Heraklion Fortress is an artificial satellite that was constructed by the Imperium on the edge of the lawless Caligari Sector. It functions as a major Imperial Navy base with the objective of defending the frontier from the various threats that lurk within the ancient region. Due to the lack of Imperial control there, Heraklion Fortress was constructed with many STC technologies in order to make it capable of withstanding large-scale invasions without reinforcements for long periods of time. The fortress is a sphere coated with a several-kilometer thick liquid metal that blocks out lasers and missiles, while letting ships pass through it to enter the docking bays inside, with a solid metal layer beneath that. Heraklion is bristling with various cannons and batteries of different types, but its primary offensive weapon is a massive Nova Cannon known as the Sword of Hercules. Most of the military functions are controlled and carried out from the outer levels of the fortress while the interior closest to core contains the civilian facilities, including entertainment venues and hydroponics farms to make food. Thus Heraklion is mostly self-sufficient.
Although Heraklion Fortress is officially an Imperial Navy installation and does not service any civilians, it sometimes provides shelter to Rogue Traders and others who are in need of assistance. Heraklion has a large docking area that can berth more than 200 ships at a time, as it serves as the only major Imperial military facility in the vast region. The Navy's Heraklion Stationed Fleet fluctuates in numbers but typically includes at least 100 vessels. Including the ship crewmen, the fortress garrison, various support and administrative personnel, and their families, Heraklion's total population ranges between five to seven million people. It is seen as the only bastion of Imperial civilization in the lawless sector, being located along one of the most traversed spacelanes used to leave and enter the region.
The massive docking bays of Heraklion Fortress are located in the northern hemisphere and take up hundreds of levels, consisting of berthing docks that can accommodate more than 200 military vessels. They also include support and repair facilities to provide for any damaged ships and serve as a resupply center for Imperial Navy battlegroups operating in the area. The defense fleet based at the fortress, the Heraklion Stationed Fleet, usually consisted of at least 100 vessels, leaving room for other Navy ships. Occasionally ships of civilians, or those sent on official business to Heraklion by the Imperium (Inquisitors, Administratum personnel, local officials), are also housed in the dockyards.
The main design includes four massive walls into which the landing bays and servicing corridors are built into. Repairs and other work on the ships are done in these areas. Running along the length of the docking walls further inside are ground escalators to provide faster movement for personnel. These four walls link up in the center where a large spire is set up that houses the space traffic control center and various administrative offices. The traffic control center is from where the gates on the outer armor layer are opened, allowing vessels from outside the fortress to enter.
Most of the bays are large enough to berth any vessel up to the size of a standard Imperial cruiser, with the larger bays for housing battleships and other ships of similar proportions located towards the bottom of the docking walls.
Most control and command functions were carried from the command center, the bridge. It was located just below the docking area in the northern hemisphere and was a cavernous space filled up with computers and monitors in front of large screens linking to cameras showing the exterior of the fortress, interior, and acting as communications devices. Behind the rows of consoles there is a large staircase leading up to a conference area for the fortress commander and staff, which also includes consoles from which some functions can be performed. The firing mechanism for the Sword of Hercules is located on the bridge.