[Spaceships] A reevaluation of missiles and point defense

[joelbf]

Originally Posted by SuedodeuS

I appears I've been working under a false assumption about proximity vs impactor warheads. I had thought that they were actually the exact same shells, just set differently.

They are the exact same, just set differently.

[SuedodeuS]

Originally Posted by Boobis

They are the exact same, just set differently.

Then the damage for the impactor warheads shouldn't be exactly what it would be for a KE penetrator. If the warhead has enough "juice" to make an effective proximity warhead, that should be reflected in its normal operation. Because it isn't, the only way the rules make any sort of sense is if the two types of shells are, in fact, completely different.

[Ulzgoroth]

Neither of them can reasonably be described as being a chemical energy-based weapon. Whether the missile proximity detonates or not, its damage is directly based on its collision speed. It's a pure kinetic kill system.

[David L Pulver]

Originally Posted by Ulzgoroth

Neither of them can reasonably be described as being a chemical energy-based weapon. Whether the missile proximity detonates or not, its damage is directly based on its collision speed. It's a pure kinetic kill system.

To get the required delta-V especially without superscience the missiles are fairly complex multi-stage designs (sort of like contemporary a-sat missiles). It's also assumed they contain various penetration aids, decoys, etc.

- prox setting: the missile detonates a considerable distance from the target releasing a cloud of missile debris and seeking submunitions (like those used in the smaller gun warheads) which themselves detonate at much closer proximity. The impact effect is an abstraction of multiple smaller objects. About 20-50% of the missile's 2nd stage mass has the potential to hit the target, though much less will do so.

- impact setting: the missile maneuvers for a higher velocity impact with the target, popping off sub munitions in divergent courses to give it some chance of a final contact-hit (since it would be trivial to intercept otherwise). The impact is an abstraction of its final strike, which might involve multiple rods released a second or less before impact to defeat last-second defenses (reactive armor, kinetic mines, etc). The damage roll determines how many struck). Only the 3rdl stage (usually somewhat less than 10% of mass, I think, though I can't recall the exact value I used)l generally impacts.

However, all of this is a bit too "specific" to cover in a generic supplement, and might be totally adverse to other assumptions you want to make about missiles, and anyway doesn't look much like the traditional sci-fi "fire the torpedo" so I really didn't want to go into that degree of detail.

[Ulzgoroth]

Originally Posted by David L Pulver

However, all of this is a bit too "specific" to cover in a generic supplement, and might be totally adverse to other assumptions you want to make about missiles, and anyway doesn't look much like the traditional sci-fi "fire the torpedo" so I really didn't want to go into that degree of detail.

Rather interesting to know the logic though. Unfortunate that the desirability of hardened armor makes the armor-piercing mode rarely relevant, unless setting rules prevent it.

Also, thank you for getting back to me about the point defense numbers.

It is indeed intended that each point defense hit shoots down a single rolled missile/fragment hit, not an entire missile. Balance-wise, I think this makes things much more interesting...missiles that needed that kind of overwhelming weight of numbers to get through point defense would almost never be worth using.

[joelbf]

While reading Davids answer and formulating a reply I realize that the question I should have asked is why would anyone use guns? :)

I think I get David model for guns and missiles and I think its a gameable (and in the missile case) cool abstraction.

Personally I would have liked guns that weren't just the last missile stages fired from a cannon, since that makes them just like crappy (but cheap) missiles. I would probably have preferred guns modeled with point-blank-range only, but deadlier penetrators. But I realize that missiles and beams are what people want, so the extra space required for a third type of guns wasn't worth it.

The only use I can come up with for the current incarnation of guns is on landing crafts/boarding crafts that might need to lay down ground support or bust through hangar doors, or maybe on stealth crafts that can get really close to an enemy, but don't want to fire up the reactors.

[joelbf]

Originally Posted by Ulzgoroth

It is indeed intended that each point defense hit shoots down a single rolled missile/fragment hit, not an entire missile. Balance-wise, I think this makes things much more interesting...missiles that needed that kind of overwhelming weight of numbers to get through point defense would almost never be worth using.

My calculations for 3-min and 10-min scale uses this assumption (note the 20 hits on 3-min scale, impossible otherwise). Though it will probably affect 20-sec scale the most.

[Ulzgoroth]

Guns are pretty respectable if you can get close enough to use them. Which I think is more possible than it might seem. And whereas missiles can possibly, at high cost, saturate point defense (so long as the point defense isn't smaller than the missile), the smaller projectiles of the guns are quite difficult to stop. VRF 20-30mm cannon look like viable fighter-killers.

I don't think ultra-powerful kinetic guns would be realistic, but if you want to head in that direction, try grav guns. They pack a punch with their post-errata 5 mps rounds.

If you just want to force people to respect your cannon, fire 10cm antimatter shells. One-shots pretty much anything, and harder to shoot down than a missile.

Originally Posted by Boobis

My calculations for 3-min and 10-min scale uses this assumption (note the 20 hits on 3-min scale, impossible otherwise). Though it will probably affect 20-sec scale the most.

I didn't follow in detail, but I'm not surprised that missiles lose out when you change the time scale. Gunnery turn scaling just doesn't produce clean results.

[joelbf]

Originally Posted by Ulzgoroth

Guns are pretty respectable if you can get close enough to use them. Which I think is more possible than it might seem. And whereas missiles can possibly, at high cost, saturate point defense (so long as the point defense isn't smaller than the missile), the smaller projectiles of the guns are quite difficult to stop. VRF 20-30mm cannon look like viable fighter-killers.

No fighter is ever going to get close to you. Unless they are equipped with say 10cm am shells and then your pretty much screwed anyaway ;)

Originally Posted by Ulzgoroth

I don't think ultra-powerful kinetic guns would be realistic, but if you want to head in that direction, try grav guns. They pack a punch with their post-errata 5 mps rounds.

Funny that you bing up superscience in (almost) the same sentence as realistic. There are lots of realistic design trade-offs you can do. I guess that ranged accuracy for close-range damage is one of them.

Originally Posted by Ulzgoroth

If you just want to force people to respect your cannon, fire 10cm antimatter shells. One-shots pretty much anything, and harder to shoot down than a missile.

Except you have to be at close range ...

Originally Posted by Ulzgoroth

I didn't follow in detail, but I'm not surprised that missiles lose out when you change the time scale. Gunnery turn scaling just doesn't produce clean results.

My point was more that your caculations will probably vary more than mine with the x10 hits possibility.

[Ulzgoroth]

My point about combat round scaling is that, to my mind, the 20-second round is the real model. The longer gunnery rounds are supposed to be representative of multiple 20-second rounds, and they really aren't.

I don't know whether they were actually intended to represent a series of 20-second rounds, but that's what I want them to do...

Originally Posted by Boobis

No fighter is ever going to get close to you. Unless they are equipped with say 10cm am shells and then your pretty much screwed anyaway ;)

Why not? Yes, they have to make it through missile range. That's absolutely possible, depending somewhat on the particular designs you're up against. Played by the book (which is to say, no sub-tertiary batteries allowed) they can easily get close to unescorted capital ships.

I need to do the math for 16cm missile vs. SM+5 fighter with three ECM units and point defense. That's going to be the defining calculation of the small-craft combat dynamic, I think.

Unguided gunfire wouldn't even be much good at Spaceships point blank. Not unless you can shoot very, very precisely, and throw your dumb metal at tens of miles per second. If you're getting much closer than that, try patching in some UT weapons. A dual-mount of the UT142 40mm rail gun ought to fit in an SM+5 spinal battery.