next-generation fighters.{{Ref/Reuse|OSFMAirForce}}

===Office of Naval Intelligence===
[[File:ONI Seal 1.png|thumb|250px|The Office of Naval Intelligence's logo.]]
{{Main|Office of Naval Intelligence}}
{{Quote|Provide technical capabilities for the support of psychological, information and cyber operations.|The Office of Naval Intelligence's official mission statement.{{Ref/Reuse|OSFMONI}}}}
The Office of Naval Intelligence (ONI) is the preeminent intelligence service within the UEG.{{Ref/Book|Id=OSFMONI|OSFM|Page=127-129}} The organisation is ostensibly and bureacratically subordinate to the UNSC Navy, though in practice retains almost complete autonomy thanks to nearly a century of growth. This has seen ONI take over the duties of previously-independent agencies such as the [[Department of Colonial Security]] (DCS) to become the sole  major intelligence organisation in human space. ONI is headed by the [[Commander-in-Chief of the Office of Naval Intelligence]] (CINCONI), who is granted a seat on the UNSC Security Council. ONI remains closely-linked with the Navy in terms of administration and overall culture, though collaboration at the flag officer level is fraught with political peril and bureaucratic manoeuvring.{{Ref/Book|Id=Enc22ONI|Enc22|Page=63}}

ONI's collateral functions include;
*Deployment of covert teams for direct action and technical data collection.{{Ref/Reuse|OSFMONI}}
*Oversight of the gathering, analysis and dissemination of national security information from around the UEG.{{Ref/Reuse|OSFMONI}}
*Development of doctrine, techniques and equipment for the collection and exploitation of information in support of UEG security.{{Ref/Reuse|OSFMONI}}
*Providing combat support intelligence for UNSC operations.{{Ref/Reuse|OSFMONI}}
*Establishment of covert observation systems around enemy colonies and facilities.{{Ref/Reuse|OSFMONI}}

To achieve its goals, ONI is divided into five sections that each specialise in different aspects of intelligence gathering, analysis and dissemination. Each section in turn, has its own compartmentalised teams dedicated to more specific long-term taskings and program management.{{Ref/Reuse|Enc22ONI}}
*[[ONI Section Zero|Section Zero]] - Section dedicated to internal affairs and security audits. Section Zero believes its existence to be a secret, but other sections are aware of their existence and often work to infiltrate it and turn it against their rivals.{{Ref/Reuse|Enc22ONI}}
*[[ONI Section One|Section One]] - Section dedicated to military intelligence gathering and analysis. This is the oldest and most traditional element of ONI, with offices and functions that predate even the creation of the UNSC.{{Ref/Reuse|OSFMONI}} As such, this is the only section to have a notable public presence, with the [[Fleet Intelligence Center]] (FIC) issuing UEG slipspace travel interdiction orders, planetary evacuation notices and thread advisories on behalf of the UNSC and UEG.{{Ref/Reuse|Enc22ONI}}
*[[ONI Section Two|Section Two]] - Section dedicated to information operations and public relations. This section began as the public relations division of ONI, but soon grew into an organisation specialising in "information shaping" across the UEG. This has seen Section Two commonly labelled as a propaganda centre, though the section's activities tend more toward disseminating accurate information and reports for use by policy makers.{{Ref/Reuse|Enc22ONI}}
*[[ONI Section Three|Section Three]] - Section dedicated to special acquisition, research and development projects for the UNSC. Section Three maintains a vast number of front organisations and wields considerable power, and leverages this both covertly and overtly in the corporate and academic worlds.{{Ref/Reuse|Enc22ONI}}
*[[ONI Section Four|Section Four]] - Clandestine survey group that conducts [[xenoarchaeology]] and planetary survey studies, claiming new worlds for ONI use without the approval or knowledge of the UEG. Section Four additionally maintains observation capabilities on ex-Covenant, Banished and independent human worlds.{{Ref/Reuse|Enc22ONI}}

===Spartan Operations===
[[File:Spartan Branch insignia.png|thumb|250px|The insignia of Spartan Operations.]]
{{Main|Spartan Operations}}
Established in [[2553]]{{Ref/Book|Id=Enc22Spartan|Enc22|Page=64-65}}{{Ref/Book|Id=OSFM32|OSFM|Page=32}}, Spartan Operations (sometimes unofficially termed the "Spartan branch") is the sixth and newest military department of the UNSC, charged with oversight of the [[Spartan]] supersoldiers. Unlike the Army, Navy, Marine Corps and Air Force, Spartan Operations is not a formal military branch recognised in UEG law but instead a "continuing organisation" that lacks explicit legal recognition.{{Ref/Reuse|Enc22UNSC}} Spartan Operations instead functions as a [[UNSC Special Forces|special forces]] command that answers directly to the UNSC Security Council, eschewing the oversight of ONI that characterised the [[SPARTAN-II program|SPARTAN-II]] and [[SPARTAN-III program|SPARTAN-III]] programs in the earlier half of the 26th century.{{Ref/Reuse|Enc22Spartan}} The Spartan Operations program is led by [[Commander-in-Chief of the Spartans]] (CINCSPAR), a position which was granted a non-voting advisory seat on the UNSC Security Council in [[2554]].{{Ref/Reuse|Enc22UNSC}}
[[File:H4SO Lancer.png|thumb|left|250px|Spartan Operations personnel are signified by their unique usage of [[MJOLNIR Powered Assault Armor]].]]

Spartan Operations is predominantly comprised of [[SPARTAN-IV program|SPARTAN-IV]] personnel; a program originated in the final months of [[2552]], alongside some remaining SPARTAN-III personnel. SPARTAN-III personnel also serve in the unit, with all known surviving IIIs offered integration into SPARTAN-IV following the war's end.{{Ref/Site|Id=HWSpartan|URL=https://www.halowaypoint.com/en-us/universe/factions/spartans|Site=Halo Waypoint|Page=Spartans|D=21|M=04|Y=2021}} Despite this, Spartan Operations only retains administrative control of the Spartans themselves, with operational authority granted to [[Unified Special Warfare Command]] and [[Naval Special Warfare Command]] for field deployments.{{Ref/Book|Id=Enc22Fireteams|Enc22|Page=74-75}} Tactical deployments of Spartan personnel are overseen by Central Command in their assigned CENTCOM Regions, who oversee the allocation of Spartans to various UNSC fleets and armies within their purview.{{Ref/Book|Id=OSFM34|OSFM|Page=34}} As such, Spartans are often deployed alongside UNICOM and NAVCOM special forces units, such as ODSTs and Army Rangers.{{Ref/Reuse|Enc22Spartan}} Spartan Operations additionally continues to operate programs inherited from prior Spartan generations such as the [[Headhunters]].{{Ref/Site|URL=https://www.halowaypoint.com/en-us/news/canon-fodder-have-s-moa|Site=Halo Waypoint|Page=Canon Fodder - Have S'Moa|D=30|M=06|Y=2021}}

Unlike the rest of the UNSC, the Spartans do not operate a strict escalating rank structure and instead operate in a strict framework that emphasises teamwork, co-operation and specialisation based on personal skill alone.{{Ref/Book|Id=H4EVG33|H4EVG|Page=33}} This is the result of a deliberate effort to emphasise the informal leadership traditions of prior Spartan programs and adapt them to emphasise independence of rigid chain of command adherence. As such, all Spartans receive a direct commission as an [[Commissioned officer|officer]] in the UNSC, though this authority typically does not extend outside of their direct chain of command. Nonetheless, UNSC personnel in the field are often expected to defer to Spartans and in turn, Spartans are expected to take the initiative in combat scenarios. The baseline Spartan role sees a given Spartan tasked with the equivalent authority of a [[Lieutenant]] in the Navy, with higher ranks awarded appropriately equivalent officer status.{{Ref/Book|OSFM|Page=32-33}} 

Spartans are typically deployed in fireteams of 4-5 personnel, with each member assumed to be omni-capable in most disciplines. As such, they are typically expected to develop specific highly-specialised skillsets known as "[[Specializations]]" to further aid their team and enhance their subject matter expert status. Fireteams are generally assigned based on social dynamics and combat efficiency, though Spartans are expected to perform well in any unit.{{Ref/Reuse|Enc22Spartan}}

Alongside the Spartan personnel themselves, Spartan Operations operates its own network of infrastructure to serve as training and stationing grounds. These include orbital training stations such as [[Laconia Station|Laconia]], [[Naxos Station|Naxos]] and [[Virgo Station|Virgo]], alongside smaller [[War Games]] platforms known as [[Munera Platform]]s.{{Ref/Reuse|Enc22Spartan}} Spartan Operations is also involved in the [[Anvil Initiative]] and [[Project CRUCIBLE]], a joint-initiative with the [[Swords of Sanghelios]] to equip and train Spartans and [[Sangheili]] for joint operations, based on [[ANVIL Station]].{{Ref/Book|Enc22|Page=37}}

==History==
{{UNSC History}}
===Origins===
{{Main|Jovian Moons Campaign|Rain Forest Wars}}
By [[2160]], two dissident movements had formed in opposition to the [[United Nations]] and the [[national government]]s of Earth across the Solar system; the [[Koslovics]] and the [[Frieden]]s.{{Ref/Reuse|xbox}} Despite empowering the United Nations to stem violence from these two new blocs, it only exacerbated it leading to the Jovian Moons Campaign and eventually the dreadful siege known as the Rainforest Wars.{{Ref/Book|Id=enc22pg21|Enc22|Page=21}} In response to this,{{Ref/Reuse|enc22pg21}} the United Nations would in [[2163]] commission the creation of a military force primarily composed of naval and marine forces.{{Ref/Reuse|waypointuniunsc}} These marine forces would be composed of the spaceborne forces of several nations.{{Ref/Reuse|Enc22Marines}} Overall, it was to be a powerful military arm to defend Earth and her colonies called the United Nations Space Command.{{Ref/Reuse|enc22pg21}} 

===Mars Campaign===
{{Main|Mars Campaign}}
In the most spectacular offensive since the start of the bloody tripartite war, UN command adopted a military strategy long-forgotten throughout the peace-dominated period prior to the outbreak of the Jovian Moons Campaign in 2160 - the "Blitzkrieg"-style lightning ground assault. After capturing both Frieden and Koslovic forces on Mars, the UN delivered the first space-deployed contingent of the newly-established [[UNSC Marine Corps|Marines]] in December of [[2163]] on a mission to crush communist infantry encampments in the basin of [[Argyre Planitia]], marking a turning-point in space warfare through dedicated deployments of Marine forces in ground assaults and ship-[[Naval boarding|boarding]] operations that would follow during the war.{{Ref/Reuse|xbox}}

The offensive was an incontestable success for the UN side. As a result, military theory and strategy implemented the use of Marines in high-priority missions as a baseline for successful operations, especially within the context of larger conflicts.{{Ref/Reuse|xbox}}

However, the most important consequence of the anti-totalitarian campaign was of both political and military nature. The United Nations itself did not control a dedicated space military prior to the Mars Campaign, a lacking element which it would replace with a special emergency military force that would come to represent humanity's overall military might. In the wake of the success of the UNSC Marines on Mars, the UN used its growing influence to not only take control of Earth's national governments, but also absorb Earth's national military organizations into a single, organized force; the United Nations Space Command was created.{{Ref/Reuse|xbox}}

===Interplanetary War===
{{Main|Interplanetary War}}
As of [[2164]], psychological results of the campaign on Mars were formidable; civilian trust in the newly-formed UNSC military was boosted by massive televised propaganda, providing the UNSC with large waves of enthusiastic volunteers from all military services around the world. A sense of urgency, courage and hope helped UN forces scramble extraordinary divisions of Marines, infantry and fliers for a final campaign to annihilate remaining communist and fascist outposts and strongholds on Earth as well as throughout the inner planets and beyond Jupiter. The final campaign for peace lasted from 2164 to [[2170]] in a series of brutal crackdowns on Frieden and Koslovic hardliners. The result of this war gathered strong civilian support for some sort of powerful international military that could repel revolts and uprisings wherever they may occur. The UNSC emerged as the leading force to further those goals.{{Ref/Reuse|xbox}}

====UN victory====
Coincidentally, the war formally ended where it had begun: in the Jovian Moons. The [[Callisto Treaty]] was signed in 2170 by commanders of Koslovic and Frieden forces in the presence of [[United Nations colonial advisers|UN colonial authorities]], definitively ending the 10-year-long conflict with a victory of UNSC forces and democratic leadership.{{Ref/Reuse|xbox}}

[[2170]] saw the creation of the first multinational and multicolonial representation of democracy in outer space. Faced with concerns of overpopulation and starvation on Earth, consequently coupled with a looming destabilization of capitalist economy, the [[Unified Earth Government]]—up until then lacking concrete power—was formed into a full-fledged governing body in a time of cultural and military reconstruction.{{Ref/Reuse|xbox}}

The brutal ten-year-long war put the spotlight on problems facing the overpopulated Earth, and the Rainforest Wars also exacerbated issues relating to food distribution; this, along with the UN overmilitarization that occurred during the war, presented immediate problems for the postwar United Nations Space Command. The ensuing famine and societal problems related to the postwar population boom provided the spark to change the political nature of governance on Earth and elsewhere, leading to widespread political reform.{{Ref/Reuse|xbox}}

===The Colonial Era===
{{Main|Domus Diaspora|Human colonies|Inner Colonies|Outer Colonies}}
[[File:HM-DomusD 1.jpg|thumb|250px|A [[colony ship]] readying for departure during the ''Domus Diaspora''.]]
The pressures engendered by the Interplanetary War made space colonization seem more attractive in subsequent centuries, and the Unified Earth Government would sign off on the first large-scale interstellar colony ship program that was revealed in [[2310]] to ease the burden of an overpopulated Earth. This would not have been possible without the invention of the [[Shaw-Fujikawa Translight Engine]] in [[2291]], which allowed the ships to travel vast distances within a reasonable time by opening portals into [[Slipstream space]].{{Ref/Reuse|xbox}} At the same time, the UEG established a separate colonial governing body known as the [[Colonial Administration Authority]] as well as the [[Colonial Military Authority]], a dedicated military force to police the colonies.{{Ref/Book|H4EVG|Page=228}}

In [[2362]], the first colony ship, the ''[[Odyssey]]'', was launched, beginning the period of human history later known as the ''[[Domus Diaspora]]''.{{Ref/Book|HM|Page=52}} This initial colonization effort was concentrated in the [[Epsilon Eridani system]], which would later become one of the centers of humanity's interstellar empire.{{Ref/Book|Id=Enc11p42|Enc11|Page=42}} Vast numbers of citizens and soldiers elected to travel to these new colonies, stabilizing the overpopulation problem on Earth and giving the military new tasks to handle. As the first colonists are stringently selected, the Inner Colonies eventually formed an elite society of the best physical and mental human specimens. A core ring of 210 Inner Colonies were not fully developed until the end of the 24th century.{{Ref/Reuse|xbox}}

The apex of this colonization movement would come in [[2492]] when more then 800 worlds were inside UNSC territory, many of them targeted for human habitation. These settlements ranged from fairly well-tamed planetary strongholds to tiny hinterland settlements. During this period, the planet [[Reach]] (orbiting Epsilon Eridani, right on Earth's metaphorical doorstep) became the UNSC's primary naval yard and training academy. Reach was a major producer of warships and colony vessels, as well as a training ground for covert operatives and [[UNSC Special Forces|Special Forces]].{{Ref/Reuse|xbox}}

Over the course of humanity's interstellar expansion, a number of alien artifacts were discovered; while unknown at the time, these were the works of a long-vanished civilization known as the [[Forerunner]]s. However, virtually all of these findings were discreetly concealed by the UNSC's [[Office of Naval Intelligence]], which exerted virtually complete control over the research and information flow about [[xenoarchaeology|xenoarchaeological]] discoveries. A noted example of this is [[Onyx]], originally surveyed as an ideal world for human settlement but declared off-limits by ONI due to the alien technology discovered there.{{Ref/Reuse|Enc11p42}}

===The Insurrection===
{{Main|Insurrection}}
By the final decade of the 25th century, a chain of [[Outer Colonies]] was providing the UEG with valuable raw materials; the political power, however, remained with the aforementioned Inner Colonies. These differences in wealth distribution and political power, led to new threats of secession from the outer territories. Over time, ideological and political causes resulted in many of the Outer Colonies engaging in open rebellion. A [[Insurrection|series of brushfire wars]] across human space sprang up, with hundreds more threatening to erupt as well. By [[2511]], UNSC estimates, largely based upon [[Carver Findings|the projections]] of [[Elias Carver|Dr. Elias Carver]], put massive, overwhelming, and uncontrollable rebellion at less than twenty years away.{{Ref/Reuse|xbox}}

Military conflicts began disrupting UNSC authority in the [[Outer Colonies]] where several uprisings among working-class agriculturalists and other social classes grew unhappy with the UNSC's largely inconsiderate governance. This unrest gave rise to the [[Insurrectionist]] movement, a loose collection of violent colonial separatists with the shared goal of liberating the Outer Colonies from the Unified Earth Government's influence.
{{Clear}}
====Spartans====
{{Main|Spartan}}
[[File:HW-Red Team.jpg|thumb|left|250px|Spartan-II [[Red Team]] in MJOLNIR armor.]]
Fearing the consequences of the possible breakup of their fledgling interstellar empire, while wishing to preserve as much infrastructure as possible, the United Earth Government would embark on a series of covert efforts to quickly and quietly deal with insurrections without incurring massive civilian casualties.{{Ref/Reuse|xbox}}

Before the UNSC expanded its forays into [[biological augmentation]] to create successful Special Forces programs in the 26th century, the [[Colonial Military Authority]] experimented with a prototype Special Forces project in the 24th century that tested the effects of bioaugmentations on [[UNSC Marine Corps|Marine Corps]] and [[UNSC Navy|Navy]] personnel. The experiments proved ineffective and were formally canceled as a result, marking the first attempt to create a specialized force of covert-warfare operators in response to insurgent outbursts within the domain of the Unified Earth Government.

Due to increasing risk of insurrectionist activity in the late 25th century, the UNSC's [[Office of Naval Intelligence]] conceived a project to train Special Forces soldiers in counter-insurgent and counter-revolutionary warfare. The ORION Project, retroactively termed as Spartan-I, was an [[UNSC Special Forces|Naval Special Warfare]] program, overseen by the CMA, created to train special advanced warfare squads to combat the Insurrection. They became experts in counterinsurgency operations, assassinations, raids, and eliminating high value targets—all considered black operations.<ref name="HCH">'''[[Halo: Contact Harvest]]''', ''Prologue''</ref> However, expectations for the new soldiers were not met, and the project was deactivated in 2506, and all members reassigned to other Special Operations units.<ref>'''Halo Wars''' ''Timeline''</ref> In the coming years, ORION's methodologies would be uses as basis for a reform in the [[Orbital Drop Shock Troopers]],<ref>'''Halo: Reach''', [[Data pads#Data pad 11|''data pad 11'']]</ref> the most famed special operations force of the UNSC Marines.

Several years later, ONI's alarming projections on colonial instability prompted them to initiate a second generation supersoldier project which would come to be known as the [[SPARTAN-II program]]. Partly informed by the pioneering efforts of ORION with new methodologies conceived by [[Catherine Halsey|Dr. Catherine Halsey]], the new program introduced highly unethical aspects such as the covert conscription of mentally and physically gifted children who would be molded into the perfect instruments to quell insurgent leadership and thus prevent the predicted scenario of indefinite all-out war. [[SPARTAN-II augmentation procedures|Physically augmented]] and equipped with state-of-the-art [[MJOLNIR Powered Assault Armor|MJOLNIR powered armor]], the Spartan-IIs would prove to be the most effective soldiers fielded by the UNSC, although not in the role they were originally intended for; the attack of the genocidal [[Covenant]] quickly saw the Spartans reallocated to combat the new enemy.<ref>''[[Dr. Halsey's personal journal]]''</ref>

During the Covenant War, the success of the Spartan-IIs would convince the ONI leadership to use similar methodologies to create hundreds of supersoldiers in the [[SPARTAN-III program]]. Despite various refinements in their training and augmentation processes, most of the Spartan-IIIs would be less well-equipped than their predecessors for budgetary reasons, and the majority of them would ultimately perish on strategically important, high-risk deployments.<ref>'''Halo Mythos''', ''page 76''</ref> Following the end of the war, the [[SPARTAN-IV program]] marked a return to ORION's recruitment protocols, drawing candidates from the UNSC's extant military forces; additionally, technological advances and the relegation of equipment manufacturing to the private sector allowed each operator to be issued with the previously prohibitively expensive Mjolnir armor. With Spartans being created in increasing numbers, their presence across UNSC-controlled space would become far more established and publicized in the years that followed than ever before.<ref>'''Halo Mythos''', ''page 128''</ref>

===Human-Covenant War===
{{main|Human-Covenant War}}
[[File:Halopedia Era UNSC.png|90px|thumb|left|The [[Symbols of the UNSC|UNSC Eagle, Globe, and Banner]].<ref>[https://www.halowaypoint.com/en-us/news/cosplay-guide-the-rookie ''Halo Waypoint'' - Cosplay Guide: The Rookie]</ref>]]
[[2525]] marked the most important turning point in human history. It would mark the beginning of the great technological advancement, the unification of a divided and fractured human race, and the [[First Battle of Harvest|first contact]] between humanity and extraterrestrial intelligence; the [[Covenant]]. It would also see a majority of the UNSC's colony worlds destroyed, with billions killed by orbital plasma bombardment, a technique latter known as [[glassing]]. The most important war in the history of the human race began with a disastrous first contact at the distant colony of [[Harvest]].

By this time, the UNSC overrode the UEG, and thus became the central civilian authority throughout its territory and Earth itself. Although the central government was more willing to step down given the magnitude of the crisis, the [[Colonial Administration Authority]] was far more reluctant. As a result, the UNSC stripped it of most of its power. By the middle to late stages of the war, the government of humanity could be accurately described as an "emergency military" force.{{clear}}

====First contact====
{{Main|First Battle of Harvest}}
[[File:HWG SecondBattleOfHarvest.png|thumb|250px|Admiral Cole's victory at Harvest.]]
Stemming from the chance encounter of human and Covenant forces at [[Harvest]], the first contact made between humanity and the Covenant involved the ship ''[[Minor Transgression]]'', and was less peaceful than the second contact made between the two factions. A meeting between representatives of the two factions took place on the fields of Harvest, but the attempt at diplomacy soon turned into a bloodbath. The Covenant claimed the planet for the numerous "[[Forerunner]] relics" their [[Luminary|luminaries]] had detected, and slaughtered most of the colony's population.{{Ref/Reuse|xbox}} The vast majority of the Covenant remained unaware that the humans they were sworn to annihilate, were in fact the very [[Reclaimer]]s (mistranslated as "Reclamation") their ancient texts spoke of.<ref>''Halo: Contact Harvest'', p. 274-278</ref>

On April 20, a scout ship, the CMA sent in a scout ship, the ''[[CMA Argo|Argo]]'', to investigate the cessation of communications between Harvest and the rest of the UEG's colonies. Before being destroyed by Covenant forces, it discovered that the planet had been incinerated, and its surface covered by fields of magma. Soon after, [[Battle Group 4]], consisting of the frigates [[CMA Arabia|CMA ''Arabia'']] and [[CMA Vostok|''Vostok'']] and the [[UNSC destroyer|destroyer]] [[CMA Heracles|CMA ''Heracles'']], were sent to investigate. On October 7, the battle group dropped out of Slipspace and to Harvest. In orbit around the remains of the colony world was a single alien ship which proceeded to attack the battle group, destroying them all except one. Intercepted communications identified the enemy as the Covenant, a caste-driven, theological organization made up of several alien species. The message "''Your destruction is the will of the gods...and we are their instrument''" was broadcast in perfect [[English]].<ref>'''[[Halo: The Fall of Reach]]''', Chapter 11, ''page 98'' (2001 paperback); ''page 117'' (2010 paperback)</ref> The war for mankind's very survival had begun. 

[[File:Covenant assault - 2.png|thumb|left|250px|The Covenant invade a population center on a human world.]]
Since the later [[Second Battle of Harvest]] in [[2526]], where an [[Battle Group X-Ray|enormous human fleet]] led by [[Vice Admiral]] [[Preston Cole]] barely won against a [[Rasus-pattern interdictor|single Covenant ship]] in a symbolic "victory", the UNSC's grip on their territories declined significantly. While the UNSC fought a formidable defensive action against the Covenant's onslaught, the Covenant's technological superiority in space overwhelmed humanity's naval defenses. Over the next 27 years, the Covenant had managed to destroy nearly all of the [[Outer Colonies]], and a portion of the [[Inner Colonies]].{{Ref/Reuse|xbox}} Recognizing that it was fighting a losing battle against a superior enemy, the UNSC adopted and enforced the [[Cole Protocol]], drafted by Admiral Cole to ensure that the Covenant never learned the location of Earth as the war continued to spread into human space.

The UNSC's military victories against the Covenant were few and far between, with Admiral Cole winning a decisive victory against the Covenant at the [[Battle of Psi Serpentis]] in [[2543]], destroying an entire enemy fleet at the cost of his own life. Behind the scenes, humanity began to extensively reverse-engineer technology recovered from both the Forerunners and the Covenant in a bid to bridge the gap between the Covenant and humanity's technological advancement. The deployment of the [[Spartan-II program|Spartan-II supersoldiers]] proved devastating to the Covenant and enabled the UNSC to stave off several major Covenant offensive operations. However, the Covenant's encroachment of human space continued largely unabated, and the ongoing war of attrition took a toll on the UNSC's offensive capability as the threat to Earth's survival drew closer.

====RED FLAG and Halo====
{{Main|Operation: RED FLAG|Fall of Reach|Battle of Installation 04}}
[[File:Autumn Arrival.png|thumb|250px|{{UNSCShip|Pillar of Autumn}} arrives at Installation 04.]]
By [[2552]] the UNSC, outnumbered and outgunned, had nonetheless managed to slow the Covenant's inexorable progress through human space. However, the situation remained dire. In desperation, [[UNSC High Command|HIGHCOM]] ordered a [[Operation: RED FLAG|high-risk operation]], sending the SPARTAN-II supersoldiers to insert into Covenant space, capture one or more high-ranking [[San'Shyuum|Prophet]], and return to UNSC space. With such valuable hostages, the UNSC would then attempt to ransom these leaders for a truce. Before the operation began, the Covenant [[Fall of Reach|found and destroyed]] the fortress world of [[Reach]], destroying a large portion of the UNSC's military forces, inadvertently stopping the operation and, seemingly, killing most of the Spartans.{{Ref/Reuse|xbox}}

A single ship, the {{UNSCShip|Pillar of Autumn}} managed to escape the planet, with one active Spartan on board; [[John-117|Master Chief John-117]]. The ship followed coordinates derived by the AI [[Cortana]] to a [[Forerunner]] ringworld known as [[Halo Array|Halo]] [[Installation 04]]. There, John-117 encountered a parasitic lifeform known as the [[Flood]], which Halo had been built to eliminate by destroying all life in the galaxy. John-117 destroyed the ring before it could be fired by detonating the [[Fusion drive|reactors]] of the ''Pillar of Autumn''. After hijacking a [[Ascendant Justice|Covenant flagship]], the Spartan reunited with the survivors from Installation 04 and the destruction of Reach. This small band of soldiers attacked a force of Covenant ships in [[Operation: FIRST STRIKE]], one of the most successful UNSC operations against the Covenant in the entire war.

====Final months====
{{Main|Battle of Earth|Battle of Installation 05|Battle of Installation 00}}
[[File:H2A - BattleofEarth.png|thumb|left|250px|The [[UNSC Home Fleet]] engages the Covenant over Earth.]]
Starting [[2552#September|September 5, 2552]], all remaining naval assets were recalled to Earth and amalgamated into a single command grouping under the [[UNSC Home Fleet|Home Fleet]] in preparation for an impending Covenant invasion.{{Ref/Generic|Id=NRA|Heading=[[Halo Legendary Crate]]|Subheading=[[Halo Legendary Crate/Data Drops|Data Drop #2]]|Detail=[[:File:LC 002 Doc 3.jpg|Naval Records Archives]]}}

By [[2552#October|October of 2552]], an estimated twenty-three billion civilians were killed since the dawn of the Human-Covenant War,<ref>'''[[Halo: Evolutions - Essential Tales of the Halo Universe]]''', "[[Palace Hotel]]", ''page 358''</ref> and the Covenant haphazardly discovered the position of the human homeworld, Earth, and sent a [[Fleet of Sacred Consecration|preliminary task force]] there, believing it to be the location of the [[Installation 00|Ark]], an ancient Forerunner relic. They encountered staunch resistance, and were initially fended off as soon as more Covenant reinforcements continued to arrive in-system days and weeks after the [[Battle of Mombasa|initial invasion]].{{Ref/Film|Id=Oct20|Film=Halo Waypoint|Story=Ten Twenty|StoryLinkText=Ten Twenty}}{{Ref/Level|Id=H2Metro|H2|Metropolis}}{{Ref/Generic|Id=FTH|Heading=[[Halo Legendary Crate]]|Subheading=[[Halo Legendary Crate/Data Drops|Data Drop #2]]|Detail=[[:File:LC 002 Doc 1.jpg|First Twelve Hours]]}} Further complications arose from the political and religious crisis that emerged in the wake of a UNSC operation to [[Assassination of the Prophet of Regret|assassinate]] the [[Prophet of Regret]], and the [[Changing of the Guard|secession]] of the [[Sangheili]] from the hegemony, leading to the [[Great Schism]].{{Ref/Level|Id=deltahalo|H2|Delta Halo}}{{Ref/Reuse|gravemind}} Overnight, the Covenant was thrown into chaos.{{Ref/Level|Id=gravemind|H2|[[Gravemind (level)|Gravemind]]}} Nevertheless, by November, the forces loyal to the [[Prophet of Truth]] had already subjugated large parts of Africa since its arrival shortly after Regret's departure from Earth by attempting to excavate a long-buried [[Portal at Voi|large Forerunner structure]].{{Ref/Level|Id=H3RCoast|ODST|Coastal Highway}} Later, Truth took the majority of remaining Covenant loyalist fleets with him after he departed aboard the Forerunner [[keyship]] ''[[Anodyne Spirit]]'' for Earth.{{Ref/Novel|Novel=[[Halo: Broken Circle]] (Google Books)|Page=286|Quote=He has taken what is left of the Covenant fleets and is heading for the human world, Earth. He is seeking the Ark.|Quotee=[[G'torik 'Klemmee]]}} Upon their arrival in the [[Sol system]], the final Covenant fleets devastated much of the planet, mostly via [[orbital bombardment]], after routing the numerically-inferior [[UNSC Home Fleet|Home Fleet]] on November 17.{{Ref/Level|Id=Truthfleet|H3|Crow's Nest|Quote=The Prophet of Truth's ships breached the Lunar perimeter. Smashed what was left of the Home Fleet. Terrestrial casualties from the subsequent bombardment were... extreme.}} Only the [[Battle Group Victory|offensive]] led by [[Commander]] [[Miranda Keyes]] through the [[Portal at Voi|Forerunner portal]] uncovered in [[Africa]], and the help of the [[Sangheili]] [[Fleet of Retribution|fleet]] prevented the eventual destruction of the UNSC and Earth itself.{{Ref/Level|Id=TheCovenant|H3|[[The Covenant (level)|The Covenant]]}}

The UNSC and [[Fleet of Retribution|their Sangheili allies]] launched a joint operation to destroy the Covenant once and for all at the Ark. Fighting against a [[Truth's fleet|massive Covenant fleet]] (3:1 numerical superiority in space), and even greater forces garrisoned on the Ark, the allies were able to stop Truth from firing the Halo Array.{{Ref/Level|Id=TheArk|H3|The Ark}} In addition, the Sangheili known as [[Thel 'Vadam|the Arbiter]] killed Truth, the Covenant's last remaining leader, while SPARTAN-117, leading the ground effort to destroy the Covenant's remaining forces, deactivated the Halo Array before the Halo installations could be fired.{{Ref/Reuse|TheCovenant}} On March 3, [[2553]], the Human-Covenant War officially ended in a victory for the UNSC and the Sangheili, but at a high price.{{Ref/Level|Id=halo3epilogue|H3|[[Epilogue (Halo 3)|Epilogue]]}} Most major military outposts, along with countless colonies had been destroyed. Earth, despite the loss of billions to orbital bombardment,{{Ref/Reuse|Id=Truthfleet}} remained battered but standing. 
{{Clear}}

===Reconstruction and new conflicts===
{{Main|Post-Covenant War conflicts}}
{{Quote|For too many years, humanity was on the backfoot. Reacting to threats, rather than preventing them. Rest of the galaxy was bigger than us. Stronger than us. We were [[Rodent|mice]], hiding in the shadows, hoping the giants would not see us. No more. Humanity is no longer on the defense. ''We'' are the giants now.|[[Captain (Navy)|Captain]] [[Thomas Lasky]]<ref>'''Halo 4''', ''[[Infinity (mode)|Infinity]]'' introductory cinematic</ref>}}
[[File:UNSC insignia (post-war).png|90px|thumb|Following the war, UNSC branding was reworked. The new logo is bold, strong, and ascendant.<ref name="new symbol">[http://halo.xbox.com/blogs/Headlines/post/2012/07/25/The-Halo-Bulletin-72512.aspx ''The Halo Bulletin - 7.25.12''] (Defunct copy on [https://web.archive.org/web/20120730133146/http://halo.xbox.com/blogs/Headlines/post/2012/07/25/The-Halo-Bulletin-72512.aspx Wayback Machine])</ref>]]

The UNSC transferred its emergency governing functions back to the UEG on [[2553|January 8, 2553]], although this formal shift of power did not significantly diminish the UNSC's practical authority.<ref name="CatalogUEG">[https://forums.halowaypoint.com/yaf_postsm2969317_Catalog-Interaction.aspx#post2969317 '''Halo Waypoint''': ''Catalog Interaction (Query Answer: Human records indicate transition to noncombatant administrative control <nowiki>[ref: UEG] [January 8, 2553]. No notable adjustment in military [bureaucratic tactical]</nowiki> behavior and scope of authority.)'']</ref>

Since 2553, the UNSC has engaged in an extensive period of reconstruction in order to restore stability to the shattered remnants of its territory. The UNSC has moved to reclaim those worlds that were not completely destroyed during the Human-Covenant War. Former colonies such as [[Eridanus II]],{{Ref/Map|H4|[[Skyline]]}} [[Meridian]] and [[Draco III]] were resettled and became strategic staging points for humanity's efforts to reunite its reach across space.<ref>'''Halo: New Blood''', ''pages 17-18'' (Google Play edition)</ref> New planets such as [[Oban]] have also been colonized for the purpose of resettling the countless millions of [[refugee]]s whose worlds were lost in the conflict. The UNSC also aimed to [[Salvaging|salvage]] any recoverable military assets lost during the war; paying companies such as [[Warner & Ives]] to [[Fetching|recover]] slipspace drives from derelict vessels, and buying scrap from clearing house auctions, such as those in [[New Tyne]] on the planet [[Venezia]].<ref>'''[[Halo: Fractures]]''', ''[[Into the Fire]], page 301''</ref> With the genocidal threat of the Covenant ended, the UNSC has employed some of its former species including [[Unggoy]] and [[Huragok]] in a limited capacity. The UNSC also maintains its earlier [[Treaty of 2552|peace treaty]] with the [[Swords of Sanghelios]] under the leadership of [[Arbiter]] [[Thel 'Vadam]]. In [[2553]] the [[Joint Occupation Zone]]s were created and are now governed by both the UNSC and the Sangheili, with former colonies such as [[Carrow]] now hosting new citizens from both sides. The UNSC has also established outposts around the Halo Array and other such Forerunner installations, which they closely monitor with the Sangheili. However, tensions remain as insurrectionist movements have grown in strength, with worlds like [[Venezia]] and [[Gao]] effectively having seceded from the UEG as recently as 2553.<ref>''Halo: Glasslands''</ref><ref>''[[Halo: Last Light]]''</ref> In early 2553, the Office of Naval Intelligence began authorizing operations to sow dissent among the Sangheili, disregarding the alliance in the hopes of rendering them unable to fight should they become a threat again. These actions culminated in a [[Blooding Years|civil war]] between the Arbiter's forces and those who opposed the alliance with humanity.<ref>''Halo: The Thursday War''</ref>

[[File:Commissioning-1.jpg|thumb|left|250px|The commissioning of {{UNSCShip|Infinity}}.<ref>''[[The Commissioning]]''</ref>]]
In spite of the catastrophic damage UNSC's infrastructure and personnel suffered during the Covenant War, various secret projects initiated in the final years of the conflict enabled the UNSC to regain some degree of military power in the months after the cessation of hostilities.<ref>''Halo Mythos'', ''page 125''</ref> To symbolize their newly regained strength, the UNSC adopted [[Symbols of the UNSC|a revised version of its original emblem]] shortly after the war.{{Ref/Reuse|new symbol}} The UNSC's rebuilding efforts were spearheaded by the symbolic commissioning of the UNSC's most powerful warship, the {{UNSCShip|Infinity}}, in February 2557. A dramatic modernization of the UNSC's military assets has been ongoing, with new warships implementing both Covenant and Forerunner technologies for use against humanity's enemies. While the reconstruction of humanity's territories continued for many years after the end of the Covenant War, various [[Covenant remnants]], most prominently [[Jul 'Mdama's Covenant|a group led by Jul 'Mdama]], defied the truce between humans and Sangheili and arose to threaten the UNSC. In July [[2557]], the [[Post-Covenant War conflicts|ongoing conflict]] against the new Covenant was joined by the [[Ur-Didact|Didact]] and his [[Promethean]] constructs due to [[Battle of Requiem|an encounter]] on the shield world [[Requiem]].<ref name="h4">''[[Halo 4]]''</ref>

===Created uprising===
{{Main|Created uprising}}
{{Quote|The UNSC is gone!|[[Warmaster]] [[Atriox]] to [[Cortana]] during [[Battle for Zeta Halo]].{{Ref/Level|HI|Silent Auditorium}}}}

Following October 28, [[2558]] the UNSC was largely immobilized by the [[Created]] when Cortana and her [[Guardian]]s took over Earth and most human colonies.<ref name="H5G">'''[[Halo 5: Guardians]]'''</ref> UNSC expeditionary forces that managed to avoid the Created's Guardians were able to regroup with the Swords of Sanghelios on Sanghelios.<ref>[https://www.halowaypoint.com/en-us/news/canon-fodder-driving-force''Halo Waypoint'' - Canon Fodder: Driving Force]</ref> 

Already crippled by the Created and fleeing, the UNSC's flagship, {{UNSCShip|Infinity}}, and several other ships were [[Battle for Installation 07|defeated]] by the [[Banished]] at [[Installation 07]] in [[2559]].{{Ref/Level|HI|[[Warship Gbraakon]]}} What remains of the UNSC is scattered across human space in disconnected pockets, without the ability to effect much change or communicate back to Earth.{{Ref/Book|Enc22|Page=17}}

===Later history===
By [[2589]], the former UNSC stronghold of [[Reach]] had been re-terraformed and resettled.{{Ref/Level|HR|[[Lone Wolf]]}}

==Military assets==
===Technology===
{{Main|Human#Technology|l1=Human technology|UNSC Navy#Equipment|l2=UNSC Naval technology}}
By the time the Covenant War began, humanity, and thus the UNSC, had reached [[Technological Achievement Tiers|Tier 3]] of the [[Forerunner]] civilization rank system. Humanity's rank continued to rise due to the capture of Covenant technology and equipment, which was studied and adapted for human needs. The very best and cutting edge of UNSC equipment was supplied to the SPARTAN-II project. Human technology was innovative, rather than reverse-engineered from Forerunner technology. This meant humanity remained flexible in their technical expertise, despite being hundreds of years behind the Covenant.<ref>''Halo: The Flood'', p. 132</ref> One such example of ingenuity was the [[energy shielding]] technology adapted and improved for use on the [[MJOLNIR Powered Assault Armor|MJOLNIR armor]]. 

==Public perception==
[[File:H4FUD UNSCTodayTomorrowForever.jpg|thumb|A UNSC propaganda poster on display at the Corbulo Academy of Military Science.]]
{{Quote|We are UNSC! Today. Tomorrow. Forever.|General [[Daniel Black]] quoting the poem [[Forward Unto Dawn (poem)|"Forward Unto Dawn"]] in a [[Halo 4: Forward Unto Dawn: Recruitment|UNSC recruitment video]].<ref name=recruit>''[[Halo 4: Forward Unto Dawn: Recruitment]]''</ref>}}
The UNSC's pre-[[Human-Covenant War|Covenant War]] and wartime policies were viewed with hostility by the civilian populace, especially within rebel movements. Starting with the implementation of the [[Cole Protocol]] and martial law, the UNSC's political takeover of the [[UEG]] and [[CMA]] branches and its generally authoritarian military policies championed over the course of the Human-Covenant War, the UNSC's public image has been stained by rebel and civilian allegations of [[fascism]], totalitarianism and oppression.<ref name="mombasastreets">''[[Halo 3: ODST]]'', [[Mombasa Streets]]</ref><ref>''[[Halo: The Cole Protocol]]'', p. ??</ref> 

These allegations are not completely baseless, considering most of this perceived UNSC-directed oppression lies with poor administration in the [[Outer Colonies]], which has led to violent [[Scyllion Warehouse District Riot|food riots]] perpetrated by proto-rebellious groups of dissatisfied colonial workers suffering from hunger and poverty at the hands of corporate planetary control.<ref>''[[Halo: The Cole Protocol]]'', p. 106-107</ref>

The UNSC also limits the freedom of the press to an extent, a measure put in place by ONI's Section Two after the [[Inner Colony Wars]]—allegedly to prevent humanity from tearing itself apart from within.<ref>'''[[Halo Graphic Novel]]''', ''[[Second Sunrise over New Mombasa]]''</ref> ONI also exerts almost complete control over information about [[xenoarchaeology|xenoarchaeological]] findings;{{Ref/Reuse|Enc11p42}} any scientists studying alien artifacts are drafted to serve under ONI's supervision.<ref>'''Halo: Evolutions''', ''"[[From the Office of Dr. William Arthur Iqbal]]"''</ref> Nepotism is notably prevalent within the organization,<ref>[[:File:MajesticBio-Madsen.png|Spartan Madsen's biography]]</ref><ref>'''Halo: Escalation''', ''Issue #5''</ref> sometimes openly; [[Corbulo Academy of Military Science]] was based around the concept of training the offspring of high-ranked military and government officials as commissioned officers.<ref>'''[[Halo 4: Forward Unto Dawn]]'''</ref>

==Production notes==
During the [[Development of Halo: Combat Evolved|development]] of ''[[Halo: Combat Evolved]]'', one working name for the UNSC was the UNSF - or United Nations Space Force.{{Ref/Twitter|joestaten|1010437502501572608|Joseph Staten|Quote=Now seems like the right time to bring up the fact that one of the working titles for the #Halo U.N.S.C. was the U.N.S.F. or “Space Force”. But we decided that sounded a little too sci-fi silly. #GoAirForce|D=10|M=05|Y=2023}}

==Trivia==
{{Other languages
|fr={{Tooltip|''Commandement Spatial des Nations Unies''|Space Command of the United Nations}} (''CSNU'') in ''Halo: Combat Evolved'', in the ''Halo'' novels until ''Halo: The Cole Protocol'', and in ''Halo Legends''.<br>
{{Tooltip|''United Nations Space Command''|(Anglicism)}} (''UNSC'') in almost all media since ''Halo 2''.<br>
|es=Full name: {{Tooltip|''Comando Espacial de las Naciones Unidas''}}<br>
Acronym: {{Tooltip|''CENU''}}
|de=Full name: {{Tooltip|''Weltraumkommando der Vereinten Nationen''}}<br>
Acronym: {{Tooltip|''WVN''}}
|it=Full name: {{Tooltip|''Comando Spaziale Terrestre''}}<br>
Acronym: {{Tooltip|''CST''}}
}}
*In reality, "UNSC" is an acronym for the [[wikipedia:United Nations Security Council|United Nations Security Council]]. The BBC accidentally once used a Halo UNSC logo in a broadcast about the United Nations Security Council.<ref>[https://www.youtube.com/watch?v=AYIDjyVneqU '''YouTube''': ''BBC News FAIL - claims Halo logo is for United Nations Security Command (Newswatch, 1.6.12)'']</ref> The video on the BBC website was quickly removed.
*The UNSC's motto is derived from that of the British [[Wikipedia:Royal Marines|Royal Marines]], "''Per Mare, Per Terram,''": "''By Sea, By Land.''"
*While the new UNSC emblem introduced in ''[[Halo 4]]'' is canonically a new symbol the UNSC adopted in the post-war era instead of an artistic retcon of the classic design,{{Ref/Reuse|new symbol}} all ''Halo 4'' multiplayer maps set during the Covenant War feature the post-war emblem. However, the original, Covenant War-era symbol is appropriately featured in ''[[Halo 2: Anniversary]]'' multiplayer maps (e.g. [[Bloodline]]) and other uses, including labels on vehicles.<ref>[http://ca.ign.com/articles/2014/10/20/zanzibar-remake-stonetown-rocks-in-halo-the-master-chief-collection-ign-first '''IGN.com''': ''Zanzibar Remake 'Stonetown' Rocks in Halo: The Master Chief Collection – IGN First'']</ref> Conversely, the post-war logo appears in the ''Halo 2: Anniversary'' campaign stamped on crates on [[Cairo Station (station)|Cairo Station]].<ref>[[:File:H2A Crates New UNSC Logo.png|This screenshot]]</ref> Due to a lighting glitch in ''The Master Chief Collection'', the war-era UNSC emblem can be seen on the bridge of the UNSC ''Infinity'' in the cutscene at the end of the ''Halo 4'' mission [[Reclaimer (level)|Reclaimer]].

==Gallery==
<gallery>
File:Halo4UNSCLogoSpinAnimated.gif|The UNSC Logo used as ''Halo 4''{{'}}s loading screen.
File:Halopedia Era UNSC.png|The original UNSC emblem, used until the Human-Covenant War's conclusion.
File:H4 UNSC logo.png|The most recent incarnation of the stylized wordmark.
File:SLoftus-UNSC-MarineAir.png|The [[UNSC roundel]] used on aircraft.
File:SLoftus-UNSC-Ground.png|The UNSC roundel used on ground vehicles.
File:SLoftus-UNSC-Space.png|An emblem associated with space assets.
File:SLoftus-UNSC-Sword Wings.png|A post-war UNSC insignia possibly associated with the [[Spartan Operations|Spartan branch]].
File:H4FUD_UNSCLogo_Alt.jpg|An alternate, slimmer, version of the UNSC logo utilised in 2526 at the Corbulo Academy of Military Science.
File:Infinite Recruitment Poster.jpg|UNSC poster from [[2560]].
</gallery>

==List of appearances==
{{Col-begin}}
{{Col-3}}
*''[[Halo: The Fall of Reach]]'' {{1st}}
**''[[Halo: The Fall of Reach#2010 bonus content|Adjunct]]''
*''[[Halo: Combat Evolved]]''
*''[[Halo: The Flood]]''
**''[[Halo: The Flood#2010 bonus content|Adjunct]]''
*''[[Halo: First Strike]]''
**''[[Halo: First Strike#2010 bonus content|Adjunct]]''
**''[[Petra]]''
**''[[Tug o' War]]''
*''[[i love bees]]''
*''[[Halo 2]]''
**''[[Conversations from the Universe]]''
*''[[Halo Graphic Novel]]''
**''[[Armor Testing]]''
**''[[Breaking Quarantine]]''
**''[[Halo Graphic Novel, Page 122|Page 122]]''
**''[[Second Sunrise Over New Mombasa]]''
**''[[The Last Voyage of the Infinite Succor]]''
*''[[Halo: Ghosts of Onyx]]''
*''[[Starry Night]]''
*''[[Believe]]''
**''[[Diorama]]'' 
**''[[Enemy Weapon]]'' 
**''[[Gravesite]]'' 
**''[[Hunted]]'' 
**''[[Museum]]'' 
*''[[Halo: Landfall]]''
**''[[Halo: Arms Race]]''
**''[[Halo: Combat]]''
**''[[Halo: Last One Standing]]''
*''[[Halo: Uprising]]''
*''[[Halo 3]]''
*''[[Halo: Contact Harvest]]''
*''[[Halo: The Cole Protocol]]''
*''[[Halo Wars: Genesis]]''
*''[[Halo Wars]]''
*''[[Halo: Helljumper]]''
*''[[The Life]]''
*''[[Halo 3: ODST]]''
**''[[Sadie's Story]]''
*''[[Halo Legends]]''
**''[[Homecoming]]''
**''[[Origins]]''
**''[[Prototype]]''
**''[[The Babysitter]]''
**''[[The Package (animated short)|The Package]]''
*''[[Halo: Evolutions - Essential Tales of the Halo Universe]]''
**''[[Blunt Instruments]]''
**''[[Dirt]]''
**''[[From the Office of Dr. William Arthur Iqbal]]''
**''[[Headhunters (short story)|Headhunters]]''
**''[[Human Weakness]]''
**''[[Midnight in the Heart of Midlothian]]''
**''[[Palace Hotel]]''
**''[[Pariah]]''
**''[[Stomping on the Heels of a Fuss]]''
**''[[The Mona Lisa]]''
**''[[The Impossible Life and the Possible Death of Preston J. Cole]]''
**''[[The Return]]''
*''[[Halo: Blood Line]]''
*''[[Remember Reach]]''
**''[[Birth of a Spartan]]''
**''[[Patrol]]''
**''[[Deliver Hope]]''
{{Col-3}}
*''[[Halo: Reach]]''
**''[[Data pads]]'' {{Im}}
**''[[Dr. Halsey's personal journal]]''
*''[[Halo: Fall of Reach]]''
**''[[Halo: Fall of Reach - Boot Camp|Boot Camp]]''
**''[[Halo: Fall of Reach - Covenant|Covenant]]''
**''[[Halo: Fall of Reach - Invasion|Invasion]]''
*''[[Halo: Cryptum]]''
*''[[Halo: Glasslands]]''
*''[[Halo Living Monument]]''
*''[[Halo: Combat Evolved Anniversary]]''
**''[[Terminal (Halo: Combat Evolved Anniversary)|Terminals]]''
*''[[Halo: Primordium]]''
*''[[The Commissioning]]''
*''[[Halo: The Thursday War]]''
*''[[Halo 4: Forward Unto Dawn]]''
*''[[Scanned]]''
*''[[Halo 4]]''
**''[[Spartan Ops]]''
**''[[Infinity Briefing Packet]]''
*''[[Halo: Silentium]]''
*''[[Halo: Spartan Assault]]''
*''[[Halo: Initiation]]''
*''[[Halo: Escalation]]''
*''[[Halo: Mortal Dictata]]''
*''[[Halo: Nightfall]]''
*''[[Halo 2: Anniversary]]''
**''[[Terminal (Halo 2: Anniversary)|Terminals]]''
*''[[Halo: New Blood]]''
*''[[Hunt the Truth]]''
**''[[All Hail]]''
**''[[The Cost]]''
**''[[Hunt the Signal]]''
**''[[A Hero Falls]]''
**''[[The Hunt Begins]]''
*''[[Halo: Spartan Strike]]''
*''[[Halo: Hunters in the Dark]]''
*''[[Halo: Fleet Battles]]''
*''[[Halo: Last Light]]''
*''[[Halo: The Fall of Reach - The Animated Series]]''
*''[[Halo 5: Guardians]]''
**''[[Halo 5: Guardians Limited Edition dossiers|Limited Edition dossiers]]''
*''[[Know Your Enemy]]''
*''[[Halo: Ground Command]]''
*''[[Halo Mythos]]''
*''[[Halo: Fractures]]''
**''[[Lessons Learned]]''
**''[[Breaking Strain]]''
**''[[A Necessary Truth]]''
**''[[The Ballad of Hamish Beamish]]''
**''[[Into the Fire]]'' {{Mo}}
**''[[Rossbach's World (story)|Rossbach's World]]''
**''[[Anarosa]]''
*''[[Halo: Tales from Slipspace]]''
**''[[Something Has Happened]]''
**''[[Fireteam Majestic Poker Night]]''
**''[[On the Brink]]''
**''[[Knight Takes Bishop]]''
{{Col-3}}
*''[[Halo: Smoke and Shadow]]''
*''[[Halo Wars 2]]''
*''[[Halo: Envoy]]''
*''[[Halo: Rise of Atriox]]''
*''[[Halo: Recruit]]'' {{C|Non-canonical appearance}}
*''[[Halo: Retribution]]''
*''[[Halo: Legacy of Onyx]]''
*''[[Halo: Collateral Damage]]''
*''[[Halo: Silent Storm]]''
*''[[Halo: Fireteam Raven]]''
*''[[Halo: Bad Blood]]''
*''[[Halo: Official Spartan Field Manual]]''
*''[[Halo: Battle Born]]''
*''[[Halo: Lone Wolf]]''
*''[[Halo: Renegades]]'' 
*''[[Halo: Outpost Discovery]]''
*''[[Halo: Oblivion]]''
*''[[Halo: Meridian Divide]]
*''[[Halo: Shadows of Reach]]''
**''[[Sacrifice]]'' {{Im}}
*''[[Halo: Point of Light]]''
*''[[Halo: Divine Wind]]''
*''[[Halo Infinite]]''
*''[[Halo: The Television Series]]''
*''[[Halo: The Rubicon Protocol]]''
*''[[Halo: Outcasts]]''
*''[[Halo: Sunrise on Sanghelios]]''
*''[[Halo: Saturn Devouring His Son]]''
*''[[Halo: Battle for the Blood-Moon]]''
*''[[Halo: Trial of Reckoning]]''
*''[[Halo: Hippocratica]]''
*''[[Halo: Flashpoint]]''
{{Col-end}}

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

==See also==
*[[UNSC rank structure]]

{{United Nations Space Command}}
{{Organizations}}

[[Category:United Nations Space Command| ]]
[[Category:Unified Earth Government]]