Weapon Profile - Iserlohn Fortress

Name: Iserlohn Fortress (named after the Iserlohn space corridor which it protects)
Origin: Legend of the Galactic Heroes
Type: Space Fortress, Home of the Iserlohn Republic (during the late times of the war)
In use by:  Galactic Empire, New Galactic Empire, Free Planets Alliance, El Facil Revolutionary Republic, Iserlohn Republic
Diameter: 60 km
Mass: 60 trillion tons (according to in-series statements, but technically even its outer hydrometal layer alone should weigh at least 500 trillion tons)
Powered by: Nuclear Fusion Reactors
Propulsion: None (but following Geiersburg's example it could be potentially outfitted with nuclear engines and a warp drive)
Destructive Capacity: City level with anti-ship beam cannons, planetoid level+ with Thor's Hammer (can vaporize ships in 0.4 lightsecond diameter cone)
Durability: Minimum country level concentrated firepower to do any visible damage to the armor, the structure can withstand semi-focused attacks from its own cannon with moderate damage (so you need at least low planet level firepower to destroy this)
Material: Hydro-metal armor
Performance: None (it's almost stationary in space), beams travel at MFTL (500c) speed
Weaknesses: The fortress is effectively immobile. Ships and other objects can harmlessly pass through the hydrometal layer it if they possess enough force/toughness but at sufficiently slow speed. A broading party can infiltrate the fortress and take over its systems from within. Destroying the main power generator would result in the Iserlohn Fortress exploding.
Terrain: Space
Needed Prerequisite for Use: Havving the neccessary crew to men the control room
Garrison: Up to 2 million soldiers and can support additional 3 million civilians almost indefinitely
Hangar: Can hold up to 20,000 warships and unspecified number of starfighters
Operational Timeframe: Almost indefinite (the fortress is practically self-sufficient, capable of processing food, materials and even fuel)
Weaponry:

• Thor's Hammer
• at least hundreds of floating/submersible turrets (sporting exit ports for soldiers and multiple anti-ship beam cannons)
• many submersible exit ports/tubes

Weapons Range: Millions of kilometers (ships are regularly engaging each other from light-seconds away), sensors can reach to billions of kilometers
Special Forms: None
Notable features: Robust structure protected by a 5km thick spherical layer of liquid metal, artificial gravity which also keeps the hydrometal layer in shape and manipulates its buoyancy to submerge/surface certain turrets or other floating parts, floating turrets that can "swim" in the hydrometal and appear at any portion of the fortress, can generate a powerful gravity well and project it afar, can focus its gravity into a makeshift shield to mitigate attacks, has a system of projectors to unleash an extremely powerful x-ray laser strike (or improvise the projectors by creating gravity lens on tits surface), various including FTL sensors, forwarship docks in the northern/southern poles, fighter launch ports via extendable tubes in the equatorial trench, agriculture blocks to produce enough food for 5 million people to live in the fortress indefinietely, purifies 2.2 million cubic meters water every day for ship fuel, supports an entire city with houses and all living requirements
Notable Attacks/Techniques:

- Thor's Hammer: Incredibly powerful x-ray laser beam cannon system designed to take out entire fleet formations. A system of projectors surface from the fortress' hydrometal armor as they briefly charge up forming an energy ring which converges to the center. Shortly thereafter the Thor's Hammer fires its destructive beam to vaporize anything caught within. In case of engaging fleets the beam seemingly expands in diameter, destroying more than 1000 ships with a beam expanded to thousands of kilometers thick. Against tougher targets like the Geiersburg Fortress it can be focused to shoot a fairly coherent beam to penetrate the enemy's hydrometal armor. Unlike most superweapons in fiction the Thor's Hammer is capable of rapid consecutive shots, unleashing the next beam only a minute after the last. Even if the enemy strikes with tens of thousands of warships, Thor's Hammer can eliminate them before they'd even get in their cannons' range.

http://www.youtube.com/watch?v=BM4tPmy-cJo

Other: In spite of it being an imperial installation that protected the Empire for almost 60 years, the Iserlohn Fortress changed hands a lot during the Imperial-Alliance War. First it was captured by the Alliance then it got overtaken by the New Empire only for Yang Wen-li's fleet of revolutionaries to take over. The remainders of this revolution later named themselves Iserlohn Republic with the fortress becoming their home.