All battles in space take place at what are, by groundside standards, extremely long ranges, measured in ten-thousands, hundred-thousands, or millions of miles. Not only do these battles take place outside visual “eyeball” range, but even starships in the same formation are outside visual range of each other, being hundreds or thousands of miles apart. (Closer formations would pose both an unacceptably high risk of collision under battle conditions, when ships in the formation are drunkwalking independently, and would be likely to cause point-defense fratricide.)
The only exception to this rule are autonomous kill vehicles (AKVs) themselves (even when not acting as auxiliary kinetic energy weapons (KEWs)), which often come within single-digit mile distances of their targets; i.e., operating effectively inside the innermost point-defense zone.
Outer Envelope: The Wolves at Hunt
The outer engagement envelope begins, depending on various environmental factors, at between one to one-half light-minutes range.
Battles taking place in the outer engagement envelope are essentially always inconclusive. While historical examples of lucky hits from these ranges do exist, the probabilities of such are sufficiently low that no-one would count on them; and at such ranges, it is virtually always possible for the weaker opponent to disengage at will.
(The exception being, of course, when someone has managed to sneak an observation platform in close to the opposing force without them noticing it, which gives them a great – albeit temporary – advantage in generating long-range firing solutions.)
Rather, the purpose of engagements in the outer envelope is to wear down an opponent closing upon one’s inner envelope, forcing them to generate heat and expend point-defense resources; and to herd opponents away from the danger zones generated by one’s fire.
While it is impossible, without both fortunate geometry and superior acceleration, for a single force to bring an opposing force to battle if it is actively trying to refuse such, it is sometimes possible through strategic outer-envelope engagement and misdirection to force them to pass through the inner engagement envelope of one of a set of multiple forces (including, for this purpose, fixed system defenses). This is the end to which tactics are directed in the outer engagement envelope.
At these ranges, the primary weapons are the spinally-mounted mass drivers of larger ship classes. Carriers may attempt to use “missiles” – actually strap-on, discardable thruster packs – to deliver AKVs close in to the opposing force, but many captains prefer to reserve their AKVs for inner-envelope battles where they can be better supported.
Inner Envelope: Let’s Dance
The inner, close-range engagement envelope – in which actual battles are fought – begins at roughly a light-second of separation. This reflects the difficulties of accurately targeting an opponent engaged in active evasion (drunkwalking, ECM, etc.) when the light-lag is greater than that; essentially, you have to close to within a light-second to get a firing solution whose hit probability is significant.
Reaching the inner engagement envelope implies either that one party is attacking or defending a specific fixed installation (such as a planetary orbit, drift-habitat, or stargate), or that both parties have chosen engagement. It is relatively rare for such battles to take place in open space otherwise, since in the absence of clear acceleration superiority, it is usually easy for the weaker party to disengage before entering their opponent’s inner engagement envelope. The only way to guarantee that an opponent will stand and fight is to attack a strategic nexus that they must retain control over.
Within the inner engagement envelope, all weapons come into play. Light lag becomes low enough that information warfare can come into play in full force, firing solutions are usually possible on all craft, and AKVs have the range and maneuverability to be committed.
As the opposing forces enter the inner engagement envelope, larger ship classes typically keep their distance, maintaining formation and lateral drunkwalk evasion, as they engage in mass driver artillery duels.
Cautious admirals also hold their screening forces back at this point, preferring to weaken the enemy force before pressing further. More aggressive admirals press in immediately, moving their lighter squadrons into the center of the battlespace and deploying AKVs likewise.
Unlike the larger ships, cruisers maneuver aggressively for advantage, forming the characteristic “furball” as fleets intermingle; once this stage is reached, it becomes very difficult to retreat in good order. Cruisers attack each other with close-in, off-bore mass driver projectiles and heat-pumping lasers; the highly maneuverable destroyers and frigates engage in “wolf-pack” tactics throughout the battlespace, both targeting each other, and swarming damaged larger ships at relatively close range.
Any battle in which the battlespace is smaller than a tenth of a light-second in diameter is referred to as taking place at “knife-fight” range. Such engagements usually occur around fixed points when the attack is pressed hard, are short and vicious, and typically result in extraordinarily high casualties – usually for both sides.
Unlike starship armor, neither the point-defense laser grid nor the kinetic barriers are subject to direct attrition; if subjected to low-volume or low-power incoming fire, either or both could continue to destroy or repel it essentially forever.
In order to defeat these defensive systems, it is necessary to swamp them; to concentrate incoming fire to the point at which the defensive systems are unable to handle it all simultaneously. At this point, attrition may take effect as kinetic effectors and laser emitters are destroyed, but more importantly, it generates heat.
Heat is the primary limitation on combat endurance. Maneuvering burns, the use of high-energy equipment such as the point-defense grid, the kinetic barriers, and so forth, as well as the ship’s normal operation, all produce heat. In combat – when the ability to radiate heat is limited, usually to radiative striping and small (and exhaustable, if the starship is forced to maneuver) droplet radiators alone – military starships generate heat more rapidly than they can radiate it to space. As heat increases beyond the critical point, the efficiency of onboard equipment begins to fall (processor error rates rise, for example, and tactical officers must conserve their remaining heat capacity), some equipment goes into thermal shutdown, and the crew spaces become increasingly uninhabitable.
While some starships in any major space battle are destroyed physically, reduced to hulks, the majority of starships are defeated by either heat-induced equipment failure, or by being forced to surrender and deploy radiators lest their crew literally cook.