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Old 06-14-2019, 11:13 AM   #1
muduri
 
Join Date: Oct 2009
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Default [spaceships] bunker-buster bombs

Intrigued by the bombs in SS4. But I'm thinking we might need something heavier - with some SM6 fighters taking on SM14 cruisers it seems like some serious penetration will be necessary to break through say nanocomposite armor.

Granted the relative velocities can get pretty high once you get up to TL10^ torch technology, so k-kills are one way to do it. But for times whem that's not possible for whatever reason, what would a bunker-buster bomb look like? Happy to keep SS's level of abstraction rather than derive it fully from real statistics. But I'm thinking it's the size of a full missile, or even larger, and does maybe even 20% more damage because it's all warhead, and maybe has improved AP.

What would you guys suggest if we were going to house-build something along these lines? Thanks for the suggestions!
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Old 06-14-2019, 11:40 AM   #2
Ulzgoroth
 
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Default Re: [spaceships] bunker-buster bombs

I would suggest a nuke if you really want to defeat armor in a way not based on kinetic energy. If you look at the pricing, nukes are pretty cheap.

Bombs as written already use missile warheads which have (admittedly completely worthless due to hardening mechanics) anti-armor features.

Spaceships bombs are kinetic weapons. Bunker buster bombs are also kinetic weapons, as far as penetration is concerned. k-kills are the answer. If your launch platform isn't capable of setting up a sufficiently high-speed attack run, the obvious fix is to get more speed by using a missile instead of an un-propelled bomb.
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Old 06-14-2019, 10:45 PM   #3
Rysith
 
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Default Re: [spaceships] bunker-buster bombs

Quote:
Originally Posted by muduri View Post
Intrigued by the bombs in SS4. But I'm thinking we might need something heavier - with some SM6 fighters taking on SM14 cruisers it seems like some serious penetration will be necessary to break through say nanocomposite armor.
Two systems of nanocomposite on a SM14 cruiser is dDR400, or approximately 115 dDice. A spinal SM7 (since bomb systems are one size smaller) mount for a dedicated bomber is 32cm, which deals a base damage of 6dx80 dDamage - the SM6 bomber doesn't even need to get the bomb up to 2mps to reliably penetrate. If it _does_ hit at a relative velocity of 1mps, it does 480 dDice of damage, which blows through the 115 dDice of armor and 200 dDice of HP and leaves the SM14 cruiser at close to -1xHP, which is probably 'no longer a functional combat unit'.

If we want to reliably disable a system on a SM14 nanocomposite cruiser, we need to deal 115 (armor) + 20 (10% of dHP) dDice of damage, which is a 10cm projectile at 1 mps for 150 dDice of damage. On a SM6 fighter, that's smaller than the smallest missile that you're allowed to mount (16cm for 240 dDice, which destroys systems and brings the cruiser to 0dHP in two hits), which a SM6 fighter can mount as a secondary missile battery, a tertiary bomb mount, or a medium gun battery. Things just get worse from there if your ships are capable of accelerating to relative speeds of more than 1mps.

Realistic kinetic weapons _hurt_.

So if you're concerned with SM6 fighter's ability to threaten SM14 cruisers at TL10 with kinetics, I conclude that either there is something much heavier than nanocomposite protecting the cruiser (You need on the order of dDR 1300 to defeat a dedicated SM6 bomber at 1mps) or you're in a universe like Star Wars or the X series where spaceships aren't actually moving at orbital velocities and you need to get your damage from elsewhere, probably something like the X-ray warheads in SS4.

More traditionally, the issue is that kinetics are short range only for accurate fire (usually, range S or worse), and so the SM14 cruiser mounts a tertiary battery of 10GJ UV lasers to hit incoming fighters with 80 dDice of damage (vs. their 30 dHP / +10 per system of nanocomposite) out at L range and the incoming fighters never even get to launch their warheads. But that's no fun for the plucky heroes in the SM6 fighters.

Can you share a bit more about the available tech and engagement parameters that you expect?
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Old 06-14-2019, 11:04 PM   #4
Rupert
 
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Default Re: [spaceships] bunker-buster bombs

Your numbers are too high, according to the SS copy I've got, Rysith. The damage of kinetics was lowered at some point - maybe you have an old copy?
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Old 06-14-2019, 11:40 PM   #5
Rysith
 
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Default Re: [spaceships] bunker-buster bombs

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Your numbers are too high, according to the SS copy I've got, Rysith. The damage of kinetics was lowered at some point - maybe you have an old copy?
Ah, yes, looks like they were lowered by a factor of 10 at some point. That means that the bomber needs to be going 3mps to penetrate with the spinal 32cm bomb mount, and 6mps for the 16cm secondary missile battery to reliably disable systems - still not unreasonable velocities, especially for the mentioned torch drives.
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Old 06-15-2019, 09:42 AM   #6
Fred Brackin
 
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Default Re: [spaceships] bunker-buster bombs

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Originally Posted by Rysith View Post
Ah, yes, looks like they were lowered by a factor of 10 at some point. That means that the bomber needs to be going 3mps to penetrate with the spinal 32cm bomb mount, and 6mps for the 16cm secondary missile battery to reliably disable systems - still not unreasonable velocities, especially for the mentioned torch drives.
Certainly usable veocities for kinetic weapons but not bunker busters with delayed action fuses. Above 2200 meters/sec projectiles made out of normal matter will structurally fail rather than penetrate intact.

Stil lots of damage particuarlly in space combat where your projectiles don't have to worry about buring up like meteors (that also starts hapenign at 2200 meters/sec) when they're in atmosphere. However, you will not be getting that follow-up explosion after penetrating the armor layer.
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Old 06-15-2019, 10:31 AM   #7
Rysith
 
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Default Re: [spaceships] bunker-buster bombs

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Certainly usable veocities for kinetic weapons but not bunker busters with delayed action fuses. Above 2200 meters/sec projectiles made out of normal matter will structurally fail rather than penetrate intact.
My point was that at SS velocities, you're no longer talking about fusing explosives and behind-armor penetration, you're calculating damage in terms of kinetic energy carried by the mass sort of regardless of what that mass actually is. Around 2mps is the threshold when you pass TNT for energy per mass (so adding chemical explosive filler doesn't help), and as you mentioned keeping a nuclear weapon together when you're impacting at those kinds of energies is impractical - about the best that I could imagine would be some sort of nuclear squash-head warhead. More or less whatever projectile you're throwing is going to vaporize on impact and the internal damage is going to be based on shock, spallation, and heat transfer rather than any explosives in the projectile.
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Old 06-15-2019, 11:10 AM   #8
Ulzgoroth
 
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Default Re: [spaceships] bunker-buster bombs

Quote:
Originally Posted by Rysith View Post
My point was that at SS velocities, you're no longer talking about fusing explosives and behind-armor penetration, you're calculating damage in terms of kinetic energy carried by the mass sort of regardless of what that mass actually is. Around 2mps is the threshold when you pass TNT for energy per mass (so adding chemical explosive filler doesn't help), and as you mentioned keeping a nuclear weapon together when you're impacting at those kinds of energies is impractical - about the best that I could imagine would be some sort of nuclear squash-head warhead. More or less whatever projectile you're throwing is going to vaporize on impact and the internal damage is going to be based on shock, spallation, and heat transfer rather than any explosives in the projectile.
Well, if the sectional density of your impactor is lower than that of the layer it's impacting.

If it's higher, you might have some of the projectile penetrate.
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Old 06-15-2019, 12:25 PM   #9
AlexanderHowl
 
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Default Re: [spaceships] bunker-buster bombs

A tungsten penetrator is probably your best bet for a KE round. It is tough and dense, meaning that only a fraction of it will vaporize before the rest penetrates. One thing to consider though it that a TL10 spacecraft can reach over 10 mps using HEDM rockets. For example:

AKV (TL10)

Size: SM+6

Components: 30 Secondary Weapon Batteries (Front Bomber Bays), 14 Fuel Tanks, 1 Nanocomposite Armor, 1 Control Room, and 1 HEDM rocket.

The AKV accelerate to 10 mps before releasing thirty 16cm KE bombs per turn. When it runs out of bombs, it rams a predetermined target for maximum damage.
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Old 06-15-2019, 08:39 PM   #10
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Default Re: [spaceships] bunker-buster bombs

The problem with bombs is their miserable accuracy. sAcc -11, and in the basic combat system range P. In the tactical system the lack of ability to manoeuvre makes them an area denial weapon at best.
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