[Spaceships] A reevaluation of missiles and point defense

[Ulzgoroth]

In light of the understanding that attacks are fully resolved one at a time, and the inference that point defense gunners can fire in sequence rather than in parallel, I've done some new missile combat numbers.

Calculations are based on TL9. TL 10 should benefit the defender significantly due to improved laser RoF. Higher TLs will benefit the attacker, but not much in the basic case as missiles are quite sufficiently accurate already. Everything uses 20-second turns, because longer ones don't make sense to me for gunnery. I believe they would usually harm missile-users, but 1-minute turns might benefit them.

Non-fragmenting missiles, including nukes, are poorly matched against PD. Even with only skill 12, a three-way split-fire from a VRF laser is expected to kill better than two missiles. With skill 14, splitting four ways brings this up to almost three. Nuke strikes are only viable against targets with extremely poor point defense. If a large vessel can't protect itself, SM+5 to +7 point defense drones/escorts can cover for it.

Proximity nukes are pointless. The only way you'd miss (outside 17-18) with a missile is if you were attacking a small target with ECM, in which case you shouldn't be using nukes in the first place.

Fragmenting missiles do better. With skill 14, it takes approximately one full point defense gun's fire, in two or three way split, to shoot down each missile's 10 fragments (all of which usually hit). They don't scale as well as beams, but pack a punch. Even at SM+15, each fragment of a tertiary missile hits almost as hard as a major beam (at higher TL, armor divisors may change this). Since point defense guns require power (making them 50% bulkier than missiles at TL9, 25% later), ships may have to rely on smaller craft to stop heavy missile volleys, and thick plating to keep out the common, PD-saturating 6dx8 16cm missile.

Small craft will need a different approach to missile survival. I suspect SM+5 units with ECM may be the solution, but have not done the math for them.

[SuedodeuS]

Actually, I think that a PD gun would end up shooting a proximity warhead before it exploded - otherwise, I'd expect for Spaceships to give an SM to the fragments (or at least a way of calculating them).


As for small craft, if technology permits, they might want to use automated gunner systems. On a SM+5 craft, a single medium battery can mount 3 VRF 30 kJ lasers at TL 9, and at TL10+ the VRF lasers can be improved for a further x2 RoF. The damage won't be much, but against missiles all you have to do is land a hit to destroy one. Heck, even without automation, having a single turret with a gunner wouldn't be unheard of - and would most certainly improve your survivability.

[Ulzgoroth]

A single turret? It's entirely likely for an SM+5 small craft to have upwards of 10 turrets, and I've made designs with more than 30. Automated gunnery preferred, but optional. That's not the problem with PD for small craft. You simply can't carry enough PD to stop 16cm missiles cold, because they're effectively more compact than the smallest PD guns, and you can't armor a small ship well enough to survive them.

If you're right about PD vs. prox warheads, then missiles are even weaker. I don't think you are though, although I don't think I've gotten an official clarification. Given how the combat system is put together, I don't think it would be possible to implement shooting down fragmentation missiles before they fragment.

My current theory is that conventional proximity warheads break into 10 independent, guided terminal attack units. My secondary theory, given that each fragment individually does the same damage as the entire missile would, is that they don't make sense.

[SuedodeuS]

Originally Posted by Ulzgoroth

A single turret? It's entirely likely for an SM+5 small craft to have upwards of 10 turrets, and I've made designs with more than 30. Automated gunnery preferred, but optional. That's not the problem with PD for small craft. You simply can't carry enough PD to stop 16cm missiles cold, because they're effectively more compact than the smallest PD guns, and you can't armor a small ship well enough to survive them.

I really don't see a massive number of warheads being fired at an SM+5 craft - not when you're likely to have a large number of them present at a time, and particularly not when there are juicier targets (e.g. the carrier that launched them) available. Against a 16cm missile/shell you're suffering a -1 to hit, which really isn't that bad. Of course, ECM is still crucial, since you need it to make fewer attacks hit - and so you can dodge the ones that made it through your PD.

Originally Posted by Ulzgoroth

If you're right about PD vs. prox warheads, then missiles are even weaker. I don't think you are though, although I don't think I've gotten an official clarification. Given how the combat system is put together, I don't think it would be possible to implement shooting down fragmentation missiles before they fragment.

My current theory is that conventional proximity warheads break into 10 independent, guided terminal attack units. My secondary theory, given that each fragment individually does the same damage as the entire missile would, is that they don't make sense.

The description of proximity warheads (p. 47) describes them as firing something like a "shotgun-like blast of high-velocity fragments." Additionally, the warheads are identical to impact warheads - you simply decide if they are proximity fused or not prior to firing, and I wouldn't expect for impact warheads to waste money having precision terminal attack units. I think the concept is that quite a few more than 10 fragments impact the hull, but for simplicity this is done as 10 "hits." As for damage, the fragments do essentially deal half damage, but only against armor. I certainly agree that a proximity warhead being able to deal more damage than an impactor doesn't make much sense. However, I think this can only occur for smaller vessels (since the heavier ones end up with very high DR), and that could be explained as the proximity warhead being more capable of shredding the small fighter.

As for how it works, I know that the damage rules (p. 60) state that each PD hit "kills one missile or shell." Personally, if I wanted the multiple hits of a proximity warhead to be fired upon seperately, I would have phrased it as something more along the lines of "negates one hit" - or, better yet, made a specific exception for proximity warheads. Of course, that's just how I would do it - it's entirely possible that the authors intended each fragment to be treated as a seperate shell.

[Ulzgoroth]

Originally Posted by SuedodeuS

I really don't see a massive number of warheads being fired at an SM+5 craft - not when you're likely to have a large number of them present at a time, and particularly not when there are juicier targets (e.g. the carrier that launched them) available. Against a 16cm missile/shell you're suffering a -1 to hit, which really isn't that bad. Of course, ECM is still crucial, since you need it to make fewer attacks hit - and so you can dodge the ones that made it through your PD.

If the carrier that launched them is an available target, somebody is doing their job wrong. That aside, the reason you need that many mounts is that you can have that many mounts. If my 'fighter' has 4 medium batteries of missiles (in turrets), and you try to take it on with a fighter with one turret, my fighter probably kills 4-6 of yours in the first exchange of fire. Whether it survives the exercise depends on what you've got to throw back at it, but I'm pretty happy regardless...

If my mechanics are right, that is. But even if they're wrong, with that little point defense I can still overwhelm two or three.

Also, remember that at TL9, missiles are the only weapon effective at L range against maneuvering targets, for an SM+5 craft. Unless you're playing with hyper-powered drives, your enemy has plenty of time to engage you with missiles before you can reply with anything else.

Originally Posted by SuedodeuS

The description of proximity warheads (p. 47) describes them as firing something like a "shotgun-like blast of high-velocity fragments." Additionally, the warheads are identical to impact warheads - you simply decide if they are proximity fused or not prior to firing, and I wouldn't expect for impact warheads to waste money having precision terminal attack units. I think the concept is that quite a few more than 10 fragments impact the hull, but for simplicity this is done as 10 "hits." As for damage, the fragments do essentially deal half damage, but only against armor. I certainly agree that a proximity warhead being able to deal more damage than an impactor doesn't make much sense. However, I think this can only occur for smaller vessels (since the heavier ones end up with very high DR), and that could be explained as the proximity warhead being more capable of shredding the small fighter.

Large ships may be well armored, but they needn't be armored at all. And at TL9, it's pretty big indeed you'd need to be before I'd be confident about doing more damage with a non-proximity missile...if, for some insane reason, you were using non-hardened armor. Which only makes sense if you're completely unconcerned with beam attacks, or playing with heat rays...

Originally Posted by SuedodeuS

As for how it works, I know that the damage rules (p. 60) state that each PD hit "kills one missile or shell." Personally, if I wanted the multiple hits of a proximity warhead to be fired upon seperately, I would have phrased it as something more along the lines of "negates one hit" - or, better yet, made a specific exception for proximity warheads. Of course, that's just how I would do it - it's entirely possible that the authors intended each fragment to be treated as a seperate shell.

I would say that however it is intended, the writing is flawed. My objection to your take is not really that I don't think it agrees with what is written. Rather, I don't think it's possible.

Consider:
-Some idiot launches a fixed battery of missiles at your fighter, set for proximity detonation. Medium, secondary, or tertiary...
-Said shooter rolls the attack and determines 24 hits.
-You achieve 10 hits with your point defense.
-How many times are you hit?

[SuedodeuS]

Originally Posted by Ulzgoroth

If the carrier that launched them is an available target, somebody is doing their job wrong. That aside, the reason you need that many mounts is that you can have that many mounts. If my 'fighter' has 4 medium batteries of missiles (in turrets), and you try to take it on with a fighter with one turret, my fighter probably kills 4-6 of yours in the first exchange of fire. Whether it survives the exercise depends on what you've got to throw back at it, but I'm pretty happy regardless...

If my mechanics are right, that is. But even if they're wrong, with that little point defense I can still overwhelm two or three.

Also, remember that at TL9, missiles are the only weapon effective at L range against maneuvering targets, for an SM+5 craft. Unless you're playing with hyper-powered drives, your enemy has plenty of time to engage you with missiles before you can reply with anything else.

If the setting you're working in is extremely missile-heavy, a single point-defense turret is going to be useless. In that case, I'd highly prefer a large number of automated turrets - and if automation isn't possible (for whatever reason - Butlerian Jihad, maybe?), I'd probably not bother fielding small fighters to start with. I should note, however, that a missile-based fighter would probably be easily overwhelmed by one with, say, half as many VRF PD-lasers as the missile-based fighter has launchers, and a single VRF gun.

EDIT: Suicide fighter craft like in Einhander might still exist, since a 30-launcher fighter could do some serious damage before it was hit - assuming it reached range L before its target was able to fire on it.

Originally Posted by Ulzgoroth

Large ships may be well armored, but they needn't be armored at all. And at TL9, it's pretty big indeed you'd need to be before I'd be confident about doing more damage with a non-proximity missile...if, for some insane reason, you were using non-hardened armor. Which only makes sense if you're completely unconcerned with beam attacks, or playing with heat rays...

I would say that however it is intended, the writing is flawed. My objection to your take is not really that I don't think it agrees with what is written. Rather, I don't think it's possible.

Yeah, there's definately some writing issues there. Because a special exception isn't stated for proximity missiles, however, I tend to think it's "1 shot destroys 1 missile - before detonation."

Originally Posted by Ulzgoroth

Consider:
-Some idiot launches a fixed battery of missiles at your fighter, set for proximity detonation. Medium, secondary, or tertiary...
-Said shooter rolls the attack and determines 24 hits.
-You achieve 10 hits with your point defense.
-How many times are you hit?

Oof, now there's a tough one. I'd probably still work it as 14 hits, however. I think the distinction between how the PD works vs proximity warheads would really only apply in borderline cases. For example, take a case where the attacker determines 12 hits, and you achieve 10 with PD. In this case, I'd go back and calculate how many hits the attacker would have scored without the +4 for proximity detonation. If it's 10 or fewer, all hits are negated. If it's 11 or 12, then he scores 2 hits.

[Ulzgoroth]

Do gun-fighters work? I had thought not... They're less accurate than missiles, but the VRFs only by a -2 penalty, which makes them still pretty accurate. And the shells can be 6 size categories smaller, which makes PD a lot weaker.

Of course, the damage gets a lot lower, but still looks high enough that SM+5 armor won't stand it.

It looks like, if you're right about the PD-missile interaction, VRF gauss guns are probably the dogfighting weapon of the TL. If I'm right, trying to take on N missile launchers with N/2 PD guns is decidedly suicidal, unless ECM can make up the difference.

Originally Posted by SuedodeuS

If the setting you're working in is extremely missile-heavy, a single point-defense turret is going to be useless. In that case, I'd highly prefer a large number of automated turrets - and if automation isn't possible (for whatever reason - Butlerian Jihad, maybe?), I'd probably not bother fielding small fighters to start with. I should note, however, that a missile-based fighter would probably be easily overwhelmed by one with, say, half as many VRF PD-lasers as the missile-based fighter has launchers, and a single VRF gun.

EDIT: Suicide fighter craft like in Einhander might still exist, since a 30-launcher fighter could do some serious damage before it was hit - assuming it reached range L before its target was able to fire on it.

If you don't field small units with point defense, your capital ships will be exposed to missile attack from other capital ships. Less exposed, because armor improves faster than missiles, but still rather vulnerable.

Besides, missiles don't disadvantage small craft, they're just the best way for those small craft to kill one another, or just about anything else. What's wrong with sticking 20-odd people in a 30 ton gunboat, though, if it's the best way to make that gunboat work? I do tend to assume that you can get gunnery automation, given that that's pretty much modern technology.

On the side, it's very hard to kill small targets at X range, in TL9. You need a hundred gigajoule laser to reach, which takes quite a lot (SM+12 spinal) of ship to carry, and then you've got a -16 penalty to hit for the range. Pecking at a fighter squadron, it's not enough to kill many before they close, unless you manage to keep evading them. And swatting them with huge capital-ship missiles isn't much good either, because the squadron can easily have more PD than the dreadnought has missile tubes. On the other hand, it's difficult for the fighter's little missiles to do more than scuff the paint on something that big, unless they can get through with nukes...

Originally Posted by SuedodeuS

Yeah, there's definately some writing issues there. Because a special exception isn't stated for proximity missiles, however, I tend to think it's "1 shot destroys 1 missile - before detonation."

I don't find your implementation quite plausible, I'm afraid. It's both too messy and too totally absent from the book. I'm going to PM the source for clarification, though...

I think you missed the possibility that those 24 hits came from only 3 or 10 rockets, by the way. In which case I presume you'd say the 10 PD hits stop it all.

[Cernig]

Great stuff folks. Very useful for us lo-brains who lock up in horror at keeping the math straight when working stuff out like this. Keep it up.

Based on a lot of what I've read on the forums and some playtesting, I've pretty much forgotten about capital missiles except as planet-bombardment weapons and kept my TL10^ (the carret is for reactionless drives, grav compensators and jump drive) capital ship missile use to 30 ton ejectable/recoverable unpowered pods, fully automated and filled with sensors and 16cm missile batteries (yes, sorta Honorverse). Capital ships also carry powered PD drones (fully automated 30 ton craft fitted with as many VRF Improved lasers as possible) and EW drones (using my Quick Contest house rule makes ECM/ECCM as important as armor or PD). My notion is why tie up a whole load of ship modules on an SM10 battlewagon with PD or tertiary missile batteries when you can launch far more PD or 16cm firepower out of a hangar bay per minute? One tertiary VRF-I battery is enough to keep an option after all pods/drones are exhausted and to provide plentiful heavier fire vs fighters which might consider using beams at close range after launching all their missiles further out.

How do folks see the math of missile vs PD and weapon vs armor affecting tactical doctrines, and thus construction philosophies, at various TLs?

Regards, C

[joelbf]

I have done some preliminary calculations on 3 and 10 minutes scale.

First I note that tertiary battery missiles decrease in efficiency when ships get large. At TL9, sm+8 you do > 100% of dHP of a ship of equal size with one missile even if the target has 2 armours. At sm+12 you only ~25% of dHP with a sm+12 tertiary battery. This gets worse (for missiles) by TL10. A sm+12 tertiary battery doesn't even do significant damage (10%) after two armours.

At TL10 sm+11 and sm+12 have good to excellent chances of withstanding and being able to function after proximity hits by 25 and possibly 100 kt nukes.

My personal conclusion is that while missiles are viable at TL9 you need nukes at TL 10 and while I haven't looked at TL 11 i suspect that even nukes won't serve you.

3-minute proximity fused TL9 vs sm+10 target:
+12 skill
+10 size
+1 sAcc
+4 proximity
+0 2 mps
+2 rof
=29, you will likely hit with ~20 impactors

Point defence:
+12 skill
+0 size
+0 sAcc
+0 range (Point Blank)
+8 rof (200 shots IE 1 fifth of your total)
=20, you will most likely eliminate at least 4 impactors.

So if 5 pd turrets distribute their fire over incoming from 5 launchers they have excellent chances of killing all missiles.

If you don't proximity fuse you will most likely hit with 10 impactors, which will require only 1-3 pd turrets; the pd-gunners won't even break a sweat ;)

10-minute proximity fused TL9 vs sm+10 target
+12 skill
+10 size
+1 sAcc
+4 proximity
+0 2 mps
+5 rof
= 32, more than ~25 hits are very unlikely

Point defence:
+12 skill
+0 size
+0 sAcc
+0 range (Point Blank)
+8 rof (300 shots IE 1/10 of your total)
=20, you will most likely eliminate at least 4 impactors.

So 10 pd-turrets that work together can reasonably shoot down all hits from 10 incoming salvoes.

Conclusion: Point defence have no difficulty defending vs incoming missiles battery for battery, and can probably without to much luck defend in a 2 vs 1 situation.

My personal guideline is that PD-beams need to do 1d dDmg to be effective. This is achieved with a VRF tertiary battery at sm+8. A sm+10 ship could possibly pack as much as 300 (automated) pd-turrets in a module.

Point to point-defence ;)

[SuedodeuS]

Originally Posted by Ulzgoroth

Do gun-fighters work? I had thought not... They're less accurate than missiles, but the VRFs only by a -2 penalty, which makes them still pretty accurate. And the shells can be 6 size categories smaller, which makes PD a lot weaker.

Of course, the damage gets a lot lower, but still looks high enough that SM+5 armor won't stand it.

It looks like, if you're right about the PD-missile interaction, VRF gauss guns are probably the dogfighting weapon of the TL. If I'm right, trying to take on N missile launchers with N/2 PD guns is decidedly suicidal, unless ECM can make up the difference.

Guns are great against enemy ships. Their accuracy leaves something to be desired (particularly when you consider that they take a penalty based on velocity), but as you noted they're very difficult to defend against and do damage far in excess of what equivalent lasers do.

Boobis was kind enough to work out the math for us on the PD situation. Although it isn't optimal, N/2 PD guns appears like it can work (and don't forget that, even if PD fails, you still have a chance to dodge).

Originally Posted by Ulzgoroth

If you don't field small units with point defense, your capital ships will be exposed to missile attack from other capital ships. Less exposed, because armor improves faster than missiles, but still rather vulnerable.

Besides, missiles don't disadvantage small craft, they're just the best way for those small craft to kill one another, or just about anything else. What's wrong with sticking 20-odd people in a 30 ton gunboat, though, if it's the best way to make that gunboat work? I do tend to assume that you can get gunnery automation, given that that's pretty much modern technology.

On the side, it's very hard to kill small targets at X range, in TL9. You need a hundred gigajoule laser to reach, which takes quite a lot (SM+12 spinal) of ship to carry, and then you've got a -16 penalty to hit for the range. Pecking at a fighter squadron, it's not enough to kill many before they close, unless you manage to keep evading them. And swatting them with huge capital-ship missiles isn't much good either, because the squadron can easily have more PD than the dreadnought has missile tubes. On the other hand, it's difficult for the fighter's little missiles to do more than scuff the paint on something that big, unless they can get through with nukes...

Hmmm... quite right. Of course, a battle in which all of your pilots have an extremely high chance of dieing is a battle one would only fight out of desperation. As far as nonautomated gunners, 30 people in an SM+5 ship seems a bit excessive to me (as in, it doesn't seem like they'd even be able to fit, at least not and be able to work). When I said I wouldn't bother fielding small fighters, I didn't mean that there wouldn't be fighters anymore - they'd just be a lot larger, in order to accomodate the necessary crew to defend them. Honestly, though, about the only way I see no automation being available is if there were some sort of anti-computer movement, preventing automation from being legal anymore.

Of course, capital ship missiles are certainly not the way to go for defending against small fighters. VRF guns (and even lasers - capital ships can still pack a punch with a VRF laser), on the other hand, would be a good secondary defense (the primary being your own fighters).

Originally Posted by Ulzgoroth

I don't find your implementation quite plausible, I'm afraid. It's both too messy and too totally absent from the book. I'm going to PM the source for clarification, though...

I think you missed the possibility that those 24 hits came from only 3 or 10 rockets, by the way. In which case I presume you'd say the 10 PD hits stop it all.

Yes, if the number of rockets is equal to or less than the number of successful PD hits, I'd say all were negated. I think proximity warheads are meant to only grant a +4 to hit, not increase your RoF against PD. If the warheads were meant to function in the manner you believe (which, I'll admit, makes a good deal of sense), I think the authors would have structured them more like shotguns - i.e., they give a RoF multiplier. I wish it had been specified better exactly how the proximity warheads are meant to function.