Dyson-class Shuttle Carrier
Overview
The interstellar equivalent of an Amphibious Assault ship, the Dyson-class was a class of carrier that entered service following the First Contact War as a response to the inefficiencies and difficulties of relying on a single career type for both fleet and planetary support. Designed to carry large quantities of ground forces to a planet's surfac, they are commonly deployed in planetary assault and planetary reinforcement operations, as well as humanitarian aid and large scale extraction of military personnel, non-combatants, equipment or VIPs from an active war zone.
Dyson-class Carriers are notably significantly smaller than the multimillion tonne Fleet Carriers. This was by design. Their smaller size makes them a smaller target and allows them to be economically fitted with proportionally larger thrusters and a larger drive core. Very useful when trying to avoid enemy antiaerospace fire. They make up for their smaller size with numbers. The Alliance typically fields the Dyson-class in far higher quantities than the Einstein-class or Tereshkova-class.
Additionally, shuttle carriers don't go on patrol. Typically operating from space stations located in major mass relay junction systems, they are only deployed when needed and typical deployment don't last more than a few hours. This reduces the space needed for crew amenities such as sleeping quarters or crew rations. Allowing most of the hull to be taken up by ground forces along with any equipment and supplies they would need planetside. And while the carrier doesn't have a medbay, it can be equipped with supplies needed to set up temporary medical facilities on the ground if necessary.
One unique feature of the Dyson-class is the Assault Operations bridge, nicknamed "the bunker" by Alliance personnel. From this strategic command center, the ship's commanding officer has complete battlefield awareness thanks to the vessel's advanced sensor suite and can use this data to coordinate with the commanding officer of the marines on the surface to provide a better understanding of the battlefield situation.
Hull and Superstructure
From stem to stern, the Dyson-class Carrier has a length of 217 meters, a beam of 92.5 meters and a height of 45 meters. With a mass of 126,000 metric tonnes.
The main hull has a length of 106 meters, a width of 29 meters and a height of 45 meters.
The hull is protected by up to 560 cm of layered ablative ceramic composite armour plating. This armour serves as the inner layer of ship defenses. The armour is primarily designed to defend against directed energy weapons like lasers by boiling away when heated. The vaporised armour material scatters the DEW beam, rendering it ineffective.
A scaffold was built around the interior pressure hull, with sheets of ablative armor hung from the structure. Ships typically have multiple layers of armor separated by empty baffles, spaces often used for cargo storage.
The exterior hull is also lined with strips of ceramic as part of it's Defused Radiator Array, used to radiate the ship's passive heat build-up from everyday functions such as running thrusters, drives and other internal systems. Under thermographic imaging, this makes the ship appear striped, leading to the nickname "tiger stripes" or "war paint". Though, they are not as efficient as regular radiator panels, they are more durable. If damaged by enemy fire, the ship only loses a small portion of it's radiation capacity. In most cases, a vessels DRA alone allows it to cruise with no difficulty. Operations inside solar systems can cause problems.
During combat, the ship utilizes droplet heat sinks built into the hull itself. Filled with lithium, these sinks capture the titanic amounts of heat generated by weapons and thrusters during combat. Once filled to capacity, the lithium is sprayed out of nossels at the bow in the form of droplets, where they are cooled in the cold vacuum of space before being sucked back in at the stern. Droplet sinks can manage 10 to 100 times more heat than a DRA, but every time they are cycled through, a portion of the lithium coolent is lost to space. Limiting their use to only when necessary.
Shielding
The Ship's anti-bombardment kinetic barrier array is linked to a Model 5 kinetic barrier generator down from the York-class
Kinetic barriers consist of hundreds of tiny emitters spaced evenly across the outer hull. An object with mass traveling above a certain velocity will trigger the barrier's reflex system, generating a localised repulsive mass effect field around the point of impact, deflecting it.
This is not without risk, however. The emitters themselves can only repel objects up to a limit. Sufficiently massive objects traveling at a high enough velocity can pass through the barriers unimpeded. Additionally, the kinetic barrier generator takes power from the ship's mass effect drive. Even if the projectiles do not penetrate, consistent impacts can put strain on the generator, this strain in turn is carried back to the drive. To prevent potential drive failure, the drive is designed to temporarily shutdown power to the shields until the field stabilises once again. The sudden, abrupt shutdown of the generator causes all emitters to discharge residual energy build-up into the vacuum of space. Triggering the characteristics "shattering" effect.
This allows the ship to withstand impacts from ship-based weapons, but doesn't do anything against Directed Energy Weapons such as lasers.
The strength of the kinetic barrier depends on the size of the mass effect drive, the amount of element zero used and overall design of the drive and generator. The more powerful the mass effect fields the ship generates, the more powerful the shields can be. Tereshkova-class kinetic barriers are rated for the equivalent of 600 tonnes of kinetic energy per square centimeter.
Power and Propulsion
The ship's drive core is a Mk IV Orion Mass Effect Drive Core. This massive drive spanned across multiple decks. It's a modification of the older Mk III that incorporates turian design principles. The drive is powered by the ship's on board helium-3 nuclear fusion power plant, which delivers a powerful electrical current to a core of element zero, causing it to radiate large amounts of dark energy, which are captured by the mass effect field generators.
The Orion Drive is used to increase the power of on board weapons, generate kinetic barriers, reduce the mass of the ship, generate gravity, power inertial dampeners and more, but the most significant advantage the drive gives is the ability for faster than light space travel. The mass effect field generator generates a mass reducing field around the ship, lowering it's mass, while simultaneously raising the speed of light around it. Allowing for faster than light travel through conventional thrust without any negative effects. Ships accelerate for half the journey, befor flipping around and decelerating for the other half. This means that there is no consistent speed. A ship's FTL travel time is largely determined by the distance they travel. Longer distances allow for higher average velocities than shorter distances.
The Mk IV Orion Drive allows for a rate of approximately 69,200 km/s of acceleration and deceleration. Allowing for the ship to travel roughly 13.7 lightyears within a 24 hour period. However, due to static build-up of the drive core, the ship can not maintain FTL flight for longer than around 50 hours at a time. Limiting it's maximum FTL speed to around 59 lightyears every 2 days.
One downside however is that as the ship accelerates, the difference in light speed between the interior and exterior of the field causes a doppler shift. Objects outside the ship redshift, eventually only becoming visible to the ship's radio telescope antenna. As the ship goes faster, high-energy electromagnetic source such as x-rays, gamma rays, and eventually cosmic ray sources become visible, replacing stars with pulsars, the accretion disks of black holes, quasars and gamma ray bursts.
To an outside observer, the ship appears to be surrounded in a blue or purple aura as the light within the mass effect field is blueshifted into higher frequencies, making the field itself visible to the naked eye. The ship's radiation emissions are also compressed as a consequence. If within a field that allows light to move twice as fast, the ship produceed twice the emissions. If in a field that allowed for 200 times faster light speed, it's visible light is emitted as x-rays and gamma rays and the infrared heat of the hull is blueshifted up into the visible spectrum or higher.
As a result ship is almost completely blind during FTL flight, requiring a specially trained navigator to plot each FTL jump and instuct the helmsman on course corrections based on calculations provided by the ship's FTL plotter. If an object of significant enough mass is in the path of a planned FTL jump, a safety lock built into the drive core prevents the ship from accelerating above safe speeds. The safety lock was intentionally designed to be integral to the FTL warm-up process. Meaning that removing or tampering with the mechanism could cause critical damage to the drive core.
Ships also can not perform an FTL jump while under fire. Accelerating to FTL necessitates that a ship reduce it's mass to levels unsafe for combat. During large-scale combat, it's common practice for a losing fleet to sacrifice a portion of their forces to draw enemy fire while the rest of the fleet escapes. These ships would then attempt to escape combat at sublight speed, where they would jump to FTL as soon as they were out of range and rendezvous with the rest of the fleet.
Conventional thrust was provided by 4 aft and 2 fore antiproton drives which inject antiprotons into a reaction chamber filled with hydrogen. The resulting matter-antimatter annihilation provides unmatched motive power. The drawback is fuel production. Antiprotons are produced one at a time in massive solar arrays orbiting energetic stars. Making them both expensive to produce and easy targets during wartime. The exhaust of an antiproton drive is measured in millions of degrees Celsius. Any ship caught behind it would melt like wax in a blowtorch.
Maneuvering is performed by an array of liquid oxygen/liquid hydrogen reaction control thrusters.
The ship features backup hydrogen-oxygen fuel cells to meet the minimum power requirements for the ship to function for a few hours, even after the fusion plant is taken offline.
Crew and Compliment
The standard crew size of an Dyson-class was 30 with facilities to accommodate upto 460 marines.
Emergency escape vehicles consist of 122 M-78 Hammer emergency evacuation pods, each equiped with their own emergency beacon, thruster module, heat shields, inertial dampeners and at least a week's rations for a crew of 8.
The Dyson-class carriers A Landing Fleet of 6 HT-50 Goliath and 12 UT-47 Kodiak Shuttles as well as upto 80 ground vehicles, including the M-35 Mako, M-44 Hammerhead and M-080 Megalodon.
Sensors and Communications
A Dyson-class features a variety of active and passive sensors that give it a detailed visual of it's surroundings.
Passive sensors are used for long-range detection and include visual, thermographic and radio detectors that monitor the ship's surroundings at all times.
Due to light-lag, passive sensor accuracy is reduced and active sensors don't work while the ship is traveling at FTL speeds.
Communication is achieved through tight-beam communication, which fires a communications laser at the nearest FTL comm bouy. Acting as mini, primative mass relays, these bouys use mass effect FTL corridors to transmit the data at superluminal speed along the comm bouy network. Depending on the distance between the sender and their nearest comm bouy, this method of communication is almost instantaneous, especially since military communications take high priority when it comes to communication bandwidth.
Armament
As the Dyson-class was primarily a transport not designed for ship-to-ship combat, it doesn't have any offensive anti-ship weapons. It's primarily armament are two twin M-500 mass accelerator turrets. Primarily used for limited air support and to defend against smaller ships like frigates and corvettes in knife fight combat.
As of 2182, Dyson-class carriers included 2 M-83 Javelin torpedo tubes as a secondary short-range weapon to compliment their point-defence network. Javelin torpedo are scaled up variants of the Fighter-launched disruptor torpedo. Like Disruptor torpedos, Javelins are equipped with element zero warheads that create random, unstable mass effect fields that warp space-time around them. In flight, they use mass increasing fields making them too massive to be blocked by kinetic barriers, but also making them sluggish and easy prey for point-defence systems. Javelins are fired in large numbers and in pairs, on converging trajectories, programmed to collide, just before impact, allowing the dark energy field emitted by the impact to resonate, magnifying the resulting warp effect.
The ship's General ARea Defense Integration Anti-Spacecraft Network (GARDIAN) is used for close-in defense against enemy missiles and fighters as well as short-range anti-ship weapons used against enemy Frigates in knife-fight combat. Completely bypassing kinetic barriers and boiling away ship armour. Consisting of 28 anti-missile and anti-fighter laser turrets on the exterior hull. Since lasers move at the speed of light, they can not be dodged by anything traveling at superluminal speeds. At the start of combat, GARDIAN is 100% accurate. It's not necessarily 100% lethal, but it doesn't have to be. Damaged fighters have to break off attack for repairs. Defraction restricts GARDIAN's effective range to only a few kilometers. Fighters attack in swarms in an attempt to overwhelm the ship's GARDIAN defenses, the first few will be shot down, but as a battle progresses, overheating deteriorates both the accuracy and strength of the laser turrets.
Layout
A Dyson-class Carrier has 8 decks.
Deck 1 was the combat deck and included a completely sealable Bridge, CIC and War Room. As well as the Captain's Cabin.
Deck 2 was for crew accommodations. Including mess halls, barracks, RR facilities, barracks and sleeper pods.
Deck 3 was the Shuttle deck. And included three heavy shuttle bays. Each with 2 HT-50 Goliath Heavy Transports. And 3 light shuttle bays. Each with 4 UT-47 and later UT-47A Kodiak Drop Shuttles.
Decks 4, 5, 6 and 7 were the vehicle decks. Each carrying upto 19 ground vehicles.
Deck 8 was the Drop Deck. Even though the Dyson-class couldn't land on a planet, it was atmospheric capable, allowing it to drop vehicles directly to a planet's surface without the need of a heavy transport. It's Goliaths would then retrieve them later. The Drop Deck took the form of a large drop bay with doors on both the port and starboard sides that ground vehicles can launch from.
The aft section of the ship plays hosts to the power plant and mass effect drive. All all available and serviceable by qualified engineers and technicians via the engineering section of deck 8.