With the setting being based to a good deal on the late 19th to early 20th century in both socio-economic and military aspects, and heavily inspired by Star Wars and other space operas,nothing I am doing in regard to space ships and fleets is really that special or anything new. You’ll have seen all of this countless times before. But most space adventures and science-fiction use the various technical terms very loosely with no indication of their original meaning being understood, and space battles are generally approached with a final vision already in place before any details are worked out. While I am going for a very adventurous space opera style, where realism is not generally much of a concern, I still really like the approach of first thinking how things would look or play out realistically and then considering if that would already be a lot of fun as it is, or if making some unrealistic changes would improve the overall experience. And in situation where the realistic option is just as fun as the fantastical one, I always go for the realistic one. The better people understand the rules of a setting, the more they understand what options characters have and what they mean. Diversions from reality need to be explained, realistic elements do not. So keeping fantastical diversions to when they are needed for stories helps with keeping a setting accessible and makes it easier to understand.
Militaries, Security Forces, and Security Services
There are dozens of independent governments in known space, all of which have their own armed forces for security and defense, and every one of them have their own unique systems how these are organized. Generally speaking, armed ships and troops employed by governments fall in three broad categories.
Militaries are armed forces trained and equipped purely for combat. They are controlled by the national government of each state, usually under the defense or exterior ministry. Small independent outposts do not have the means to maintain militaries, and even some smaller sovereign planetary or system governments do not have them. In colonies, military forces are usually not under the command of the governor, unless the colony is run by a military governor in charge of both troops and civilian administration.
Security forces are most commonly seen in the form of police and customs services. These are generally under the control of the local civilian administration. They are primarily law enforcement services, though since most of them also patrol in space, they employ quite heavy equipment and field considerable firepower, which makes them more paramilitary in nature. Almost all worlds all the way down to the smallest outpost have some kind of security force, even if it’s only a handful of officers without any spacecraft.
Security services are private security companies that offer their services both to governments and private clients. While moat such services simply provide personal or object protection, there are also many large mercenary companies that offer armed escorts for spacecraft, securing the orbital space around planets, or even the hunting and destroying of pirates. Most governments are highly reluctant to employ private security services for police duties in civilian areas, but larger independent outpost in particular often use them to supplement their own security forces when they experience threats their own forces can’t handle. It is also not uncommon for larger states to employ mercenary escorts to guard space convoys or facilities when their own forces are overstretched. Many of the largest companies in known space have their own security services to guard facilities, escort transports, and protect high ranking company officials. These frequently far outsize independent mercenary companies and can rival the militaries of smaller states.
Combat Ship Types
Combat ships come in a range of different sizes and there are dozens of different shipyards throughout known space that manufacture their own designs. But doctrines, experience, and practical concerns have led to five broad categories of design that are followed by almost all fleets. The names for these types are shared in almost all space settings, but very few actually consider the functions of the ships these names originally come from, and there are several cases that don’t even get the sizes right.
These are the smallest class of combat ships. They often range from 20 to 50m in length with relative masses of 8 to 125, with crews between 10 and 2o. The main function of patrol craft is essentially that of a space police car. They are crewed by a squad of security officers whose duties consists of stopping and searching ships arriving in a system if they have reasons to want to make a check before they get close to a port. They also respond to ships having emergencies and to fight off small pirate ships. Patrol craft are rarely equipped with hyperdrives, and they normally carry only enough supplies for a day or two in case of engine malfunctions that require recovery to return to their base. Their weaponry is intended to force force cargo ships to stop or change course and to scare of pirates, and their armor is not worth mentioning, which makes them useless for actual battles.
Corvettes are the smallest ships that are capable of engaging in real battles. Their length is usually around 100m with a relative mass if 1,000, and crewed by 20 to 40 people. Corvettes are used to bring more serious firepower to situations where patrol crafts are seriously outmatched. They are used for hunting pirates based within the system or to stop suspicious ships when security forces are expecting trouble. All but the smallest colonies employ at least two or three corvettes which are usually part of local security forces, but might also be under the command of the military in systems that are guarded by a permanent military fleet. While corvettes are equipped to patrol for several weeks before returning to their base, large numbers of them are not equipped with a hyperdrive to reduce costs and make them more affordable for small governments. Though corvettes with hyperdrives are sometimes used by private security services to escort cargo ships between multiple systems. As they are designed to land on planets, they are severely restricted in their weight, limiting the amount of armor they can be fitted with. While they are quite capable of dealing with pirates using old patrol craft or armed freighters, they are not send into serious battles outside of cases of extreme desperation.
Frigates sit at the lower end of what most people consider to be proper warships. They typically have lengths around 200m with a relative mass of 8,000 and have crews between 60 and 120. Frigates are sometimes employed by security forces, but are usually part of a larger military. Unlike corvettes, they are designed to operate between various systems and carry supplies for several months in space. Only a few of the smaller types are capable of landing on planets and they usually require orbital facilities as their home base. While a hyperdrive is a key component for any frigate that sets it apart from an oversized corvette, a frigate’s hull and other systems can be constructed in relatively modest shipyards that usually build freighters, which has lead to countless different designs used by various minor states, many being build in very low numbers. For many smaller planetary governments, frigates are the main component of their defense force and there are many thousands of these in service throughout known space. A single frigate is generally enough to deal with any threat to frontier systems aside from organized invasion fleets by other systems.
The destroyer is the primary warship of most larger military fleets. Its size is usually around 300m with a relative mass of, 27,000, and its crew ranges from 100 to 200. A destroyer is designed for a single purpose, and that is to fight and destroy other warships. Everything about its design is intended to improve its capabilities in battle. Their armor and weapons usually found on a destroyer are a considerable step up from most frigates. While states controlling multiple systems often have frigates stationed in each systems under the control of the system commander, destroyers are usually based at the main fleet headquarters and deployed as needed. Constructing destroyers requires specialized facilities that are well beyond shipyards that usually build cargo ships, and there are only a handful of producers for these warships. Most states that employ destroyers buy them from allied powers rather than investing in facilities to build their own.
Cruisers are the undisputed masters of fleet battles. These giant behemoths are 400 to 500m in length with relative masses from 64,000 to well over 100,000. Their crews range from 400 to 1,000 people resembling small towns in space. Their massive sizes are the result of extremely powerful sublight engines combined with extremely heavy armor and the largest guns that can be put on a ship. The enormous mass makes them slow to maneuver and gain speed, but in a sustained chase they can easily catch up to and overtake almost any other ships, and the only hope to escape from one is to reach sufficient distance from the star to escape into Hyperspace before it gets into weapon range. The heavy protection and armament of a cruiser allows it to take on two destroyers at once with very little danger to itself, and there have been cases where a single cruiser prevailed against four destroyers. This allows them to both operate by themselves far away from friendly ports or as part of larger attack fleets. Cruisers are extremely expensive to build and maintain and there are only six shipyards in existence than can build them. Occasionally other states buy a single cruiser as a matter of prestige, but these are often very controversial moves that get criticized as huge wastes of government funds. They are far more powerful than anything required to guard systems or fight pirates, and as full scale battles between states are extremely rare, most cruisers see very little action where their extraordinary capabilities become relevant.