All of this requires that for effective missile fire, the missile drive must still be active and capable of terminal attack maneuvers right up to the instant of detonation.
A missile's effective powered flight envelope can be increased by setting it for a lower rate of acceleration, which delays burnout time on its small but powerful impeller drive. Eighty-five thousand gravities represents the maximum attainable acceleration, used for snapshots at closer ranges in order to achieve the shortest possible flight times. At this acceleration rate, the missile has a maximum powered endurance of sixty seconds, which restricts it to a powered engagement envelope (assuming target and firer were at rest relative to one another at the moment of fire) of approximately 1,500,000 kilometers and a terminal velocity of approximately 50,000 KPS. By setting the drive down to 42,500 gravities, time to burnout can be extended to 180 seconds, producing a maximum powered engagement range of 6,755,000 kilometers and a terminal velocity of 75,000 KPS. Lower accelerations are possible, but the maximum range and velocity actually begin to drop as acceleration is further reduced, and most navies adopted hardwired minimum settings in the vicinity of 42,500 g. The RMN, however, had not, as it believed there were instances in which absolute engagement range and velocity were less important than powered flight time to follow an opponent's maneuvers. All of these attack envelopes, of course, can be radically extended or reduced by the relative velocities and accelerations of the ships engaged.
Because the chance of knocking a missile down increases geometrically in the last 50,000 or 60,000 kilometers of its run, as it steadies down on its final attack vector, direct hits against modern point defense are virtually unheard of. As a result, the standard megaton-range nuclear warhead was falling into general disuse for ship-to-ship combat by Honor Harrington's time, replaced by the laser head. The terminal bus of a laser head mounts sophisticated targeting systems and powerful attitude thrusters to enable it to align itself so as to direct the greatest number of bomb-pumped laser beams at the target, but it is also designed to have a "porcupine" effect, radiating lasers in all directions. Each laser inflicts less damage than a direct hit could have, but the chances of a hit—even multiple hits—from a single missile are greatly increased. Not only does a laser head's stand-off range lessen point defense s chance to kill it short of detonation, but the cluster effect allows each to cover a much greater volume of space.
Active antimissile defenses consist of countermissiles, laser clusters, and (in navies further from "state of the art" hardware) autocannon. Countermissiles are much smaller versions of shipkillers, with more limited endurance and no warheads but capable of even higher acceleration. Their weapon is their impeller wedge. If any portion of it impinges on an attacking missile's active wedge, both vaporize as their drives burn out; if the target's drive has already burned out, the "grav shear" of the counter missile's wedge is more than adequate to rip it apart. Because of their overpowered drives, however, maximum effective counter missile range is seldom more than 1,000,000 kilometers or so.
If the countermissiles miss their prey, stopping them is up to the computer-commanded laser clusters. Unlike missiles, these require direct hits, but by the time they come into play, their target is normally steadying down for its final attack run, which gives them much simpler fire solutions.
In some navies, the lasers were backed by a last-ditch autocannon defense. The theory was simple: throw so many shells that they built a wall of metal in the missiles' paths. Given missiles' closing velocities, any hit could be counted on to vaporize them, but the development of laser heads made autocannon largely irrelevant. When a missile can attack from 20,000 or 30,000 kilometers, no last-ditch ballistic projectile can reach it in time.
Note that all of the above comments apply only to engagements under impeller drive. All normal space combats are, of course, fought out under impeller drive, as are those in hyper-space but outside the boundaries of a grav wave. Within a grav wave, however, where movement is possible only under Warshawski sail, missiles cannot be used. Only energy weapons are effective there, and combat under those conditions tends to be very close and extremely brutal.
The energy weapons of choice are the laser and graser, of which the graser has both a longer range and greater effect. But grasers are considerably more massive than lasers, so most ships have mixed batteries, accepting the lower effectiveness of the laser in order to mount greater numbers of weapons (which let them engage greater numbers of targets) while retaining the "smashing" ability of the graser. Ships smaller than light cruisers are normally so cramped for weapons space that they have pure laser energy armaments.
Another energy weapon, though seldom used at this period, was the energy torpedo, which fired what were for all intents and purposes packets of plasma confined in electromagnetic bottles. Energy torpedoes moved at near-light speeds, which made them very difficult for point defense to engage, but the energy torpedo had no homing capability. This made it a purely ballistic weapon, so the initial (and only) fire control solution was far more critical than for missiles, and the endurance of its "bottle" was barely more than one second, limiting absolute energy torpedo range to 300,000 kilometers or so. In addition, the fact that they were totally ineffective against an intact sidewall restricted them to down the throat or up the kilt shots, which made them of strictly limited utility. Despite this, some navies' capital ships (the RMNs among them) incorporated light torpedo batteries for use if the enemy's T" could be crossed or if his sidewall failed due to other battle damage.
A new development, the grav lance, offered the ability to burn out a sidewall by hitting it with a disrupting burst of focused gravitic energy, but this weapon had a maximum effective range of little more than 100,000 kilometers. It was also extremely slow firing, mass intensive, and temperamental, and very few captains were willing to sacrifice displacement which could be used for tried and proven weapons to squeeze in something that might work... if they could survive to get into its range of the enemy.
THE BALANCE OF NAVAL POWER
The pre-war naval balance between Manticore and Haven was the result of an arms race which had lasted for almost fifty years. Despite the Star Kingdom of Manticore's wealth and the Peoples Republic of Haven's ramshackle financial structure, the PRH was so much bigger that the smaller percentage of total income it could devote to its military budget was larger in absolute terms. Moreover, the Star Kingdom, the core of the Manticoran Alliance, possessed only three inhabited planets; the PRH contained over a hundred, which provided a far larger pool from which to draw starship crews and support personnel, and it had begun its initial buildup well before Manticore.
The actual strengths of the two sides in 282 A.L. (1904 P.D.) broke down as below:
The Peoples Navy thus had a tonnage advantage of almost exactly two to one, yet its overall advantage in hulls was only 1.2 to 1, despite the fact that the RMN's ships were almost uniformly more massive on a per-class basis. This apparent discrepancy resulted from the composition of the two forces. The People's Navy was designed not only for wars of conquest but to police the enormous sphere the PRH had already conquered. The large number of battleships in its order of battle were intended not for the wall of battle, where their smaller size would place them at a grievous disadvantage against "proper" ships of the wall, but to cover occupied systems against anything smaller than a wall of battle ship. (This was of particular importance against Manticore, which had always favored the battiecruiser. The BC's combination of acceleration and firepower made it ideal for raids on the orbital industrial infrastructure of enemy star systems, and the RMN had refined these tactics to a fine art over the centuries.)