Project CHRYSANTHEMUM

Project CHRYSANTHEMUM was the codename given to the biological augmentation procedures performed on the Spartan-III supersoldiers. They represented a significant improvement over the augmentations used in the previous SPARTAN-II program, being safer and less invasive to perform while producing similar results.

Background
The CHRYSANTHEMUM bioaugmentation set improved upon the augmentations of the SPARTAN-II program, pioneered by Dr. Catherine Halsey. With advances in technology, the casualty rate for Spartan-III candidates was usually 0%, as opposed to the 56% casualty rate of the Spartan-IIs. Most of the Spartan-IIIs' augmentations were chemically induced instead of surgically implanted like many of the Spartan-II enhancements.

The genetic requirements for the Spartan-III candidates were loosened from the exceedingly strict criteria of the SPARTAN-II program, although the range of compatible individuals still remained incredibly narrow, with any aberrations from the required genetic set geometrically increasing the failure rate. Colonel James Ackerson, the mastermind of the SPARTAN-III program, requested to have mandatory genetic screening put in place in the Outer Colonies in order to find more genetic matches for his program, but the Office of Naval Intelligence leadership felt this would only provoke the colonists for further aggression against the UNSC. As a result of the more lenient selection criteria, the Spartan-III candidate pool was less physically and psychologically consistent, with a higher likelihood of behavioral problems; many of the Spartan-III candidates were more lively and predisposed for aggression than their forebears. In contrast to the Spartan-IIs who were consistently taller than the average human, the Spartan-III candidates were also less uniform in terms of physical stature.

While the CHRYSANTHEMUM augmentations still had to be administered at the onset of puberty as the bodies of either prepubescents or adults would reject the chemicals, Colonel Ackerson's age restriction protocol for the SPARTAN-III program was considerably looser than that of the Spartan-IIs. The Spartan-III candidates' ages upon induction typically ranged from four to six years old, with the nominal ages of some of them (such as Carter-A259) exhibiting more extreme deviation from the standard age range. The schedule of the SPARTAN-III program was also accelerated from that of the Spartan-IIs; because the Office of Naval Intelligence wanted to have the Spartans deployed in the field as rapidly as possible, the candidates were augmented at an average age of twelve, whereas the Spartan-IIs were fourteen during their augmentations. As puberty had not yet started for the majority of candidates at this time, they were given human growth hormone as well as cartilage, muscle and bone supplements added into their food over several months to artificially induce the onset of puberty. As a result, the candidates had the bodies of near-adult Olympic athletes at an average of only twelve years of age, and it took some time for them to acclimatize to their larger physiques.

All Spartan-IIIs
In addition to their chemically-administered primary augmentations, Spartan-IIIs were subjected to a number of surgical alterations to enhance their capabilities. Their circulatory systems were also augmented from the human baseline.

Gamma Company
In addition to the standard set of chemicals, Kurt Ambrose covertly had a set of three additional drugs added to the augmentations of Gamma Company in hopes of increasing their survivability in the field. All of the three had been outlawed by the UNSC Medical Corps in 2513.

Procedure
The CHRYSANTHEMUM procedures took place aboard the mobile hospital ship. Because of the SPARTAN-III program's secrecy, the Hopeful was stationed in interstellar space at Vice Admiral Parangosky's order for the duration of the procedures. The ship's docking cluster Bravo and the eight decks surrounding it were entirely cleared of personnel to allow ONI to move in their personnel and equipment.

The augmentations were administered over the course of a week; the subject was kept in a mostly sedated state throughout the process, which was conducted in a large, open operations room housing 400 sections separated by semi-opaque plastic curtains. Each compartment was filled with medical equipment, including a sterile field generator overhead as well as vital signs monitors and a chemotherapeutic infuser. The infuser contained vials for the various chemicals, which were administered to the subject via IV and osmotic patches. The Spartans were given a number of drugs to allow them to withstand the procedures themselves and counter their potential negative effects; these included shock reducers, analgesics, anti-inflammatories, anticoagulants, and pH buffers.

Performance
Despite the Spartan-IIIs' expendable nature and lower-grade equipment than the Spartan-IIs, their enhancements represented a "quantum leap" over the previous program's bioaugmentation set. While most Spartan-IIIs were issued with SPI armor as opposed to MJOLNIR for budgetary reasons, a small number of Spartan-III candidates — called "cat 2s" by Kurt Ambrose — were removed from their mainline companies, given MJOLNIR armor and assigned to separate special forces units. Selected from the general population of the program by Ambrose and Franklin Mendez on the basis of their exceptional skill and performance,  these Spartan-IIIs were considered to be on par with the Spartan-IIs. Additionally, Dr. Catherine Halsey noted how SPARTAN-B312's "hyper-lethal" rating was shared by only one other Spartan, and remarked that Jun-A266's skills as a sniper were "unmatched". Similarly, Mark-G313 was noted as being the "best sharp shooter" of his detail, which at the time consisted of Team Saber and Fred-104, who was the second-best sniper among the Spartan II's.

While making his last stand on Reach, SPARTAN-B312 knocked out a Sangheili General with a single elbow strike and shot him twice in the head as he was struggling to get up. He then continued to make his final effort by dealing single strikes to multiple Ultras and Zealots causing them to forcefully stagger backwards, before being subdued himself.

During Operation: TORPEDO, Tom-B292, 12 years old at the time and equipped only with SPI armor, engaged a Sangheili armed with a plasma pistol and an energy sword in hand-to-hand combat. The Spartan's enhanced reflexes allowed him to dodge a plasma pistol bolt and sword swing at point blank range. He then proceeded to throw the Elite to the ground and finish it off with his assault rifle. During the battle, Elites and Kig-Yar moved out of cover because they realized that it was suicidal to face Spartans in close quarters.

The muscular augmentations administered gave a Spartan-III the strength of "three normal soldiers". During Operation: TORPEDO, Spartan-IIIs ran at a speed of nearly 30 KPH (around 18 MPH). Spartan-IIIs were also described to have been moving with "speed and reflexes that no Covenant could follow". "They dodged, snapped necks and limbs, and with captured energy swords, they cut through the enemy until the field ran with rivers of gore and blue blood". The Spartans of Team Foxtrot engaged six Kig-Yar in close quarters and left the aliens' bodies "snapped like rag dolls". Approximately 300 Spartan-IIIs faced thousands upon thousands of Covenant, including Covenant air support, and were described to have been winning the battle until 7 Covenant cruisers emerged as reinforcements.

During the Battle of Onyx, one of the Spartan-IIIs briefly fought the MJOLNIR-armored Kelly-087. The Spartan-III in question was able to momentarily hold their own against Kelly, being strong enough to twist Kelly's wrist and escape from her arm lock as well, despite wearing only SPI armor. While Kelly was able to quickly defeat the Spartan-III afterward with a palm strike, she took note that she would have easily torn her opponent's arm off if he or she were unaugmented.

The Spartan-IIIs' augmentations also allow them to survive in the vacuum of space exposed for up to a minute. However, the Spartans still suffer from the negative effects of exposure to space and require medical treatment directly after to recover.

During the battle on Pegasi Delta, most of Beta Company were roughly twelve years old. The physical abilities of any Spartan-IIIs who lived long enough to mature would supposedly have improved significantly as CPO Mendez stated that Spartans only grew stronger and faster as their bodies grew accustomed to their augmentations. While his statement was in reference to the Spartan-IIs, it can be assumed to hold true to their successors due to the similar nature of the augmentations.

Gamma Company
"Veta Lopis"

- Ash-G099

The mutagen 009762-OO, administered only to the Spartans of Gamma Company, makes the Spartans almost completely immune to shock under extreme stress, allowing them to endure injuries and physical pain beyond a Spartan-II; for example, Dante-G188 remained standing momentarily after a number of Needler rounds had blown his chest open, initially not even realizing his grave injuries. As a side effect, the drug suppresses higher brain functions over time; without the regularly administered counteragents, cyclodexione-4 and miso-olanzapine (the cocktails containing which are colloquially known among the Gamma Company Spartans as "Smoothers"), the Spartan will lose their strategic judgment and become more prone to impulsive, instinct-driven behavior. This may also occur in combat under extreme pain and stress; after both of her legs were broken, Olivia-G291 engaged and destroyed an Aggressor Sentinel by smashing it repeatedly with a "rock as large as her torso" in an uncontrolled berserk rage. Her superior, Fred-104, noted she could easily have indiscriminately attacked both allies and enemies in this state, and in order to immediately return her to normal, Fred was forced to strike her in the head with the butt of his rifle. The blow had enough force to knock off her helmet and was just enough to snap her out of this state.

There are several different types of "Smoother". The most common type used during combat operations is administered via a hypodermic injection and lasts approximately twelve hours, after which its effectiveness begins to steadily decrease. Several factors such as stress and fatigue can precipitate the mental unraveling process. The first symptoms, appearing within several hours after the Smoothers' effect wears off, include nervousness and irritability, eventually followed by paranoia, fits of temper and physical outbursts. After well over a day without a Smoother injection, Mark-G313 began having difficulties distinguishing friend from foe in the middle of a firefight, holding a combat knife to a Marine sergeant's throat before being successfully convinced by Fred-104 that the Marine was an ally rather than an enemy infiltrator. Another, significantly more expensive type of Smoother is a subcutaneous insert with a longer-lasting effect. While they can only be changed out in a medical facility, they also cannot be lost or destroyed during a mission like the more commonly used kind.

Trivia
The Birth of a Spartan live-action commercial for Halo: Reach depicts Carter-A259's eyes changing color from hazel to light blue as a byproduct of his retinal augmentations, a side effect not described in any other media. Several augmented Spartan-IIIs have been shown to have different eye colors, implying that the effect was not universal. The effect may have stemmed from Carter being much older than his peers when undergoing the augmentations.

List of appearances

 * Halo: Ghosts of Onyx
 * Remember Reach
 * Birth of a Spartan
 * Halo: Glasslands
 * Halo: Last Light
 * Halo Mythos: A Guide to the Story of Halo
 * Halo: Fractures
 * Lessons Learned