Is spaceship armor useless?

[Xplo]

Originally Posted by Ulzgoroth

Well, you're missing that guns are pretty much worthless unless other options are forbidden, due to their awful range and penalties to hit, and you seem to have the damage very wrong somehow.

Spaceships 68 shows 2cm guns doing 6dx5 - and as with everything in Spaceships, that's decade-scale. Electromagnetic guns triple this (at least) due to their minimum velocity. If the damage is wrong, show me.

On a 1-minute scale, our small fighter armed with a Very Rapid Fire gun can fire 300 rounds. Cumulative modifier to hit with at least one of these kinetic kill monsters is only -2; a professional (skill 12) can do it half the time and an expert (skill 16) can do it, what, 90% of the time? (In fact, with Rcl 3, he's probably hitting at least twice.)

Admittedly, guns do have a poor range, but that doesn't mean you can't shred anything within that range.

Alternately, the smallest missile is 16cm, fits on our SM +5 fighter, and does 6dx40 (or about 800) x5, or x10 at longer ranges. An unstreamlined SM +15 ship with 3 layers of TL9 armor per section has dDR 600. The missile goes through it like soft cheese - and at TL9 it has an overall +1 to hit before ECM and other defenses are taken into account. Honestly, it makes me wonder why anyone would bother with larger missiles or nukes, and why there isn't some kind of micromissile option (other than balance, since micromissiles might as well be the wrath of God).

(All of which suggests that large ships have point defense like crazy. Admittedly, so do oceanic combat ships, for much the same reason.)

The uselessness of armor depends on what's hitting you. If blunting ... a small-caliber autocannon is useful, you can do some good with a modest amount of armor.

I think I've shown otherwise.

[ericbsmith]

Originally Posted by Xplo

Spaceships 68 shows 2cm guns doing 6dx5 - and as with everything in Spaceships, that's decade-scale. Electromagnetic guns triple this (at least) due to their minimum velocity. If the damage is wrong, show me.

Download a more recent PDF. Or check the errata. Note that with the printed GURPS Spaceships book both the Book Errata and PDF Errata applies, and there are quite a few major changes made in the PDF errata not the least of which is the conventional warhead damage because it wasn't actually in decade scale in the original printing and PDF.

[Ulzgoroth]

Originally Posted by vicky_molokh

Let's look at a generic TL10 SM+10 ship. 150 dHP.

A layer of Nanocomposite gives 30 dDR.
A single Tertiary missile with no warhead to speak of hits for 6d×7(2) worth of dDamage. That's an average of 132 injury past DR.

For a proximity-fused warhead, injury becomes 117 . . . per hit. Since proxdet gives +4 to hit, that means that on average, there are 5 hits instead of one. Or an average of 585 injury per attack.

That's if the missile flies at 1 mps. Assuming it accelerates more or starts at a higher relative velocity (extremely likely), damage will be appropriate.

You need 3-4 armour systems (dDR90-120) on your targeted side before you can claim to no longer be shredded by Tertiary ProxDet missiles. At 1 mps. You're still likely to be one-shotted by a sufficiently fast dummy (kinetic) warhead. After all, those 120dDR become 60 vs. normal missiles, which is a laughing matter for a Major battery (6d×12, or average 252 damage at 1 mps).

--------------

Incidentally, autocannon's minimum speed is 1 mps, but damage is half that of missiles. So a Tertiary no longer one-shots armoured craft, but that's about it.
A Tertiary particle beam does 2d×5(5) burn sur, and thus average dDamage of 35 . . . but those 120 dDR become 24. Against the original single-layer (dDR 30), it does 29. Sure, not a one-shot kill, but this is a tertiary, and a beam, thus PD does not apply.

Now, I'm pointing at missiles because for what they do, they're extremely cheap and reliable. Even nukes cost many times less than the hypothetical missileboats that launch them. An SM+4 Control Room, Major Battery and three armour systems cost almost $200K. A nuke costs $50K (for 4d×1000, which is enough to cripple an SM+21 vessel with a layer of Nanocomposite, or an SM+19 one with six layers, before the density bonus).

You know I know all this, right? Which is why I specifically said that if you need to repel missiles you may as well give up.

And an 8cm cannon is not a small-caliber autocannon. A small caliber autocannon is the 2cm or maybe 2.5cm.

Originally Posted by Xplo

Spaceships 68 shows 2cm guns doing 6dx5 - and as with everything in Spaceships, that's decade-scale. Electromagnetic guns triple this (at least) due to their minimum velocity. If the damage is wrong, show me.

The damage is wrong by an order of magnitude. I don't know why your Spaceships would say that, my best guess is that ericbsmith got it and you're looking at a very old PDF.

Originally Posted by Xplo

On a 1-minute scale, our small fighter armed with a Very Rapid Fire gun can fire 300 rounds. Cumulative modifier to hit with at least one of these kinetic kill monsters is only -2; a professional (skill 12) can do it half the time and an expert (skill 16) can do it, what, 90% of the time? (In fact, with Rcl 3, he's probably hitting at least twice.)

Admittedly, guns do have a poor range, but that doesn't mean you can't shred anything within that range.

The ability to shred ships at point-blank range is only useful if there's some way to get to point-blank range while still being able to fire.

Originally Posted by Xplo

Alternately, the smallest missile is 16cm, fits on our SM +5 fighter, and does 6dx40 (or about 800) x5, or x10 at longer ranges. An unstreamlined SM +15 ship with 3 layers of TL9 armor per section has dDR 600. The missile goes through it like soft cheese - and at TL9 it has an overall +1 to hit before ECM and other defenses are taken into account. Honestly, it makes me wonder why anyone would bother with larger missiles or nukes, and why there isn't some kind of micromissile option (other than balance, since micromissiles might as well be the wrath of God).

(All of which suggests that large ships have point defense like crazy. Admittedly, so do oceanic combat ships, for much the same reason.)

I quite definitely noted that missiles made your conclusion largely accurate.

There is a reason to bother with nukes, though larger conventional missiles have it harder. It's possible to design huge warships that actually have enough armor to repel 16cm conventional missiles. Also, note that the range on missiles only goes to the X band at 32cm+ (And in the advanced combat rules, such missiles have twice as much delta-V), so they're not trivially useless. On the other hand, note that maximum range is one band longer against targets that can't maneuver, and most realistic drives...pretty much can't.

Unfortunately for the armored behemoths, without houseruling things heavily there's no way they can carry a useful number of point defense guns, since you can't have more than 30 guns per system, so when the enemy comes to nuke them they really can't do anything about it.

EDIT: Micromissiles, on the other hand, would probably be less useful than just using 16cm set for fragmentation. They're already overwhelming to PD, and something like a 4cm missile would be vulnerable to relatively light armor.

[David Johnston2]

Originally Posted by vicky_molokh

Now, I'm pointing at missiles because for what they do, they're extremely cheap and reliable.

Armor isn't for missiles. Point defense is for missiles.

[Fred Brackin]

Originally Posted by vicky_molokh

Armour is indeed very low, but the effect is made worse by just how much damage kinetic weapons do.

This is unavoidable given realistic assumptions. Very high velocity missiles (even if small) would destroy even very large ships. evena t abse 1 mile per second you're looking at a regime where solid matter doesn't really stay solid. At 10 miles per second you're looking at solid matter exploding with a force of many times (c. 40x) its' own weight in TNT.

If want to duplicate the battles seen in some fiction you need unrealsitic assumptions and rules because those battles are unrealistic. This means looking for high TLs and most especially the ^ sign and optional/cinematic rules.

[Langy]

Originally Posted by Xplo

Today I was reading through Spaceships and trying to design a TL9 civilian ship that could defend itself against pirate attacks. And it seems to me that armor is nearly useless; any ship of a given size can easily mount weapons that can defeat any reasonable quantity of armor that ship could carry.

In fact, it's worse than that. The smallest conventional projectile listed - 2cm - does 6dx5 dDam, or about 100 on average, which vastly exceeds the dDR on all but the largest and more ridiculously armored ships. In other words: small fighters can kill nearly anything.

Is there something I'm missing here, or is armor really that useless?

You may be using an out-of-date book. The weapons table was revised in one of the first errata updates to Spaceships.

[vicky_molokh]

Originally Posted by Fred Brackin

This is unavoidable given realistic assumptions. Very high velocity missiles (even if small) would destroy even very large ships. evena t abse 1 mile per second you're looking at a regime where solid matter doesn't really stay solid. At 10 miles per second you're looking at solid matter exploding with a force of many times (c. 40x) its' own weight in TNT.

I remember hearing that such attacks are defeated by something called 'whipple shield principle'.

Originally Posted by Fred Brackin

If want to duplicate the battles seen in some fiction you need unrealsitic assumptions and rules because those battles are unrealistic. This means looking for high TLs and most especially the ^ sign and optional/cinematic rules.

Well sure, okay, but why do I have to invent systems and modifications from scratch to do it? Why is the TL11^ force shield totally wonderful compared to TL11 armour, but TL^ beams totally pointless compared to TL missiles? (There also isn't much of a serious reason to ever bother with bombs.)

Right now, anything short of an invulnerability field or indestructible armour is worse than having:
1. At least 11% as many missiles in a salvo as the target has PD guns and
2. The willingness to press 'Proximity Detonation'.
(Note: even if we postulated automated gunners that automagically hit with every shot for PD, then same has to apply to missiles.)

[Ulzgoroth]

Originally Posted by vicky_molokh

I remember hearing that such attacks are defeated by something called 'whipple shield principle'.

Well sure, okay, but why do I have to invent systems and modifications from scratch to do it? Why is the TL11^ force shield totally wonderful compared to TL11 armour, but TL^ beams totally pointless compared to TL missiles? (There also isn't much of a serious reason to ever bother with bombs.)

TL^ is not a power level. TL^ beams exist to represent fictional beam weapons that don't act like anything really possible. They are probably mostly not drawn from settings where realistic kinetic-kill missiles are competing with them.

Originally Posted by vicky_molokh

Right now, anything short of an invulnerability field or indestructible armour is worse than having:
1. At least 11% as many missiles in a salvo as the target has PD guns and
2. The willingness to press 'Proximity Detonation'.
(Note: even if we postulated automated gunners that automagically hit with every shot for PD, then same has to apply to missiles.)

Have you forgotten about the rapid and very rapid fire options? A PD gun will almost certainly be VRF.

[vicky_molokh]

Originally Posted by Ulzgoroth

TL^ is not a power level. TL^ beams exist to represent fictional beam weapons that don't act like anything really possible. They are probably mostly not drawn from settings where realistic kinetic-kill missiles are competing with them.

My point is that TLx and TLx^ items don't really compare most of the time. Some of them are outrageously superior to mundane ones. E.g. reactionless drives (with power plants) are in all ways better than any other engine for purposes of achieving orbit.

What would be nice is to have a variation of modules listed in the official PDFs such that picking some subset of them (without as much tweaking as is required now) would allow one to achieve the desired feel. Right now it just takes too much effort to make space-operatic spaceships. (Though I'm semi-ready to restart the discussion of houserules that make it possible.)

Originally Posted by Ulzgoroth

Have you forgotten about the rapid and very rapid fire options? A PD gun will almost certainly be VRF.

Seems like I did. So, more power to the defence. Point taken.

Still, the combat devolves into a contest of saturation.

Hmmm. Crits normally mean that defence isn't possible, though I wonder if that applies to PD too.

[apoc527]

Originally Posted by vicky_molokh

Seems like I did. So, more power to the defence. Point taken.

Still, the combat devolves into a contest of saturation.

Hmmm. Crits normally mean that defence isn't possible, though I wonder if that applies to PD too.

Honorverse, here we come. Seriously though, there's nothing unrealistic about this issue. If combat in space comes down to missiles, then naturally the tension between missile numbers and penetration aids and point defense and jammers/spoofers will overtake that of warhead vs. armor. I'm sure, on some level, it will be both, but the main thing when you don't have the Honorverse's impenetrable grav shield from your reactionless drives is point defense.

Defensive doctrine would evolve with the weapons. The enemy shoots missiles at you. You start doing everything in your power to make it so those missiles don't hit you. You can (1) dodge them, (2) confuse them, (3) outrun them, (4) destroy them, or (5) have armor sufficient to ignore them. If GURPS spaceships lacks rules for ECM/ECCM, jammers, decoys, etc, then those are all things to create to make an interesting missile-based space combat paradigm. Destroying them would also happen in stages--you might have a small craft screen tasked with destroying missiles. Then you'd have a countermissile stage, where you launch your own small missiles to take out the larger incoming ones. Any that get through the countermissiles are engaged with point-defense weapons (lasers and autocannon). Hopefully there are very few left to deal with, but it depends on the lethality of the missiles. If just one is enough to blow up a ship, then point defense is going to be HEAVILY favored because it's suicide not to.

In my opinion, to have any meaningful discussion about space combat tactics, you have to do a tremendous amount of world-building first. Cost matters, resources matter, laws may even matter. Technology is just the start! The Honorverse was exhaustively set up to create a desired style of space combat, and except for the reactionless grav engines, tries to be consistent with physics (ok, he also has FTL grav communicators, but in his defense, at the time he wrote about those, real physicists weren't sure how fast gravitons propagated).

Anyway, I'm not sure what my point is any longer, except that there's nothing wrong with wars of saturation!