The SPARTAN Programs are a series of UNSC projects designed to create generations of physically, genetically, technologically, and mentally superior "supersoldiers" as a special fighting force within the UNSC Military.
The basic concept of the SPARTAN program has been around since the late 22nd century when the first bioengineering protocols were developed for interplanetary war. Since the establishment of these protocols humans have been using performance enhancing equipment and augmentations to make them stronger and faster than previously thought possible. These super soldiers have been deployed numerous times throughout human conflict, leading up to and during the Human-Covenant war. The SPARTAN program first arose as a brilliant plan to enhance normal human soldiers into powerfully augmented special operations commandos. Initially the three separate programs were humanity's various attempts to create the perfect soldiers, in order to patrol the colonies, protect civilian and government populations, crush uprisings in their infancy and ensure others didn't rise up as a result.
The SPARTAN soldiers of the UNSC are named after the ancient Spartans of Greece, specifically during the famous Battle of Thermopylae. Catherine Halsey had three reasons to choose SPARTAN, rather than many other suggested code names. She believed the story of Thermopylae continued to be well-known and cherished throughout the 26th century. Coincidentally, the project was originally funded for 300 applicants. The Spartans' fierce reputation resulted from their legendary training, which began at the age of 6. Dr. Halsey planned to recreate a training system similar to the Spartans' in order to create the ultimate warrior. Spartan culture was based primarily on warfare, destroying newborns unable to meet strength and fitness requirements. Although considered barbaric during the modern era, Dr. Halsey arranged similar demands.
The precursor to the SPARTAN program began on April 13, 2321 with the activation of the ORION Project. Launched by the Office of Naval Intelligence, the project was named after the Orion Arm of the Milky Way galaxy. The aim of the ORION project was to increase the effectiveness of the Colonial Military Authority's soldiers in charge of colonial security. The project failed due to poor results and lack of funds and the five test subjects were reintegrated into active duty, but would die within the year from undisclosed causes.
The Relaunch of ORION
On January 29, 2491 the Colonial Military Administration in conjunction with the Office of Naval Intelligence relaunches ORION in secret, the new goal of ORION is to learn from the mistakes of the previous attempt and, using advancements in bioengineering technology, create a genetically enhanced and mechanically augmented super-soldier - and to deploy these soldiers behind enemy lines where they would quell insurgences in their infancy, or neutralize established insurgences by destroying their chain of command. The Project is headquartered in one of the many orbital docks on Reach, the candidates are, once again, selected volunteers from all Special Force branches of the military. This iteration of the project uses more advanced indoctrination and biological augmentation techniques - 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 the Secessionist Union who executed a series of attacks on Eridanus II, which resulted in numerous deaths and kidnappings of civilian and government officials in 2494 - this marked the first operational deployment of the ORION soldiers. They 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 which proved to be very helpful to ONI's propaganda efforts in the coming decades. Though the Orion super-soldiers were effective; their abilities fell short of the scientists' hopes, and they cost far too much to develop and field - and the fact that during Operation: VERITAS it was revealed that the Colonial Military Administration had been infiltrated by the Secessionist Union, resulting in the shutdown of the CMA and the cancelling of the Orion project with the 165 surviving Orion super-soldiers returning to active duty. 
The SPARTAN-II Project
In the years following the deactivation of the ORION Project in 2506 the reduced effectiveness of small special forces combating the insurrectionists becomes a serious concern for the UNSC. As the Insurrectionist attacks become more effective and the military's responses heavier; the need for a large-scale military engagement becomes ever-more apparent. The SPARTAN-II project is conceived by Dr. Catherine Halsey of ONI's Section 3 as the successor to the original ORION project and the best possible solution to end the conflict with the Insurrectionists. In 2517 the project begins, although viewed as unethical and marred by controversy, the program produces excellent results - SPARTAN-II soldiers proved to be the most effective weapon in the battle against insurgents. At the outbreak of the Human-Covenant war in 2525 the SPARTAN-IIs are outfitted with the most advanced mechanized armor in human history to help better defend against the alien menace. While the war with the Covenant Empire continues to progress, leaving the insurrection effectively cut off, the SPARTAN-IIs continue to engage Insurrectionist factions who remain significant enough a threat to require SPARTAN-II activity. The SPARTAN-IIs continued to perform their missions effectively, successfully killing off Rebel leaders, and engaging Covenant forces - continuing a seemingly endless series of battles both in the ongoing war against the Covenant, and in the interests of the UNSC.
The SPARTAN-III Program
As the Human-Covenant war progresses and casualties mount exponentially, ONI activates another program that is even more morally questionable than the SPARTAN-II program. Spearheaded by a prominent opposition to Halsey's SPARTAN-II program, Colonel James Ackerson, establishes the SPARTAN-III Program using the previous program as a proof of concept. Designed to be produced more quickly, at a lower cost, and with a lower life expectancy, the SPARTAN-III program is intended for extremely high risk operations conducted in the highest level of secrecy. The SPARTAN-III candidates are once again children, this time taken from orphanages as a result of the loss of their home and family from the Covenant invasion - the S-III candidates are taken to the planet Onyx and are under the leadership of Lieutenant Commander Kurt Ambrose. Throughout the Human-Covenant war three companies of SPARTAN-IIIs are trained, deployed and killed. The first company of S-IIIs Alpha Company is successful in destroying Covenant and Rebel forces during the battles of Mamore, New Constantinople and in the Bonanza Asteroid Belt - their last mission Operation: PROMETHEUS in 2537 is deemed a success, however all of the Spartans of Alpha Company are killed in action. The second company Beta Company, trained soon after the loss of Alpha Company, carried out their first mission Operation: TORPEDO in 2545 which was also also deemed a success, although only two SPARTAN-IIIs, Tom-B292 and Lucy-B091 survive out of the 300 that take part in the operation. Tom and Lucy become trainers for the third company of S-IIIs Gamma Company, the third company of SPARTAN-IIIs complete their augmentation and many are deployed on missions elsewhere during the final years of the war when the Shield World on Onyx is activated. Several teams of SPARTAN-IIIs survived the Battle of Onyx and were trapped in the Shield World with SPARTAN-II Blue Team.
The SPARTAN-IV Program
The SPARTAN-IV Program was initiated by Admiral Parangosky in September 20, 2552 Instead of kidnapping young children to serve as SPARTANs, the IVs are volunteers from different branches of the military. A number of SPARTAN-IVs are stationed onboard UNSC Infinity. The SPARTAN-IVs are a separate branch within the UNSC Defense Force.
- Main article: ORION Project
The ORION project or the SPARTAN-I program is first phase of the SPARTAN program. Initiated in January 29, 2491, as an element of the ORION project. The original Spartan project is created to test genetic enhancements on volunteers from the armed forces. Despite a high mortality rate, the ORION project is successful enough to warrant the development of the SPARTAN-II program.
- Main article: SPARTAN-II Program
The SPARTAN-II Program is the continuing effort to produce super-soldiers and is notable for being the first of the programs to mix an Advanced Powered Exoskeleton System with the subjects' superior physiques. The SPARTAN-IIs are heavily engaged in the Human-Covenant war. Since the end of the Human-Covenant war, survivors of this group include Linda-058, Kelly-087, Frederic-104, and John-117 who are still active, while other surviving SPARTANs are either MIA, such as the members of Red Team, or their whereabouts unknown, such as the members of Gray Team. The SPARTAN-II Program's official symbol is an eagle posed with its talons forward ready to strike, holding a lightning bolt in its left talon and arrows in its right.
- Main article: SPARTAN-III Program
Outfitted and engineered by James Ackerson and the Office of Naval Intelligence, the SPARTAN-III program is the next generation of Spartan super soldiers, perfecting and rectifying all that the SPARTAN-II program could not. They are more numerous, better trained, cheaper, and more expendable.
- Main article: SPARTAN-IV Program
The SPARTAN-IV Program was initiated by Admiral Margaret Parangosky after the Human-Covenant war. Instead of kidnapping young children to serve as SPARTANs, the IVs are volunteers from different branches of the military. Some are stationed near the UNSC Infinity in the Oort Cloud. When the Infinity was commissioned a contingent of Spartan-IVs were stationed onboard participating in many engagements.
- The United Nations Space Command, in order to keep morale high, enforced the unreal concept that SPARTANs can't be killed. This is why all deceased SPARTANs are listed as MIA, or WIA.
- Several code names were suggested by Dr. Halsey to replace "Generation-II Orion." Those names included Titans, Argonauts, Odysseus, Olympians, Zulu, Kronos, Promethean, Armor, Nemesis, Daedalus, Viking, Hercules, Hyperion, Praetorians, Landsknecht, Immortals, Minutemen and eventually SPARTAN.
- Both SPARTAN and Program are seven letter words. This is a possible 7 reference.