...Besides the Digital Age technologies presented in the previous chapter, and the various orbital stations and colonies in the final chapter, three broad categories of spacecraft are used by modern interstellar society. These are considered the only true "spaceships", in any meaningful sense.
The first category, which you as an astropilot are unlikely to ever encounter in the course of your career, is that of the capital ship. Depending on local custom, such ships may be called "frigates", "destroyers", "cruisers", "battle-cruisers", "battleships", or any number of colorful but arbitrary designations. All are essentially mobile defense platforms, weighing over one million tons, and therefore requiring either antimatter- or singularity-based drives to move their tremendous bulk at a reasonable speed. Alert readers will have recalled that one million tons is the median mass of late-Digital space arks, and indeed, those still in service are routinely classified as "capital ships", regardless of whether they are armed. (In practice, virtually all intact colony ships have undergone extensive refits, replacing their engines and using their former habitat or cryogenics decks for "broadsides" of capital-grade weapons.) Even a wealthy planetary system, with all its worlds united under a single government, cannot afford to build and maintain more than one of these behemoths. Only the Three Alliances are capable of fielding entire squadrons of capital ships, typically two or three per squadron, and then only in the most strategically vital systems.
The second category is the escort ship, a term which also covers a broad range of classes. "Corvettes", "cutters", "scout ships", and "mine-layers" are all common appellations. They are distinguished from drop ships by their longer range and possession of a capital-grade weapon (albeit only one), and from capital ships by their smaller size. Because escorts rarely weigh more than 250,000 tons, any sort of nuclear- or ion-based drive can serve their needs quite adequately. In addition to its single capital weapon, all escorts have between two and three dozen secondary weapons, used for point-defense at ranges of less than 100 kilometers. The same weapon systems, in much smaller numbers, are mounted as the primary weapons on heavy Mecha, and include such classic designs as Archfiend lasers, Vadhar auto-cannons, and Chronysis rail-guns.
Finally, there are the clippers, freighters, transports, and landing craft of the galaxy: drop ships. These are blended-wing or lifting bodies which, unlike escort and capital ships, can "drop" from orbit onto a planetary surface. Since they are expected to contend with atmospheres and gravitational wells, drop ships are restricted to primitive -- but ecologically harmless -- chemical rockets, and manageable masses from 2,000 to 200,000 tons. Such small vessels can only accommodate Mecha-scale weapons; Cherenkov Rays are popular among astropilots expecting stratospheric combat, while a squadron of "bombers" equipped with Omen Barrels can pose a serious threat to lone escort ships. The smallest drop ships cost no more than a few squads of heavy Mecha, so both civilian corporations and mercenary companies often invest in a drop ship of their own, rather than chartering a government vessel. Unfortunately, while chemical rockets are sufficient for orbital missions and trips among a planet's moons, they are effectively worthless for journeys of more than one light-minute. Thus, a drop ship's captain must often arrange to dock with an escort ship, and be carried to his destination. Most nation- and planet-states charge exorbitant fees for this privilege, usually in the form of a 10% tax upon the cargo's market value (payable in niodes), or by taking 10% of the cargo itself.
--Sidebar: Capital-Grade Weapons--
Escort and capital ships move at significant fractions of the speed of light. A standard antimatter drive, for example, has a top velocity of 0.5 to 0.9 c (depending on the efficiency of its Penning tanks, the density of cosmic dust in the vicinity, etc.), or 150 to 270 kilometers per millisecond. Such a speed is effectively impossible for even the most advanced fire-control systems to track, at ranges under 1,000 kilometers. The obvious solution, of course, is to fight at ranges between this distance and approximately two light-seconds, which has been found to be a convenient practical limit. (Two light-seconds is a distance slightly greater than the distance between Old Earth and Luna.) This, in turn, requires directed-energy weapons of some kind, as any missile or projectile fired at that range could never move fast enough to reach its target. Traditionally lasers have filled this role, but since the introduction of plasma weapons in the 3100s, designs based on the Helios Forge have become popular, especially in the Illyrian Navy.
The exception to this rule is found aboard mine-layer escorts. Their capital-grade weapon is a keel-mounted mine dispenser, used during the hours before a battle to place thousands of thermonuclear bombs in the enemy's most likely path. If a ship comes within a bomb's detection range without transmitting the proper identification code, the bomb explodes. In effect, the "missile" does not have to intercept the ship: the ship intercepts the missile. Any unexploded mines deactivate themselves upon receiving the appropriate signal from the mine-layer, and use their station-keeping thrusters to gather in one convenient spot for collection and reloading.
Submitted by Damien Valentine#885659