Power Armour

Power armour is an advanced form of combat armour, worn primarily by the Space Marines and the Chaos Space Marines. It is a completely enclosed suit of combat armour, composed of thick ceramite plates. The armour would be heavy and cumbersome to wear but for the electrically motivated fibre bundles within the armour that replicates the wearer's movement and enhances his strength beyond its already considerable superhuman baseline (for Space Marines).

Design
Power armour is fully sealed, isolating the wearer from the outside environment and protecting him from chemical and/or biological weapons and toxic atmospheres. It also commonly includes numerous auxiliary systems such as radio frequency communicators, auto-senses, etc.

Space Marines go through an arduous process where they receive various biogenetically-engineered implants culminating with the implantation of the black carapace which allows the Marine a direct and instinctual neural interface with his power armour, transforming it into effectively a second skin. The advanced systems of Space Marine power armour also monitor the Marine's biological functions, feeding the collected medical information to the Marine.

The armour's backpack contains the suit's main power plant, environmental system and additional movement stabilizers.

History and development
Power armour has been in use since before the Age of the Imperium, worn by the techno-barbarians that dominated Earth during the Age of Strife. It was also worn by the genetically-engineered warriors that formed part of the Emperor's retinue during his unification of Earth towards the end of the Age of Strife. In the armour's earliest incarnation, the suit was not fully sealed or life-supporting, this being unnecessary while its use was still confined to Earth. Over the history of the Imperium, power armour has developed into many different forms. Need, circumstances and the recovery of new materials and advanced technology has shaped the armour's evolution.

Mk I Thunder Power Armour
The first Power Armour suit type created for the Space Marines was the Mark I Thunder Power Armour. It was developed from the armour worn by the techno-barbarians that plagued Terra near the end of the Age of Strife. It was used during the Emperor’s campaign to retake and unite the Terran solar system before the Great Crusade. It was by no means unique to the first Space Marines - in fact, the techno-barbarian warriors the Emperor fought during the conquest of Terra wore it too, and the Emperor's forces were wearing it even before the first true Space Marines were developed. However, because it was designed with fighting in a terrestrial environment in mind, it is not fully enclosed, with no means to support the wearer in a vacuum. Only the upper body is powered, due in part to the fact that during the Conquest of Terra, ranged weapons were difficult to make due to technological constraints, and so a warrior's upper-body strength was his most important asset. It takes its name from the thunder bolt symbol the Emperor used before adopting the double-headed eagle known as the Imperial Aquila during the Great Crusade.

Mk II Crusade Power Armour
Mark II Power Armour was developed towards the end of the Age of Strife and was used during the dawn of the Imperium by the Space Marines who carried out the Emperor’s Great Crusade to reunite the lost worlds of mankind in a new Imperium. It was designed as a fully enclosed suit with life-sustaining systems that now allowed the Space Marines to fight in deep space and on alien worlds with hostile atmospheres or environments. The armor was made up of circular armor rings fitted under and over each other, making this armour relatively tedious to repair (see also Lorica Segmentata). These precious relics are still used during formal ceremonies and rituals by some Chapters and given to the Chapter's champions as actual battle armour in others. These suits are also referred to as Crusader Armour. This is the type of Power Armour worn by most Chaos Space Marines, as they have access only to the technology they took with them into the Eye of Terror ten millennia ago. Some Chaos Marines mix and match more modern pieces of armor with their ancient Mk II suits to replace damaged portions. These more modern pieces are stripped from the bodies of Loyalist Space Marines killed in battle.

Mk III Iron Power Armour
As the Great Crusade reached the planets towards the center of the galaxy, some of the worlds encountered were the Squat Homeworlds, which were not pleased to find themselves the object of a galactic conquest. High casualties suffered by the Space Marine Legions during the Crusade led to the development of the Mark III model of Power Armour, best suited for spacecraft boarding actions and combat in confined subterranean tunnel complexes with little cover. This armour was ideally used by Space Marines when cover was minimal and combat was a matter of a simple frontal assault.

The Mk III was intended to be a specialised suit to provide heavier protection than the normal Mark II suit. The frontal armour was much thicker (thereby giving greater protection), but the rear armour was thinner to compensate. The wedge-shaped helmet (designed to deflect incoming fire) formed the basis of the distinctive Corvus Beak helmet.

Mk IV Maximus Power Armour
This armour was to be the replacement for the standard Mk II Power Armour of the Great Crusade era. It was the first suit of Power Armour to incorporate many of the components used in the present-day suits of armour worn by the Space Marines. However, it was made from rare alien materials, and when the Horus Heresy broke out soon after it was issued, it was discovered that most Loyalist Space Marines cut off from supplies could not find the materials needed to make it or repair it, and as a result the armour often suffered irreparable damage in relatively minor battles.



Mk V Heresy Power Armour
This suit of armour was developed as a solution to the supply problems caused by the Horus Heresy. It was manufactured from the most basic of materials, and it was easy to maintain. Almost all of its users used spikes to hold the armour layers together, and the studs of these spikes became a distinctive marker of this version of power armour. In time, it became traditional for the studs to be found on the head, lower legs, and left shoulder pad of the armour.

Due to the sub-standard materials used in the construction of this armor variant, it had a tendency to over-heat quickly, and many Space Marines had to endure sub-standard performance by turning down the power output of their backpack to prevent intolerable heat build-ups.



Mk VI Corvus Power Armour
This classic power armour variant can be traced back to the time of the Horus Heresy and is still commonly used even in contemporary Space Marine Chapters. It is characterized by the beak-like muzzle on the helmet and a studded auto-reactive shoulder plate on the left shoulder of the armour. The beak or muzzle led fans to nickname this variant "Womble armour" or "Beakie armour", and a dictionary of the Orkish language in the 2nd Edition Ork Codex listed Marines as "beakies". This was the style of the first Space Marine models released by Games Workshop and did not get its Mk VI terminology until after models with the Mark VII styling were released. Models with this style were not part of new releases until the launch of the next range of 25 mm plastic models.



Mk VII Aquila Power Armour
This version of basic power armour was also known as Imperator Armour. It is the contemporary variant most commonly used by the Space Marine Chapters of the Imperium. The Mk VII armour is characterised by the grim looking Vox caster (external vocalizer) on the faceplate, and the plastron displaying the Imperialis (a winged skull), which has given the armour different names such as Armorum Impetor or Eagle Armour ("Aquila" being the name of the two-headed eagle which symbolizes the Imperium of Man).

Mk VIII Errant Power Armour
This is an update to the Aquila pattern armour, and is distinguished by a raised collar at the front, and armoured plating for the torso cables. Full versions of this armour are almost never seen; however, it is common to find parts of it being used by Space Marine officers and veterans on the battlefield. The Mark VIII is not widespread in the Imperium yet and it will take quite a few centuries before the Forge Worlds of the Imperium have brought every Chapter up to the new standard.

Design Notes
One design feature of Power Armour suits Mks VI through VIII is their adaptability; it is fairly common within most Space Marine Chapters to see a suit combining parts originally created for three or four different types of suits, salvaged from dead Battle-Brothers on the battlefield. Mk VII armour, in particular, was created with this simple modularity in mind.

Other Imperial Users
Although Power Armour is most closely associated with the Adeptus Astartes, is is also used by the Sisters of Battle, the Grey Knights and some more martial-minded Inquisitors of all three Ordos. However, the Sisters of Battle and Inquisitors who use power armour do not possess the black carapace implant, and so can not be directly linked to the suit's advanced movement enhancement and fire control systems in the way Space Marines are, which decreases the armour's effectiveness. Some members of the Adeptus Mechanicus, the Machine Cult, use power armor. Engineseers of the Imperial Guard use it to protect them from enemy fire as they tend to the machine spirit of Guard vehicles.