Editing MJOLNIR Powered Assault Armor/Mark IV

{{Era|UNSC|HCW|Post}} 
{{Armor Infobox
|image=[[File:MJOLNIR MARK IV ARMOUR.png|350px]]
|manufacturer=[[Materials Group]]
|testsite=[[Damascus Testing Facility]]
|type=[[MJOLNIR Powered Assault Armor]] GEN1
|role=General combat
|weight=
|features=
|hideb=yes
}}
{{Quote|You're the only ones who can use them, Petty Officer. Who else could we give them to?|[[Catherine Halsey|Doctor Catherine Halsey]] to [[John-117]].<ref name="for115"/>}}

The '''Mark IV MJOLNIR Powered Assault Armor''' was (despite its name) the first version of the [[MJOLNIR Powered Assault Armor]] series. The suit was issued to [[SPARTAN-II program|Spartan-II commandos]] on [[2525#November|November 27, 2525]],<ref>'''Halo: The Fall of Reach''', ''page 113'' ''page 136'' (2010 edition)</ref> and was in service until it was replaced by the [[MJOLNIR Powered Assault Armor/Mark V|Mark V]] on [[2551|November 24, 2551]].<ref>[http://halo.bungie.net/News/content.aspx?type=topnews&link=BWU_012910 '''Bungie.net''': ''Bungie Weekly Update: 01.29.10'']</ref><ref group="note">''Halo: The Fall of Reach'' states that the Mark V was issued on August 29, 2552. However, the aforementioned Weekly Update and Dr. Halsey's personal journal retcon this, instead stating that the Mark V was issued on November 24, 2551. The test performed by John-117 was intended to gauge the pairing of the Mark V suit with a piggy-backed AI, not to observe the suit's performance ''per se''. ''Halo Waypoint''<nowiki>'</nowiki>s ''MJOLNIR Project 2'' video erroneously presents the date given in the novel as valid.</ref> A hybrid variant could still be requisitioned by Spartan personnel as late as [[2558|October 2558]], albeit upgraded to function with the [[MJOLNIR Powered Assault Armor (GEN2)|MJOLNIR [GEN2]]] suite, and is notably still used by select Spartan-IIs.<ref name="H5G">'''[[Halo 5: Guardians]]'''</ref>

==Introduction==
[[File:HM-MarkIV.jpg|200px|thumb|left|Diagram of the Mjolnir Mark IV.]]
Developed parallel to the SPARTAN-II program<ref name="Sybex">'''Sybex [[Halo PC]] Strategy Guide''', ''page 5''</ref> by the [[Office of Naval Intelligence]]'s [[Materials Group]], the MJOLNIR powered assault armor was a radical redesign from previous large bulky exoskeletons, streamlining their design into a compact suit of armor practical for use in the field. The brainchild of Dr. Catherine Halsey, the MJOLNIR armor represented her vision of creating a slim powered exoskeleton capable of taking full advantage of the physical capabilities of a SPARTAN-II.<ref name="Sybex"/> Planning and research for the revised MJOLNIR battlesuit began in 2511<ref name="halsey1">'''[[Dr. Halsey's personal journal]]''' ''July 30th, 2511 entry''</ref> alongside the SPARTAN-II project; over the course of fourteen years its development gave birth to many new technologies that would later see major adoption throughout the military. 

MJOLNIR is a sealed system capable of [[extra-vehicular activity]] or operations in toxic atmosphere and vacuum. It is hardened against [[electromagnetic pulse]] and radiation, and has filters that are completely effective at removing toxins and bacteria from local atmosphere.<ref name="xbox">'''[http://www.xbox.com/en-US/games/h/halo/spotlight2.htm Master Chief's Armor: An Overview]'''</ref><ref name="FoR120">'''Halo: The Fall of Reach''' ''page 120'' ''page 143'' (2010 edition)</ref>

The armor's outer shell is composed of a multilayer alloy of remarkable strength which has been augmented with a refractive coating capable of dispersing a limited amount of Covenant [[Directed energy weapon|energy weapon]] impact.<ref name="xbox"/><ref name="FoR">'''Halo: The Fall of Reach''' ''page 114-115'' ''page 137'' (2010 edition)</ref> Underneath the alloy shell is a thick black armored titanium nanocomposite bodysuit. Underneath that layer is a gel-filled layer. The gel layer regulates temperature and can reactively change its density in a few seconds.<ref name="xbox"/><ref name="FoR"/> The inner skinsuit is made of a moisture-absorbing synthetic material linked to an environmental control computer and the occupant's [[Spartan neural interface|special-issue neural interface]].<ref name="xbox"/><ref name="FoR"/> This network translates electrochemical signals to digital code and routes them through an interface connection at the rear of the skull.<ref name="xbox"/> Through this interface the user's thoughts commands the armor's movement and weapons and input from the on-board sensors comes directly to the user's mind.<ref name="xbox"/> The synthesis of machine and mind is so fast that it is almost impossible to chart the reaction time. Unfortunately, the system is so reactive that normal human beings cannot use the suit without injuring or even killing themselves. Only humans who have undergone the skeletal, neural and muscular [[Biological augmentation|augmentation]] shared by the Spartans are able to safely operate the suit.<ref name="for115">'''Halo: The Fall of Reach''', ''page 115'' ''page 138'' (2010 edition)</ref>

Sandwiched between the external armor and the internal padding is the most devastating weapon the suit carries: a layer of [[polymerized lithium niobocene]], a form of reactive metal liquid crystal.<ref name="xbox"/> Woven by molecular tools into a super-dense layer, this layer is amorphous, yet it amplifies force, doubling lifting capability and increases reaction time by a factor of five.<ref name="Sybex"/> Such technology did not exist when work began on the [[MJOLNIR Powered Assault Armor#Mark I exoskeleton|Mark I prototypes]].<ref name="Sybex"/><ref>'''Halo: The Fall of Reach''' ''page 70'' ''page 89'' (2010 edition)</ref>

Because of these advancements the design is more akin to an actual suit of armor as opposed to a powered exoskeleton; the user moves the suit and in return the suit moves the user. This allows for an highly compact design when compared to other combat systems. The armor contains numerous features including an integrated computer system which continuously monitors weapons, biological functions, and a limited function motion sensor system. The suit also contains a built-in rebreather system that can provide air for up to 90 minutes.<ref name="FoR120"/> The suit's helmet also features imaging and video recording, and thermal sensors among other features.

In its final phase the MJOLNIR armor weighs half a short ton (453.6 kilograms),<ref>'''Halo: The Fall of Reach''' ''page 2'' ''page 16'' (2010 edition)</ref> and was at the time of its creation the most advanced piece of tactical military hardware in human hands.<ref name="xbox"/>

==Armor platforms==
[[File:Mark_IV_schematic.jpg|200px|thumb|A schematic used by Dr. Halsey for the development of future Mark IV variants.]]
Throughout the [[Human-Covenant War|Covenant War]] the Mark IV saw several generational design changes and became a testbed for new technologies and hardware to help improve its integrity and efficiency in certain combat conditions.<ref name="mjolnir">'''[http://halo.xbox.com/en-us/intel/theuniverse/tech/video/the-mjolnir-project-1/cf313a1a-e1e5-4be8-a9a2-7071eda6ca8f Halo Waypoint: The MJOLNIR Project Part 1]'''</ref> While some of these variants are rumors and have never been witnessed in the field, others have become common knowledge.<ref name="eync8889">'''[[Halo Encyclopedia]]''' ''pages 88-89''</ref> By [[2535]] fourteen variants had already been developed.<ref name="journal">'''Dr. Halsey's Personal Journal''' ''January 7th, 2535 entry''</ref> Mark IV went through multiple external design iterations<ref>[http://halo.xbox.com/blogs/Headlines/post/2012/07/19/The-Halo-Bulletin-71812.aspx ''The Halo Bulletin: 7.18.12'']</ref> and variants designed for a specific purpose tend, by necessity, to look different from the contemporary core model.<ref name="way-mjol"/> However, each generational "Mark" is categorized by its internal components and software suit, not by its superficial design: therefore, while a first-generation Mark IV suit may look drastically different from a third-generation suit, they are still essentially the same model.<ref name="way-mjol">'''[http://halo.xbox.com/en-us/intel/related/video/the-mjolnir-project-2/46e89c1a-f619-41e2-ad7f-ab65c61ca2df Halo Waypoint: The MJOLNIR Project Part 2]'''</ref>   

<!--Please do not add Mark IV into the titles below as the Mark categorization was not mandated until 2535.--> 
===First prototypes===
There were numerous early prototypes of the Mjolnir armor. One such prototype was upgraded to withstand concussive force; the design of this prototype was later used for the [[GRENADIER-class Mjolnir|GRENADIER]] armor system.<ref name="EVGG">'''[[Halo: The Essential Visual Guide]]''' ''- Page 85''</ref>

===Functional prototype===
The Materials Group developed this prototype to test the technologies that were being developed for the MJOLNIR battlesuit. In February 2525 this model was sent to [[UNSC Special Forces#Naval Special Warfare Command|Naval Special Warfare]] for evaluation and final testing. Over the next four months the model was tested to ensure proper function and to evaluate its capabilities. The prototype was built and fine-tuned for the SPARTAN-II supersoldiers. A test was conducted to see if a normal human could operate the suit. Because of an override in the prototype's safe mode to prevent unintended use, the operator was killed by his own muscular twitch.<ref name="for115"/><ref name="hals2">'''Dr. Halsey's Personal Journal''' ''June 30, 2525 entry''</ref> A short time after the failed demonstration limited production of the MJOLNIR battlesuit was approved.<ref name="hals2"/>

===Initial production model===
Five months after production began the MJOLNIR PAA entered service.<ref name="hals2"/> The initial version was bulky, angular, and restrictive in mobility. Due to its design philosophy being centered around a human insurrection this model was not adequately prepared for dealing with advanced alien technology and weapons.<ref name="journal"/> Although highly advanced the suit entered service in an accelerated state due to the Covenant threat. As such, upgrades to the suit were already in the works when it was issued to the Spartans;<ref name="journal"/> at least seven variant models had been introduced by [[2526#April|April 2526]].<ref name="TAS"/><ref name="FUD">''Halo 4: Forward Unto Dawn''</ref> In [[2531]] the suit was replaced by a generational upgrade to better combat the alien threat.<ref name="mjolnir"/><ref name="journal"/>

===Final production model===
By 2535 the MJOLNIR system had become the single most expensive item ever produced by the UNSC.<ref name="Halo page 45">'''Halo: Ghosts of Onyx''' ''page 45''</ref> It had been intended as a continuous, pioneering effort to shatter technological barriers. However, with each suit costing as much as a [[UNSC destroyer|destroyer]] to manufacture<ref>'''Halo Legends''', ''Halo: The Story So Far''</ref> the budgetary commission overseeing the MJOLNIR project mandated a simplified generational system to categorize, prioritize, and serialize development neatly into fiscal-year budgets. Thus the "Mark" system was added to MJOLNIR, with the current version being retroactively designated "Mark IV" to suggest continuity with the powered exoskeleton program that had preceded MJOLNIR's development.<ref name="hals3"/>

With the adoption of the "Mark" categorization, an updated model of the suit that had entered service four years earlier was adopted as the standard-issue suit. Its design would inform all future "Mark" generations. The third-generation suit included numerous improvements not available at the beginning of the war, including a standardized vacuum survival system, standard fusion power, and a new radar sensory package.<ref name="hals3">'''Dr. Halsey's personal journal''' ''January 7, 2535 entry''</ref>

==Armor variants==
===Advanced Hardware Program===
The MJOLNIR Advanced Hardware Program concerns the development and furthering of hardware and technologies for testing, evaluation, and incorporation into later versions of the MJOLNIR armor. The original goal of the program was to produce new technologies to aid the Spartan-IIs in the war against the Covenant,<ref name="eync8889"/> such as the prototypical [[energy shielding]] tested by [[Red Team]] in [[2531]].<ref>'''Halo: The Essential Visual Guide''', ''page 119'': ''"Energy shielding was a key feature of Mark V, although other Spartan squads had field-tested prototypes of this technology as early as 2531."''</ref><ref>[https://www.youtube.com/watch?v=E2geKWjvhPY YouTube: Halo Canon Exclusive Interview]</ref> Any changes in appearance of the armor are for research and development of future MJOLNIR components.<ref name="eync8889"/>

==Suits==
The MJOLNIR Mark IV platform had several different variants of suits used during its lifespan, with numerous helmets compatible with it.

===Base suit===
This suit was the one that was first distributed to [[Spartan-II]]s during the [[Battle of Chi Ceti IV]].

====Variants====
[[File:TFoR AS - Baby Blue Team.jpg|thumb|250px|Various types of Mark IV armor worn by [[Blue Team]] during the Battle of Chi Ceti IV.]]
*'''[[AIR ASSAULT-class Mjolnir|MJOLNIR/AA]]''' - Air Assault - Developed as an improvement of the ODST armor.<ref name="EVG">'''[[Halo: The Essential Visual Guide]]''' ''page 4''</ref>
*'''[[CQC-class Mjolnir|MJOLNIR/CQC]]''' - CQC - Variant for close-quarters combat, including boarding actions and [[Wikipedia:Military Operations in Urban Terrain|MOUT]].<ref name="armor"/>
*'''[[EOD-class Mjolnir|MJOLNIR/EOD]]''' - EOD - Variant that improves the survivability of the user in close proximity to an explosion.<ref name="armor">'''Halo: Reach''', ''The Armory''</ref>
*'''[[GRENADIER-class Mjolnir|MJOLNIR/G]]''' - Grenadier - An up-armored prototype based on the 2535 model of the Mark IV (the first to bear the Mark IV designation) that was used as a testbed for incorporating [[energy shielding]] technology into the MJOLNIR program.<ref name="armor"/>
*'''[[COMMANDO-class Mjolnir|MJOLNIR/K]]''' - Commando - Developed to improve a Spartan's tactical awareness on the battlefield.<ref>'''Halo: The Essential Visual Guide''', ''page 33''</ref>
*'''[[OPERATOR-class Mjolnir|MJOLNIR/Operator]]''' - Operator - Variant for the ONI's Beta-5 Asymmetrical Action Group.
*'''[[PILOT-class Mjolnir|MJOLNIR/Pilot]]''' - Pilot - A variant developed for use by the [[UNSC Air Force]] that was adapted for compatibility with Mark IV.<ref>'''Halo: The Essential Visual Guide''', ''Pilot page''</ref>
*'''[[SCOUT-class Mjolnir|MJOLNIR/S]]''' - Scout - Variant uses advanced materials to provide stealth properties.

====Unidentified variants====
*'''Mark VI-like variant (2525)''': John-117 was equipped with this variant during the [[Battle of Chi Ceti]] on [[2525#November|November 27, 2525]]. It resembles a cross between Mjolnir's initial production model and the later [[Mark VI]]. [[Cortana]]'s upgrade of John's Mark VI suit superficially resembles this model, particularly in the shape of the helmet.<ref>''[[Halo 4: The Essential Visual Guide]]'', page 10</ref>
<gallery>
File:TFoR Animated - John Mark IV.png|John wearing the variant aboard the Covenant vessel ''[[Unrelenting]]''.
File:TFORAS_MarkIV_Helmet_Turnaround.jpg|Turnaround of the helmet.
File:TFORAS_MarkIV_Armor_Turnaround.jpg|Turnaround of the armor.
</gallery>

*'''Argus-like variant''': Linda-058 wore this helmet during the Battle of Chi Ceti. It is very similar in appearance to the Mark VI Argus helmet she would later wear.
<gallery>
File:Mark IV Argus.png|Linda wearing the variant.
File:TFORAS_Argus_Helmet_Turnaround.jpg|Turnarounds of the Mark IV Argus helmet.
</gallery>

*'''Centurion-like variant''': Fred-104 wore this helmet during the Battle of Chi Ceti. It is very similar in appearance to the Mark VI Centurion helmet he would later wear.
<gallery>
File:Mark IV Centurion.png|Fred wearing the variant.
</gallery>

*'''CQB-like variant''': Though the [[CQB-class Mjolnir|CQB variant]] proper did not enter service until 2535, the helmet's architecture saw use as early as 2525,<ref>[https://www.halowaypoint.com/en-us/forums/db05ce78845f4120b062c50816008e5d/topics/about-that-fall-of-reach-animated-series-trailer/e114975f-ddcc-4109-bf72-e4d8efc29ec5/posts?page=2#post37 '''Halo Waypoint''': ''GrimBrotherOne'': Nothing has changed about the CQB variant of the Mjolnir armor system. Samuel is utilizing a developmental helmet permutation that shares visual cues with the eventual CQB. This kind of cross-germination of physical shape and design between all Mjolnir platforms was pervasive in the early development of Mjolnir at the Materials Group facilities.]</ref>
<gallery>
File:HTFORTAS Mark IV CQB-like Mjolnir.png|[[Samuel-034]] wearing a proto-CQB helmet at Chi Ceti IV in November 2525.
File:Homecoming_DaisyCQB_Concept.png|[[Daisy-023]] wearing a CQB-like helmet.
</gallery>

*'''EVA-like variant''': A Spartan-II was issued this helmet during the Battle of Chi Ceti.
<gallery>
File:Mark IV helmet unknown fishbowl.png|A Spartan-II equipped with the helmet.
</gallery>

*'''Hermes-like variant''': Kelly-087 wore this helmet during the Battle of Chi Ceti. It is very similar in appearance to the [GEN2] Hermes helmet she would later wear.
<gallery>
File:Mark_IV_Hermes.png|Kelly wearing the Hermes-esque helmet.
File:TFORAS_Hermes_Helmet_Turnaround.jpg|Turnaround of the Mark IV Hermes-like helmet.
</gallery>

*'''Unspecified variant''': During the Battle of Chi Ceti, a Spartan-II tested out this helmet.
<gallery>
File:Mark IV helmet Prefect-like.png|A Spartan-II wearing helmet.
</gallery>

===Mark-V(B)-like suit===
Around [[2526]] to [[2546]] a variant of suit was utilized that looks similar to Mjolnir [[B-class Mjolnir|MJOLNIR/B]].
====Variants====
*'''[[B-class Mjolnir|MJOLNIR/B]]''' - B - Variant worn by [[Fred-104]] during the [[Battle of Circinius IV]].<ref name="FUD"/>

====Unidentified suit====
*'''Air Assault-like''': During the Battle of Circinius IV in April 2526, [[Kelly-087]] utilized a variant that had similar architecture to Air Assault armor. She wore the helmet in conjunction with the [[B-class Mjolnir|Mark IV (b) armor]].<ref name="FUD"/>
<gallery>
File:FuD Kelly variant.png|The variant worn by Kelly-087 in April 2526.
File:H4FUD Kelly and John.png|Another look of the armor worn by Kelly-087 in April 2526.
</gallery>

===Mark-VI-like suit===
Around [[2526]] to [[2546]] a variant of suit was utilized that looks similar to Mjolnir [[Mark VI]].

====Variants====
*'''[[EVA-class Mjolnir|MJOLNIR/V]]''' - EVA - Variant that specialized to improve survivability of Spartans when performing extra-vehicular activity in vacuum.

====Unidentified variants====
*'''Mark VI-like variant (2526)''': John-117 was outfitted with this variant during at least three separate engagements during the [[Human-Covenant War]]. Considerably slimmer than Mjolnir's initial production model, this variant bears a strong resemblance to the later Mark VI.
<gallery>
File:H4FUD-MasterChief-John117.png|John wearing the variant on [[Circinius IV]] in [[2526]].
File:H4FUD-MasterChief-MkIV-Views.png|John wearing the Mark VI-like variant.
File:Homecoming_John117_Concept.png|John's armor during the time of Daisy-023's death.
File:HaloLegends-MasterChief.png|John wearing the armor during [[Operation: WARM BLANKET]] in [[2544]].
</gallery>

*'''Mark VI-like variant (2544)''': [[Solomon-069]], [[Arthur-079]], and Fred-104 utilized this helmet during [[Operation: WARM BLANKET]]. The only notable difference between this variant and the similar model John wore during the operation is the more prominent external rebreathers.
<gallery>
File:Mark IV helmet unknown.png|Solomon-069 wearing the helmet during Operation: WARM BLANKET.
File:Fred Combat Knives Halo Legends.jpg|Fred-104 wearing the same variant.
</gallery>

===Unknown Mark IV suit===
*'''Gray Team variant''': [[Jai-006]] of [[Gray Team]] wore a distinct variant of the Mark IV in [[2535]]. Another member of Gray Team wore armor with a wider left pauldron.<ref>''Halo: The Cole Protocol'' cover art</ref>
<gallery>
File:CP armor.png|A member of Gray Team wearing the variant at [[the Rubble]].
File:Grey_Team_Mark_IV_variant.png|Jai-006 in his Mark IV armor.
</gallery>

===Project: COBALT===
[[Project COBALT|Project: COBALT]] is a project that introduced a new chassis of Mark IV for [[Blue Team]] to use during the [[Human-Covenant War]].<ref name="HCDHBJ117">''[[Halo: Collateral Damage]]'', Hardcover bonus - John-117</ref>

===GEN2===
====Hybrid GEN2/MARK IV [GEN1]====
After the [[Human-Covenant War]], a [[MJOLNIR Powered Assault Armor (GEN2)|GEN2]] variant was developed that uses many components of the original Mark IV armor after firmware updates. This suit is still used as of [[2558#October|October 2558]],<ref name="H5G"/> with [[Tom-B292]] using the armor's forearms.<ref name="GC">[https://www.halowaypoint.com/en-us/news/golden-clouds '''Halo Waypoint''': ''Community Update - Golden Clouds'']</ref>

<gallery>
File:H5-Guardians-Mark-IV-Gen1-Blue-FrontBack.png|The Mark IV adapted for MJOLNIR [GEN2].
</gallery>

====Red Team's hybrid GEN2/MARK IV====
After Douglas-042's Mjolnir Mark IV armor was damaged by [[Atriox]] in May [[2559]], core components of the suit could not be replicated by the ''Spirit of Fire''. Red Team took advantage of the GEN2 parts recovered from UNSC outposts, reverse-engineered solutions developed by [[Serina]], and deft modifications made by [[Isabel]] to stay in the fight. The potential amalgamation of these changes could lead to completely new design permutations, customized for the needs of each Spartan.<ref name="art of war">[https://www.halowaypoint.com/en-us/news/the-art-of-war-s '''Halo Waypoint''' - ''Canon Fodder: The Art of War(s)'']</ref><ref group="note">[[Jeff Easterling]] [http://www.haloarchive.com/forum/topic/9-canon-fodder-and-random-lore-chat/?do=findComment&comment=216910 confirmed] that the armors' appearance in ''Halo Wars 2'' differs between [[Blur Studios]]' cinematic models and [[Creative Assembly]]'s in-game models due to resource management.</ref>
<gallery>
File:HW2-Spartan.jpg|GEN2 Mark IV
File:Jerome Halo Wars 2 leader portait.png|Jerome's GEN2 Mark IV.
</gallery>

==Inner armor components==
*'''Inner skinsuit:'''
The inner skinsuit is made of a moisture-absorbing synthetic material linked to an environmental control computer and the occupant's neural interface. It controls the suit's temperature and actively changes how the suit fits the user.<ref name="for115"/>

*'''[[Hydrostatic gel]]:''' 
On top of the inner skinsuit is a gel-filled layer, which regulates the temperature of the suit and can change its density to conform to the wearer's shape. The temperature inside the suit is controlled by the moisture absorbing cloth suit underneath the hydrostatic layer. The hydrostatic gel layer can also be pressurized to various levels to potentially save the wearers life should the wearer be subjected to high G forces or a high velocity impact; however, over-pressurizing this layer can cause nitrogen embolisms.<ref>'''Halo: First Strike''' ''page 13'' ''page 20'' (2010 edition)</ref><ref>'''Halo: Ghosts of Onyx''' ''page 36''</ref> 

*'''[[Polymerized lithium niobocene|Liquid metal crystal piezoelectric layer]]:'''
Fitted in between the outer plates and the inner padding, is a layer of liquid crystal within a piezoelectric material that deforms along a preferred axis when exposed to an electric charge.<ref name="journaljul">'''Dr. Halsey's Personal Journal''' ''July 11th, 2511 entry''</ref> This layer acts as a sheath or a suit artificial muscle; this reactive piezoelectric effect increases the strength, reaction time, mobility, speed, and all around physical performance of the suit's user.<ref name="journaljul"/> The material is amorphous, thus circumventing a major obstacle in its design: custom-fitting millions of the polygonal pieces under the second armor layer.<ref name="journalsep">'''Dr. Halsey's Personal Journal''' ''September 1st, 2525 entry''</ref> Knitted together at a molecular level the liquid crystal material is merely "poured" into a multilayered Sierpinski capillary system where microelectric fields can direct crystallization geometries.<ref name="journalsep"/> The only downfall is the materials production, which involves classified super-toxic precursor materials and requires a zero-gravity environment.<ref name="journalsep"/> As such this layer accounts for over eighty percent of the MJOLNIR armors cost of construction and materials.

*'''[[Pressure seal]]:'''
The pressure seal is a vital component to the MJOLNIR system as it keeps the system airtight whether underwater, in vacuum, or in a hostile atmosphere. The seal is very strong and will only break under extreme pressure, such as in a high velocity impact or when the hydrostatic gel has been over-pressurized.{{Citation needed}} 

*'''Titanium nanocomposite bodysuit:'''
Sandwiched between the external armor and the internal padding is a thick, black armored bodysuit. This suit has numerous functions, small but vital to the safety and survival of the wearer. The bodysuit is made of a titanium-based material, making it very strong and yet very flexible. It also serves as another layer of protection against ballistics attacks and is coated with a heat resistant material to disperse heat from plasma weapons.<ref name="enyc"/>

*'''Lock-down system''': The lock-down system protects muscles and joints from traumatic, high-impact injuries by seizing the suit into a rigid posture through modifying the density of the hydrostatic gel layer.<ref>'''Halo 3''', level ''[[Arrival]]''</ref><ref>'''Halo Encyclopedia''', page 91</ref><ref>'''Halo: Reach''', campaign level ''[[Tip of the Spear]]''</ref><ref>[http://www.youtube.com/watch?v=eLmtVh_bmhs '''Youtube''': ''Halo Reach Legendary Edition'' developer commentary, part 4]</ref><ref group="note">No source has stated that the Mark IV was equipped with a lock-down system. However, this article assumes that the Mark IV did possess such a system, due in part to [[Jorge-052]] being able to lock his upgraded Mark IV/G armor in the level ''Tip of the Spear'' in ''Halo: Reach''.</ref>

==Outer shell and components==
The outer shell of the MJOLNIR armor is comprised of a thick titanium alloy. This alloy is very resilient, being nearly impervious to small arms fire. While enough impacts from armor-piercing rounds will breach the outer shell, the suit can take a few glancing blows from them without compromising the armor. The outer shell of the MJOLNIR suit is covered with a refractive coating to help disperse the heat discharged by Covenant energy weapons. However, one or two direct hits from any plasma weapon will compromise the armor plating.<ref name="enyc">'''Halo Encyclopedia''' ''page 90''</ref>  

*'''Integrated Communications Helmet:'''
The MJOLNIR helmet (properly the Integrated Communications Helmet) is one of the most vital aspects to the MJOLNIR armor system. It is made of [[titanium]] and features a [[heads-up display]] (HUD) that links to the brain and hands; the HUD can identify equipment and display information about it when it is picked up by the wearer. It also features an environmental control unit that includes filters to remove toxins from the atmosphere, as well as a rebreather to automatically supply oxygen to the wearer during EVA. In addition the helmet contains thermal and motion sensors, communications, solar-powered lighting, and imaging and video gear.<ref name="hals3"/>

The helmet's most important feature is the direct neural-interface system which connects to a Spartan's neural implants. Two core processor chips are implanted into the subject's skull in the rear of the head. This is essentially comparable to an on-board computer using parts of the human brain for processing - when the connector at the rear of the subject's head and receptors in the brain link to the helmet's on-board sensors it creates the neural link needed to move the MJOLNIR suit.<ref name="hals3"/>

The first-generation helmet was retained for use with the 2535 model<ref>[[:File:Mark IV schematic.jpg|2535 Mark VI schematic]]</ref> and was later upgraded for use with the Mark V.<ref>[http://www.readyuplive.com/forum/showthread.php/5088-Halo-Reach-Armory-*COMPLETE-LIST* ''Halo: Reach'' Armory - hosted by Ready Up Live]</ref>

*'''Titanium alloy outer shell/chest:'''
The titanium chest plating provides maximum ballistics protection across all generations of the Mark IV. The original version consisted of wide plating to allow for free rotation of the head and neck; the external microphone was located below the collar area and below that an environmental control unit. This model also had large arm sockets and the waist area consisted of free-rotating bearings which lock into the lower body or jumper armor section. Later versions of the chest plates are more angular and are joined via a hinge system on both the central brace and the shoulder connectors, allowing them to rise and fall with the user's movements.<ref name="hals3"/>

*'''Titanium alloy outer shell/arms:'''
The first version's shoulder and arm plating consisted of an organic shape with larger shoulder area for ample protection; the upper assembly piece sat flush inside the upper-arm armor. The elbow armor was hinged to fit flush when the wearer's arm was straight, making hyperextension impossible without force adequate to destroy the plating. The forearm armor is the same with locking pieces to prevent over-rotation and the lower portion is attached to the handguard. The range of motion is adequate for firearm use and hand-to-hand combat, however the guard prevents hyperextension of the wrist. Later revisions to this armor discard this for more nanofabricated pieces and more mobility focused plating. The pauldrons are mounted at a downwards diagonal angle at the upper edge of the shoulder, independently of the armor below them. This allows the lower arm pieces to slide and rotate beneath them, and when the arms are raised, the angled pauldrons move with them.<ref name="hals3"/>

*'''Titanium alloy outer shell/waist:'''
The MJOLNIR armor's torso plating is connected to the upper-torso plating by free-rotating waist connectors the waist plating contains ammunition/utility pouches. The lower-abdomen plate connects into a track for upper torso bending, the codpiece is connected to the femoral-artery armor.<ref name="hals3"/>

*'''Titanium alloy outer shell/legs:'''
The MJOLNIR PAA's leg armor consists of two major plating sections, with a third piece protecting the knees. The earlier version of the armor consisted of the thigh armor which is actually two sections held together by two locking collars, the knee pads are secured on the sides. The lower leg contains reinforced piezoelectric bladders which secure ankle and lower legs to prevent impact injury from high-elevation jumps. The boots consist of 15mm-thick soles, which are secured by a foot covering hinge locking bolt.<ref name="hals3"/>

*'''Magnetic weapon holder strips:'''
Available on updated outer armor components of the Mark IV the magnetic strips are very small yet powerful magnets placed on the legs, waist, and back of the suit and is used to hold any equipment with a magnetic property. The suit also contains a magnet system on the boots of the MJOLNIR suit that allow its wearer to stay attached to a metal surface in zero-G environments and can be toggled on or off by the wearer. In addition to the magnetic holders, the default Mark IV is also equipped with utility pouches on the waist and a clip for a holster capable of accommodating most UNSC sidearms.<ref name="journal"/><ref name="hals3"/>

*'''Biofoam injector port:'''
The [[biofoam]] injector is a port where a direct supply of biofoam or other medicines must be administered from a standard military first aid kit when the wearer is injured, as the suit does not hold or generate its own supply inside the suit.

*'''Fission reactor:'''
Integrated in the limited production model of the MJOLNIR PAA the nuclear fission reactor was the MJOLNIR armors source of power, the reactor was built into the suit and allowed for unlimited power. However, because of the delicacy and radioactive nature of the fission reactor its use was limited until it was replaced with a micro-fusion plant in the final production model in 2535.<ref name="Halo page 45"/><ref name="hals3"/>

*'''Microfusion reactor:'''
Integrated in the final production model in 2535, the microfusion cell is the most vital component to the MJOLNIR system as it provides power to all components of the MJOLNIR armor. The reactor is built into the suit and allows for nearly unlimited power. The fusion reactor in all versions of the MJOLNIR armor is half the size of a normal battery pack that conventional marines carry around.<ref>'''Halo: The Fall of Reach''' ''page 114'' ''page 137'' (2010 edition)</ref>

*'''[[MJOLNIR power supply control unit|Power supply control unit]]''': 
The power supply control unit is integrated into the miniature fusion reactor located on the back of the MJOLNIR suit. It provides power distribution to the suit's functions and can be overloaded when too much power is allocated to one function or all functions for long periods of time.

*'''[[Fail-safe detonation system]]''':
This system functions as a self-destruct mechanism in order to prevent a dead Spartan's armor from being compromised by hostiles. It is activated by a series of digits that only the Spartans know. When engaged, it produces a reactor overload that burns everything within a ten-meter radius, then produces a large blast.<ref>'''Halo: First Strike''', ''page 315''</ref>

*'''Thruster pack''':
Located at the back of the suit beneath the fusion reactor, this component provides the ability to propel the MJOLNIR user over short distances and maneuver in zero-gravity environment.<ref name="TAS">'''[[Halo: The Fall of Reach - The Animated Series]]'''</ref><ref>'''Halo 4''', ''[[Prologue]]''</ref><ref>'''[[Halo Mythos]]''', ''page 61''</ref><ref group="note">The ''Halo 4'' Prologue cinematic and ''Halo: The Fall of Reach - The Animated Series'' depict the Mark IV with built-in thrusters. In the novels, however, the Mark IV is described as requiring a separate thruster pack attachment for maneuvering in a vacuum. [https://www.halowaypoint.com/en-us/universe/tech/jetpack Halo Waypoint notes] that integrated thruster packs were added in a later phase of MJOLNIR GEN2 upgrades (presumably in [[2558]]), despite the GEN2 models in ''Halo 4'' appearing to possess the hardware already. It is unlikely that the Mark IV would feature maneuvering jets only for the technology to be abandoned until GEN2's release. The depictions of the Mark IV with built-in thrusters may stem from the admittedly non-canonical use of John-117's unique Mark VI armor in the Prologue cinematic, while the use of built-in thrusters in ''Halo: The Fall of Reach - The Animated Series'' may be due to simplification for the sake of the visual medium.</ref>

==Performance and durability==
{{Quote|As I suspected, nothing but a man.|Atriox crushing Douglas-042's Mark IV helmet.<ref name="TS">''[[Halo Wars 2]]'', campaign level ''[[The Signal]]''</ref>}}
[[File:Chief gets hit by a Hunter shield.png|thumb|250px|Mark IV MJOLNIR armor taking a hit from a Mgalekgolo's shield.]]
The Mark IV armor was the most advanced piece of military equipment humanity had created at the time of its distribution. This iteration of MJOLNIR is extremely resistant to gunfire, with most bullets simply bouncing off of the armor. Its gauntlets are also capable of shattering concrete without being damaged.<ref>'''Halo: The Fall of Reach''' ''page 134'' (Definitive edition)</ref> The armor is able to take the blunt force of a two-ton [[Mgalekgolo]]'s shield strike while simultaneously keeping the Spartan alive in the process.<ref name="FUD"/><ref>'''Halo: Ghosts of Onyx''' ''page 360''</ref> The helmet of Mark IV is extremely durable as well, being capable of withstanding the force of a gravity hammer swing by a Brute and sustaining the Spartan's life for a short period of time thereafter.<ref>''Halo Legends'', "The Babysitter"</ref> The armor itself, albeit able to withstand such heavy blows, is not designed to continuously withstand high pressure or power. Douglas' left shoulder was broken after Atriox's armored hand was able to break through his armor.

During the Skirmish over Netherop, the Spartans of Green Team, Gold Team, and Blue Team launched themselves from the ''Starry Night'' during the vessel's slingshot manoeuvre. Although they eventually yielded against an abrupt roll in their trajectory, the Spartans clutching one another in a swaying column behind their respective team leaders proved strong enough to hold fast in the moment of their linear course; despite having thirty gees of force being applied against them.<ref>'''Halo: Silent Storm, page 13'''</ref>

On-board their targeted Covenant vessel, John displayed a level of strength sufficient to pry open one of the ship's interior iris hatch-panels with his bare hands.<ref>'''Halo: Silent Storm, page 43'''</ref> A month afterwards, in a Covenant space elevator near the planet Naraka, John used his armor's strength enhancements to launch a Covenant pickup vehicle onto the far side of a large conveyor belt - providing cover for an M41-equipped ODST to barricade himself behind.<ref>'''Halo: Silent Storm, page 345'''</ref> Later, in the upper-terminus leading to a transit tube, John encountered an emergency iris hatch - this time, denting the thick panels with a frustrated bang of his fist.<ref>'''Halo: Silent Storm, page 362'''</ref>

Demonstrated during the Battle of Sigma Octanus IV, John-117, Kelly-087, and Fred-104 shifted a large, cuboid quartz monolith.<ref>''Halo: Fall of Reach - Covenant''</ref> Massing approximately 143 tonnes,<ref>''Halo: The Fall of Reach'' novel describes the monolith as being a 3x6 meter shard of silicon dioxide, which has a density of 2.65 tonnes per cubic meter.</ref> this performance of strength would require each MJOLNIR-equipped Spartan-II to apply an average force ranging from 19 to nearly 48 tonnes<ref>quartz-on-quartz is functionally similar to glass, which features a static friction coefficient ranging between [https://www.engineeringtoolbox.com/friction-coefficients-d_778.html 0.4 to 1.0µ].</ref> into the monolith.<ref group="note">This correlates well with the forces Blue Team resisted in their Mark IV MJOLNIR armor during the Skirmish over Netherop; where the Spartans experienced 30 gees of force against the slingshot maneuver from the ''Starry Night''.</ref>

Though if the armor takes damage it is no longer vacuum-sealed, this can be rectified using armor patches which seal the holes and make the armor vacuum-sealed again. Mark IV MJOLNIR armor is compatible with the patches used by [[ODST]]s on their armor, making it easier to get extras in a combat situation. This was used twice by [[Blue Team]] during the Attack on Naraka to seal their armor when going into vacuum after the armor had sustained such damage that it was no longer vacuum-sealed. The lack of armor patching during the [[Battle of Chi Ceti]] had forced [[Samuel-034]] to remain behind on the ''[[Unrelenting]]'' to die, causing the Spartans to start carrying armor patches in case such a situation ever arose again.<ref>'''[[Halo: Silent Storm]]'''</ref>

{{Clear}}

==In-game information==
===''Halo 5: Guardians''===
'''Unlock''': Mythic [[REQ]] card
*Helmet Description: A battered Mark IV helmet once worn by the Master Chief is the last thing that SPARTAN-IV candidates see before beginning their grueling evaluation and preliminary augmentation cycle.
*Body Description: As the basis for the GEN1 Mjolnir standard, many components of the original Mark IV can be used with GEN2 techsuits and VISRs after firmware updates. This hybrid GEN2/MARK IV [GEN1] suit is still used by select Spartan-II's.
'''Available Skins''': Arcadia<br>
'''Arcadia Unlock''': Mythic REQ card<br>

==Trivia==
{{Linkbox|gallery=yes|gallerypage=Images of MJOLNIR Mark IV}}
*The sketches of the limited-production Mark IV in [[Dr. Halsey's personal journal|Doctor Halsey's journal]] are almost identical to [[:File:Masterchief sheik.png|an early concept]] for the MJOLNIR armor, apart from the helmet.
*Kelly-087's and Fred-104's Mark IV suits in ''Halo 4: Forward Unto Dawn'' are [[Wikipedia:Kitbashing|kitbashed]] from the [[MJOLNIR Powered Assault Armor/AA variant|Air Assault]] and [[MJOLNIR Powered Assault Armor/B variant|Mark V[B]]] suits used in the live-action "[[Deliver Hope]]" trailer for ''[[Halo: Reach]]''. Fred's armor was later canonized as the Mark IV(b), though Kelly's remains unidentified.<ref name="HWFred">[https://www.halowaypoint.com/en-us/universe/characters/frederic-104 '''Halo Waypoint''' - ''Frederic-104'']</ref>
*During the development of ''Halo 5: Guardians'', the Mark IV armor was codenamed "''A088''" when it was conceived.<ref>[https://cdn3.artstation.com/p/assets/images/images/001/660/747/large/airborn-studios-h5-a088-marmo.jpg The link reveals the armor was named A088 during production]</ref>

==Gallery==
===Production===
Early drawings and renders of Mark IV that did not make the cut into the relevant media.
<gallery>
File:XHW - unscunit.jpg|An early model of the MJOLNIR in ''Halo Wars'' alongside a [[Hellbringer]].
File:HW Spartan PromoArt.jpg|An early piece of promotional art for ''Halo Wars'', used for internal briefs for Microsoft.
File:HW_Mjolnir_EarlyRender.jpg|Another early render of the ''Halo Wars'' Mark IV.
File:HW_Mjolnir_Render.jpg|A concept of the ''Halo Wars'' Mark IV.
File:Halo Wars - Mark IV.png|Another early design of the MJOLNIR in ''Halo Wars''. This version is featured in the game's [[Halo Wars announcement trailer|announcement trailer]].
File:MarkIV model.jpg|An early render of the ''Halo Wars'' Mark IV model.
File:XHW - spartan03.jpg|A later pass on the MJOLNIR design from ''Halo Wars''.
File:Mjolnir MkIV.png|An early version of the Mark IV for the Blur cutscenes in ''Halo Wars''.
File:Halo Character Spartan Render.jpg|An early version of the Mark IV for the Blur cutscenes in ''Halo Wars''. 
File:ThePackage John117 Concept.png|Concept art of the Mark IV version featured in ''[[Halo Legends]]'': ''[[The Package]]''.
File:H5GC-MarkIV.jpg|Concept art of the Mark IV for ''[[Halo 5: Guardians]]''.
File:Omega Team.png|Concept art of Omega Team's Mark IV for ''[[Halo Wars 2]]''.
</gallery>

===Normal gallery===
<gallery>
File:Douglas-042.png|[[Douglas-O42]] wearing early Mark IV armor.
File:HWunit Spartan.png|In-game model of a Spartan's armor in ''Halo Wars''. The pauldrons are symmetrical in-game.
File:MarkIV render.png|[[Jerome-092]] in his first-generation suit.
File:The Package poster.jpg|Three Spartans wearing the previous suit with MOS-specific modifications.
File:The Babysitter Cal-141.jpg|[[Cal-141]] wearing a suit resembling the original model on [[Heian]] in ''[[The Babysitter]]''.
File:John117FOReach.png|John-117 wearing the Mark IV on the 2010 reprint of ''Halo: The Fall of Reach''.
File:The Covenant - MJOLNIR.jpg|John-117 in his newly issued MJOLNIR armor in ''[[Halo: Fall of Reach]]''.
File:H4L Awakening 1.jpg|[[John-117]] being equipped with his original MJOLNIR armor in ''[[Scanned]]''.
File:H4L Awakening 2.jpg|Technicians securing the back section of John's MJOLNIR.
File:Covenant assault - Aftermath.png|John-117 wearing the non-canonical Mark IV design from ''Halo 4''<nowiki>'</nowiki>s [[Prologue]].<ref group="note">[[Josh Holmes]] has [https://web.archive.org/web/20160413032116/https://twitter.com/JoshingtonState/status/474224115608731650 confirmed] that the use of John-117's unique Mark VI model to represent the Mark IV in ''Halo 4'''s Prologue cinematic is not canon. The geometry was recycled because the production team did not have time to create a unique Mark IV model that would have only seconds of screen time. ''[[Halo 4: The Essential Visual Guide]]'' notes that John's upgraded Mark VI suit resembles an earlier Mark IV line (likely as a tongue-in-cheek nod to the cutscene), though this does not mean that the two designs are canonically identical. The cutscene uses the same model to represent the Mark V suit John canonically wore when he met [[Cortana]], further invalidating its canonicity.</ref>
File:Spartan-II defense - 2.png|A team of Spartans in the non-canonical ''Halo 4'' armor.
File:MJOLNIR_MARK_IV_ARMOUR.png|The MJOLNIR Mark IV in ''[[Halo: The Fall of Reach - The Animated Series]]''.
File:H5G-MarkIVmodels.jpg|Models of the Mark IV for ''[[Halo 5: Guardians]]''.
File:H5G-Mark IV screenshot.png|A Spartan-IV wearing the hybrid (GEN2)/Mark IV (GEN1) in ''Halo 5: Guardians''.
File:H5G-MarkIV.png|Front and back of the Mark IV for ''Halo 5: Guardians''.
File:H5G-Helmet-MarkIV.png|REQ Card for the MJOLNIR Mark IV helmet.
File:H5G-Armor-MarkIV.png|REQ Card for the MJOLNIR Mark IV armor.
File:H5G-MarkIVSpartanemblem.png|The Spartan emblem on the Mark IV armor in ''Halo 5: Guardians''.
File:H5G-MarkIVArcadia.png|Mark IV Arcadia.
File:TFS-Jeromethrusters.png|Jerome-092 using his Mark IV's thrusters in ''[[Something has Happened]]''.
File:HW2-Shadows.png|Red Team wearing MJOLNIR Mark IV in ''[[Halo Wars 2]]''.
File:HW2-Knivesstilldonothing.png|Douglas-042's Mark IV being crushed by [[Atriox]]'s power gauntlet.
File:HW2-BrokenMarkIV.png|Douglas-042's Mark IV helmet is crushed by Atriox.
File:HW2 Blitz Jerome-092.png|Jerome-092's GEN2 Mark IV in-game.
File:HW2-Jerome-03.jpg|Jerome-092's GEN2 Mark IV in cutscenes.
File:HW2 - Douglas-042 with Mark IV-GEN2 hybrid armor.jpg|Douglas-042's GEN2 Mark IV in-game.
File:HW2-Omega.jpg|Blitz card of Omega Team's customized Mark IV.
File:Halo_Complete_Video_Collection_full_cover.jpg|John-117 wearing his unidentified Mark IV variant on the cover of [[Halo: The Complete Video Collection]].
File:HCD Blue Team.png|Blue Team's Cobalt Mark IVs in ''[[Halo: Collateral Damage]]''.
File:Oblivionart.PNG|John-117 wearing his Mark VI-like Mark IV on the cover of ''[[Halo: Oblivion]]''.
</gallery>

==List of appearances==
{{col-begin}}
{{col-2}}
*''[[Halo: The Fall of Reach]]'' {{1st}}
*''[[Halo: Ghosts of Onyx]]''
*''[[Halo: The Cole Protocol]]''
*''[[Halo Wars]]''
*''[[Halo Legends]]''
**''[[Homecoming]]''
**''[[Origins]]''
**''[[The Babysitter]]''
**''[[The Package]]''
*''[[Halo Evolutions - Essential Tales of the Halo Universe]]''
**''[[Dirt]]''
*''[[Remember Reach]]''
**''[[Deliver Hope]]''
*''[[Halo: Reach]]''
*''[[Halo: Fall of Reach]]''
**''[[Halo: Fall of Reach - Covenant|Covenant]]''
{{col-2}}
*''[[Halo 4: Forward Unto Dawn]]''
*''[[Scanned]]''
*''[[Halo 4]]'' {{C|[[Prologue]] only}}
*''[[Halo: Nightfall]]''
*''[[Halo 2: Anniversary]]''
**''[[Terminal/Halo 2: Anniversary|Terminals]]''
*''[[Halo: The Fall of Reach - The Animated Series]]''
*''[[Halo 5: Guardians]]''
*''[[Halo Mythos]]''
*''[[Halo: Tales from Slipspace]]''
**''[[Something Has Happened]]''
*''[[Halo Wars 2]]''
*''[[Halo: Legacy of Onyx]]'' {{C|Forearms only}}
*''[[Halo: Collateral Damage]]''
*''[[Halo: Silent Storm]]''
*''[[Halo: Official Spartan Field Manual]]''
*''[[Halo: Oblivion]]''
{{col-end}}

==Notes==
<references group="note"/>

==Sources==
{{Reflist|2}}
{{armor}}

{{Armor/Permutation}}
{{Mjolnir}}
[[Category:MJOLNIR Armor]]