By Omori Kazan, Captain (Retired), Space Defense Force

The instinctive need to sort and name things is a common one for intelligent beings, and spacecraft are definitely things that fall into this category. How does one decide what kind of spaceship they operate, and how can they quickly communicate that information to others in a way that is easily understandable by all?

In the old days, when private merchants, privateers, and warships sailed over water, they used standard terminology to describe vessels designed to float on water in a manner that anyone who knew the terminology would understand. For example:

• Ships were large vessels, capable of independent operation for extended periods of time away from port.

• Boats were small vessels, capable of independent operation for only a short period of time, and capable of operating in waters shallower than ships could. Ships could, and usually did, carry boats for transfer of personnel and cargo between ship and shore. Submariners also nicknamed their preferred mode of transportation 'boats', from the word Unterseeboot (and probably as a way to distinguish them from what they perceived as large floating targets on the surface, but that's a story for a different book).

Professional sailors also used terms to describe fighting ships. Sometimes the purpose of a specific type of ship changed over time, but as a general rule, the relative size didn't.

• Corvettes, brigs, and pinnaces were the smallest combatants mounting more than a single naval gun, and could operate close to shore due to their relatively shallow draft. As time went on, some of them evolved into torpedo boats, gunboats and cutters, and they eventually evolved into swift, unarmored 'knife-fighters' capable of operating in shallow-water littoral regions, where they would hide in the radar noise formed by hills, mountains, and other structures on land, and pop out with no warning to strike at larger ships with missiles and guns.

• Frigates were the next size up, and mounted a single row of guns, called a 'broadside', on each side. Later on, the name was used to describe the smallest ships capable of operating independently for extended periods of time, designed to serve as escorts for larger ships.

• Destroyers evolved from frigates, and were swift, long-endurance escorts designed to protect larger ships from small, fast threats like torpedo boats; they were originally called 'torpedo boat destroyers'.

• Cruisers began as sailing ships intended for scouting, raiding, or commerce protection during the Age of Sail. Later, they would evolve into fast, armored warships carrying their primary weapons in large, protected turrets. Depending on the amount of armor carried, they were classified either 'heavy' or 'light'. Cruisers became warships capable of individually supporting amphibious operations, providing fleet air defense, and engaging in commerce protection or commerce raiding operations.

• Battlecruisers originally came into existence as a loophole to bypass treaties restricting armaments and ship tonnage. Carrying battleship-sized armament but lighter armor (or sometimes no armor), they were generally considered capable of sinking any ship fast enough to catch them, and fast enough to outrun any ship capable of sinking them. Battlecruisers were designed to be deployed in four missions: heavy reconnaissance, capable of sweeping away an opposing fleet's screen of cruisers; close fleet support, to prevent opposing cruisers from harrassing their fleet's battleships; pursuit of enemy ships, hopefully causing sufficient damage to slow them down for their battleships to arrive and rejoin the fight; and commerce protection, hunting down enemy cruisers and commerce raiders.

• Dreadnoughts were the first heavily-armed and -armored warships. Sporting steam turbines and an “all-big-gun” armament, they were useful for killing other large ships. Dreadnoughts were the first class of ship appearing with an armored 'citadel' containing the magazines and propulsion components and protecting them from attacks from the sides and above. Like most ships of the era, because obsolete when the battleship, with its larger main guns, arrived on-scene. (HMS Agincourt, a ship built at the very end of the Age of Dreadnoughts, carried FOURTEEN twelve-inch main guns in seven armored turrets, but was considered outgunned -and would have been outmaneuvered - by more modern battleships, such as USS Iowa with her nine sixteen-inch guns, and IJS Yamato, with her nine eighteen-inch guns)

• Battleships evolved from dreadnoughts, with better armor and more powerful guns. Considered the peak of surface gun combat technology, they proved to be vulnerable to bombs, torpedoes, and mines, and actually saw relatively little action, being relegated in the end to fire support for amphibious operations.

Battles like Midway proved that a very large, very expensive warship could be sunk by relatively cheap bombs and torpedoes dropped from relatively cheap airplanes. As a result, the emphasis began to shift away from naval gunfire and heavy armor to faster, more maneuverable ships, and larger ships that could support flight operations (but would need escorts or a combat air patrol for self-defense). Guided missiles and nuclear-powered submarines (capable of stalking a target for extended periods of time while remaining undetected) only hastened the demise of the 'Surface Gun Duel' school of tactics.

Missiles and torpedoes, along with bombs dropped from aircraft, because the long-range weapons of choice, capable of killing a ship while still over the horizon. Even today, the guided missile continues to be the long-range weapon of choice for the Space Defense Force and other fleets, with guns reserved for short ranges.

These days, spacecraft are usually classified according to their intended purpose in space. For example, while traditionalists may use terms such as 'frigate', 'destroyer', or 'cruiser' to describe a combatant vehicle's size, they all fall under the general classification 'space dominance vehicle'.

Some common examples are:

• Transatmospheric Vehicle (TAV) - A generic catch-all term for an aerodynamic, single-stage-to-orbit vehicle. They are classified as short- or long-range, with long-range TAVs being technically capable of interstellar travel. Militaries will generally use 'assault shuttle' or 'aerospace fighter' to describe short-range TAVs, and 'gunship pinnace' or 'missile pinnace' to describe long-range TAVs. Civilians will generally use short-range TAVs as cargo shuttles or passenger shuttles, and refer to them as such.

• Deep Space Operations Vehicle (DSOV) - These are the ships that function for extended periods of time away from home, primarily as a research vessel. They carry a lot of fuel, and are normally equipped with enhanced sensors and plenty of cargo space for mission equipment. The DSOV will also have some way of generating artificial gravity inside a rotating habitat module, and are only capable of operation in space. DSOVs will usually carry a complement of short-range TAVs and work pods.

• Executive Space Vehicle (ESV) - A fast transport equipped with passenger cabins but little cargo space. Governments often use these as consular ships. They are almost always transatmospheric.

• Passenger Space Vehicle (PSV) - A transport equipped with lots of passenger cabins, and spin gravity (if designed to operate solely in space). They can carry up to five short-range TAVs for transferring passengers to and from the ship.

• Scout Vessel (SV) - the DSOV's smaller sibling. This is a transatmospheric ship capable of interstellar travel, but generally lacks the extra fuel/cargo capacity of the DSOV.

• Space Dominance Vehicle (SDV) - A heavily armed and armored space-only vehicle. They can carry up to five short-range TAVs and/or work pods, and a squad of marines. Traditionalists will refer to these as frigates, destroyers, cruisers, or battlecruisers, depending on their relative size at the time of commissioning.

• Space Control Vehicle (SCV) - A space-only vessel designed for planetary assaults. They carry a platoon- to battalion-size force, plus a flight of up to twenty short-range TAVs. Traditionalists will refer to these as carriers or 'gators'.

• Space Defense Platform (SDP) - An orbital battle station. They range in size from small satellites to asteroid-sized monitors. They bristle with weapons, but have little to no maneuverability, and rely on short-range TAVs to transfer personnel and cargo to and from orbit.

• Utility Space Vehicle (USV) - A generic 'freighter' used to carry people, haul cargo, prospect in asteroid belts, etc. Smaller transatmospheric USVs are sometimes nicknamed 'free traders', 'far traders', and 'fat traders“ or “subsidized merchants” depending on their size, fuel-to-cargo capacity ratio, and ownership. Larger space-only USVs are sometimes called “heavy freighters”, carrying short-range TAVs to transfer large amounts of cargo to and from planetside.

• Work Pod - A cheap one-person class-zero spacecraft with maniupulator arms and simple engines. They function only in vacuum.