missile effectiveness

[simontmn]

I created starship combat rules for my game based on the 'Imperium' board game. I wanted a system that has long range missiles but keeps battleships viable (unlike in modern naval combat). The obvious problem is that the missiles are bound to carry thermonuclear warheads, and even though ships routinely carry effective shields, if starship lasers are to have any chance of penetrating the shields, they can't be _too_ effective. Which implies that multi-megaton nuclear missiles ought to be able to destroy ships quite easily.

I was wondering if anyone has good in-game justifications for the limited effectiveness of nuclear missiles? I really hate the "nuclear explosion merely powers 1d6 X-ray lasers" justification, it just seems really cheesy. I mean reasons why starships might survive nuclear blasts from multi-megaton warheads.

Thoughts so far:
No missile is going to score a 'direct hit' in starship combat, it would always be shot down by point-defense lasers. Therefore missiles are set to explode in proximity, probably tens of km away. Since there is no blast wave in space, that means the victim only takes heat/EM radiation from the nuke, and only a tiny proportion of the blast, rendering it potentially survivable.

Any thoughts/ideas?

 

[tjoneslo]

There is no atmosphere in space to carry the effects of a nuclear blast. Nuclear bombs generate a large pulse of x-rays causing very bad effects on a ship but only at very close range, like a few km. Beyond that range the inverse square law takes over and the x-ray pulse is too diffuse to have an effect on a starship, particularly a heavy armored warship.
This is the original reason for the bomb pumped x-ray lasers. There is no way to get any missile close enough to a target through an effective PD screen to make any nuclear missile effective. So by putting a rack of bomb pumped x-ray lasers onto the missile, you could increase its threat range, hopefully beyond the range of the target PD systems.

Besides, swarms of Kinetic Kill missiles are the most effective way to go. At the velocity most Traveller missiles are moving when the hit ships, the conversion of missile kinetic energy into an explosion is on the order of a nuclear weapon. Make them cheap, and fire them in huge swams to overwhelm the target PD.

 

[simontmn]

<BLOCKQUOTE>quote:</font><HR>Originally posted by tjoneslo:
There is no atmosphere in space to carry the effects of a nuclear blast. Nuclear bombs generate a large pulse of x-rays causing very bad effects on a ship but only at very close range, like a few km. Beyond that range the inverse square law takes over and the x-ray pulse is too diffuse to have an effect on a starship, particularly a heavy armored warship.
This is the original reason for the bomb pumped x-ray lasers. There is no way to get any missile close enough to a target through an effective PD screen to make any nuclear missile effective. So by putting a rack of bomb pumped x-ray lasers onto the missile, you could increase its threat range, hopefully beyond the range of the target PD systems.

Besides, swarms of Kinetic Kill missiles are the most effective way to go. At the velocity most Traveller missiles are moving when the hit ships, the conversion of missile kinetic energy into an explosion is on the order of a nuclear weapon. Make them cheap, and fire them in huge swams to overwhelm the target PD. <HR></BLOCKQUOTE>

Thanks - I'm extremely sceptical that the bomb-pumped X-ray laser concept could ever be accurate enough to hit anything smaller than a planet. I'm not sure about the kinetic missiles either - presumably the missile will have to maneuver to hit the target, won't that mean a low relative velocity when it impacts? Plus the more it goes in a straight line, the easier it is to shoot down first.

My current view on nuclear missiles in my game is that each missile fired by a ship is large (similar to modern ICBM) and holds dozens of warheads, most are decoys, a few are armed. Missiles 'burst' into multiple warheads when approaching enemy laser range, circa 8-10,000 km. Armed warheads are multi-megaton yield (probably around 60 MT) set to explode on approach to enemy starship, maybe 10 km. The X-ray and other E-M energy then damages the target. Under my rules, each nuke is thus equivalent to a single hit from a 300 MJ laser barbette at 5,000 km range (no gravitic focusing in my game).

Sound at all reasonable?

-Simon
-Simon

 

[tjoneslo]

<BLOCKQUOTE>quote:</font><HR>Originally posted by simontmn:
Thanks - I'm extremely sceptical that the bomb-pumped X-ray laser concept could ever be accurate enough to hit anything smaller than a planet. I'm not sure about the kinetic missiles either - presumably the missile will have to maneuver to hit the target, won't that mean a low relative velocity when it impacts?
<HR></BLOCKQUOTE>
Both of these depend upon how advanced sensor technology is IYTU. Both assume the use of small, very sensitive sensors capable of accuratly finding a starship sized object at between 1,000km and 10,000 km.

<BLOCKQUOTE>quote:</font><HR>
My current view on nuclear missiles in my game is that each missile fired by a ship is large (similar to modern ICBM) and holds dozens of warheads, most are decoys, a few are armed. Missiles 'burst' into multiple warheads when approaching enemy laser range, circa 8-10,000 km. Armed warheads are multi-megaton yield (probably around 60 MT) set to explode on approach to enemy starship, maybe 10 km. The X-ray and other E-M energy then damages the target. Under my rules, each nuke is thus equivalent to a single hit from a 300 MJ laser barbette at 5,000 km range (no gravitic focusing in my game).

Sound at all reasonable?

-Simon
-Simon <HR></BLOCKQUOTE>

This sounds fine.

One suggestion would be: Is it possible to build a shaped charge nuke, not quite a laser but capable of directing more of the x-ray pulse in one (cone shaped) direction. This may allow you to use smaller warheads.

What are the missiles using for thrust? If you are using Traveller Magi-tech reactionless Thrusters it may be better to build many small single warhead missiles than one larger multi-warhead missile.

Add to the decoy missiles: Sand warheads

 

[phydaux]

IMTU, Point Defense is exactly what turret lasers are for. they shoot incomming missles. this makes turret lasers almost entirly defencive and missles entirly offencive. that's why the imperium allows common tramp shits to be armed: pirates might use missles. on the other side of the coyn, no civilian ship will be allowed to have missile racks. i IGNORE sandcasters.

that's fine for small ships. what about big ones? well, those kinetic energy missiles hit HARD. harder that a kilo-ton nuke, and WAY harder than any bomb-pumped X-ray laser. just one 50-ton missile bay can put out enough misile to dissable a heavy cruiser. and it can launch all those missiles from well outside turret, or even spinal mount, range. that is, IF they all hit. so even big ships will have lots of hull space devoted to turret lasers for PD.

so, ships up to 5000 tons will be turret-only. some might have a missile bay, but it won't be a survivable platform. ships less that 5000 tons with one or 2 missile bays will be able to maul much larger ships in a supprise attack, but will go down in flames after the first real volley. if they have energy bays, rather than missile bays, then they are meat for any ship with a missile bay. they just won't have the numbers to sustain an effective PD. so, 5000 tons and less, turret only.

over 5000 tons, and they will install bay weapons at 2-1 missile-energy, but still leave at LEAST 75% of possible turret capacity for PD. over 30k tons, they will be all energy weapons - 100 ton bays and spinal mounts, again with 75% of possible turret capacity for PD. in that size, however, they should have enough armor to shrug off a few dozen Kinetic Kill missile hits and keep fighting.

 

[simontmn]

<BLOCKQUOTE>quote:</font><HR>Originally posted by tjoneslo:
This sounds fine.

One suggestion would be: Is it possible to build a shaped charge nuke, not quite a laser but capable of directing more of the x-ray pulse in one (cone shaped) direction. This may allow you to use smaller warheads.

I'm not sure how practical this is, since adding the 'cone' will take up mass and decrease total missile yield, but it's an idea, thanks.

What are the missiles using for thrust? If you are using Traveller Magi-tech reactionless Thrusters it may be better to build many small single warhead missiles than one larger multi-warhead missile.

Add to the decoy missiles: Sand warheads<HR></BLOCKQUOTE>

Sand warheads - very good point!

Re missile thrust, I'm assuming magitech reactionless thrust (well, reaction against the total gravity of the solar system or universe, let's not get carried away!) but that there's a minimum size limit for these 'gravitic drives' - the large missiles can carry them, but the small warheads need reaction drives.

 

[tjoneslo]

<BLOCKQUOTE>quote:</font><HR>
One suggestion would be: Is it possible to build a shaped charge nuke, not quite a laser but capable of directing more of the x-ray pulse in one (cone shaped)direction? This may allow you to use smaller warheads.

I'm not sure how practical this is, since adding the 'cone' will take up mass and decrease total missile yield, but it's an idea, thanks.
<HR></BLOCKQUOTE>
If you project the bulk of the x-ray pulse in a 30 degree cone, you can make the yeild of the nuke 144 times smaller and still get the same strength of x-ray pulse at a given distance. Even with the inefficencies of the x-ray refocus and weight of the device, you can sill make the bomb 100x smaller and still get the same effective damage.

<BLOCKQUOTE>quote:</font><HR>
Re missile thrust, I'm assuming magitech reactionless thrust (well, reaction against the total gravity of the solar system or universe, let's not get carried away!) but that there's a minimum size limit for these 'gravitic drives' - the large missiles can carry them, but the small warheads need reaction drives.<HR></BLOCKQUOTE>
Depends upon your handwaves. MTU uses the Striker/GT reactionless grav drives, which can be made as small as you would like.

If, as you assume, there is a minium size to a vessel (like a missle) which can use the really efficient reactionless drives then the bus missiles become more prevelant. If you remove that restriction, you get smaller, single warhead missiles.

 

[simontmn]

<BLOCKQUOTE>quote:</font><HR>Originally posted by tjoneslo:

If you project the bulk of the x-ray pulse in a 30 degree cone, you can make the yeild of the nuke 144 times smaller and still get the same strength of x-ray pulse at a given distance. Even with the inefficencies of the x-ray refocus and weight of the device, you can sill make the bomb 100x smaller and still get the same effective damage.

Good point, thanks. The idea of a non-directed blast was simply to help ensure a 'hit', but maybe a 30 or 60-degree cone would be reasonable. Funny, the point of this thread was for ideas on why nukes might be relatively _in_-effective vs ships!

Re missile thrust, I'm assuming magitech reactionless thrust (well, reaction against the total gravity of the solar system or universe, let's not get carried away!) but that there's a minimum size limit for these 'gravitic drives' - the large missiles can carry them, but the small warheads need reaction drives.<HR></BLOCKQUOTE>
Depends upon your handwaves. MTU uses the Striker/GT reactionless grav drives, which can be made as small as you would like.

If, as you assume, there is a minium size to a vessel (like a missle) which can use the really efficient reactionless drives then the bus missiles become more prevelant. If you remove that restriction, you get smaller, single warhead missiles.

The ship construction rules I use work a lot better if ships only carry a few, large, missiles. I think a minimum size for the gravitic drive is also reasonable - it's a Tech Level 13 setting BTW, but with some variant tech fields. I don't think I'll be allowing any personal grav belts, for instance.

 

[tjoneslo]

<BLOCKQUOTE>quote:</font><HR>
If you project the bulk of the x-ray pulse in a 30 degree cone, you can make the yeild of the nuke 144 times smaller and still get the same strength of x-ray pulse at a given distance. Even with the inefficencies of the x-ray refocus and weight of the device, you can sill make the bomb 100x smaller and still get the same effective damage.

Good point, thanks. The idea of a non-directed blast was simply to help ensure a 'hit', but maybe a 30 or 60-degree cone would be reasonable. Funny, the point of this thread was for ideas on why nukes might be relatively _in_-effective vs ships!
<HR></BLOCKQUOTE>

True. The realistic approach to nukes may make them too ineffective, particularly if you are making the PD very effective. The cone or bomb pumped laser allows detonation from a greater distance allowing more survival from PD countermeasures.

 

[phydaux]

snip

The cone or bomb pumped laser allows detonation from a greater distance allowing more survival from PD countermeasures.

/snip

yes, but it also makes each individual missile far LESS effective. the Kinetic Kill missiles are still the best bang for you buck (sorry for the pun).

that is, at least, compaired to the bomb-pumped x-ray laser warheads. i haven't really concidered cone-blast nukes. how would you justify it? gravity focusing? some sort of "Shaped Charge" for a Monroe effect?

well, i guess if i'm ignoring sandcasters, i can ignore cone-blast nukes.

 

[simontmn]

<BLOCKQUOTE>quote:</font><HR>Originally posted by tjoneslo:
True. The realistic approach to nukes may make them too ineffective, particularly if you are making the PD very effective. The cone or bomb pumped laser allows detonation from a greater distance allowing more survival from PD countermeasures. <HR></BLOCKQUOTE>

My players do grumble - their ship is a heavy cruiser (designed by one of them) - massing 40,000 tons, it only carries 6 missiles, along with 8 300 Mj laser barbettes and 9 shield generators - barbettes, missile racks (1 missile) and shield generators all take up the same amount of space under my rules. Each missile is roughly as effective as a single turn's fire from a laser barbette, although effective out to a much much longer range (limit of sensor range, 1 million lm+, as opposed to ca 8000 km for the lasers). And each shield generator can absorb roughly the amount of damage inflicted by 1 'hit' from nuke or laser, every turn - so weapons are fairly ineffective and there is a strong impetus towards larger ships for defense; although a mass of small unshielded missile boats or beam-armed starfighters can also be effective.

 

[simontmn]

<BLOCKQUOTE>quote:</font><HR>Originally posted by simontmn:
My players do grumble - their ship is a heavy cruiser (designed by one of them) - massing 40,000 tons, <HR></BLOCKQUOTE>

Displacement of about 10,000 tons. The important stat is its 'Hull Rating', which determines how long it takes to build and how much stuff you can put in it. This heavy cruiser is hull rating 10, which hives 40 build points to assign to missile racks, beam weapons, shield generators and power plant (Energy). Energy is needed to power shields & lasers and (Energy/Hull)x7 determines 'Defense Class' which covers maneuverability and the effectiveness of point defense systems, ECM/ECCM, et al.

So this ship has:
Hull 10
Missiles 6
Beams 8
Shields 9
Energy 17 (so it can use all beams & shields at once - some designs are underpowered)
DC 12

'To hit' is determined by attacker's skill asset+d20, they have to beat defender's relevant asset+DC. Each hit then does d2 damage, damage exceeding Shields is deducted from Hull and 4 points of the systems (missile racks, beams, etc).

 

[Mused]

Originally posted by phydaux:
...that's why the imperium allows common tramp shits to be armed...

HAR HAR HAR! I assume that was a typo.

Nothing quite like typo to make your day.

That said, are all missiles alike?

In modern ship warfare we have missiles for close in, missiles for PD, torpedoes...

A beef I always had with Traveller was that missiles felt like rockets

 

[TJP]

<BLOCKQUOTE>quote:</font><HR>
A beef I always had with Traveller was that missiles felt like rockets<HR></BLOCKQUOTE>

Same here. I never liked the idea of huge salvoes of small missiles. IMTU space missiles are mostly big, expensive, x-ray laser detonation missiles that use reaction rockets to move to firing range and then go boom. There are no impact missiles (be it a nuke, HE, or kinetic kill) for ship-to-ship battles in space.

 

[Vargas]

It sounds to me a better analogy would be to use modern torpedoes when thinking of missiles in Traveller. Current torpedoes can launch and then go dormant looking for a target via passive sensors until they spot something that meets preset criteria.

 

[simontmn]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Vargas:
It sounds to me a better analogy would be to use modern torpedoes when thinking of missiles in Traveller. Current torpedoes can launch and then go dormant looking for a target via passive sensors until they spot something that meets preset criteria.<HR></BLOCKQUOTE>

I describe the missiles in my game as 'like torpedoes' - although with their MIV ability they're also like ICBMs. Certainly they're of similar or larger size, and designed to destroy the enemy 100 planetary diameters away or more, long before lasers are effective.

 

[aramis]

IMTU, missiles are also small, everybody has access to them. At least the standard 10x100 cm turret missiles. And Canonically, there are nukes for these. I don't allow civilians to HAVE nukes (save licenced starmerc units during wartime, and then they really are not civillians). Missile bays typically fire larger, smarter missiles.

Sand is just a shotgun, with little to no effect against lasers, until TL14, when tractor and presser tech comes to use, and then they can be placed and SWUNG on line between target and firer, assuming that the gunner has reason to put them out there. (10 L of sand isn't enough to stop a reasonable laser, but it might stop a missile from triggering or damage tracking.)

Missile civilian warheads are basically either HEAP contact missiles, or "Giant Shotguns" (ala many modern air-to-air missiles).

But, IMTU, main guns are the queen of battle. A meson gun is death incarnate (reread the striker descriptions, and realize that a type A meson has a radius of 10 table-cm, each table-cm being 10m, and everything inside is ruinied. An "On Target" hit froma type A will destroy a CE outright, and heavily damage many largish warships.

------------------
-aramis
=============================================
Smith & Wesson: The Original Point and Click interface!

 

[Ben W Bell]

I have a problem with Licensed Star Mercs being allowed Nukes in war time. Nukes are banned under the Imperial Rules of War are they not? So they're not likely to allow mercaneries access to them are they?
I could be wrong but I'm pretty sure that is one of the rules laid down.

 

[tjoneslo]

The unwritten rules of war state no use of weapons of mass destruction. TacNukes are a wonderful way to remove annoying obsticals like GravTanks when you've run out of plasma guns.

The problem comes in when your troopers get a little too nuke happy...

 

[phydaux]

no use of weapons of mass destruction on a planet. in space to space combat, anyone can use nukes. so, according to canon, nuke tipped missiles in a free trader turret is ok.

as a GM, though, i have a MAJOR problem with that. so far it hasn't happened in any game i've run, but sooner or later a PC is going to say to himself "Say, don't we have about 50 kiloton nuke warheads right in our turret?"

ten minuets later, the Regina High Port is toast.

"That'll show those Customes Inspection ASSHOLES who thay can ⌧ with!"

"Say, who are all those guys in maroon berets?"

so IMTU, no missles on cive ships.