The United Nations Space Command (commonly abbreviated as UNSC) is a fictional organization in the Halo series of games and novels.

The UNSC is the military wing of Earth's United Nations government that is governed by the High Command and is headquartered on Reach (until 2552) and Sydney, Australia, Earth. The UNSC is tasked with enforcing law and order (including suppressing rebel insurrections), and protecting the Inner and Outer Colonies through the Colonial Military Administration.

The UNSC is currently involved in a 30 year war with the technologically superior Covenant. Recently, the Covenant civil war allowed the UNSC to form an uneasy truce with the Separatist forces led by Covenant Elites including the Arbiter.

Military units and divisions

• Marines are the most commonly encountered trooper in the UNSC. They are used in a range of activities from defending installations and ships, to actively engaging enemy forces. It is unknown whether or not there is a UNSC Army.

• Orbital Drop Shock Troopers, also known as the "Helljumpers", are elite special forces of the Marines that can be deployed into a combat zone by low-orbit drop.

• Office of Naval Intelligence (ONI) is responsible for gathering, interpreting, and disseminating information gathered by UNSC forces. In addition, it maintains many top secret projects, such as the SPARTAN II project.

Technology

Despite the fact that the Halo universe is in the 26th century, human technology is largely unchanged. However, mankind has reached the stars and created a modern interstellar empire, made only possible with space crafts and Shaw-Fujikawa slipstream drives, which allow quick travel over extremely long distances, although the accuracy of the system is still rough.

A jump in technology was made once the Covenant became a major threat to the survival of humanity. Like the Covenant with the Forerunner, the UNSC has managed to procure Covenant technology and apply it. Unlike the Covenant, human scientists are able to innovate from this advanced technology and do more than merely copy weaponry. Much of the SPARTAN II Project's technological area, which includes the development of the MJOLNIR MK5 battle armor and its shielding system, is largely derived from Covenant technology.

The SPARTAN Projects

The SPARTAN projects was conceived as a project to create a new generation of "super-soldiers" that would be able to be sent into any outer-colony which rebelled. In the first SPARTAN project, volunteers with military backgrounds where accepted but the results left much to be desired, mostly in psychological conditioning and performance. With the SPARTAN-II project, children throughout the colonies were genetically tested, and the children who tested positive for all the genetic markers were visited by the UNSC to narrow down the number, as there were only enough resources for about half as many children as were genetically suitable. The children who made it into the project were chosen by a coin-flip.

After the children were selected, they were kidnapped and replaced with quickly grown clones so that nobody would discover their abductions, and taken to the military stronghold of Reach, where they would be trained to be the ultimate soldiers. When they were old enough, they were surgically modified to be stronger, faster, smarter, have faster reflexes and better eyesight. Those that survived the procedures went on to become SPARTAN-II soldiers. While the feature most associated with the SPARTAN-IIs is the MJOLNIR combat armor, their first mission was done without use of any form of it, and later missions done only with a stripped down version. It wasn't until the Covenant assaulted Reach that they were given the full MJOLNIR, which until that point was still in research.

Weapons

See the main article on List of weapons in the Halo universe.

Vehicles

For more information see: UNSC vehicles

Vessels

The UNSC fleet has been decimated by 30 years of war with the Covenant, but the shipyards continue to produce vessels to defend humanity. Below is a list of known UNSC ships.

• Trafalgar, a supercarrier.
• Pillar of Autumn, a Halcyon-class cruiser. See the main article on Pillar of Autumn.
• Leviathan, a Marathon-class cruiser.
• Iroquois, a destroyer, an unseen Covenant tracking device on that ship led to the Fall of Reach.
• In Amber Clad (FFG-142), a frigate captained by Miranda Keyes and involved in the Battle of New Mombasa. Abandoned at Delta Halo and subsequently captured by The Flood and crashed into High Charity.
• Circumference, an ONI stealth-ship; prowler.
• Commonwealth, a frigate.
• Gettysburg, a destroyer.