Project ORCHID

The SPARTAN-IV Augmentation Program is the formal name for the biochemical and surgical augmentation procedures performed on the SPARTAN-IV supersoldiers.

Background
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. Unlike the Spartan-III augmentations, which were almost entirely based upon chemical injections, the SPARTAN-IV augmentations combine chemicals and surgical procedures like those pioneered by Dr. Catherine Halsey in the SPARTAN-II program. The technology used in the two preceding SPARTAN programs necessitated that the candidates meet exceedingly strict genetic qualifications as well as the application of the enhancements on preteens, to avoid the catastrophic failure rates produced by the augmentation of adult subjects in the ORION Project. By the time of the initiation of the SPARTAN-IV program, the technology had advanced to the point that adults could be augmented seemingly without major risk.

Augmentations
The SPARTAN-IV augmentation procedures take three weeks to perform, with recovery and subsequent training usually lasting several months. While the enhancements have not been described in detail, they incorporate technologies originating from prior SPARTAN programs as well as completely new additions. However, the neural augmentation utilized in the previous programs, which provided the SPARTAN-IIs and SPARTAN-IIIs their superhuman reaction times, is seemingly absent.

Experimental phase
A series of additional augmentations were included in the earliest, prototypical phase of the program. These enhancements would have made the Spartans significantly stronger and more resistant to injury, the goal being that they could operate without MJOLNIR armor. However, these procedures proved to have an unacceptable casualty rate, killing or crippling nine of the ten initial candidates; the sole survivor, Ilsa Zane, was rendered mentally unstable. Demonstrating the effectiveness of these experimental enhancements, Zane was able to engage a MJOLNIR-armored Sarah Palmer in hand-to-hand combat without the use of any protective equipment, and survived Palmer violently driving her head into a metal bulkhead face-first, as well as her subsequent prolonged exposure to the vacuum of space.

Performance
The synthetic cardiac weave allegedly allows a SPARTAN-IV to "outrun a horse"; this would imply speeds of up to, or over, 50 kilometers per hour. The enhancements performed on the lungs potentially allow a SPARTAN-IV to breathe methane for around an hour.

SPARTAN-IVs must follow a rigid set of guidelines to maintain their physical fitness and health. These include undergoing regular medical examinations, including physiological scans, reviews and treatment before and after each mission. A SPARTAN-IV is expected to perform at optimum capacity with a minimum of two-and-one-half hours of sleep per a 48-hour cycle; for cryosleep, standard UNSC practices apply. They are also instructed to follow standard UNSC physical training practices. Due to their augmented physiques, however, they are provided their own, custom-built gym equipment. Official meals are specifically prepared to meet the caloric, nutritional and medicinal needs of each individual Spartan. These personal needs are measured based on activity data recorded by the Spartan's individual physiometer. Ancillary medications may be provided to ensure the Spartan's well-being and to reduce risk of potential implant rejections.

List of appearances

 * Halo 4
 * Infinity Briefing Packet
 * Halo: Initiation