ORIGINS:
Launched by ONI, the project was named after the Greek mythological hero Orion.The aim of ORION was to build on bioengineering protocols established two centuries ago and create stronger and better soldiers than any before them.
The initial beginnings of ORION were merely a test to see what could be accomplished with the advancements of that time, and candidates of the ORION project were all volunteers from the armed forces of the military - these handful of candidates went through numerous testing and augmentations throughout the duration of the project. However, the results were far less than expected and eventually the candidates were seeded into the regular chain of command after the project was declared ineffective and terminated.

RELAUNCH:
In 2491, the Colonial Administration Authority relaunched ORION in secrecy, with the new goal of learning from the mistakes of the previous attempt, and creating a soldier unlike anything seen before - and to deploy these soldiers behind enemy lines and quell insurgencies in their infancy, or destroy established insurgencies by destroying their chain of command and expanding outward.

The project was headquartered in one of the many orbital docks on the military hub colony: Reach, and the candidates were, once again, selected volunteers from the UNSC Special Forces. This iteration of the project used more advanced indoctrination and biological augmentation techniques, and after a grueling series of physical and mental tests, the first batch of soldiers, 165 in total, successfully passed and moved on to the next phase. 
In 2496 the UNSC launched Operation: CHARLEMAGNE in response to colonial insurrectionists who executed a series of attacks on an outer colony, which resulted in numerous deaths and the kidnappings of civilian and government officials in 2494. This marked the first operational deployment of the ORION soldiers, who scored a decisive victory and emerged from the battle with only a single casualty. 
The Spartans were able to complete the mission without even being seen, thereby fueling a range of conspiracy theories and media speculation. This proved to be very helpful to ONI's propaganda efforts in the coming decades. Though the Spartans were effective, their abilities fell short of the scientists' hopes, and they cost far too much to develop and field. In 2506, the project was deactivated and the soldiers were reassigned to various special operation units

Spartan-I's... They sound fun.

Approved!

Can't wait for the sequel!

Secondary Approved!