Missile design for noobs: the Kiwi/Emu approximation

[blue emu (OP)]

Designing effective missiles is both a craft and an art. I am offering this small analysis in hope that other Aurora noobs (like myself) might benefit from it.

This has probably all been done before, but Search didn't turn up much and the article in the Wiki didn't mention any of this.

Your missile to-hit chance depends on the speed and agility of the missile, and on the speed of the target. For anti-Ship missiles, a 100% to-Hit vs speed 10,000 kps targets is probably as much as you'll ever need... at least, in the early-to-mid game... but for anti-Missile (PD) missiles, the higher the to-Hit, the better; since enemy missiles might move at 50,000 kps or more.

A complicating factor is the rounding that takes place with both Speed and Agility. Capt Kiwi and I have been able to figure out the Agility rounding, but the Speed rounding is still a minor mystery... so we can offer only a partial solution to the missile design problem.

After allocating enough Warhead to get the "bang" you want, and allocating enough fuel to get the range you want, you will be left with a certain number of MSP to be distributed between Engine (increasing your speed) and Agility. Both contribute to your final to-Hit capability, but not equally.

These MSP should first be distributed as follows:

If S = the missile size,
and M = your current missile agility per MSP (depends on tech),
and T = the total MSP available for Engines plus Agility,

Then E = (T/2)+(5xS/M) is the amount of MSP that should be used for Engines
and A = (T/2)-(5xS/M) is the remaining MSP that should be used for Agility.

These numbers should then be adjusted up or down so that your actual missile agility is a whole number... ideally, a whole number that is an even multiple of your missile size...  like so:



This should give you something approaching an ideal design for that size of missile... although if it is a ship-killing missile (instead of a PD missile) and your to-Hit greatly exceeds 100% vs a 10,000 kps target, you might want to transfer more MSP from Agility to Engine to increase the speed at the expense of superfluous to-Hit. To-Hit numbers above 100% aren't much use against ships, while Speed is always useful to avoid the defender's PD fire.

Note that this solution is only approximate, since it takes no account of the engine/missile-size/speed rounding.

Thanks to Capt Kiwi for the basic continuous-function formula.

[Girlinhat]

A small note (that took me a while to realize) is to set some stat to max and then start tweaking with fuel size.  For instance, set your warhead to 4.5 and fuel to .5, if you're making a size 5 missile.  Then start nudging it towards 4.4 and .6 and keep going until you get the flight range you want.  Then reset the warhead to whatever desire and your range is already balanced for a full sized missile.  I had issues where I'd make a missile but didn't hit my target range, but then I realized that it was just like a ship, and all the size counted the same and to just design the fuel first and fill in the rest ^^

Is there any good description on how agility changes with interception?  Like, does a higher agility missile avoid PD better, and if so how?  Either way, a good to-hit formula is great, I knew there was a balancing point somewhere in there~

[blue emu (OP)]

Is there any good description on how agility changes with interception?  Like, does a higher agility missile avoid PD better, and if so how?  Either way, a good to-hit formula is great, I knew there was a balancing point somewhere in there~

The only role that agility plays (AFAIK) is in target-seeking, not in evasion. So a high-agility missile is good at hitting targets, and a high-speed missile is good at evading enemy PD. Agility does NOT help you penetrate enemy PD (AFAIK)... only to score a hit.

One thing that DOES help penetrate enemy PD is salvo dispersion. An opposing FC can only fire at one target per increment, and all PD missiles fired in that AMM salvo must attack the SAME incoming salvo. So splitting up your ASMs into a larger number of salvos might help penetrate the opponent's PD, be giving him more things to shoot at than he has FCs to shoot with.

Naturally, full fleet synchronized salvos (instead of "fire at will") is also the way to go, to maximize PD penetration.

[Girlinhat]

So, just to confirm, when the map shows 5xGlider MkI (x20) that means that the enemy PD is targeting 20 different salvos, not "one group" of missiles?  If so, then rock on, double FC on my missile boats was the right idea!

That's also somewhat interesting though...  I'm curious how best to weaponize this.  For instance, would it pay to fire off a dozen decoy salvos and 5 seconds later fire a payload missile, or would it be better to fire them all as a group?  I'm guessing a delayed payload would encourage enemy PD to target the decoys first...

[blue emu (OP)]

So, just to confirm, when the map shows 5xGlider MkI (x20) that means that the enemy PD is targeting 20 different salvos, not "one group" of missiles?  If so, then rock on, double FC on my missile boats was the right idea!

That's also somewhat interesting though...  I'm curious how best to weaponize this.  For instance, would it pay to fire off a dozen decoy salvos and 5 seconds later fire a payload missile, or would it be better to fire them all as a group?  I'm guessing a delayed payload would encourage enemy PD to target the decoys first...

Here's 51 salvos of one missile each, if that answers your question:



One problem with decoy missiles is speed and running-time... they tend to lose their effect if they aren't speed-matched to the salvo that they are intended to screen. Having said that, I've had some success with using my size-1 PD launchers to fire slow-speed, long-range size-1 decoys (at a way-point) that were deliberately speed-matched to the follow-up fleet salvo.

EDIT: it also helps if your ASM salvos are split into (3xN)+1 missiles per salvo... 1, 4, 7, 10, whatever. That's because the AI likes to fire AMMs in clusters of three... so dividing your own ASMs into clusters of (3xN)+1 makes him waste one extra shot per salvo.

[Girlinhat]

Speed matching isn't hard, not when the entire point is to be speed-matched.  I'm now curious though, the best way to link 1 FC to each launcher for maximum spread...

[blue emu (OP)]

I'm now curious though, the best way to link 1 FC to each launcher for maximum spread...

Fighters. Give each Fighter an FC and one size-6 Box Launcher. Screenshot above.

I don't bother giving each ASM tube in a missile boat its own FC, because that would drop my number of tubes too low because of the parasitic weight of all those FCs.

[Elouda]

You can also, assuming your fighters or FACs (or even big warships, if youre a VLS fan like me) are well trained, 'ripple' fire multiple tubes, with a 5 second delay between them, by setting the FC to one tube, firing, moving it to the next, firing, etc. This means the enemy faces multiple waves of many single missiles.

Sort of unfair, but oh well.

As for missile design, theres also a spreadsheet around here somewhere thats pretty accurate.

[Din182]

The spreadsheet: https://docs.google.com/spreadsheet/ccc?authkey=CImjy-8G&key=0AjI_7txsaYq4dHNXLXRfaGZhck5SRzJrTzkxTEtfVlE&hl=en&authkey=CImjy-8G#gid=3

[Garfunkel]

Thanks Blue Emu! Nice to see you spread your analytical mind from Hearts of Iron to Aurora!

[Theokrat]

Blue Emu, how come I am not surprised to find you here, having conducted (and posted) the same bit of analysis I had in mind.  Even in the very same math terms.  Emu'd once again, oh well reminds me of the good old Hoi times.

Anyway, two points I would like to add:

1.  The first point of maneuver rating (above the default 10) is significantly cheaper than the next points, due to the rounding.  This means that a 11-maneuver rating missile can have nearly the same hit chance as the "optimum" derived above, while retaining a significant speed advantage.  It can also be the actual optimum, when M/S*T is approximately 12.
Technically this is because maneuver rating is rounded to integer number, so the first point (beyond the initial 10) costs just Agility/(2*Size), while every further point costs twice as much.

2.  Speed is not as secondary as it is portrayed here.  Specifically it should not only be a concern once 100% hit chance is achieved, instead missiles should be "notched" towards larger engines from the derived optimum.  Agility increases the hit chance, but engines increase speed which has three more advantages:

• Speedy missiles are harder to hit.  Hit chance is (anti-)proportional, so missiles that travel faster are less likely to be hit, when intercepted (or striking a ship with beam PDs)
• Speedy missiles cross the PD-zone of the enemy more quickly, providing less interception points
• Speedy missiles hit the enemy earlier, meaning he has less time to put salvos in the vacuum, engage or disengage

The effect can be quite significant.  One might note that in your example you did  present a missile that would not be optimal according to the formula.  According to the formula it should have around 0. 52, whereas you put it at 0. 2.  Or put differently the formula indicates an engine-to-agility of little more than 1:1, whereas you used 5:1.  - And I think the 0. 2 you chose is a much better design, because of the speed.  Just as an illustration: The 0. 2-agility missiles arrive at a target at the maximum range more than 450 seconds earlier (enough for 11 salvos at my current tech level), and combining the duration that they spend in my PD zone + PD missiles (in my current game), I can expect to shoot down only half as many (2 per PD tube, compared to 4 otherwise)

[blue emu (OP)]

Hi Theokrat... good to hear from you.

Did you read over the 7,700+ post "Ad Astra" game thread in the Paradox Forum Games section? We had over 100 Paradox forum members involved in the game at one point... as warship captains, fighter pilots, planetary governors, research scientists, diplomats, spies, geologists, scouts...

Another good reason for preferring an increase in speed to a minor boost in accuracy is that faster missiles will run out to range more quickly, allowing you to assess the damage and decide on follow-up strikes earlier. This adds a bit more flexibility to your planning.

One point that should be kept in mind is that missile combat in Aurora often closely resembles submarine combat in World War II... emphasis on spotting the enemy early, followed by long range shots, with a long running-time to target, a pause for damage assessment and threat estimates, then follow-up salvos to finish off the cripples.

EDIT: I would also enjoy hearing your comments on my "Modular Ship Design" philosophy, mentioned in my thread in the "Bureau of Ship Design" section.

[Rawb]

I remember when you posted this guide on one of my topics .

I think this definitely needs to be stickied.

[Theokrat]

Hi Theokrat. . .  good to hear from you.

Did you read over the 7,700+ post "Ad Astra" game thread in the Paradox Forum Games section? We had over 100 Paradox forum members involved in the game at one point. . .  as warship captains, fighter pilots, planetary governors, research scientists, diplomats, spies, geologists, scouts. . .

Yes, indeed you drew my attention to this game by that threat.  And I have to say: Thank you for that! Amazing game really, being the wet dream of an analyst like me.  I decided it was time for my own campaign though at around page 20 or so of your AAR (so I would not see too many spoilers in your game).  I will get back to it though one day!

Another good reason for preferring an increase in speed to a minor boost in accuracy is that faster missiles will run out to range more quickly, allowing you to assess the damage and decide on follow-up strikes earlier.  This adds a bit more flexibility to your planning.

One point that should be kept in mind is that missile combat in Aurora often closely resembles submarine combat in World War II. . .  emphasis on spotting the enemy early, followed by long range shots, with a long running-time to target, a pause for damage assessment and threat estimates, then follow-up salvos to finish off the cripples.

Nice analogy.  Am I correct in assuming that if a ship is destroyed, then all salvos its fired that have not reached their target yet are destroyed/useless unless the missiles host sensors? If so then having faster missiles than your enemy could also constitute a nice defensive bonus. . .

EDIT: I would also enjoy hearing your comments on my "Modular Ship Design" philosophy, mentioned in my thread in the "Bureau of Ship Design" section.

Ok, you took the better part of my day, with the issue sparking some very intersting thoughts about the combat in general.  I have a some small observations, which I ll post in a bit, but I also have a much more detailed model in mind, if I manage to patch all things together. . .  Oh By the way does Kanitatlan know about this game/was he active in your AAR?

[blue emu (OP)]

... I decided it was time for my own campaign though at around page 20 or so of your AAR (so I would not see too many spoilers in your game).  I will get back to it though one day!

The best part of the AAR is the Battle of Wolf 294, where we take on a huge fleet of high-tech opponents with our early-game tech fleet. It was the toughest battle I've ever fought in a computer game.

... Am I correct in assuming that if a ship is destroyed, then all salvos its fired that have not reached their target yet are destroyed/useless unless the missiles host sensors? If so then having faster missiles than your enemy could also constitute a nice defensive bonus.

Correct, as far as I know.

Ok, you took the better part of my day, with the issue sparking some very intersting thoughts about the combat in general.  I have a some small observations, which I ll post in a bit, but I also have a much more detailed model in mind, if I manage to patch all things together. . .  Oh By the way does Kanitatlan know about this game/was he active in your AAR?

I haven't seen Kan around, no... neither in this forum nor in the Ad Astra thread.