Urbs class Sublight Generation Ship
An Urbs class Generation ship is perhaps the largest mobile inhabited structure ever seen in the three Galaxies, and certainly the largest in Ender's Cluster. 60 kilometers 37.5 miles) long and 20 kilometers (12.5) in diameter, these cylindrical craft house huge interior living spaces. inside the vessel is a 16 kilometer (10 miles) wide by 50 kilometers (31.25miles) long cylindrical area, filled with air and held against the outside of the cylinder by the vessels 4 rotations per minute spin, which provides the equivalent of one gravity. inside this space is a complete 'inside out' world, with fields, hills, cities, even a small ring shaped freshwater ocean. three equally spaced lighting strips provide illumination, brightening and dimming on a 24 hour cycle to simulate day and night. At each end of this space are industrial areas that form the 'caps' to the tube, offering variable gravity industries. in the hundreds of cubic kilometers not taken up by the hull and living space are massive storage and industrial areas to hold and process the food, water, and materials required for long duration sublight travel. At the front of the vessel is a large armored shield providing protection from impacts while traveling between stars. this shield is sectional, and when in orbit around a planet or star can be opened to reveal a dockyard facility to produce, launch, and service smaller spacecraft. to the rear of the vessel is a massive pusher plate, a circular assembly connected to immense shock absorbers and reinforcing arms. this plate is part of the vessels drive system, which uses 1.2 gigaton nuclear charges (equal to 1.2 Billion tons of TNT!), in shaped charge casings that focus their explosive power towards the ship, to provide propulsive force. detonated at a rate of one per second, these nuclear charges can accelerate the vessel at a steady, albeit slow, rate. the hull of the vessel is lined with radiators for maintaining thermal balance, as well as feild coils and ionizers for a minimagnetosphere plasma drive, or 'plasma sail'. while this drive is far weaker than the thermonuclear pulse primary drive, it provides a reaction mass free method of braking while in interstellar space, and a form of defensive screen against radiation and hostile fire.
The urbs class is a common sight in Ender's Cluster. several hundred wander the cluster, their inhabitants rarely setting foot on planets. another two dozen are known to have left ender's cluster entirely, headed for the Gaelera arm of the Thundercloud galaxy after refitting to include sufficient cyro-sleep systems for their entire populations. it is believed these vessels are still in transit, their inhabitants kept in stasis while they undertake the multi-millenia journey across intergalactic space.
Model Type: Interstellar Sublight Generation ShipClass: Urbs classCrew: 8 million, crew and passengers. can hold up to a maximum of 20 million safely, but this would put strain on the vessels life-support system.M.D.C. by Location:
[1] Pusher Plate (1, aft) - 8,000,000 M.D.C.
[2] Bow Shield (1, bow) - 2,000,000 M.D.C.
[3] Outer hull (main body) - 37,680,000 m.D.C.
Outer hull section (18,840 sections) - 2,000 M.D.C per square kilometer
[3] Inner Hull (main body) - 4,521,600
Inner Hull section - 500 M.D.C. per square kilometer.
[4] Radiators (4,000 - outer hull) - 500 each
Notes:
[1] the pusher plate is heavily reinforced and coated with special ablative materials designed to minimize the damage taken from the thermal and kinetic effects of a shaped nuclear detonation. the pusher plate is effectively immune to plasma damage, and reduce all other damage to 1/10th normal.
[2] the bow shield is a thick armored section designed to protect the vessel from impacts during interstellar travel. it's special construction reduces damage from kinetic impacts by 1/10th.
[3] both the inner hull and outer hull are classified as the main body. the outer hull is armored for protection, while the inner hull is the 2km/1.25 miles deep framework of the ship and industrial spaces. in order to damage the inner hull, you must destroy all or part of the outer hull. depletion of the inner hull M.D.C. destroys the vessel, leaving it an airless derilict hulk.
[4] The vessel requires a minimum of 1000 radiators active to safely maintain it's life support system. these radiators are armored systems spaced along the outerhull. in an emergency, the vessel can use it's supplementary water supply/radiation shielding as a heat sink to store heat for later disposal (either by radiators or by venting part of the water supply being used), but this only gives a 48 hour period of safety. without sufficient radiators, the life support system of the vessel will begin to break down within 24 hours, and after 7 days the damage will be fatal. replacement radiators are stored on board, and can be produced, however replacing radiators requires the vessel to cease using it's drives, with the physical replacement requiring a space walk and several hours.
Speed:
Externally Pulsed Plasma Propulsion (EPPP drive): this Thermonuclear drive detonates 1.2 gigaton nuclear shaped charges charges at a rate of 1 hertz (one per second), providing a maximum acceleration of 1 mach per month/31 days (.000112g's). the vessel contains sufficient storage and resources for 5.3 billion charges, or 2000 thrust points. these charges inflict the following damage: 3d6x1200 md to a 18,288meter (60000ft) radius, 2D6x1200 md to a 18,288 meter (60000ft) to 146,304 meter (480000ft) radius, 1D6x120 md to a 146,304 meter 480,000ft) to 438,912 meters (1,440,000ft) radius, 1D6x12 md to a 438,912 meters (1,440,000ft) to 713,232meter (2,340,000ft) radius. any object passing through this spherical area immediately behind the vessel will take damage if the drive is in use.any object passing more than 800 kilometers (500 miles) behind the vessel will take no damage.
Mini-magnetospheric Plasma Sail: This 'braking' drive employs charged plasma to inflate a magnetic sail out to 12,000 kilometers/7,500 miles in diameter. In Interstellar space, this sail drive reduces the vessels speed by 1 mach every year/365 days (.0000095g's). inside a solar system, this drive works roughly twice as efficiently, able to accelerate or decelerate the vessel at a rate of 1 mach every 6 months/186 days (.0000186g's).
Range: interstellar. the ship is effectively self sufficient, requiring minimal resupply and able to travel for 1000 years before non-reusable resource levels become critical.
Statistical Data:
Height: 20 kilometers (12.5 miles)
Width: 20 kilometers (12.5 miles)
Length: 60km (37.5 miles)
mass: 420,000,000,000,000 tons.
Cargo: the ship is a hollow cylinder with an internal space 16 kilometers (10 miles) in diameter and 50 kilometers (31.25miles) long. within this space, along anchored to the walls through centrifugal force, is an entire self-contained world, with urban and rural areas.
Power System: Stellar Fusion core, with sufficient on board fuel for a 1000 year lifespan.
Market Cost: unknown. effectively priceless.
Weapons/Systems:
1) Bomp-Pumped X-ray lasers: The use of a thermonuclear charge based drive allows the employment of powerful x-ray lasers for defense. individual X-ray laser rods, which are comprised of a lasing cavity attached to a self-aiming system, are ejected into the blast area of the drive, lock onto a target, and then a charge is ejected and detonated, which energizes the rods. this generates powerful X-ray laser beams capable of immense damage to most targets. this weapon can be deployed even when not under thrust, by allowing the ejected rods and charge to clear 400 kilometers/250 miles before detonation (takes about 1 mele/15 seconds, this allows 360 degree weapons coverage.)
Primary Purpose: Anti-Starship
Secondary Purpose: anti-station
Weight: each rod masses roughly .25 tons.
Range: 1,600 kilometers (1,000 miles)
Mega-Damage: 1D6x10,000 M.D. each.
Rate of fire: up to 300 at a time, 4 times per melee. (these weapons use the "random missile volleys" rules to determine how many strike each target)
payload: roughly 500,000 lasing rods,
special: each lasing rod has a +3 to strike, but receives no other bonuses. image recognition systems and IFF-software prevents these weapons from firing on known freindlies (updated before release)
2) casaba-howitzer:
special nuclear shaped charges can be employed that are optimized for generating focused plasma streams of destructive potential instead of propulsive. these charges are equipped with self guiding targeting systems that orient the round towards the enemy. when detonated, they create a powerful focused plasma stream, aimed at the target.primary Purpose: anti-starshipSecondary Purpose: anti-stationWeight: each charge masses roughly 3 tons.Range: 400km/500 miles (in one melee/15 seconds) using the EPPP drive's ejector, 800 kilometers/500 miles for the charge's plasma stream, which can be at angles to the charges direction of travel.mega-damage: the plasma stream produced inflicts 3D6x12,000 M.D.. the detonation also inflicts the following; 3d6x1200 md to a 18,288meter (60000ft) radius, 2D6x1200 md to a 18,288 meter (60000ft) to 146,304 meter (480000ft) radius, 1D6x120 md to a 146,304 meter 480,000ft) to 438,912 meters (1,440,000ft) radius, 1D6x12 md to a 438,912 meters (1,440,000ft) to 713,232meter (2,340,000ft) radius.Rate of Fire: volleys of up to 3, 5 times per melee. uses the random missile volley rules for determining how many hit each target.Payload: 100,000 charges. additional charges can be produced, but at a slow rate and using materials required for propulsion charges.Special: each charge has +6 to strike, but receives no other bonuses. image recognition systems and IFF-software prevents these weapons from firing on known friendlies (updated before release)
3) Mini-magnetosphere defensive screen: the magnetically charge plasma provides protection from radiation, plasma, lasers, and particle beams when active. the system can also be activated in a 'defensive' mode that generate a 8 kilometer/5 mile radius field that provides no propulsive effect but provides protection from weapons fire. the system completely protects from plasma weapons, these weapons do 1/1000th damage. particle beams inflict 1/10th damage, and lasers have their damage reduced by 1/2. The downside of this defensive application is that weapons fired from within the screen are effected in the same way, and while active the EPPP drive cannot be active.
4) Embarked craft: The dockyard facilities of the Urbs class can hold two dozen cruiser sized (700 meter/2296.5ft) craft in it's main bays. any of these bays may be employed as construction slips. the urbs class can also hold up to 200 heavy shuttles in it's secondary bays (or about 600 three galaxies fighter craft, if they had them). these craft enter through a central hanger, and after docking with an appropriate cradle are moved via elevator to the docking slips. entry and launch are slow procedures, requiring precision maneuvering with thrusters only, and can take up to 30 minutes for a large craft and 10 minutes for small craft to dock or launch. (primarily due to the danger of damaging the docking faculty with the exhaust from their main drives. maneuvering thrusters are too weak to inflict damage, but are also too weak to move a ship rapidly on their own.)
5) sensors and communications:
Radar- maximum range of 300,000 km. -40% to detect small objects (fighters, missiles) beyond 100,000 km.
Infrared tracking and scanning- passive IR camera's used to detect enemy ships by their heat signature. has an effective range of 6 light minutes. -20% to detect small objects.
Radio- directional, maximum effective range of 12 light minutes.
