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ThinksMarkedly wrote:

Jonathan_S wrote:Though the modern GA ship can't produce a bow wall and a stern wall at the same time. (It's explained when the bow wall is introduced that the physics precludes closing off both ends) I assume however that it could produce a bow wall plus a stern buckler; as the buckler doesn't close off the end (which is also why a ship can accelerate with buckler(s) up).

That's true if the ship wants to keep accelerating. But it doesn't have to: if the ship or fleet is expecting the need to withstand an Alpha launch, they can simply stop accelerating for just long enough as the missiles fly past. That does mean they are flying ballistically instead of evading, but if the presence of bow and stern walls improves survivability even more, then do it. This is only needed for under half a second anyway.

Actually, no. Putting up either a bow or stern wall already removes the ability to accelerate or maneuver using the wedge; the physics still prohibits putting up both a (full) bow and stern wall simultaneously.

Echoes of Honor wrote:"As we all know, it's impossible to close the bow or stern aspect of an impeller wedge with a sidewall, right?" Heads nodded once again. "And why is that, Lieutenant Takahashi?" she asked genially.
[...]
"Because cutting off the stress bands' n-space pocket with a closed wedge prevents you from accelerating, decelerating, or using the wedge to change heading, Ma'am," he replied. "If you want the math—?"
"No, that's all right, Lieutenant," she said. "But suppose you don't want to accelerate or decelerate? Couldn't you generate a 'bow' sidewall then?"
"Well, yes, Ma'am, I suppose you could. But if you did you'd be unable to change—" Takahashi stopped speaking suddenly

Ashes of Victory wrote: Just as powerful as the new "bow-wall" that closed off and protected the front of a Shrike's wedge as it bored into energy range, the Ferret's "sternwall" closed off the rear of the wedge. Power requirements and the physics of the wedge meant only one aspect, bow or stern, could be closed at any given moment, but it gave a Ferret's skipper a much more flexible choice of breakaway vectors.

The power requirements might be irrelevant on a full up warship, but the physics of the wedge would still restrict it to only protecting one aspect, bow or stern, at any given moment. (But, as I said, I believe the other could likely be partially protected by a buckler)

Daryl wrote:I haven't been following all of this, so apologies if this has already been covered.
With militaries in our time line on the cusp of developing laser and directed energy weapons, one of the advantages is that you don't need to lead the target, as its speed is inconsequential to that of a light speed laser.
However in the scenario under discussion you will still have to take the target's speed into your calculations, as it is of the same magnitude as your weapon. I'd also imagine that the time of contact would be reduced, leaving less time to burn through the casing, and there is no atmospheric buffeting to assist your strike.

It isn't actually on the cusp anymore Daryl. It is a reality. I don't know if you know about the LAWS system, the world's first laser weapon system. It does not need to lead the target as you said. It is the navy's answer to drone warfare. The system only needs a supply of electricity, and shooting down drones only cost about $1 per shot. As opposed to shooting down a $2000 drone with a $2M missile.

https://youtu.be/9ElNjgZCDpQ?si=_1WoKZZO1WroGdl3

It also takes out small surface boats as would be used by small navies.


Anyway, targeting the missile is directly related to my notion of dropping spent stages. That is why I suggested that dropping a stage could be saved until the missile penetrates the CM zone and ship's sensors are tracking it. This is when Daryl's notion kicks in. The missiles are moving so quickly that targeting the missile is left up to the computers. As Daryl said, leading the target might be necessary since the speed of both the PDLC and the missile are ~ comparable.

Which is why I suggested that separating a spent stage could be reserved until this moment. If the missile's acceleration suddenly changes due to dropping a spent stage, then the extra boost of acceleration might be enough to throw the PDLC computer off for a split second. A split second delay might as well be an hour delay in this threat environment.

penny wrote:Which is why I suggested that separating a spent stage could be reserved until this moment. If the missile's acceleration suddenly changes due to dropping a spent stage, then the extra boost of acceleration might be enough to throw the PDLC computer off for a split second. A split second delay might as well be an hour delay in this threat environment.

You need to clarify about your current thinking. At some point the separation was going to occur after the wedge drop, so the only acceleration is provided by the separation process itself and is not going to be major.

tlb wrote:

penny wrote:Which is why I suggested that separating a spent stage could be reserved until this moment. If the missile's acceleration suddenly changes due to dropping a spent stage, then the extra boost of acceleration might be enough to throw the PDLC computer off for a split second. A split second delay might as well be an hour delay in this threat environment.

You need to clarify about your current thinking. At some point the separation was going to occur after the wedge drop, so the only acceleration is provided by the separation process itself and is not going to be major.

You really need to follow the discussions. A multistage missile should have two to three stages it might possibly shed. One, or two or both stages could be saved until it breaches the CM zone.

penny wrote:You really need to follow the discussions. A multistage missile should have two to three stages it might possibly shed. One, or two or both stages could be saved until it breaches the CM zone.

How would that work? Weren't you suggesting that they'd drop the stages as the drive rings burned out?

That'd leave the dropped stages way, way, way behind the missile by the time its final stage reached the CM zone.

(Take a 3-stage missiles with the same drive specs as a Mk23 and assume only a 50 million km shot. The warhead hit standard CM range -- 1.5 million km from the target -- in 464 seconds, moving at 0.7c.
The first stage burned out and was dropped after 180 seconds at 7.3 million km, moving 0.27c. By 464 seconds from launch it's fallen 20 million km behind the warhead -- no distraction there.
The second stage burned out after 360 seconds at 29 million km, moving at 0.54c. By 464 seconds from launch it's fallen 4 million km behind the warhead -- still no distraction there)

To have any hope of causing a distraction the burned out stages would have to remain attached all the way to the CM zone, and only then could the missile drop them.
But even there they'd seem poor distractions -- the final stage would still be accelerating hard under wedge, while the spent stages it drops would be coasting ballistically without any wedge.
So they don't look anything like another missile, they don't have the FTL signature of another missile, and they rapidly get left behind.
If you want a decoy use a ECM missile with decoy abilities -- like Manticore's Dragons Teeth. That'll be way more effective that dropping a couple chunks of relativistic missile body

Jonathan_S wrote:

penny wrote:You really need to follow the discussions. A multistage missile should have two to three stages it might possibly shed. One, or two or both stages could be saved until it breaches the CM zone.

How would that work? Weren't you suggesting that they'd drop the stages as the drive rings burned out?

That'd leave the dropped stages way, way, way behind the missile by the time its final stage reached the CM zone.

(Take a 3-stage missiles with the same drive specs as a Mk23 and assume only a 50 million km shot. The warhead hit standard CM range -- 1.5 million km from the target -- in 464 seconds, moving at 0.7c.
The first stage burned out and was dropped after 180 seconds at 7.3 million km, moving 0.27c. By 464 seconds from launch it's fallen 20 million km behind the warhead -- no distraction there.
The second stage burned out after 360 seconds at 29 million km, moving at 0.54c. By 464 seconds from launch it's fallen 4 million km behind the warhead -- still no distraction there)

To have any hope of causing a distraction the burned out stages would have to remain attached all the way to the CM zone, and only then could the missile drop them.
But even there they'd seem poor distractions -- the final stage would still be accelerating hard under wedge, while the spent stages it drops would be coasting ballistically without any wedge.
So they don't look anything like another missile, they don't have the FTL signature of another missile, and they rapidly get left behind.
If you want a decoy use a ECM missile with decoy abilities -- like Manticore's Dragons Teeth. That'll be way more effective that dropping a couple chunks of relativistic missile body

You misunderstood. I am saying that the tactic would have several possibilities available to it. And the MAN can choose to mix and match settings, according to what worked in the field. Obviously spent stages do not have to be dropped. So, they could be held in abeyance until the extra accel might confuse point defense. Extra acceleration might be desired inflight or after it breaches the CM zone.

And if it turns out that the equation with volume and compensation is really partial towards dropping the final stage (or all stages) ... (as in a lot more acceleration ... and we can't know that it wouldn't) then Bob's your uncle. That could really confuse point defense computers. Inside the CM zone sure would be a good time for the turbo to kick in. Especially if the computer's processing power is leading the PDLCs as Daryl suggested.

penny wrote:Which is why I suggested that separating a spent stage could be reserved until this moment. If the missile's acceleration suddenly changes due to dropping a spent stage, then the extra boost of acceleration might be enough to throw the PDLC computer off for a split second. A split second delay might as well be an hour delay in this threat environment.

tlb wrote:You need to clarify about your current thinking. At some point the separation was going to occur after the wedge drop, so the only acceleration is provided by the separation process itself and is not going to be major.

penny wrote:You really need to follow the discussions. A multistage missile should have two to three stages it might possibly shed. One, or two or both stages could be saved until it breaches the CM zone.

We all understand that a Cataphract style multi-stage already drops the exhausted stages.

We also realize that the only significant amount of weight that could be dropped from a Manticoran multi-drive missile is the reactor; which implies after the wedge is dropped. Even if the exhausted drive nodes could be dropped from such a missile, it is an insignificant percentage of the total weight of the missile.

So what conceptual break-though have I missed? Do you want a Cataphract where the exhausted stage is kept until it is time to fool the defender?

tlb wrote:

penny wrote:Which is why I suggested that separating a spent stage could be reserved until this moment. If the missile's acceleration suddenly changes due to dropping a spent stage, then the extra boost of acceleration might be enough to throw the PDLC computer off for a split second. A split second delay might as well be an hour delay in this threat environment.

tlb wrote:You need to clarify about your current thinking. At some point the separation was going to occur after the wedge drop, so the only acceleration is provided by the separation process itself and is not going to be major.

penny wrote:You really need to follow the discussions. A multistage missile should have two to three stages it might possibly shed. One, or two or both stages could be saved until it breaches the CM zone.

We all understand that a Cataphract style multi-stage already drops the exhausted stages.

We also realize that the only significant amount of weight that could be dropped from a Manticoran multi-drive missile is the reactor; which implies after the wedge is dropped. Even if the exhausted drive nodes could be dropped from such a missile, it is an insignificant percentage of the total weight of the missile.

So what conceptual break-though have I missed? Do you want a Cataphract where the exhausted stage is kept until it is time to fool the defender?

Again. The equation with compensation is concerned about volume, not weight. And again, I was talking about missiles being redesigned for this purpose. Also, how do you know that the net gain in acceleration would be slight? We do not have access to the equation. Plus, we do not know if the Cataphracts are anything like the actual missiles that will be deployed by the MAN.

penny wrote:Again. The equation with compensation is concerned about volume, not weight. And again, I was talking about missiles being redesigned for this purpose. Also, how do you know that the net gain in acceleration would be slight? We do not have access to the equation. Plus, we do not know if the Cataphracts are anything like the actual missiles that will be deployed by the MAN.

The Ninurta is very likely to be very similar to the Mk23, simply because the MAN is likely to have copied the design as much as it could. I'll grant you there's a possibility it's something completely different, but I am talking about likelihood here.

tlb's point is that for Mk23, the volume lost due to dropping one or two rings is minimal, at most 15% of the missile. And therefore, the likelihood is that the same would apply to the Ninurta.

What we don't know is how much that affects the acceleration. It might affect considerably or not at all. And mind you that on th "considerable" side, it might be a negative correlation (though that's even less likely). I speculated that the missile body is already so small compared to the compensated volume that removing anything from the missile affects the acceleration not at all. And my reasoning is that all the RMN missiles for the past 20 years have had the exact same acceleration, from SDMs all the way up to 4DMs. That can't be a coincidence, it's intentional. And that being so, it indicates that the size and volume of the missile is absolutely unimportant.

Maybe, maybe, if you start with a much smaller compensated volume, basically skin-tight to the missile, you could get what you're saying. If that were the case, then I expect that their Ninurta have far higher acceleration than then 46000 gravities to start with. But that would mean an MAN 2-stage missile launched from escort ships couldn't be used in the same salvo as a 3-stage missile launched from the capital ships it is protecting, because they won't fly at the same acceleration. Maybe it doesn't matter, but I expect it does because that removes flexibility and thickening of a salvo.

ThinksMarkedly wrote:
What we don't know is how much that affects the acceleration. It might affect considerably or not at all. And mind you that on th "considerable" side, it might be a negative correlation (though that's even less likely). I speculated that the missile body is already so small compared to the compensated volume that removing anything from the missile affects the acceleration not at all. And my reasoning is that all the RMN missiles for the past 20 years have had the exact same acceleration, from SDMs all the way up to 4DMs. That can't be a coincidence, it's intentional. And that being so, it indicates that the size and volume of the missile is absolutely unimportant.

And I think possibly more telling, as I've said before, is that going from the Mk31 CM to the Viper didn't affect acceleration one iota.

The Mk31 was already a brand new breakthrough in CM performance, the highest acceleration of any missile the RMN has and the first extended drive CM. And then they stuck a single-rod laser-head onto its nose, which has to be at least a 15% increase in length, and it didn't lose even a single g of acceleration.



(Okay you could attempt to argue that they made another massive breakthrough in drive performance that somehow, in a utterly mind-boggling coincidence, managed to exactly and only offset the performance hit the longer Viper should have had; balancing out to the exact same performance numbers as the Mk31.

But if so why on earth wouldn't they have turned around and applied that breakthrough drive into making a Mk32 CM that's even quicker than the Mk31? That'd improve their missile defense, so they'd be idiots to have a better CM drive and not use it to make a better CM. So I think the only logical conclusion is that, within reason, volume isn't affecting missile acceleration)