Future Point Defense Options

Jonathan_S wrote:Finally if you also want to give a CM even more range you need to either further increase it's acceleration, increase the 75s endurance even further, add a 2nd drive ring, or build a CM drive that can be stepped down to 50% power for increased endurance (but then you need to launch even earlier to pull off an intercept). Most of those are non-trivial and are likely require either lots of R&D or a significantly bigger CM.

Counter-missile drives can be stepped down to lower power acceleration to increase their endurance, speed and range. We saw an example of that as early as:

On Basilisk Station, Chapter 30 wrote:Cardones started to reach for his counter-missile firing key, then paused and glanced over his shoulder at her.
"Not yet, Mr. Cardones," she said quietly. "Let the plot settle. Fire at a half-million kilometers to catch them as their drives go down."

...Snip...

"Understood, Mr. Webster." She returned her attention to the tactical display, watching the missiles race towards her, and counted down the range. There! Cardones's counter-missiles streaked away at over ninety thousand gravities, charging to meet them, and she watched the incoming weapons' drives burn out. They coasted onward, suddenly sitting targets, unable to maneuver, and the counter-missiles adjusted their own vectors with finicky precision. They carried no warheads; their small but powerful impeller wedges were their weapons, sweeping the space before them, and she watched Sirius's missiles vanish from the display.

...Snip...

He watched his display, noting the cool professionalism with which Fearless had held her counter-fire until she had perfect targets, and filed that away with all his other data on Commander Harrington's capabilities. A dangerous, dangerous woman, he told himself as two of his missiles were decoyed off course and exploded harmlessly outside Fearless's sidewalls. But not dangerous enough to make up for the difference in firepower.

...Snip...

Honor certainly hoped he would. The Q-ship's missiles were still burning out before they came in, but the engagement time between salvos was too short for Cardones to wait them out. He had to launch sooner, with poorer solutions and lower counter-missile accelerations to give him more time—and range—on their impeller wedges. The laser clusters began to fire as a handful of Sirius's shots got past his counter-missiles, and she looked up at the main visual display as incandescent bursts of brilliance pitted the starfield ahead of her. Unless she missed her guess about the warheads those missiles carried, she had to stop them at least twenty thousand kilometers short of her ship, and they looked frighteningly close.

Italics are the author's, boldface and underlined text is my emphasis.

We first see counter-missiles initially launched as full-power shots. No numbers are given for the later counter-missile launches, but it is clear that the acceleration is dialed back to increase endurance, final speed and interception range for the later CMs in the initial pursuit* of Sirius by Fearless.

* Initial pursuit only, when Sirius is at long range from Fearless. Once Fearless closes on Sirius to the point where Fearless can fire full-power attack missiles (drive burnout time of 60 seconds), the range from Fearless to Sirius has dropped to the point where a CM's flight time can reach Sirius from Fearless in 60 seconds or less for full-power shots. So there is no point in launching CMs at lower accelerations at that the missiles Sirius is launching at Fearless at that short a range.

Weird Harold wrote:Why duplicate the anti-LAC mode of a MK-9 Viper -- with added complications?

The Viper has an X-Ray Laser warhead -- which is NOT used in anti-missile mode because the firing solution is too complex at missile closing speeds -- which has a longer range and is more powerful than a PDLC. If you could sove the firing solution complexity, which you would also need to do for your idea, it would be better to just load your canister with enhanced-Vipers.

From David's post on the Bar:

Your "gunslinger" notion, unfortunately, would appear to me to depend upon an ability to engage multiple, widely separated targets with pinpoint precision which exceeds the abilities of current-generation (and foreseeable-generation) laser heads. The laser heads of a single missile do not target separate ships; while they theoretically could, assuming the proper geometry for the ships in question, they are actually designed to hit a single target with a cascade of bomb-pump lasers. And since the missile normally carries only a single nuclear device to pump all the laser heads, all of the lasers are generated simultaneously (or effectively so) which tends to further limit the flexibility of the system. Even if that weren't the case, you are assuming far too great a capability on the part of the missiles' sensors to find and kill incoming missiles. Shipkiller vessels are designed to kill ships, not missiles, and they would not work well at all (as in not work at all) against missiles.

***

Okay, don't absolutely hold me to this, because I'm tired and I'm not sure how well my brain is working. However, walk with me here.


A laser head missile carries a single nuclear charge. It carries multiple independently targeted lasing rods, with their own thruster and attitude systems, which is what people in the Honorverse are talking about when they use the term "laser head" and which are carried in a single bus, from which they are dispensed when the missile attacks.

Although they are technically "independently targeted" (since they are independently deployed weapons), they are not really intended to engage more than one target per attack missile. The laser heads deploy from the bus with their target(s) already assigned and use the main missile's onboard sensors to align themselves with their targets. Theoretically, a single laser head missile could engage multiple targets simultaneously. To do that, however, the multiple targets in question would all have to lie within the field of fire of a laser head located the proper distance "ahead" of the nuclear charge when it detonates. To complicate matters further, laser heads do not have a spherical detonation front to work with. The missile incorporates a collar of focusing gravity generators which effectively "shape" the detonation's front, concentrating a much greater percentage of the detonation's total energy on the lasing rods of the laser heads. This means their firing point is even more restricted, and it also makes it even more unlikely that they will be able to obtain shots at multiple targets which are not obstructed by an impeller wedge somewhere along the line.



Now, as I understand your proposal, you are talking about targeting these laser rods on individual missiles traveling under acceleration towards their targets. This is a much smaller and much more difficult target than a starship. It can pull a far higher acceleration in a maneuver, it's smaller, and it is far more likely to alter course, interposing its own wedge, at an inconvenient moment. If the missile you're trying to kill is coming straight down the throat of your MDM (or any other capital ship missile), you might be able to pull this off. Generally speaking, however, for a missile to be headed straight towards one of your launch platforms, it's going to be in the terminal phase of its attack run, and you'd have a far better chance of achieving a kill with a standard counter missile than with something like this. In order to attack a missile that isn't headed straight down your throat, you'd have to position your MDM in front of it, presumably with the ability of the MDM's onboard sensors to see the target (that is, it would have to be visible through the open front of the MDM's own wedge) and generate a firing angle into the target missile's wedge at the same moment. I'm not going to say this is flatly impossible, but it's certainly not going to be a trivial accomplishment. Moreover, if the other side has Apollo, then assuming that you've managed to pull this off once or twice, the op force is going to be watching for maneuvers precisely like this one, and all of those shipboard computers that are linked in through the control missile are going to have plenty of free capacity to recognize missile flight profiles designed to do this -- or, for that matter, to routinely steer around anything that looks like it might be positioned to do this. I strongly suspect that what would happen would be the "triple ripple" all over again -- an effective defense the first time or two you managed to arrange for it, but not particularly difficult to neutralize/avoid after the other side's ops officers have had a good look at it.



It's also true that the position of an attack missile is not usually as firmly fixed within its wedge as you appear to be thinking. Remember that attack missiles can actually be set for variable acceleration rates. They don't have to be launched at exactly half power, for example, to triple endurance. The drive can be set for any acceleration value between zero and its maximum obtainable acceleration rate. Certain standard settings tend to get used a lot for two reasons. First, because there's no particular point in finely finagling acceleration rates to obtain a given maximum range. Second, because if the acceleration rates aren't maxed out, the missile can be located at a different point within the impeller wedge, exactly the same way a starship can. This no appreciable effect on standard counter missiles (one reason that standard counter missiles are "standard" counter missiles), which depend on wedge-on-wedge kills, but it can make tracking more difficult for the fire control assigned to the point defense clusters during the missile's final powered run in on the target.



All of this, taken together, is the reason that I think it would be very difficult to use a shipkiller as a counter missile. Obviously, it wouldn't be flatly impossible, but I strongly suspect that you'd have better luck trying to use the missile wedge than attempting to physically target the incoming missile body with laser heads. Even there, though, you need to bear in mind that whereas counter missiles have insanely powerful and deliberately huge impeller wedges, the designers of shipkiller missiles put a lot of thought into making their weapons' impeller wedges as small as possible, expressly to make the counter missile's job harder. That means that a shipkiller, by its very nature, makes not only a lower but a less efficient "missile sweeper" when used in the missile-defense role.

What makes this worse is that a Viper has only one laser head, so instead of hitting the 10KM wide missile wedge with a 10KM wide viper wedge, you are trying to hit the 5 meter wide missile body with a 3 meter wide viper xray laser. I predict this results in a larger number of misses.

kzt wrote:What makes this worse is that a Viper has only one laser head, so instead of hitting the 10KM wide missile wedge with a 10KM wide viper wedge, you are trying to hit the 5 meter wide missile body with a 3 meter wide viper xray laser. I predict this results in a larger number of misses.

What I am talking about when I mention the MK.9 Viper is its ability to be a fire and forget weapon I think I have actually said this but what I am suggesting is that you take a MK.9 Viper you remove its laser head and its nuclear warhead and you fill the space which this frees up with additional computer and targeting sensors so that this new missile lets call it MK.10 is a high performance fire and forget counter missile which will kill attacking missiles with its wedge.
If you do this then you no longer need to provide constant guidance to the CM because the MK.10 would be able to guide itself onto the attacking missile using its onboard sensors and ai. For longer range engagements the launching ship would only need to provide mid course updates because the MK.10 would be able to guide itself onto the attack missile once the MK.10s sensors can see the target. Now looking at the 3D render made by MaxxQBuNine of the MK.9 missile if you were to remove the lasing rod and nuke you would free up a huge amount of space which you could cram full of a large amount of additional sensors and computers which should be more than capable of what I am suggesting if the MK.9 is already a fire and forget weapon against LACs

Duckk wrote:Okay, don't absolutely hold me to this, because I'm tired and I'm not sure how well my brain is working. However, walk with me here.

You misread my post. I was disparaging sharkhunter's idea of putting scaled down PDLCs on fusion-powered CMs.

I explicitly noted that Vipers DO NOT use their anti-LAC warheads against missiles; not even single missiles, let alone multiple missiles.

captinjoehenry wrote:Now looking at the 3D render made by MaxxQBuNine of the MK.9 missile if you were to remove the lasing rod and nuke you would free up a huge amount of space which you could cram full of a large amount of additional sensors and computers which should be more than capable of what I am suggesting if the MK.9 is already a fire and forget weapon against LACs

The idea of building on the Viper's fire-and-forget ability has been raised multiple times. The objections seem to center around the closing speeds of missile+counter missile; the time for computations during the final attack phase is smaller than even the most capable AI can handle, let alone one that can be crammed into a counter missile.

The intercept solution would be a couple of orders of magnitude greater than the intercept solution for a LAC -- even without the need for aiming a warhead.

Weird Harold wrote:The intercept solution would be a couple of orders of magnitude greater than the intercept solution for a LAC -- even without the need for aiming a warhead.

People keep saying this, but the sidewinder missiles that could perform supersonic direct hit intercepts in the 1950s did this without integrated circuits, much less high performance computers. Continually producing a collision course just isn't that hard.

Weird Harold wrote:

Duckk wrote:Okay, don't absolutely hold me to this, because I'm tired and I'm not sure how well my brain is working. However, walk with me here.

You misread my post. I was disparaging sharkhunter's idea of putting scaled down PDLCs on fusion-powered CMs.

I explicitly noted that Vipers DO NOT use their anti-LAC warheads against missiles; not even single missiles, let alone multiple missiles.

captinjoehenry wrote:Now looking at the 3D render made by MaxxQBuNine of the MK.9 missile if you were to remove the lasing rod and nuke you would free up a huge amount of space which you could cram full of a large amount of additional sensors and computers which should be more than capable of what I am suggesting if the MK.9 is already a fire and forget weapon against LACs

The idea of building on the Viper's fire-and-forget ability has been raised multiple times. The objections seem to center around the closing speeds of missile+counter missile; the time for computations during the final attack phase is smaller than even the most capable AI can handle, let alone one that can be crammed into a counter missile.

The intercept solution would be a couple of orders of magnitude greater than the intercept solution for a LAC -- even without the need for aiming a warhead.

Ok the terminal guidance can actually be pretty simple technically if the missile can generate a lock on target it does not really need to compute any sort of firing solution all it needs to do is use proportional navigation (http://www.moddb.com/mods/wicmw/feature ... principles) so even if the attack missile is preforming a large amount of evvasive manuvers for final guidence you can use this proportional guidence which in truth needs no real computing power. Read the article I link for all of the details because I am not able to summarize this subject very well. Now the missile can use this guidance system for most of the flight depending on the extent that the attack missile maneuvers as this navigation system should be fully functional if the attack missile does not do large changes in its approach vector.

Also there is a HUGE amount of volume that removing the war head and lasing rod from the MK.9 frees up I mean if the MK.9 is able to generate firing solutions on LACs with whatever space it has for sensors if you were to remove the lasing rod and war head you would easily have 10x as much space at a very low estimate so if you were to fill up all of that space with computers i am pretty sure it would be able to generate the firing solution it needs to hit the attack missile

MK.9 Viper cut away (http://maxxqbunine.deviantart.com/art/M ... -465723662)
MK.9 Viper without capacitors (http://maxxqbunine.deviantart.com/art/M ... -465723786)
MK.9 Viper with cover (http://maxxqbunine.deviantart.com/art/C ... -465722583)

captinjoehenry wrote:What I am talking about when I mention the MK.9 Viper is its ability to be a fire and forget weapon I think I have actually said this but what I am suggesting is that you take a MK.9 Viper you remove its laser head and its nuclear warhead and you fill the space which this frees up with additional computer and targeting sensors so that this new missile lets call it MK.10 is a high performance fire and forget counter missile which will kill attacking missiles with its wedge.
If you do this then you no longer need to provide constant guidance to the CM because the MK.10 would be able to guide itself onto the attacking missile using its onboard sensors and ai. For longer range engagements the launching ship would only need to provide mid course updates because the MK.10 would be able to guide itself onto the attack missile once the MK.10s sensors can see the target.

As you kind of alluded to the Viper is fire and forget when launched at 3.5 million km or less against LAC sized targets with (presumably) 100+ km wide wedges, and accelerations of < 1000g.

A closing MDM target has a <10 wide wedge, and get launched at when its more like 20 million km away, and accelerating at 46000g.
(To be fair though, for simplicity, I ran those numbers as if the LAC was itself the target for a max range MDM. If it is 2-4 million km downrange, and/or the MDM is launched from less than its max powered range, then the MDM won't be going quite as fast and you won't have to launch quite as early to intercept it out near Viper burnout)


The LAC has way less ability to dodge, and is a physically larger and much closer target to track. There's no guarantee that a viper is noticeably better at fire-and-forget against incoming MDMs than any other CM.

kzt wrote:People keep saying this, but the sidewinder missiles ...

Sidewinders never had to deal with relativistic, C-fractional closing velocities.

Weird Harold wrote:

kzt wrote:People keep saying this, but the sidewinder missiles ...

Sidewinders never had to deal with relativistic, C-fractional closing velocities.

They also didn't have FTL sensors. They just don't get going that fast, and the minor time dilation problems are all on the fast moving side, which are the MDMs that are trying to avoid the collision.