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Gameplay articles
Fallout 4X-01 power armor
Fallout 76X-01 power armor

X-01 power armor is a prototype model of power armor developed by the United States shortly before the Great War. It was the last and most advanced model of power armor developed before Great War, and serves as the predecessor to all post-war models of advanced power armor used by the Enclave.


Fo4 Power Armor X01

X-01 power armor

Commissioned by the Joint Chiefs of Staff, the development of the X-01 began shortly before the Great War.[1] It represented a radically new approach to designing powered armor, eschewing traditional design philosophies that defined the T series,[Fallout Bible 1] and was a high-profile research project meant to supersede previous power armor models. However, although the suit was technically functional by late 2077, it was burdened with numerous issues that precluded widespread use in the field. While the first test models were issued to Presidential bodyguards, the X-01 was never deployed in larger numbers.[2] A single suit of X-01 was provided to the Nuka-Cola Corporation, as part of Project Cobalt. While the suit served as a successful proof of concept of using a strontium-90 based plating over the armor,[3] this improvement was not adopted into the armor's schematics, before the onset of the Great War. Further development was made impossible due to the outbreak of the Great War.[1]

After the Great War, a select few suits were engineered further and employed by remnants of the U.S. military, like the Enclave and Brotherhood of Steel, as well as the Institute.[4] The schematics for the armor were saved by the Enclave just before the bombs fell, with the organization keeping copies in the archives of their Poseidon and Whitespring facilities. This allowed the Enclave to create a limited production run of the suits, and for work to eventually continue on the model's development.[1]

Full development was restarted by the Enclave in 2198, although it wasn't until 2215 that the research efforts began in earnest under Presidential mandate, resulting in the creation of the first model of Advanced power armor in 2220.[Fallout Bible 1] Another group to develop upon the X-01 design, after the war, is the Institute. Despite lacking access to the prototype's schematics, by 2287, the Institute had developed a modified polymerized casting mix to coat the armor, as well as other modifications that enhance the user's intelligence.[5]


The X-01 advanced powered infantry combat armor is designed for a single human operator, provided with the comfort and protection of a next-generation suit of armor. While the T-51 power armor relied on a lightweight poly-laminate composite shell for protection, the advanced model uses lightweight metal alloys as basis, reinforced with ceramic castings at key points. The resulting space savings allowed for reducing the armor's profile without compromising protection. Perhaps the most noticeable change was a completely new helmet assembly. The unusual, insect-like design features a pair of polarized eyepieces in place of the usual vision slit, providing superior battlefield awareness. The helmet's eye pieces also served as the suit's lamps, replacing the traditional single-lens attachment used in older models. The helmet's angled surfaces also help maximize the chance of outright deflecting projectiles and incoming fire.[6]

Classic power armor pauldrons were retired in favor of a "hump" that encloses the operator's head, significantly reducing the chance of enemy fire damaging the vital areas surrounding the head. Despite these advancements, the X-01 suffers from severe design flaws that prevent it from seeing large scale deployment.[1]


Prototype X-01 power armorEdit

F76 X01

Prototype X-01 paint scheme

Gameplay articles: Fallout 4, Fallout 76

While all units of X-01 were experimental prototypes, this model represents the earliest functional version of the power armor suit, unfinished before the Great War. The schematics for the armor were saved by the Enclave just before the bombs fell, with the organization keeping copies in the archives of their Poseidon and Whitesprings facilities. This allowed the Enclave a limited production of the suits.

Quantum X-01 power armorEdit

FO4 NW Quantum X-01

Quantum X-01

Gameplay article: Fallout 4

Thanks to strong ties with the U.S. military, the Nuka-Cola Corporation managed to secure a suit of the experimental X-01 Mk V armor just prior to the Great War. The company intended to use the armor as part of Project Cobalt, and to help promote their new Nuka-Cola Quantum soft drink. The corporation plated the armor in a compound made with the strontium-90 isotope used in the Quantum soda, allowing the wearer to more rapidly recover after physical exertion. Only 1 example of this variant was produced before the bombs fell and prevented any further production.

X-01-I power armorEdit

Fo4 Institute Paint

X-01-I "Institute Paint" paint scheme

Gameplay article: Fallout 4

Centuries after the Great War, suits of X-01 were found by The Institute around the Commonwealth. The Institute developed a modified polymerized casting mix to coat them with, among other upgrades that improved the intelligence of the wearer. [7]

Behind the scenesEdit

  • The introduction of the X-01 in Fallout 4 was the subject of a minor controversy, as the lore of the advanced power armor was never published in any of the official games, and it was assumed, based on the Fallout Bible, that it was a purely Enclave design. It wasn't until Nuka-World and Fallout 76 that the armor was established as an experimental pre-War design used by the Enclave as basis for the Enclave developed from 2220 onwards.
  • The designation "X" is used by military R&D as shorthand for "experimental". X-01 translates to "experimental model number 1".


  1. 1.0 1.1 1.2 1.3 Archival terminal, Prototype Power Armor Schematics
  2. X-01 Mk I power armor: "The guys who protected the President wore this. It's THAT good."
  3. Bradberton's office terminal entries#10-20-2076 JCB
  4. Fallout 4 loading screens: "The X-01 series of Power Armor was specially engineered and employed by remnants of the U.S. military after the Great War, and offers increased protection over the older, pre-war models."
  5. Institute paint
  6. Fallout 2 Item description: "{34800}{}{Advanced Power Armor}
    {34801}{}{This powered armor is composed of lightweight metal alloys, reinforced with ceramic castings at key points. The motion-assist servo-motors appear to be high quality models as well.}"
    (PRO ITEM.MSG (Fallout 2))
  7. The Institute skin bears the label "X-01-I P10 POLYMERIZED CASTING MIX C78A18N3G1".

Fallout BibleEdit

  1. 1.0 1.1 Fallout Bible 0:
    "2055 The West Tek Research Facility starts working on a new virus to kill the New Plague. Their viral research and close ties to the federal government eventually lead to them being chosen for the Pan-Immunity Virion Project twenty years later as well as Power Infantry Armor and laser research.
    2065 August Increasing need for mobility in the United States mechanized cavalry leads the military to focus the efforts on creating a man-based tank - essentially, a two-legged walking armored unit: Power Armor.
    2065-2067 Power Armor research grows and several prototypes are developed, many of which prove to be unworkable in the field. These prototypes pave the way for future advances in military, construction, and fusion technology.
    2066 Summer Adding further insult to the Chinese-American relations, the first crude fusion cell is unveiled, one of the results of the Power Armor project. Devices designed for the fusion cell begin to be manufactured. Incorporating fusion power into the general US infrastructure begins, but the process is too slow to supply power to the regions that need it. Nearly eleven years later, few sections of the United States were supplied with fusion power.
    2067 The first suit of Power Armor is deployed in Alaska. While lacking the full mobility of future versions, this Power Armor is incredibly effective against Chinese tanks and infantry. Its ability to carry heavy ordinance becomes key in various localized conflicts, and it has the power to destroy entire towns without endangering the wearer. China rushes to create its own versions, but they are many years behind the United States.
    2074 Contrary to their claims of seeking only to retake Alaska from the Reds, American Power Armor units, infantry, and mechanized divisions are deployed to China, but they become bogged down on the mainland, putting a further drain on American resources and supply lines.
    2076 June Power Armor prototype completed, resulting in the Power Armor players find in Fallout 1. This is the pinnacle of Power Armor technology before the Great War. Many of these units are sent to China, and they begin to carve a swath through the Chinese forces. The Chinese resources are strained to the breaking point, and the supply lines from the nations China has annexed begin to break down.
    2077 January 22 The first domestic use of Power Armor within the United States for crowd and quarantine control. Units originally serving in China and the Anchorage Front Line find themselves fighting Americans at home. Food riots increase, and many civilians are killed. Several soldiers defect from the military both in Canada and the United States. They are captured, and are sent to military prisons.
    2198 Enclave works on various new technologies, including Power Armor variations. None of these are much of an improvement over the conventional old school Power Armor, and some are actually worse.
    2215 Under Presidential Order, Enclave scientists begin to work on an upgraded version of Power Armor. Many prototypes are developed and tested.
    2220 October Enclave scientists develop a reliable version of the Mark II Power Armor. The prototype results (and accidents... and explosions... and deaths) are classified by order of the President Richardson for the sake of morale."
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