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Pearls of Weber

A collection of posts by David Weber containing background information for his stories, collected and generously made available Joe Buckley.

Shipkiller missile evasive maneuvers

There's been some discussion about whether or not shipkiller missiles routinely follow evasive routing to make life harder on counter-missiles. As part of the same thread, someone has suggested that it might be feasible to fit clusters of "counter-counter-missiles" into a few shipkiller-sized missile bodies in place of standard warheads. As I understand it, the idea is that the "counter-counter-missiles" would be relatively small (I believe 50 kg was mentioned) and very short-lived. Their function would be to get out in front of a salvo of shipkillers and hopefully target counter-missiles coming in on the salvo. I believe that it's also been mentioned that they should also be equipped with EW capabilities which would make it possible for them to appear to be shipkillers in final acquisition themselves, in order to saturate the target's close-in defenses with hundreds of false targets just before the true laser heads attack.

 

Shipkillers generally don't worry about evasive maneuvers until they are about to enter effective counter-missile range. There's not much point evading when no one's shooting at you, anyway. Evasive maneuvers may or may not be used across the counter-missile engagement envelope. That's normally a decision for the tactical officer planning the attack, and he'll make that decision based on several variables. The biggest three are:

(a) How accurate are the other side's counter-missiles likely to be?

(b) How effective at decreasing the counter-missiles' probability of a kill would evasive maneuvering be?

(c) How much of an adverse effect on his shipkillers' accuracy will evasive maneuvering have?

If the other side's counter-missiles are relatively inaccurate and evasive maneuvers would significantly degrade his chances of scoring hits, then he probably wouldn't maneuver against the counter-missiles, figuring that the decrease in his chances of scoring hits would more than offset the chances of dodging interceptions. If, on the other hand, the counter-missiles waiting for him were relatively accurate and evasive maneuvers would make them less accurate, then he might accept the lowered hit probability for his shipkillers in order to get more of them into attack range in the first place. Obviously, the questions which have to be answered will vary from navy to navy. Against something like Shannon Foraker's defense in depth (which, I suspect, is the specific situation people had in mind when the possibility was raised), evasive maneuvering probably wouldn't be worth the effort. Shannon's defense relies not on the individual accuracy of any given counter-missile but on the erection of a roadblock composed of hundreds of individually very inaccurate counter-missiles. Evading one of them would be just as likely to take you into the flight path of another, and the hit your shipkillers' terminal accuracy would take -- especially at extended ranges -- would be significant.

As far as the counter-counter-missile is concerned, I don't see it as a viable option, for several reasons. Any "submunition" which could be carried in large enough numbers to be particularly useful would have to be much too small to mount anything like a shipkiller or counter-missile's impeller wedge. While impeller wedge missiles are used against atmospheric targets, these are generally very small, very short-lived, and (relative to space-going missiles) very slow weapons. They don't begin to have the power necessary to knock down a counter-missile's impeller wedge. They don't have the acceleration capacity to get out in front of a shipkiller. They don't have the acceleration capacity to masquerade as a shipkiller -- they'd be so much slower it would be child's play to differentiate them from a real threat. And they certainly wouldn't have the onboard tracking and control systems necessary to handle this sort of knife-range, ultra-high-velocity intercept solution. And as far as the notion of "false targets" is concerned, the current Manticoran Dragon's teeth decoys are far, far more effective in just about every conceivable way.