Jupiter

The great gas giant of **Jupiter** is the primary Forge World of the Jovian Mechanicum and used to be the fifth world of the Sol System in the Proxima Solar, but due to the event now known as the The Sol Scouring it has become third. The Jovian Mechanicum as present has built an orbital platform capable of orbital extraction of Jupiters precious minerals and rare elements from within the dangerous atmosphere of the Gas Titan.

Due to the immense scale of Jupiter and her moons the World Titan has become the site of massive manufactoria and starship construction facilities of the Jovian Mechanicus' ancient orbital Shipyards, and is further dotted with Golden Age of Technology mining facilities, floating manufacturing cities and unseen technologies that would allow it to operate as the sole Forge World for the entire Imperium Dominus during its early years. Jupiter alone and at full functionality had the potential to fuel the entirety of the Solar Proxima. And could crank out goods for the entirety of the Imperial Marine Legions, namely the monumental task of the Construction of 20 Imperial Throne Ships that would become the flag ships of the Legions.

This immense production potential and the complex web of dozens of smaller satellite moons, has made Jupiter into a solar system in miniature scale, with the gas titan at its core rather than the blazing orb of a sun. Due to this the true population of Jupiter and Her Moons is incalculable, for with the construction of a hundred floating cities within it's clouds, each with the surface area of an entire Terran-sized planet, the Jovian Mechanicum still has only covered 20% of its entire surface area.

This cloud of satellites and Trojan asteroids surrounding Jupiter are full of ancient human colonies, manufactoria and Mechanicus forges, powered by drinking in the radiation surging from the titan planet and feeding on the mineral riches that in their millennia of exploitation have yet to be fully exhausted. Jupiter is the Imperiums primary shipyard, and its sky has forever been filled with vessels.

Centered upon Jupiter's greater Galilean moons and a dozen other smaller moons, and the Mechanicum's spacedocks and fabricators that work ceaselessly to construct everything from the single-crew Raven Light Assault Vtol and up to the gargantuan hulls of the mighty *Throne*-class Battleships.

The early history of Jupiter remains largely lost to Imperial savants. But during the Long Dark, half of Jupiter's moons would be occupied by cruel xenos overlords of an unknown race. And following the Jovian Edicts, when the Gas Titan was first incorporated into the burgeoning Imperium, the Great Crusade would finally begin in earnest.

The rest of the Sol System was the first region of space to be conquered by the Emperor and His newly rearmed and re-equipped *Legiones Angelus*. These Alien invaders were flushed from the moons of Jupiter and their wretched human slaves repatriated back to Terra.

The Jovian Mechanicum' Shipyards and their Void Clans were utilized throughout the Great Crusade to build a fleet of vessels for the *Armada Imperialis*.

### The Golden Age

The Greater Galilean moons would be terraformed

The Long Dark

The Great Crusade

## The Great Moons

### Ganymede

One of the greater Galilean moons of Jupiter that was known to have had ancient Mechanicum habitats on its surface during the Great Crusade and Horus Heresy eras and served as the central hub of the massive complex that made up the Jovian Shipyards. Later, it was transformed into a Warp-tainted wasteland created by the malfunction of experiments designed to test the limits of Squat Warp-coil technology. In the Era Indomitus, Ganymede was transformed on the orders of the Primarch Roboute Guilliman into a massive hub-fortress of the Officio Logicaesticarum called Aquila Adamant. Its purpose is to supply, support, and archive the actions of the Indomitus Crusade's fleets and battle groups as they advanced across the galaxy.

### Callisto

One of the greater Galilean moons of Jupiter that was also known to have had Mechanicum habitats in orbit above it by the time the Horus Heresy began.

#### Rings of Iron and Steel

The **Rings of Iron and Steel,** is the name given to the massive twin complex of orbital shipyards, refineries and construction facilities that encircle the equator of the Jovian Mechanicum' Forge Worlds of Ganymede and Callisto in the Sol System.

The exploratory and expeditionary fleets of the Emperor of Mankind's Great Crusade were constructed in the orbital shipyards of the Rings of Iron and Steel during the late 90th and early 91st Millennia.

In the late 91st Millennium, spacecraft and other large starfaring structures are constructed within the Ring's extensive orbital factories, and many of the warships of the Battlefleet Solar are based in their huge floating docks. They are considered the largest known man-made structures in the Milky Way Galaxy.

### The Golden Age

The Greater Galilean moons would be terraformed

The Long Dark

The Great Crusade

### Ganymede

One of the greater Galilean moons of Jupiter that was known to have had ancient Mechanicum habitats on its surface during the Great Crusade and Horus Heresy eras and served as the central hub of the massive complex that made up the Jovian Shipyards. Later, it was transformed into a Warp-tainted wasteland created by the malfunction of experiments designed to test the limits of Squat Warp-coil technology. In the Era Indomitus, Ganymede was transformed on the orders of the Primarch Roboute Guilliman into a massive hub-fortress of the Officio Logisticarum called Aquila Adamant. Its purpose is to supply, support, and archive the actions of the Indomitus Crusade's fleets and battle groups as they advanced across the galaxy.

### Callisto

One of the greater Galilean moons of Jupiter that was also known to have had Mechanicum habitats in orbit above it by the time the Horus Heresy began.

#### Rings of Iron and Steel

The **Rings of Iron and Steel,** is the name given to the massive twin complex of orbital shipyards, refineries and construction facilities that encircle the equator of the Jovian Mechanicum' Forge Worlds of Ganymede and Callisto in the Sol System.

The exploratory and expeditionary fleets of the Emperor of Mankind's Great Crusade were constructed in the orbital shipyards of the Rings of Iron and Steel during the late 90th and early 91st Millennia.

In the late 91st Millennium, spacecraft and other large starfaring structures are constructed within the Ring's extensive orbital factories, and many of the warships of the Battlefleet Solar are based in their huge floating docks. They are considered the largest known man-made structures in the Milky Way Galaxy.

### Io

One of the greater Galilean moons of Jupiter that was known to have had Mechanicum habitats on its surface during the Horus Heresy era.

### Europa

One of the greater Galilean moons of Jupiter, this geo-engineered Ocean Moon was known to have had Mechanicum habitats on its surface during the Horus Heresy era.

#### Ananke

- Ananke is a lesser moon of Jupiter known to have had Mechanicum habitats on its surface during the Horus Heresy era.

#### Iocaste

- One of Jupiter's lesser moons known to have had Mechanicum habitats on its surface during the Horus Heresy era.

## Manufactoria Capabilities

During the Great Crusade, the Jovian Shipyards would play a vital role in the construction of the fleets of the Imperial Navy in combination with the Rings of Iron and Steel held by Ganymede and Callisto respectively. The space docks and orbital workshops that circle Jupiter, like an artificial ring of more moons, are home to the millions of the technoclurgy and drone Servitors that work under the supervision of the Jovian Mechanicus' Artisan and Rune Tech-Guilds to build the Imperial Navy's warships.

Each vessel is a vast undertaking, often taking solar decades or even centuries to complete for the largest and most powerful warships. Many of those who work on the construction of an Imperial Navy warship will live and die during the process, never seeing the magnificent starship they struggled to bring to life as a mobile cathedral dedicated to the greater glory of the God-Emperor.

Each of the Imperium's warship designs is constructed by only a single Jovian orbital shipyard; for instance, the *Emperor*-class Battleship, as well as *Tyrant* and *Dominator*-class Cruisers, are typical of the Imperial warships produced at the Jovian Shipyards and are each produced by a completely different orbital manufactoria.

The Jovian Shipyards are also responsible for the manufacture and production of the Plasma Drives that provide power to all of a starship's systems and the construction of a vessel's vital launch bay components and landing bays, which are equipped with dedicated ports for launching Attack Craft and magnetic guidance coils for steering them safely back aboard after a mission.

To further enhance their vessels, the Jovian Shipyards also possess the capabilities to manufacture their own pattern of Nova Cannon, which replaces the standard explosive shells with Vortex Warheads. The resultant rifts into the Warp have been known to rend target vessels cleanly in half.