The first exploration-able space vessel was developed in 22xx. The space vessel at that time was no more than few insolated cubes attached together with a primary propulsion system, which was a simple gas-based thruster.
A more advanced space vessel was developed in 26xx. Space vessels of this era resembled that of a submarine. Even its internal structure was similar. Main propulsion system was based on ion and was powered by nuclear power.
With growing number of space ships, added with breakdown of united nation, small conflicts in space started to break out, and the need for weaponry grew. Initially, projectile (kinetic) weapons were favored for they did not use already-precious energy to fire and maintain. At this time, nuclear power was barely enough to maintain a main thruster.
With development of fusion generator in 28xx, space vessels started to implement energy-based (laser) weapons on their ships. It is also worthwhile to note that space vessels of this era had its main bridge exposed on surface. Battles between space vessels were simple. Whoever took out their opponents' bridge was the winner.
In response to the major weakness of having an exposed bridge, thermal resistant armor was used. However, this was countered by implementing more powerful laser and warheads (for missiles). Many attempts were made to have a bridge under ship's main plate. However, visual projection system wasn't advanced enough to replace direct visual.
In early 31xx, a major breakthrough in holographic system enabled complete overhaul of space vessel's layout. Physical monitors were removed, which saved much materials, and replaced by holographic monitors. Visual projection system, however, wasn't still advanced enough to have a ship's bridge under its plate.
Ships became bigger, more powerful in weaponry, and were used for longer voyages. Power became an issue again. Fusion-based generators weren't providing enough powers that a ship needed. Bigger ships of this era used two or more generators.
Plasma generators were developed (However, invented a long time ago) and used in space ships in 37xx. Ships of this era no longer used any projectile weapons for having to carry ammunition became a chore for longer voyages. Ships became thinner but became wider / longer in length. Bridge still remained exposed even at this time. Shield technology was invented. However, it was not practical due to it requiring unacceptable amount of energy.
In 43xx, visual projection went though a few major breakthrough, and it enabled ships to have her bridge under its hood. With this major change in ship's layout, space battles became different. Taking out a ship's bridge was no longer an easy task. Bridges were also powered by its own generator. Space battles lasted much longer from this point. Captains' abilities to use tactics started to matter.
"Ship" in our time is generally understood as a naval vessel intended for sailing on water.
"Ship" in Two Clusters is generally understood as a space vessel. The term "sailing" was still used for space vessels.
Ship types were generally determined with its size and crew capacity.
Pod was a one-man space craft. It wasn’t a space vessel by definition as it did not have an engine and a bridge. Pod was not normally used. The most common usage of pods was escape pods.
Pod came in various shapes, but the most common shape was an egg shape. Strictly speaking, pod was basically a giant toilet. In a pod, there was a comfortable seat which also acted as a toilet. Frozen food was stored in its storage compartment. A person in a pod could usually last for two months before food would run out. Pod carried little water, certainly not enough for two months. Pod reused and purified urine as a source of water.
Pod was equipped with the most basic radio communication. It had no external monitors. Naturally, a pod was programmed to return to its home station or planet automatically. Therefore, when an escape pod was launched, no extra programming was required to return home.
Shuttle was often used for simple transportation. Capacity of shuttles varied. There were one-man shuttles and there were luxury shuttles that are capable of holding up to seven people.
Shuttles were expensive but could legally be purchased by civilians. "Luxury shuttle" referred to shuttles with overloaded features and more exquisite interior. A luxury shuttle could be used as a house as it has all features required for living.
Shuttle was the most basic form of a space vessel. It had a cockpit, which was defined as a bridge, it had a reactor and an engine.
3rd party companies existed for shuttles : Lightwave shipyard, Red Plate shipyard, SuperStar shipyard, etc
Frigate was the smallest warship in Two Clusters. It was more than ten times larger in size than a shuttle. Its crew capacity was between 15 to 30. Frigate was also the smallest space vessel that was capable of an A.C.M. reactor. However, due to complication in maintenance, frigates were normally equipped with dual plasma reactors instead.
Frigates were used mainly for patrolling. They were not used for fleet battles because their armors were too fragile. Frigate was not capable of shields. However, newer frigates were sometimes capable of the most basic shielding.
Corvette used to exist to fill the gap between frigate and cruiser. However, corvette was phased out. Therefore, no corvette class warship exists in Two Clusters.
However, corvette class warships reappeared in Alien arc when mankind did not have enough resources for constructing cruisers. Corvettes became specialized offensive frigates.
Cruiser was the most common type of warship in Two Clusters. Its crew capacity was between 50 to 200. Cruiser featured balance between fire power and speed.
Cruiser featured ab A.C.M. reactor and advanced shielding. Because it had shields, cruisers generally had weaker armor plating. Fire power of a cruiser was more than ten times powerful than a frigate's. Cruisers were the main vessel for fleet to fleet battles.
Liberty captains used cruisers exclusively also.
One 3rd party company existed for cruisers: Kikan shipyard
The main purpose of light cruiser was to save money. Light cruisers were used mainly by United Sol in its declining days. United Sol could not afford full cruisers in its last days and had to find a way to provide cruisers still. Therefore, they developed a new kind of "Light cruiser" : The Mice
Mice was a cruiser with paper-thin armor plating. It still carried the same amount of turrets and missile banks. It still had the same engine, but it lacks an A.C.M. reactor. Instead, it featured five plasma reactors to support the ship.
Because the ship had virtually no armor at all, its shielding was reinforced slightly, not by much however. Furthermore, due to having excessive amount of reactors, it needed more engineers per ship.
By size, colony vessels were the largest of its kind. They were as big as a small planet. Their enormous size allowed them to have Earth-like (1g) gravity by spinning slowly.
The main purpose of a colony vessel was to hold life in barren space. It was also much cheaper to build a colony vessel than developing a planet. Furthermore, a colony vessel was mobile.
A colony vessel was capable of millions of people, and it was often seen with their own independent government. No colony vessel has been destroyed by mankind because a colony vessel carried too many lives.
Thrusters had the same purpose of engines. They both were propulsive devices. The main difference would be their size. Thrusters provided much smaller propulsive powers to alter a space vessel's course. An engine provided a space vessel a main source of forward propulsive powers.
Once a space vessel had a main source of forward-thrust power, its course could easily be altered by very small amounts of additional propulsive forces, and this was where thrusters come in.
There were two kind of thrusters in Two Clusters. The first one was a thruster in a traditional sense where a small propulsive device was attached to a fuel source. The latter one was called "Emergency thrusters". Emergency thrusters were not attached to any fuel source for it had its own source of powers for a few times of usages.
Emergency thrusters were often programmed to act on its own and had its own array of sensors. Even if a space vessel was in a bad shape and on course to collide, emergency thrusters would activate on its own to alter a ship's course. Emergency thrusters could be turned off from a ship's OS level.
However, despite of this, emergency thrusters were often too weak to prevent inevitable collusion.
Something that everyone in the world of Two Clusters knows was that the space was quiet. In fact, it was too quiet for anyone's sanity on long voyages. Therefore, in order to preserve sanity, recreation facilities were needed.
However, not all space vessels had necessary spaces for proper recreation facilities. Any ship that is above cruiser class had a cafeteria as a main source of recreation.
Shuttles had barely enough space for its own components. Therefore, recreation for shuttle was extremely limited to only visual entertainment such as movies and TV programs. Luxury shuttles may have had a few additional recreation items such as a karaoke system.
Frigate also did not posses enough necessary space for proper recreation facilities and have the same recreation options as shuttles.
Cruiser was a spacious vessel, and so it had a cafeteria. A cruiser's cafeteria was capable of serving half of maximum crews that a cruiser may hold. A cruiser's mainframe was also powerful enough to host games for all crewmen. Overall, a cruiser was a very customizable vessel when it comes down to recreation choices, and depending on a captain's taste, it may feature additional recreation facilities such as pools.
Anything was possible for recreation facilities after cruiser class vessels. But the general combination was a cafeteria, and a pool, a playground, and a private radio station.