300 at height of program.
- "Spartans pick their battles."
- —James James
The ORION Project was a unit of the UNSC Navy, under the operational control of Naval Special Warfare Group ONE, created to combat the growing insurrection throughout the human Outer Colonies. Shortly following their disbandment and the establishment of the second generation, the ORION Project would be retroactively dubbed as "SPARTAN-I." 
The ORION Project was a Special Operations force in the UNSC. Administratively, the ORION project was under the control of ONI Section III, particularly the Special Projects section of ONI's Beta-5 Division. However the ORION soldiers themselves were under the operational authority of Naval Special Warfare Command/Naval Special Weapons. The ORION Program was an all-volunteer force composed of the best soldiers from the UNSC Marine Corps and Special Forces branches of the military — the ORIONs performed specialized, high-risk operations including: counter-insurgency operations, unconventional warfare, direct action and black operations. The ORION/SPARTAN program was headquartered on one of the many orbital docks on Reach, and at its height the program had 300 active-duty personnel.
The members of the ORION program were biologically augmented soldiers, using new training methods and the latest breakthroughs in biochemical developments. Augmentations to the ORION soldiers included muscular enhancement injections, pulmonary respiratory enhancements, retina-inversion injections and cochlea enhancement tuning. In addition, mental augmentations were performed to enhance brain functions including enhanced learning capabilities to allow a subject to learn at a faster and higher rate and enhanced motor skills to improve body movements. The ORION training regime was very difficult and included many tests both mental and physical, including work done in the lab. All 65 initial volunteers made it through the training and augmentation procedures and were placed on active duty some time after completing their training. After their initial deployment and success, funding for training the next group of SPARTAN-Is was approved, and within a few years the ORION program had 165 active duty personnel.
The beginning of the ORION program dates back to the 23rd century, when the newly formed UNSC began developing bioengineering protocols and experimenting with biochemically altering human soldiers. Although these performance enhancing substances were very primitive and nowhere near as effective as the chemicals used to augment the soldiers of the SPARTAN Programs, they did show promise and gave results and serve as the catalyst for future endeavors. Since then, human soldiers have used performance-enhancing equipment for decades.
 Expansion and conflict
With the formal establishment of the Inner Colonies in 2390, mankind's expansion era had begun, and the next century would be an important boom for Humanity. As mankind expanded, the political and military power that the UEG desired to maintain began to diminish, and sentiments of reform and political independence spread among the colonists. As the Colonies began to separate themselves from Earth, the UNSC took every step necessary to keep its grip on the Outer Colonies that were developing during this time. By the 2400s, Outer and many Inner colonies soon began to question the often-draconian interference of the UEG in what was originally intended to be a confederation of independently governed worlds.
The dream that had swept humanity into new worlds had begun to sour in the minds of its colonies. This inevitably led into open rebellion among the various worlds and soon led to civil war among the populations. Decades before the first colony ship left Earth, the Office of Naval Intelligence initiated the ORION Project, named after the Greek mythological figure Orion.[note 1] The aim of Orion was to build upon bioengineering protocols developed during the Interplanetary Wars of 2163 in order to to generate tougher, faster soldiers. Five military candidates were selected and "tested," the project was declared ineffective and the candidates were seeded into their respective chain of command.
 The relaunch of ORION
As the civil wars began to intensify in the Outer and Inner Colonies, many of the Colonial Military Administration's resources were taken over by the UNSC and ONI. Using data supplied by ONI, along with subtle background manipulation by the Assembly, the CMA relaunched ORION in secrecy in response to insurgent attacks in the colonies. The project began in January of 2491 with sixty-five test subjects, after completing their training an additional one-hundred volunteers were accepted into the new ORION program. The first ORION deployment occurred in January of 2496 as part of Operation: CHARLEMAGNE, during this operation the full unit of ORION soldiers were deployed to recover the sub-orbital transit station over Eridanus II. This marked the only time a full unit of Spartans were ever deployed in the entire program — they completed their mission with only a single casualty and without being seen. The resulting success of CHARLEMAGNE, and tales of the military deploying advanced super-soldiers were born, this became fuel for a range of conspiracy theories and media speculation. As the legend of the super soldiers continued to grow they gave birth to a new round of propaganda efforts by ONI in the coming decades.
 Effectiveness and shortcomings
As the war against the Insurrectionists continued to escalate, the UNSC stepped up their counter-insurgent activities under Operation: TREBUCHET, created in response to the defector UNSC Marine Colonel Robert Watts. The ORIONs became a key member in the fight against the rebel attacks across the colonies, taking down insurgents as soon as they cropped up — however as time went on the insurgent attacks became more effective, and insurgent personnel more difficult to root out, and over the ensuing decades, became more organized and difficult to combat. Bombings continued despite the best efforts of both regular military personnel and the ORION soldiers — civilians became caught in the crossfire of these conflicts and casualties began to mount exponentially, adding to fuel to the simmering hatred harbored against the UNSC by many colonists. This prompted the UNSC to recruit more soldiers to the SPARTAN-I Program, which eventually had around three-hundred active personnel. Though the ORIONs continued to prove their effectiveness, some of the older conscripts began to exhibit flaws, passed off as natural defects or stress from the war. Many ORION candidates exhibited post-traumatic stress disorder or repressed insurgent sympathies; some in the latter category refused to participate in the program post-augmentation and were incarcerated. Despite all of this, the results of the ORIONs' abilities were falling short of the scientists' hopes. However, due to their combat-effectiveness, the UNSCDF decided to use the ORIONs as models for the Orbital Drop Shock Troopers.
 KALEIDOSCOPE and deactivation
In 2502, Operation: KALEIDOSCOPE—part of the UNSC's greater plan to pacify the entirety of Human-colonized space, was put into action. Many ORION supersoldiers were deployed to take down insurrectionist strongholds, but one of the key goals was to eliminate Jerald Mulkey Ander, the leader of another major insurrectionist faction, the Secessionist Union. On March 13th 2502 Ander was assassinated by an ORION operative, Corporal Avery Junior Johnson — with Ander dead, the Secessionist Union fell apart, however Ander's death did not deter those who wished to be free from the control of the UNSC and only strengthened the resolve of the insurrectionist movement in the colonies. Although KALEIDOSCOPE successfully dealt a heavy blow to the insurgents, the overall strategy of KALEIDOSCOPE failed to pacify the colonies. Worse was the fact that some of the older ORION soldiers were beginning to develop severe side effects from their augmentations, that ranged from physical to mental illnesses. Their performance was also continuing to decline in addition to the ineffective strategies the UNSC were using. Operation: TANGLEWOOD would be the last operation the ORIONs participated in, the exact nature of this operation is not known other than it was to combat insurrectionist forces. In 2506 The ORION project was quietly deactivated and the surviving members reassigned to other special operations units in the field. However these soldiers often exhibited side effects as a result of their augmentations and many members were discharged from the military as a result of mental instabilities. In order to ensure absolute secrecy, the side effects caused by the genetic augmentations were masked as a disease known as Boren's Syndrome — many ORION soliders retired and some eventually having children. Due to their augmentations their children must also be given injections to ensure no defects.
- Sergeant Major Avery Junior Johnson  — Served throughout the Insurrection and Human-Covenant War, died on Installation 04B on December 11th, 2552.
- Gunnery Sergeant Gladys Wilson — Retired from the Marine Corps sometime following the Eridanus campaign.
- Gilly — Discharged following the end of the ORION Project. Married James James (formerly Lee) and gave birth to one child, Janissary James.
- James Lee/James — Discharged at the end of the ORION Project, killed in 2552. Married to Gilly, father of Janissary.
- Morales — Discharged following the end of the ORION Project. Father of Kevin.
- ORION candidate 047 — Unknown status
The children of the SPARTAN-Is are sometimes referred to as Spartan 1.1s. There are sixteen Spartan 1.1s, including Janissary James and Kevin Morales. Due to their parents' augmentations, the Spartan 1.1s had to receive injections in order to ensure normal growth without defects. A small vigilante group of SPARTAN 1.1s, seemingly led by Kevin Morales, formed a plan to fight the Covenant. However, before this could come to fruition, the Covenant invasion of Earth began. Their whereabouts following the attack on Earth are unknown.
In the real world, Project Orion was a spacecraft program was the first engineering design study of spacecraft powered by nuclear pulse propulsion. Its supporters felt that it had great potential for space travel, but it lost political approval because of concerns with fallout from its propulsion. The Partial Test Ban Treaty of 1963 is generally acknowledged to have ended the project.
 List of appearances
- Halo: The Fall of Reach (First appearance)
- Halo: Combat Evolved
- Halo: The Flood
- Halo: First Strike
- Halo 2
- Halo Graphic Novel
- Halo 3
- Halo: Contact Harvest
- Halo Wars (Mentioned only)
- Halo 3: ODST
- Halo Legends
- Halo: Reach
- Data pads (Mentioned only)
- Halo: Fall of Reach
- Halo: Glasslands (Mentioned only)
- ^ According to the Halo Encyclopedia (page 44), the project was named after the Orion Arm of the Milky Way galaxy.
- ^ a b c d e f g h Halo Encyclopedia page 81
- ^ Halo: The Flood page 16
- ^ Dr. Halsey's personal journal
- ^ Halo Encyclopedia page 80
- ^ a b Halo Encyclopedia page 44
- ^ cochlear_tuning Axon
- ^ a b c Halo Encyclopedia page 44
- ^ a b c Halo Encyclopedia page 43
- ^ Dr. Halsey's personal journal, June 19, 2513
- ^ Halo: Reach, Data pad 5
- ^ say_please Axon
- ^ a b Halo Encyclopedia, page 45
- ^ Dr. Halsey's Personal Journal
- ^ Data pad 11
- ^ a b Halo Graphic Novel page 122
- ^ a b Miracles Axon
- ^ dream_child Axon
- ^ Halo: Contact Harvest page 47
- ^ Axon Clips Chapter 8 The Funeral (Janissary)
- ^ Enter Kevin Axon Clips Chapter 12