The UNSC is the totality of the combined military powers of humanity in the Halo universe. In the games, we don't ever really go into the details of how the UNSC runs or is organized, and if we ever do get an inside look, it is usually something relating to the various iterations of the Spartan Program.
If one does decide to look into the details of the UNSC, it's actually pretty interesting. That's why we've put together a list of ten facts about them that any fan of Halo should know.
10 History Linked To World War I
The UNSC isn't just completely pulled out of nowhere in the world of Halo lore they actually follow a natural timeline that happened in real life. The very beginnings of the UNSC start all the way back after the end of World War I with the start of the League Of Nations, which would act in a fashion similar to that of the United Nations briefly before being shut down. This lead to the creation of the actual UN which the UNSC is a division of.
9 Galactic Colonization
In the Halo universe, space travel technology was much further along than in our timeline. In 2021 there were already colonization operations that could go underway but just required international support. Eventually due to some, what we will just call political shenanigans many countries differed power to the UN. With this sudden shift in power and focus, humanity was able to begin to colonize the solar system by the mid 21st century.
8 Creation Of The UNSC
Just because most countries and political bodies had given a large amount of power and authority to the UN, that doesn't mean that there was no more political tension between nations. This lead to many uprisings throughout the solar system by various groups.
This lead to many conflicts throughout the solar system that the UN was unprepared and unorganized for, leading to the creation of the United Nations Space Command to represent the overall military power of the UN and humanity as a whole.
7 The Insurrection
As humanity traveled outside its own solar system for colonization various planets, it became obvious where most of the resources and attention went. Colonies known as the outer colonies, which were situation farthest from Earth, felt that they were not receiving the support that they needed, while also giving up a large portion of their resources to the inner colonies. This lead to many uprisings by working-class members of these colonies, being the start of what would be called the insurrectionists.
6 Spartans Were Originally A Police Force
In Halo, we hear a lot about Spartan IIs, Spartan IIIs and Spartan IVs but not so much about the very first generation of Spartans. While it's probably mostly due to them never having dealt with fighting the Covenant, there might be another reason.
The Spartan I project, also known as the ORION Project, were originally created as a military police force originally to help stop the inner colonies' conflicts and later the rebellions of the various insurrectionist factions.
5 First Encounter With Aliens
In the year 2524, a civilian ship of the UNSC suffered a malfunction to its slipspace drive, which forced them to travel in space the old fashioned way. This was terrible timing as shortly after they exited from slipspace this ship encountered a Covenant missionary ship, which then led to a battle, starting the Human-Covenant war. The war initially was fought on the Outer colonies, with the Covenant systematically massacring each and every Outer Colony planet they came to.
4 Age Prevention Technology
If you just played through the Halo games like most players and didn't look into the lore too much past what as given to you, you might not have noticed that certain characters are a lot of older than they look. Remember the Spartan-1/ORION project, yeah we'll Sargent Avery Johnson was one of those original Spartans. On top of that, he is also at the very least 78 years old when he dies in Halo 3, despite appearing at most to be in his late 30s due to the slowed ageing process provided by the Spartan program.
3 BBC Incident
Yes, the UNSC is actually a thing in real life, though definitely not as cool as in the Halo universe. Instead of dealing with cool space adventures, it's the United Nations Security Council. On a story the BBC was covering regarding the real-life version of the UNSC, the BBC accidentally used the UNSC logo from the Halo games during their segment.
2 Original Name
The UNSC was always going the be the name of humanity's combined military power. Originally the working title for the UNSC during the development of Halo: Combat Evolved was the United Nations Space Force or the UNSF. This was later changed to the less-weird sounding UNSC. This is made even funnier in our modern-day and age with some people talking about making a legitimate Space Force.
1 Post War Alliances
After a majority of the Sangheili (the Elites) broke off from the Covenant in an event known as the Great Schism they became allies with the UNSC and became known as the Swords of Sanghelios. The Elites worked with the UNSC up until the end of the Human-Covenant war. After the war the two groups maintained a positive relationship, working together to help rebuild and secure the remaining Halo rings. The Swords of Sanghelios also have some Grunts and Jackals in their ranks.