MJOLNIR armor

The MJOLNIR Powered Assault Armor is a state-of-the-art UNSC power armor system developed under the direction of Dr. Catherine Halsey of the Office of Naval Intelligence for use by the Spartan-II supersoldiers. Various MJOLNIR-based armor systems would later be issued to select Spartan-IIIs in the late-war and post-war eras.

Development
Each "Mark"-designated generation is its own iterative platform, and each of them evolved considerably over the years, both generation-wide and individually. The Marks were paradigm shifts that completely overhauled both the suit's hardware and software, and for the most part required their own unique production lines and procurement chains. In addition to the best-known changes, there were numerous tune-ups and adjustments to every Mark-designated platform, both internal and external. The more notable changes within each generation are sometimes referred to as "phases", though these do not always fully reflect the true gamut of variety within those generational platforms, especially amongst individual suits. Due to the realities of military logistics and funding, as well as select benefits unique to given platforms, different models and subcomponents sometimes remained in use in parallel by different Spartan units for some time.

Notably, Dr. Halsey did not initially categorize MJOLNIR development into neat generational phases, and disliked the Mark system as an unnecessary bureaucratic technicality. Marks I-III were all designed as one iterative platform, with multiple in-between models and variants piloted between 2525 and 2535, when Halsey was forced by the ONI brass to segment her project into a generational model. This is also when the Marks I-III were formally identified as such, with Halsey picking the most substantial upgrades made to the ever-evolving MJOLNIR platform in the last ten years.

While Dr. Halsey served as the overall head for Project: MJOLNIR and the visionary behind its conception, many of the technicalities of the suit's day-to-day development were carried out under the oversight of Materials Group's head engineer Augustus Lehto. Engineer Abraham Hannaford prominently contributed to the later-generation Mark IV and Mark V suits, as well as the later Mark VII model.

Predecessors
The MJOLNIR project was preceded within the UNSC by Project HRUNTING, which saw the development of a series of large mechanical exoskeletons in the late 25th and early 26th centuries. These were bulky and needed to be tethered to a power source at all times due to the immense power needs. ONI initially proposed to Halsey that she either use the HRUNTING technology for the SPARTAN-II program or build on it, though Halsey quickly decided it was necessary to scrap the old technology entirely and design her new power armor from the ground up. Halsey's requirements for her Spartans' power armor were ambitious: the suits would have to be much sleeker and slimmer, have a self-contained power source, and incorporate novel technology, namely a piezoelectric liquid crystal layer to amplify the wearer's movement as opposed to HRUNTING's traditional mechanical joints and servo motors. Meanwhile, the UNSC picked up the efforts of Project HRUNTING, which also later spun off into various parallel programs such as the HRUNTING Mark III Cyclops logistics exoskeleton.

Mark I (2525)
The MJOLNIR Mark I suit was the initial, prototype phase of the MJOLNIR armor system. Pressed into service weeks if not months before its projected completion due to the start of the Human-Covenant War, the Mark I MJOLNIR remained in many ways incomplete despite being far more advanced than its HRUNTING predecessors.


 * Features and improvements
 * Piezoelectric liquid crystal layer of polymerized lithium niobocene for movement amplification
 * Integrated micro-fission power pack. The Mark I backpack was notably different in design from its successors due to its reactor being integrated into a single central pod, as opposed to the twin-pod designs used since fusion became standard. The power pack had various issues, most notably heat buildup in a vacuum, which restricted the length of EVA operations and led to the development of dedicated EVA operability kits in the years after the armor's development.
 * Iridescent refractive coating to disperse directed-energy strikes. Added only days before the suit was issued to the Spartan-IIs based on data from the few engagements with the Covenant, the refractive coating was the first in line of UNSC-wide improvements refocusing armor from protecting primarily against ballistic attacks to plasma and particle beam damage. Still, the first version of the coating was fairly rudimentary, due to the little data available on Covenant weapon damage at the time, and did little to defend from all but glancing blows.
 * Vacuum-sealed but no standard vacuum survival kit (e.g. sealant foam dispensers)
 * Prototype MJOLNIR BIOS

While a quantum leap in technology for its time, the Mark I was quickly found to have numerous teething troubles and issues beyond the designers' control: the suit was fine-tuned for fighting human insurrectionists with ballistic weaponry, not aliens with energy weapons. In addition, the suit was pressed into service faster than originally planned due to the threat of the Covenant, which led to various issues. Even the refractive coating was hastily applied in the final weeks of development based on sparse data from early encounters with the Covenant, and was considerably inferior to its later successors.

The issues led to the rapid field-iteration programs Projects COBALT and CRIMSON between 2526-2528. Rather than all-new suits, these projects were parallel rapid field-testing and iteration projects of several individual suits over the course of two years, culminating in what would later be known as the second-generation MJOLNIR suit.

Mark II (2527)
The formalization of the rapid-iteration and field-testing Projects COBALT and CRIMSON, the Mark II MJOLNIR was a generational upgrade that fixed the Mark I's most urgent and widely-reported issues in the field. The Mark II also brought the suit fully up to speed with data and experiences gathered from engagements with the Covenant, including the effects of the aliens' energy weaponry. The upgrade was implemented gradually over the course of several months between 2527 and 2528.


 * Features and improvements
 * Structural overhaul of undersuit and plating to facilitate partial disassembly/assembly of armor, e.g. for field repairs and first aid. The undersuit still had to be assembled from multiple parts but could now be more easily removed in piecemeal.
 * Upgraded skinsuit, enhanced thermal regulation and management system, heat sink and superconducting EM mesh to distribute incoming energy to a wider surface area.
 * Enhanced refractive coating, with further incremental upgrades applied over time
 * Initial provisions for plating modularity. Introduction of modular purpose-built variants with the EVA variant/conversion kit (MJOLNIR/V)
 * Improved micro-fission pod design, fixing widely-reported power issues.
 * Numerous upgrades to the internal and external electronics; improved sensors and a generational BIOS upgrade; Mark I's buggy prototype firmware replaced with purpose-built VISR software & added target acquisitions database

Mark III (2530)
In many ways an intermediate generation, the Mark III improved on the Mark II as well as some of the issues present since the first generation. The Mark III MJOLNIR was initially known as Project OBSIDIAN by Halsey.


 * Features and improvements
 * Various upgrades to the bodysuit and techsuit to improve ergonomics and comfort for wearer along with easier disassembly and outfitting.
 * Fission pod as standard; field tests with micro-fusion power plants.
 * Second-generation piezoelectric layer system.
 * Structural upgrades to facilitate field repairs.
 * Overhauled plating design to improve modularity, range of motion and protection against energy weapon attacks as a full transition to an "anti-plasma" schema.
 * Piloting of increased variability and modular components, with select non-classified materiel shared to other branches and contractors for innovation programs.
 * Various sensory upgrades and BIOS tune-ups.

Mark IV (2535)
In 2535, Halsey was forced to segment Project: MJOLNIR into neat generational models for budgetary reasons, as opposed to her prior approach of applying constant - and often costly - upgrades and overhauls to both individual suits and having new suit prototypes built near-constantly. By this point, 14 distinct variants of the MJOLNIR system existed. These models would retroactively be categorized under the Mark I, Mark II, and Mark III generations based on major trends in their underlying hardware. Since the Mark IV would be the last major version of MJOLNIR for some time, potentially for years, Halsey sought to make sure it could stand the test of time by incorporating, for example, further modular features and the option for rapid iteration at a lower cost than the previous platforms. This included improved compatibility with various other armor systems.

The Mark IV suits represented a transition to a newer type of plating architecture that was both designed from the ground up to counter plasma and energy weapon strikes, along with accommodating increased modularity and field repairs. In many ways, the Mark IV was the prototype for what the Mark V would become, pioneering many of the technologies used other than energy shielding. Though the result of several pilot programs, the Mark IV MJOLNIR was initially known as Project THUNDERBOLT by Dr. Halsey.


 * Features and improvements
 * Overhauled techsuit and exo-frame design with improved fall damage mitigation
 * Microfusion power plant as standard
 * Integrated vacuum survival package with integrated sealant foam dispensers and improved EVA navigation system
 * Streamlined design for increased variability, field repairs, upgrades and individual specialization, including increased compatibility with other UNSC gear, partly due to the Spartans being increasingly spread out across dozens of light-years and often operating on their own. Introduction of versatile lines of "Up-Armor" components and modular hardpoints for the attachment of webbing, UA components, and external electronics/sensor modules.
 * New materials and outer padding in the bodysuit, designed for enhanced protection and thermal management. Partly based on study of Covenant technology.
 * Improved life-support system, more versatile gel layer with hyperpressurization capability for emergencies
 * Embedded proto-shield/dispersal field modules (later models)
 * VISR/BIOS updates and improved onboard computer. Embedded dumb AI routines and target recognition software
 * Sensor and communications upgrades; radar as standard, along with external uplinks to local data networks & battlenets
 * Improved life support system with integrated biofoam injection ports

The Mark IV also saw the emergence of the MJOLNIR's first private-sector variants and "off-brand" versions developed by Watershed Division for use by the Spartan-IIIs without Halsey's authorization or knowledge. A handful of defense contractors began to produce suit components, both as proof-of-concept prototypes for later development and for purpose-built variants for the MJOLNIR suits themselves.

Later upgrades to the Mark IV included primitive reactive shielding in certain parts of the plating. This was an electromagnetic impeller system contained within the plating designed to mitigate the effects of plasma weapons by disrupting plasma bolts' containment fields before impact. However, this was still far from full-fledged energy shielding.
 * Energy shielding tests

Starting in the early 2540s, the UNSC began a collection of discrete rapid iteration and field testing programs on the Mark IV platform to pilot novel energy shielding solutions on individual suits, some of which saw the first field-tests with external shielding modules. These pilot programs also led to the creation of the "armor lockup" module, a design based on a specific type of Covenant overshield. The system immobilized the wearer in order to tap into the full power output of the suit's reactor, which caused various power issues and presented an obvious obstacle for mass adoption. As such, the armor lockup was deemed unstable and virtually unusable in all but emergency conditions.

Mark V (2548)
The Mark V armor not only brought the MJOLNIR suits' aging design architecture up to date with advances made in materials science and power transmission during the second half of the war, but also introduced full energy shielding as an integrated fixture of the suit. While experimental variants of the Mark IV had been fielded previously with external shield units, these were cumbersome and initially error-prone.

The Mark V also added a full AI processing memory-crystal layer, which remains the single most expensive addition to the MJOLNIR platform. This was a testament not only to Project MJOLNIR's groundbreaking engineering, but also Dr. Halsey's dogged persistence in fighting ONI's procurement bureaucrats, ultimately only succeeding thanks to Admiral Stanforth's patronage of her. Previous generations of MJOLNIR were capable of hosting a basic "dumb" AI, but their lack of a quantum nanocrystal processing substrate made them insufficient for "smart" AI housing. The addition of the AI support delayed the Mark V's production considerably: the integrated shield system was finished long before the AI substrate layer and interface, which would remain the armor's most expensive component.

However, it was found in field tests that the shield systems of the initial Mark V suits interfered with the embedded AI nanocrystal matrix, leading to various maintenance problems and even suit failures. Coupled with the expense of the nanocrystal layer, this led to the decision to omit the layer from most suits of the initial production run before the problems could be solved. Although this delayed Halsey's planned Spartan-AI integration tests, it was deemed an acceptable compromise. Ultimately, the AI crystal layer was integrated to the final production run of the Mark V, issued to most of the Spartan-IIs in August 2552 in preparation for Operation: RED FLAG. The final Mark V model also contained numerous lesser upgrades, yet omitted just as many that Halsey did not have time to incorporate before Admiral Stanforth and the rest of FLEETCOM forced her to finish her work on the suit and initiate Operation: RED FLAG. At the time of the Mark V's final production run, the suits had already been surpassed in many ways by the Mark VI team on Earth, but the sixth generation failed to make it for RED FLAG.

The Mark V improved on the Mark IV's modular design, and many components were largely cross-generation compatible.


 * Features and improvements
 * Enhanced gel layer
 * BIOS & onboard computer updates.
 * Integrated first-generation energy shielding
 * Full processing memory crystal mesh & updated onboard computer system and firmware to accommodate AI (omitted in initial production model)
 * Enhanced sensor suite with improved radar, motion tracker as standard and various low-light sensors
 * Overhauled power system and reactor design with overload capability
 * Helmet with embedded COM links; added integrated wavespace uplink for Covenant battlenet infiltration
 * Upgraded life support and survivability suite with prototype biofoam injectors

Project BULWARK / MJOLNIR(B)
By the late 2540s, a subgroup of the Watershed Division operating under Colonel Ackerson's Asymmetrical Action Group had managed to procure a number of discarded prototypes from the mainline Project MJOLNIR, various suit components, and even full MJOLNIR suits slated for decommissioning by Dr. Halsey. Coupled with up-to-date plans for MJOLNIR provided at the behest of Ackerson's connections within ONI, the Watershed Division was able to produce an "off-brand" version of the MJOLNIR armor under the codename Project BULWARK and otherwise known simply as MJOLNIR (b). The BULWARK suit was directly based on the Mark V armor albeit with cheaper components and was functionally identical with the core suit in most respects, though it lacked some of the more sophisticated sensor systems, later optimization packages or Halsey's upgrades to the Spartan-IIs' individual suits. However, it remained compatible with all Mark V supplementary hardware. The BULWARK suits were robust and equaled the baseline Mark in performance, though some specific components required more frequent replacement. A secondary goal of the project was to research ways to adapt MJOLNIR-based force-amplifying power armor for baseline humans; this spun off into the parallel Project HRUNGNIR, which would eventually produce a suit of power armor for the Army's TITAN-II commando program.

The BULWARK suits were issued for a handful of off-company Spartan-III teams operating under UNICOM. Like all of AAG's activities, its existence was hidden from Dr. Halsey, though she suspected the existence of a parallel armor development program for some time. These suspicions were confirmed after she encountered NOBLE Team during the Fall of Reach and her subsequent intrusion into Ackerson's files. The BULWARK variant remained in use for some time after the war among Spartan-IIIs, though it was eventually phased out in favor of the AQUILA suits.

Mark VI (2552)
Largely developed in parallel with the Mark V, with development starting in Earth's Seongnam and Chiron over Mars in 2551, the Mark VI began as a radical innovation splinter program that overtook the main one after the destruction of Reach and Halsey's disappearance.

The final Mark VI suit focused on optimizing the technologies developed for the Mark V and integrating them more thoroughly into a coherent whole. While advanced for its time, the Mark V's shield system was still relatively wasteful and crude in light of new advances made over the past two years. As well, the AI crystal layer had been hastily added to the Mark V suit that still partly relied on legacy technology, causing issues with power management in particular. Later upgrades to the existing Mark V suits would partly remedy these issues, though the armor would remain prodigiously expensive for some time due to the complex manufacturing process required for the unique symbiosis of exotic technologies.

While mostly developed in parallel with the Mark V, the final iterations to the Mark VI's design were made with an exceedingly hectic pace in the weeks since the Fall of Reach. Functionally, the Mark VI differs quite little from the Mark V, outside some alternate materials choices and technical solutions, essentially being the product of a competing Materials Group team with only external input from Dr. Halsey. Because Halsey was extremely ambitious about the upgrades made to each MJOLNIR generation, she would have been against differentiating the Mark VI from the Mark V suit in the first place. Regardless, Halsey wasn't there when Navy procurement bureaucrats decided to call the suit Mark VI, some time before the Gettysburg survivors returned to Earth in early October 2552. Indeed, the final upgrades to the upcoming Mark VI suits were made based on data from said survivors' experiences on Reach, Halo and the Unyielding Hierophant.

In terms of design and architecture, the Mark VI was designed with the potential for future mass-production in mind, with a streamlined manufacturing process as well as increased modularity, based on the example of the preceding Marks. Consequently, specifications of the suit or components thereof were partially divulged to a handful of defense contractors tasked with developing use case-specific variants.

As one notable change to the Mark V, the Mark VI relies more on its shield than the physical armor, using a lighter, more streamlined plating architecture and slimmer techsuit to allow for increased mobility. This decision was made by the Materials Group's Seongnam contingent in contrast to Halsey's team on Reach, who preferred a bulkier and more robust plating setup. Aside from that difference in schools of thought, the Mark VI's shield and power system are unquestionably better, if damage-prone; the shield-shaping waveguides in particular can be damaged quite easily.

The Mark VI's passive stealth system, EVA features and core sensor package have also been improved from those of the Mark V.

One of the most notable differences between Marks V and VI is that the former (particularly the [B] variant) is more robust and easier to repair and upgrade in the field; whereas the Mark VI is a fine-tuned high-tech instrument that requires frequent maintenance by a dedicated crew. In terms of electronics, the Mark VI opts for a contact-based rapid data interface that can transfer an entire AI in a mere second. While an ambitious show of technological prowess, this can compromise the suit's cybersecurity much easier than the Mark V's data-transfer system, which relies on more robust and reliable physical transfer along with hardened electronics.

The Mark VI's power distribution was one of the first UNSC systems to use Covenant-derived superconducting metamaterials, as well as a fine-tuned waveguide array to optimize the energy shields' shape in much more detail as well as reducing power consumption. This required a complete overhaul of the suit's internal architecture, which enabled several further improvements to the AI processing layer. However, the system was more also delicate than that of the Mark V, and required more frequent maintenance.


 * Features and improvements
 * Streamlined third-generation piezoelectric layer. Possibly designed with the provision of being wearable by unaugmented or lightly-augmented humans, though the suits' costs and large size prevented them from being issued to non-Spartans.
 * Upgraded techsuit structure; the techsuit can now be outfitted as a single piece with minimal assembly required, though it can, along with the skinsuit, still be removed piece by piece for emergencies or field repairs.
 * Embedded gravitic assist for fall damage mitigation
 * New plating structure, improved lightweight composites and titanium alloys. Upgraded layer construction.
 * Optimized shielding and power management suite.
 * Next-generation power system
 * Embedded next-generation EVA package
 * Active AI transfer protocols

MJOLNIR development and innovation ground to a relative halt in the decade following the war. Over the last two decades, the numerous high-end features the MJOLNIR system had accrued made it one of the most complicated and expensive pieces of human technology at the time. As the UNSC gradually wound down from war footing, Section Three's research and development budgets were significantly downsized, and Project MJOLNIR faced increased scrutiny due to its astronomical development and upkeep costs, especially in light of the small number of remaining Spartan-IIs. With the disappearance of the project's primus motor, Dr. Halsey, largely responsible for maintaining the project's tempo during the war, Project: MJOLNIR passed under new management within Section Three, and the refocusing of Section 3's budgets saw many of its surviving personnel reassigned to work on offshoot projects. These projects focused on developing less expensive and less high-end suits that incorporated some of the technologies and lessons learned from MJOLNIR, but eschewed prohibitively expensive features like the AI crystal layer or full conformal shielding. A base staff was retained to maintain the core features of the Mark VI suits still in service, while the production and maintenance of variants and add-on modules was largely given over to private contractors. Although the AI processing layer and several elements of the shield and power distribution systems remain proprietary to Materials Group, the most significant innovations to the Mark VI platform in the post-war era have originated in the private sector, rather than Materials Group.

The initial production run of Mark VI suits remains as spares and for specialist uses by the Spartan-IIs and select Spartan-IIIs, and they continued to receive periodic upkeep. For the bulk of the IIIs, the MIRAGE Semi-Powered Infiltration Armor is deemed an acceptable alternative as its manufacturing process is much more easily scalable to mass production, sacrificing the bleeding edge of power armor technology in favor of a less technically impressive but more economical compromise.

Project AQUILA
AQUILA was an offshoot program of Project MJOLNIR launched after the war. With the budget cuts to Project MJOLNIR and Halsey's disappearance, Materials Group assembled the Project AQUILA team with the goal of creating a leaner and more cost-effective MJOLNIR variant through outsourcing many of the suit's discrete components to private manufacturers, continuing a trend that had already begun in the Mark IV generation. This, in turn, would inform future efforts in further standardizing MJOLNIR hardware, thus making it producible in much larger volumes in the seventh generation. It also fed into the concurrent HOPLITE program and its bespoke ASPIS semi-powered assault armor. After the shuffling of ONI's various departments that followed ONI's post-Parangosky "cleanup", the assets involved with the still-ongoing Project BULWARK were pooled into AQUILA.

Initially planned as a modernization package for the remaining Mark V suits, Project AQUILA also produced a line of new battlesuits built on a core architecture combining technologies from the Mark V and Mark VI suits. Its most notable omission was that of the prohibitively expensive AI substrate layer as well as the embedded wavespace uplink, which would be incorporated as a separate plug-in module. Something of a stopgap solution, the AQUILA suit was issued mostly to some SPARTAN-IIIs and SPARTAN-IIs operating without integrated AI, though its adoption remained relatively limited as development resources were shifted increasingly toward the Mark VII. The Mark VII armor finally led to the AQUILA suits being phased out by the late 2560s.

Mark VII (2566)


Codenamed Project KEYSTONE, the Mark VII was the seventh generation of the MJOLNIR suit. Its development was primarily motivated by the Delta Company of Spartan-IIIs, though it was also issued to the other remaining active Spartan-IIIs and IIs. Mostly importantly, however, the Mark VII suits could be configured for non-Spartans, making their mass production more viable. The suit contains numerous upgrades and tune-ups over the Mark VI platform, which it eventually replaced beginning in the late 2560s. Building on lessons learned from the prior Marks, Mark VII was the first true "assembly-line" MJOLNIR generation with most of its components privatized to external contractors, enabling a much smoother production process. While the suits remained expensive and virtually exclusive to the Spartans, their costs were no longer as astronomical as before.


 * Features and improvements
 * Upgraded plating architecture, representing a partial return to the plate-arrangement schema Mark IV and Mark V suits. Full intercompatibility with most concurrent UNSC armor systems.
 * Upgraded BIOS, various cybersecurity upgrades
 * Full AI/operator integration with datacrystal mesh capable of accommodating most military-standard "smart" AI
 * Improved paragravitics engine with advanced fall damage mitigation and inertial/shock dampening.
 * Enhanced sensor suite, e.g. motion tracker
 * Next-gen active energy shield shaping and power conservation; the shield system actively senses threats and incoming impacts, adapting the shields locally to match and optimizing power use.
 * Fourth-generation piezoelectric system based on Covenant technology; shift away from toxic PoLiNb derivatives. Possibility to accommodate non-augmented or lightly-augmented wearers as default.
 * Proto-laminar metamaterial coating and refractive paint with limited camouflaging features
 * Miscellaneous materials improvements
 * Integrated emissions masking and stealth features
 * Further enhanced field module system
 * Provision for energy weapon recharging systems via suit reactor

Mark VIII
Introduced in the 2580s with the SPARTAN-IV project, the MJOLNIR Mark VIII is the eighth major shift in the MJOLNIR line, developed specifically for the next generation of Spartans.


 * Features and improvements
 * Next-generation manufacturing process with Covenant-derived hybrid technologies
 * Next-generation cybernetic suit/operator interfaces
 * Next-generation AI/operator hybridization interface and datacrystal processing layer
 * Covenant-derived lightweight nanolaminate alloys for armor plating
 * Advanced energy shield shaping and management for optimized power use; AI-controlled active shielding
 * Full stealth coating through photoreactive metamaterials
 * Slipspace de-insertion capability

The Mark VIII's physical design reflects its state-of-the-art nature, with a smooth, minimalist, and nearly organic design.

Variants and components
Some variable MJOLNIR components, such as helmets, shoulder pads and various UA plating components, are intercompatible between MJOLNIR generations as well as some non-MJOLNIR personal armor systems, though electronics and firmware upgrades are usually required when using legacy or external components. In addition, as MJOLNIR is superior to the majority of other UNSC armor platforms in most ways, there is generally little incentive to use external components, barring cases of extreme specializations that lack dedicated MJOLNIR subvariants. Such intercompatibility only started to become standard post-Mark IV, as budgeting and practical concerns often called for modular solutions.

The addition of conformal energy shielding in the Mark V generation made backwards compatibility of older components more difficult, as even the armor plates now had to be fitted with internal waveguides. The Mark VI's waveguide network is designed to be more streamlined, but retains some of the same issues; the system can be configured for legacy helmets, for example, but the lack of waveguides results in less precise shield coverage.

MJOLNIR-exclusive variants

 * AQUILA: Semi-privatized variant produced to explore MJOLNIR's potential for mass production and non-SPARTAN adoption. Used mainly by the still-active Spartan-IIIs before the adoption of Mark VII. A hybrid of Mark V and VI technology. Built partly on the work of Project BULWARK.
 * BULWARK / MJOLNIR(b): "Off-brand" variant line developed in secret from Halsey under the Watershed Division for UNICOM-assigned Spartans. Development first initiated for the Mark IV in the mid-2540s. Although the suit itself was widely-used, the helmet was solely adopted by SPECWAR/GroupThree.
 * CQC: Variant line used for close-quarters/MOUT, boarding actions, etc in the Mark IV generation. Served as basis for the subsequent CQB armor program.
 * Grenadier: Up-armored Mark IV variant. Part of the shield tests for the MJOLNIR Mark IV.
 * EVA: Extravehicular conversion, navigation and maneuverability package for MJOLNIR suits. First launched for the Mark II in the late 2520s, EVA was Project MJOLNIR's first standardized variant after several years of ad hoc EVA life survivability and maneuvering solutions. It took into account lessons learned in the Summa Deep Space Incident.
 * Scout: Purpose-built stealth variant for recon operations. Uses advanced photoreactive metamaterials to provide stealth. Initially developed during the Mark V generation.

Adapted or parallel-developed variants

 * EOD: Heavy/demolitions variant based on Marine Corps/ODST EOD gear.
 * CQB: Successor to the MJOLNIR/CQC variant; developed to be compatible with other NAVSPECWAR forces, e.g. TRIDENT, ODST
 * Recon: Developed in parallel with ODST armor recon variant in the early 2550s. Mainly relies on active emissions masking and elimination of reflective surfaces for stealth at a minimum loss of endurance.
 * Commando: A supplemental armor and functionality package developed in parallel with select non-Spartan NAVSPECWAR and Marine Corps armor development programs.
 * Mariner: Designed for Project JAVELIN's pilot and command teams and optimized for use on advanced C718 Sabre space fighters.
 * GRD: Introduced to satisfy the need for a cyberwarfare variant, GRD later saw extensive service with ONI Security teams.
 * HAZOP: Developed based on operations on hab rating-VI worlds and other zones with major chemical, biological or radiological hazards. Shared asset with various other NAVSPECWAR units.

Compatible armor systems

 * ODST: Late-war ODST armor systems are fully compatible with MJOLNIR, as both development programs effectively fed into one another since the Mark IV generation.
 * JFO: Used by Marine Corps artillery crews; advanced shock dampening system and rangefinding/targeting features. Compatible with MJOLNIR since the Mark V generation.
 * Air Assault: Originally developed for the UNSC Army Airborne's Project VALKYRIE; helmet/armor design compatible with MJOLNIR since the Mark V generation.
 * Pilot: a helmet created as part of Project AMALGAM, which sought to introduce enhanced neural laces for strikecraft pilots.
 * ECH43: The sealed variant of the current-standard CH252 cross-branch infantry helmet.
 * GUNGNIR: Borne out of the parallel supplementary armor and weapons development project, GUNGNIR.
 * Security: First developed for proprietary armor systems used by Misriah's security forces on and around Mars in 2528; compatible with MJOLNIR from Mark IV generation onward.
 * Operator: Developed for and fielded exclusively by unaugmented S-III "dropout" teams within Asymmetrical Action Group; associated with Project YOKAI; later adopted for use by other Beta-5 black ops operatives.
 * Rogue: Helmet designed for long-term solo operations by Marine Force Recon units. One of the first applications of MJOLNIR-derived tech in the private sector.
 * Hayabusa: An eccentric corporate security armor built by RKD for Ishimoto Corporation with bleed-off technology from MJOLNIR and other UNSC systems.
 * ASPIS: The mainline helmets, supplemental armor (e.g. shoulder pauldrons) and webbing used in the ODST Hoplites' ASPIS Semi-Powered Assault Armor were developed in parallel with later MJOLNIR generations and are fully intercompatible.

Offshoots
The MJOLNIR system pioneered numerous technologies later applied in other fields in a more piecemeal fashion. It was fitted with the smallest fusion reactor ever built at the time, was one of the first pieces of UNSC technology to use fully-conformal energy shielding, and the piezoelectric liquid crystal used to enhance the wearer's movements would later see numerous applications in both power armor and various industrial uses. The AI-processing distributed datacrystal layer introduced in the Mark V was the most compact computing substrate ever built, with conventional armored matrices paling in comparison. The titanium-ceramic composites used in the armor plating are perhaps the most widely-adopted technology pioneered by the MJOLNIR suit, with most UNSC body armor systems having adopted some variant thereof by the end of the Human-Covenant War; the helmet-integrated high-bandwidth neural interface system has likewise seen widespread adoption following its introduction in non-MJOLNIR systems, particularly in the suits used by vehicle operators and pilots.


 * Project YGGDRASIL was the Materials Group's name for the various initiatives carried out to incorporate the various technologies pioneered by Project MJOLNIR for mass production and deployment across other armor systems in the UNSC. This also included the gradual piecemeal privatization of the production of various MJOLNIR components to ease the burden on Materials Group itself, though the increasing standardization also meant rapid iteration became less viable in the project's later years and upgrades had to be planned out well ahead of time.
 * Project HRUNTING was picked up by the Navy after the success of MJOLNIR, resulting in the development of various mechanical exoskeletons such as the Mark II prototype and the Mark III "Cyclops". Unlike MJOLNIR, HRUNTING could safely be worn by non-Spartans.
 * Project HRUNGNIR was a spin-off project that sought to develop a MJOLNIR-based battlesuit with piezoelectric force amplification wearable by baseline humans. Initial progress was modest not only for technological reasons but also due to the technology's immense costs, though the percolation of MJOLNIR-based technology across the industry and the reprieve provided by the post-war era saw the technology finally becoming more available.

Production notes
The Daybreak Continuum's overhauled MJOLNIR generations are one example of the ways the project's authors seek to re-examine post-2009 Halo canon with an open mind and rethink if need be elements that have since been regarded as staples of the setting.

In MJOLNIR's case, fans and the current franchise stewards alike have long operated under the assumption that the suits issued to the SPARTAN-IIs at Chi Ceti were designated Mark IV, while the preceding three generations were variations on the pre-Halsey mechanical exoskeletons. In truth, this has no backing in pre-Halo Encyclopedia canon. The supposed pre-MJOLNIR Marks II and III and their respective features have been in Halopedia's article for MJOLNIR armor since circa 2005-2006 (see this revision), and were never given a source prior to the publishing of the nascent 343 Industries' Encyclopedia. The Encyclopedia is widely notorious for its blatant copying of outdated content from Halopedia at a time the wiki's sourcing standards were not as high as they would become in subsequent years. The Encyclopedia led to various fan-sourced names and concepts being adopted as 343i canon, such as the supposed "United Rebel Front", the "First" and "Second" battles of Earth, or the naming and nature of various Earth-based national governments — and the mangled nature of MJOLNIR development. With its clean-slate approach, Project Daybreak is the ideal opportunity for correcting these mistakes, especially where they actively make the fictional universe lesser with their presence.

Out of sources regarded as canon in Project Daybreak, Halo: The Fall of Reach only mentions the Mark I exoskeletons, and never gives Mark-based designations for the subsequent MJOLNIR armor suits designed by Halsey. Meanwhile, the suit seen in Halo: Combat Evolved is given the designation Mark V on the game's now-defunct official website at Xbox.com. While The Fall of Reach never explicitly shows the Spartans receiving intermediate armor generations between 2525 and 2552, the book also skips over that time period almost entirely, so it is not difficult to imagine three suits being issued in the intervening time — especially given the comparatively rapid development cycle of Marks V and VI. It is also possible that given the novel's breakneck writing process, allegedly lasting a mere seven weeks, led to miscommunications between the Bungie and/or Microsoft Game Studios writing teams and the author Eric Nylund, who may have otherwise mentioned the Mark generations in the novel.

The elusive Mark II and III generations, as described by an anonymous fan in noughties-era Halopedia and subsequently adopted into canon by the Encyclopedia, are also questionable in light of how Halsey refers to the Mark I suits in The Fall of Reach. One would think she would mention the intermediate two generations or have them used in the Spartan-IIs' training exercises, but instead only the Mark I is ever mentioned. Since Halsey barely considers Project MJOLNIR to be of the same lineage as the old mech suits (later established as HRUNTING), it stands to reason that MJOLNIR would have its own generational system starting with Mark I and advancing to Mark V throughout the Human-Covenant War.

The last and most pressing reason for Daybreak's adoption of Marks I-III as proper MJOLNIR generations rather than preceding HRUNTING suits is Dr. Halsey's journal, shipped with Halo: Reach. While technically a post-2009 source, the journal is regarded as authoritative in Daybreak as it conflicts little with prior material on top of its myriad positive contributions to Halo's universe, lore and narrative. The journal clearly indicates that the MJOLNIR Mark IV was not yet in service by 2535, when Halsey wrote her entry about MJOLNIR's development cycle. Not only does the entry in question have Halsey commenting on the Mark system as something unnecessary she has to follow for bureaucratic reasons, but it also speaks of the Mark IV in the future tense, along with sketches and brainstorming for potential features to be added to the Mark IV generation, alongside the subsequent Mark V, VI and VII. Alongside the journal is a blueprint for a type of Mark IV suit not yet realized in other visual media.

Ultimately, spreading the development of the Mark I-IV generations out over the decades of the war was deemed a beneficial divergence from 343 Industries canon. It allows for more meaningful development to happen within the 27 years of the war, whereas in current 343i canon, the Mark IV remains in service for the entirety of that time. In spite of this, "Mark IV" is shown to encompass numerous variants which often have little in common with one another. With Daybreak's version of MJOLNIR development, we are able to both acknowledge the continual iteration Halsey mentioned in her journal, and give the suits a more logical aesthetic and technological progression over the Human-Covenant War.

No GEN1/GEN2/GEN3 divide exists in Daybreak, as the Mark system is already sufficient to fulfill the purpose of a generational designation system. Other than this, the number of MJOLNIR variants and subtypes has been considerably cut down in Daybreak to keep their numbers in reasonable limits for such an expansive and niche program. In addition, each armor generation is given a certain signature look for reasons of recognizability and consistency.