SPARTAN-IV program

"There won't be any program; not like the Spartan-Twos, anyway or the Spartan-Threes, if I can help it. We're back to using consenting adults now, like we did in Project Orion."

- Margaret Parangosky

The SPARTAN-IV Program is the fourth iteration of the SPARTAN supersoldier program. Like the original ORION Project, the SPARTAN-IV Program utilizes consenting adult volunteers selected from the other branches of the UNSC Defense Force, in contrast to the previous two programs which used children as candidates. Recruits are drawn from both career military veterans and young soldiers who show considerable promise. The SPARTAN-IVs serve in the wholly new Spartan branch of the Defense Force.

Background
Commissioned as a result of the success of the preceding SPARTAN-II and SPARTAN-III projects, the SPARTAN-IV Program was originally conceived by Commander Musa-096, a former SPARTAN-II candidate who was crippled by the augmentation process. Despite his grudge toward Dr. Catherine Halsey and ONI, Musa recognized the crucial role of the Spartans in defending humanity and the continued importance of the supersoldiers in the aftermath of the Human-Covenant War. The proposal was approved by Admiral Margaret Parangosky, the former Commander-in-Chief of the Office of Naval Intelligence and the new program was initiated under her orders. Parangosky initially planned to have SPARTAN-III lead Colonel James Ackerson heading the program, with SPARTAN-II project lead Dr. Catherine Halsey to be reassigned as Ackerson's subordinate. Ackerson was killed following the Battle of Mare Erythraeum and Halsey was arrested after returning from Onyx, though ONI continued the program without the two, with the help of Musa and Jun-A266, a former SPARTAN-III Alpha Company member.

In addition to the significant numbers of adult volunteers which make up the majority of the SPARTAN-IVs, the SPARTAN-IIs and SPARTAN-IIIs who survived the Human-Covenant War were offered to be integrated into the SPARTAN-IV Program. Some of the SPARTAN-IVs were already active by early 2553. Many of the SPARTAN-IVs are assigned to the, the most powerful warship ever constructed by mankind. They train with one another in simulations known as "War Games" on the Infinity 's state-of-the art combat deck (a training chamber that is capable of replicating environments), in order to constantly stay battle-ready.

The SPARTAN-IVs serve in a dedicated branch of the UNSCDF known simply as "Spartan", whereas their forebears operated within other chains of command. Unlike their predecessors, the SPARTAN-IVs are identified by their surnames rather than numeric tags (due to their volunteered enlistment rather than kidnapping/conscription). Unusually, the SPARTAN-IVs have shown a great deal of solidarity, especially impressive given the short time they have served together. Many of them have adopted colloquialisms first used by the SPARTAN-IIs, such as "Alpha Bravo" for "Alien Bastard". Psychologists assert that this camaraderie and cohesiveness will help distinguish the SPARTAN-IVs, and the Spartan branch as a whole, from the other UNSCDF branches.

List of Spartan-IV units

 * Unknown
 * Edward Davis KIA
 * Gamma Company
 * Jun-A266
 * Several SPARTAN-IV killed by Gek 'Lhar
 * Joel Thomas
 * Vladimir Scruggs
 * Yeong-hao Holst

MJOLNIR Armor
SPARTAN-IVs are equipped with the MJOLNIR [GEN2], the second-generation version of the MJOLNIR Powered Assault Armor. The standard-issue armor set for Spartan-IVs, at least those serving aboard UNSC Infinity, appears to be the Recruit variant, colored gray and orange. However, Spartans are capable of customizing their individual armor set with modular components from a wide range of special-purpose variants, based on their personal preferences, specialization and mission requirements. Unlike the largely uniform green coloration of the SPARTAN-IIs' first-generation MJOLNIR armor, SPARTAN-IV armor comes in a profusion of distinct color patterns, with the members of specific teams often sporting a consistent coloration.

Augmentation procedures
Like the augmentations performed for the SPARTAN-IIs and the improved procedures utilized in the subsequent SPARTAN-III Program, the SPARTAN-IVs underwent a series of procedures to enhance their physical capabilities and to wear MJOLNIR armor. The augmentation procedure surgeries took three weeks to perform. Their bones were impregnated with a substance that made them nearly unbreakable. Their muscles were coated in a substance that allows them to work harder without breaking their skeleton. They were also given corneal implants that made it easier to see in the dark. Their hearts were enhanced to the point that they could "outrun a horse". Their lungs were lined with a polymer that enhances oxygen intake and allows them to process toxins or foreign gas mixtures; for example, they are capable of breathing methane for around an hour. The bacteria in their intestines were altered to help them get more nutrients out of the food they eat. Their pancreas' were replaced by a completely new, vat-grown organ. They also had their blood altered to allow for faster clotting. Lastly they were given several implants to help med teams keep tabs on them.

List of appearances

 * Halo: Glasslands
 * Halo: The Thursday War
 * Halo 4
 * Spartan Ops
 * Halo: Spartan Assault
 * Halo: Initiation
 * Halo: Escalation