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Terminal.png This article, United Nations Space Command (StoneGhost), was written by StoneGhost. Please do not edit this fiction without the writer's permission.

UNSC Athena.png
United Nations Space Command
Unit Background

Sydney, Australia, Earth


military branch of the Unified Earth Government

Subordinate Units
Present for Events

Human-Covenant War
Remnant War


The United Nations Space Command was the armed force of the Unified Earth Government, and consisted of the UNSC Navy, UNSC Army, UNSC Marine Corps and UNSC Defence Intelligence. The uniformed services of the UNSC were responsible for defending the territorial integrity of the UEG, maintaining peace and order through armed presence, deterring and dealing with internal and external armed threats and otherwise supporting the UEG. With the exception a long period during the Human-Covenant War, the UNSC was civilian-controlled, and acted to further aims dictated by civilian governance in areas such as foreign policy. This was handled by the civilian Ministry of Defence, headed by the Secretary of Defence, although ultimate authority lay with the UEG President. Military command was the responsibility of the Joint Chiefs of Staff, headed by the Chief of the Defence Staff, the professional head of the armed forces.

The UNSC was formed in 2163 as a fusion of most of the worlds' leading military forces. This was a result of the tumultuous Interplanetary War, which caused the merging of most Earth governments out of sheer necessity. The combined forces of the UNSC ultimately triumphed over Communist and Fascist forces on Earth and throughout the Sol system, and in the post-war years its stabilising presence overcame the difficulties of expanding and entrenching a global, unified government. In the following decades, the UNSC swelled in manpower and fighting strength in the midst of a general economic and colonisation boom within the Sol system, but also an increase in fringe lawlessness.

Following the proliferation of faster-than-light propulsion technology, the UNSC found itself increasingly stretched in attempting to police newly colonised, sparsely populated and often remote regions. A new sub-command, the Colonial Military Administration, was established to deal with these remote areas. Over time, animosity festered between outer colonists, who felt a strong affinity with an increasingly independent CMA, and inner colony civilians, who aligned with the UNSC, whose large presence reassured them against perceived threats. This was compounded by social and economic inequalities between the inner and outer colonies, caused by an unequal distribution of economic sectors, trade, infrastructure and wealth. The turn of the century marked a time of dramatic increases in civilian uprising against UNSC rule, and terrorist atrocities committed under the banner of colonial independence from Earth. This was the start of a wider insurrection that would consume the UNSC's attention until the sudden emergence of a far greater, far more terrifying threat on Harvest in 2525.

With the outbreak of the Great War, the UNSC's priorities and threats changed literally with a single incident, and combating the insurrectionists took a secondary role. During this time, all Humanity was threatened with annihilation by the genocidal Covenant Empire. In response, the UNSC progressively assumed more emergency powers, eventually making it the de facto governing body of most of Humanity. This was necessary to for the economy to be refocused entirely on the war effort, and to allow colonies, resources and populations to be managed for a state of total war. Most historians agree this was a key factor in extending the Human race's long campaign for survival. Many of these emergency powers remained in effect until the latter stages of the Remnant War, after which time increasing public pressure saw day-to-day governance fully return to the Unified Earth Government.


Interplanetary War

Birth of the Insurrection

Following the proliferation of FTL (faster-than-light) propulsion technology, the UNSC found itself increasingly stretched in attempting to police newly colonised, sparsely populated and often remote regions. A new command, the Colonial Military Administration, was established to deal with these remote areas. Humanity continued to grow outwards during this time, with the CMA assisting colonists on new worlds and protecting them from lawlessness and piracy, gaining the respect of frontier colonists and counting them among most of its recruits. At the same time, the central UNSC commands began to usurp CMA juristiction in an attempt to expand their area of influence to the inner colonies. Under CMA administration, the newly formed outer colonies became increasingly rebellious. While the UNSC at large became to be seen as protectors of the core (and, by the outer colonies, a distant and authoritarian military force), the CMA became increasingly associated with defending the interests of frontier colonists. Sporadic insurgencies throughout several middle colonies in the 2400s brought tensions to a head, as the UNSC perceiving the Colonial Military Administration's response as ineffectual, at least in part deliberately so. By 2472, the CMA could not account for 30% of its minor vessels and personnel at any one time, pointing to the vast emptiness of its territory and difficulty of communications at the edge of Human space. This internal schism between the CMA and the rest of the UNSC, and the associated links between disgruntled frontier colonists and inner colonists fearing for their security, is cited as a core long term cause of the insurrection.

From the end of the 2400s onwards, the UNSC was increasingly preoccupied with combating low level insurgency in the outlying systems, with the disorder threatening to spread to the inner colonies, and on some outer worlds escalating as far as full scale revolt. Towards the end of the 2400s, UNSC encroachment on CMA operating juristiction became increasingly overt, as evidence mounted that portions of the latter held sympathy for organisations opposed to Earth-based government rule. Animosity between the UNSC and citizens of the outer colonies had escalated to armed insurrection, and the UNSC's almost fervent desire to dissolve the CMA (which it believed correctly to hold rebel sympathies) and combat the uprisings itself contributed enormously to the outer colonists' pro-CMA, anti-UNSC sentiment. In 2497, it became publically known that dozens of mid-ranking CMA officers were diverting military hardware to terrorist organisations. Now with grounds to override the CMA's charter, and UEG support, the CMA was gradually bled of manpower, resources and jurisdiction, although siphoning of weapons and ships to insurrectionists continued apace. The UNSC's primary focus became enforcing UEG rule in far-flung regions, countering a diverse group of foes across a wide range of environments. The insurrectionists hid among the very people the UNSC tried to protect, and carried out both conventional and unconventional warfare tactics, presenting the UNSC with enormous challenges.

Human-Covenant War

Remnant War

Relinquishing power

"Without the restructuring of the United Nations Space Command between 2525 and today, Humanity likely would not have weathered the last forty years. But the fact remains: as it stands, the UEG isn't a state with a military attached- it's the other way around."
―Chief of the Defence Staff, Admiral of the Fleet Sir Terrence Hood, August 2555

Interwar period and Galactic War

Swarm War

Service Branches


UNSC navy.png

The UNSC Navy was the largest UNSC service branch by expenditure, and was responsible for defending UNSC worlds and territories in the vacuum of space, in addition to facilitating expeditionary forces. The Navy comprised the Active Fleet, which numbered approximately 100,000 warships and logistical vessels and roughly 620 million personnel, and the Navy Air Corps, formed of 2.65 million aircraft and 30 million active personnel. This was in addition to the Fleet Auxiliary, which in peace time operated a further 150,000 logistical and support vessels by rotating reserve personnel, and in times of war manned an additional 35,000 armed vessels. The Active fleet consisted of battleships, carriers, cruisers, amphibious assault ships, destroyers, frigates, corvettes, prowlers, and a range of miscellaneous support craft.

The UNSC Navy maintained nine fleets prior to the Great War, although this shrank to just three seriously under-strength formations by 2552, and had swelled again to 16 fleets by 2564. The UNSC Navy maintained a strong presence in the core worlds, having several key installations, ports and ground garrisons on worlds such as Reach and Earth. Regional bases throughout the outer colonies gave the Navy the capability to protect and patrol Human space, as well as conduct exploration and armed deterrence into unclaimed or unknown territory. The Navy maintained some form of presence in every inhabited UNSC system, ranging from a single orbital sensor or defence platform for a low risk world, to a Strike Force's home port for systems at high risk or with multiple inhabited worlds. The Navy's emphasis in the post-Great War period shifted from one solely of defence to a more balanced one focusing both on defensive and expeditionary warfare, with an enhanced amphibious capability said to be among the best in the known galaxy. Consequently, the Navy had a particularly close operational relationship with the UNSC Marine Corps, the UNSC's ground fighting expeditionary force.


UNSC Army (Athena32).png

The UNSC Army was the largest UNSC branch measured by manpower, and was responsible for protecting, defending and supporting UEG colony worlds on the ground and in the air. The UNSC Army maintained a garrison on every Human-populated world, ranging from a small force for a sparsely populated colony to a significant garrison on a high-value world such as Reach. While the Navy was responsible for defence of UNSC colony worlds in orbit, the UNSC Army was charged with terrestrial (ground-based) defence, encompassing ground forces and an atmosphere-based Army Air Corps. The primary doctrinal function of the UNSC Army was to repel and defeat space-borne invasion fleets during and after their landing phase, assuming that such a force had bypassed any UNSC Navy presence. In reality much of the Army's history saw it function as an anti-insurgency force on worlds struggling with unrest or insurrection. This trend would disappear during the Human-Covenant War.

The UNSC Army can trace its history back to 2162, where the newly formed UN Army defeated Frieden and Koslovic forces in South America, although its official formation came with the establishment of the UNSC in 2163. As the UNSC Navy and Marine Corps established themselves in the niche of expeditionary warfare, the Army re-roled as a garrison force able to keep the peace on restless colonies and fend off concentrated attacks from irregular forces. This was a role it continued in throughout the Insurrection, where it faced persistent low-level insurgency on many of the worlds it found itself stationed on. Due to the vast disparity in fighting strength between Humanity and the Covenant, the UNSC's tactics inevitably shifted towards defensive warfare, resulting in the valiant but futile attempt by the Army to defend UNSC worlds from annihilation.

Post-war, the UNSC Army was incrementally built back up to pre-war levels of manpower and equipment, achieving full strength again after the Remnant War. During this time the Army maintained an active strength of just over 1.4 billion personnel and roughly 350 million reserve personnel.

UNSC Marine Corps

UNSC marine corps.png

The UNSC Marine Corps was the UNSC branch responsible for expeditionary warfare and protection of UNSC vessels and orbital facilities. The Marine Corps functioned as the UNSC's primary method of terrestrial power projection, supporting a large and actively maintained amphibious capability facilitated by an extremely close relationship with the Navy. Using the mobility of the Navy, the Marine Corps was tasked with rapidly delivering combined-arms task forces, comprising armour, infantry and artillery and close air support. This role put the Marine Corps at the very forefront of any offensive warfare undertaken by the UNSC, frequently under the challenging conditions resulting from simultaneous orbital and ground fighting, and earned them a well deserved reputation as the UNSC's 'sword'.

UNSC Office of Defence Intelligence

The Office of Defence Intelligence was an intelligence organisation providing military intelligence services within the United Nations Space Command. Defence Intelligence was formed in 2554 as part of a larger reorganisation effort within the UNSC, and combined the Office of Naval Intelligence, Army Intelligence and UNSC Joint Intelligence Bureau into a single military intelligence organisation. Despite this, Defence Intelligence maintained an extremely close working relationship with both non-military intelligence organisations and the military, cooperating closely with both on matters of military and defence intelligence. Defence Intelligence had a dual remit for intelligence, filling both governmental and military requests for analysis and collection of intelligence. While technically under the authority of the civilian government under the Defence Secretary, more than two thirds of its personnel were serving military, leading to it being tasked with objectives more or less equally between the two.


  • United Nations Space Command
        • Joint Chiefs of Staff
        • Personnel Command (PERSCOM)
        • Unified Ground Command (UNICOM)
        • UNSC Astrophysics Division
        • UNSC Medical Corps (MEDCORPS)
        • UNSC Engineering Corps (ENGCORP)
        • UNSC Test and Evaluation Corps
        • UNSC Department of Research and Development
      • UNSC Office of Defence Intelligence
      • UNSC Navy
        • Naval Command
          • Fleet Command
            • First Fleet
            • Second Fleet
            • Third Fleet
            • Fourth Fleet
            • Fifth Fleet
            • Sixth Fleet
            • Seventh Fleet
            • Eighth Fleet
            • Ninth Fleet
            • Tenth Fleet
            • Eleventh Fleet
            • Twelfth Fleet
          • Naval Intelligence Command
            • Naval Intelligence Corps
            • UNSC Prowler Corps
          • Logistical Operations Command
          • Naval Special Warfare Command
      • UNSC Army
      • UNSC Marine Corps

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