SW shielding (split from SB)

[apocolypse]

Yeah, I know it's been done more times than most people want to think about, but bear with me.

Over at SB, there was a Halo/Wars thread that I and white rabbit were in, and we got onto a sidetrack involving shields, heat sinks, etc. (I thought about just splitting in the SB General forum, but figured it'd do better in the PSW forum here)

Specifically, this is in regards to the Acclamator. To me, I've always took the peak shields of the Acc as 16.6 TTs/sec, and that you'd need overwhelming firepower (greater than 16 TTs) to get through the shields and overload the generators. Further, I always thought the generators work together to provide overall shield coverage. I know that they're sectionalized, and that was something that WR brought up as well. But to me it seemed like they worked in unison, not one generator solely for one section.

WR had some other points than this, but I thought I'd see what people thought so far before going any further. If I'm completely off, then it's better for me to know now. Also, WR feel free to jump in too. Thanks.

Edit: also, while I'm at it. With the shielding rate given per second, that would mean that X amount of firepower has to hit within one second of time AFAIK. However, would a somewhat smaller amount of firepower eventually degrade the generators too over time?

[Spartan]

Well this should answer you questions regarding shield function. It was posted back when ATOC 0 ICS came out, after Dr. Saxton clarified the reasoning behind the figures. in the book.

Darth Wong wrote:

According to ICS shields can dissipate energy at a rate of X watts. This is the rate at which they can dump energy to the environment (ie. space). An energy weapon will transfer part of its energy to the system. If the rate of energy is below X watts, it will have no effect whatsoever because the system will be able to dump the energy as quickly as it comes in. If the rate of energy transfer is above X watts, it will be stored in the system until it is dumped out. For example, if it is 4X watts. Then it will take 3T seconds for the system to dump this energy to space. The system’s ability to store energy is not quantified by ICS; we can only speculate, based on its survivability in battle against its level of weaponry.

To illustrate:

Imagine that the shield generator is a sink. The sink can hold "x" gallons of water. It can be drained at a peak rate of "y" gallons/min. If you pour water into the sink at some rate “r” less than “y”, you will never fill the sink. If you put more than "y" gallons per minute into the sink then you will slowly fill the sink. It will eventually fill the sink and overflow and flood the surrounding ground. In other words if your rate of adding energy to the system (call it "r") exceeds the rate of dispersal then eventually the shields will fail. If you can not maintain your pouring of more than “y”, then the sink will just drain out again.

Thus the equation we are always solving for is R*T - Y*T >= X
This would give us time of shield failure.

In the case of the Accumulator, we know how big the sink’s drain is “y”. We know the rate “r” at which water is typically poured into the sink. We just don’t how large the sink is.

I hope that helps.

[apocolypse]

Yeah, I recall part of that, thanks for reposting it though as it does help. I guess something else I'm trying to figure out is the shield generators themselves. Do you know if they are section specific? As in, this generator helps shield starboard, this one port, etc. Or do they all work as one to provide overall shielding?

[Spartan]

According to ROTS: ICS the shield generators of the Venerator are regionaly placed, and yes there is a large dedicated shield generator for the port and starbord sides. The Acclamator in ATOC:ICS has a similar generator placement. The number of shoe generators isn't very large, but each generator apparently feeds into multiple shield projectors, that are then broken up into sheild sections. I imagine that that is why shield power can be shunted around ships so easily.

[Mad]

The shields can be taken down individually, at least depending on the circumstances:

Engaging in a straight-up fight with even a Victory-class Star Destroyer like the Corrupter would be suicide for a squadron of X-wings. [..] If the whole squadron fired a salvo of torpedoes at the same time, they could certainly bring the Star Destroyer's shields down, but any captain worth his rank cylinders would roll the ship to present undamaged shields and keep shooting.

The torpedoes do have to be fired at the same time in order to overload the shields. This means the energy must be delivered within a certain timeframe or the shield system can handle it. (The power must be beyond what the weakest link in the shield system can handle for long enough to cause physical damage.)

What happens when they try it?

Wedge felt a moment's joy at the collapse of the Corrupter's shields, but it died as the big ship began to maneuver. It rotated in space above him, executing a roll that swapped up for down and presented the squadron with its undamaged starboard shields as a target. Convarion knows we have a limited supply of proton torpedoes. If he survived this salvo, we've got one last shot to take him down. If he repairs his shields and rolls again, we're done, because then he can take all the time he wants to come after us.

Didn't really work. It appears that a properly-timed salvo of torpedoes can overcome that threshold (whatever it happens to be). Likely, this is what happened:

When overloaded by incoming energy charges, a shield projector's matrix boards will burn out rather than flooding the generator with energy and destroying the entire shield system. Tech crews can repair burned out-out projectors in just a few minutes to get the shields back up to full power.

The shield projectors burned out, but could be quickly replaced.

Shields that are battered down from quick strikes seem to come back online fairly quickly. I'm not entirely sure if shields that are worn down over a longer period of time take longer to come back online, but if they do take longer then there would appear to be different points of failure between the two cases.

[apocolypse]

Thanks for all the info, that helps. Now, as shield segments can be taken down individually, does that mean that each segment is as strong as the overall shield? Sorry for all the questions, but I'd always assumed that it was an overall strength, whereas (and WR, feel free to correct me if I'm miswording this) WR feels that you can breach shields with less firepower.

I guess what it comes down to is, can an Acclamator's shields be breached by firepower less than 16 TTs? (god I feel dirty for asking, but I'm having a hard time corrolating everything in my head right now.)

[Connor MacLeod]

Thanks for all the info, that helps. Now, as shield segments can be taken down individually, does that mean that each segment is as strong as the overall shield?

By themselves, no. What you have here is a number of overlapping segments each protecing a specific section of the ship. Now, as they do "overlap" to an extent. Given the "splintering" nature of bolt/shield interactions, if you spread the energy of the bolt over a wide enough area, you'll get that energy spread over multiple shield segments (rather than having a single segment try to handle it all by themselves - thats partly the justification behind the timed and coordinated torpedo attacks Mad mentioned.) You can also do this by "angling" shields to reinforce each other too - this concentrates greater protection into a more limited arc, but it can leave you exposed elsewhere. (likewise, you can reduce protection in some arcs to bolster others that are weakened.)

This doesn't neccesarily hold true for the heat sinks or radiators though - shields are pretty complex devices. They can absorb (energy going into the shield), store, and reradiate (energy going out of the shield) at fixed rates, and there can be differences or weaknesses in each segment of the process.) This is where alot of variation can creep up - you can have a single huge heat sink that multiple segments feed into, or you could have smaller but independent "local" heat sinks too (redundancy versus durability. A single large sink can obviously soak up more punishment in a given direction, but if you lose that sink you're also outta luck.) Same with the radiators.

On top of that, you can have disparate "values" for each system. You could have a shield with a low absorption or dissipation rate, but a very large heat sink capacity. Likewise, you could have a low heat sink capacity, but have the absorbed energy radiated away so fast that it doesn't stay "full" for long. There are even some kinds of shields that can "recycle" the energy absorbed by heat sinks and make use of it in combat (Viper Automadon battle droids are an obvious example, but accoridng to some books, customized pirate ships like the Falcon and military warships can also have this sort of shielding.)

Sorry for all the questions, but I'd always assumed that it was an overall strength, whereas (and WR, feel free to correct me if I'm miswording this) WR feels that you can breach shields with less firepower.

Well, as I said, as I've understood it (and had it explaiend to me) it can be pretty complicated (hell, the example I provided is rather simplified. I don't even cover things like volumetric effects, shield geometry and the "reflection" of bolts, or things like that...)

I guess what it comes down to is, can an Acclamator's shields be breached by firepower less than 16 TTs? (god I feel dirty for asking, but I'm having a hard time corrolating everything in my head right now.)

Well the ICS values are "power" - you don';t neccesarily need to deliver 16 TT per say to overwhelm the dissipation capacity. The shields could dissipate 16 TT in one second, 4 TT in 1/4th of a second, ,or 1.6 TT in 1/10th of a second. The faster you deliver the energy (which means that the "power" rating is higher), the faster it can get rid of it.

Now, what about say a nuke that delivers its energy in a microsecond? It might overwhelm the dissipation capacity, but there is always STILL the heat sink. You might (for example) have a megaton-range nuke delivering its energy in a microsecond, but the energy that bypasses the dissipation rate is quite simply going to go into that heat sink. And in general, heat sink capacity is at least several times to an order of magntidue the dissipation rate. More likely to be two, even three times that.

Edit: and of course, that's simply dealing with energy. Force, pressure, and momentum only complicate things further.. although bracing of the generators tends to play as much a role there as does shield strength (conservation of momentum and such.)

[apocolypse]

Okay. I think it's starting to click in my head. Let me see if I'm getting it straight.

Each shield generator feeds to shield projectors, and the shields themselves are segmented. Now, if a ship attacks an Acclamator, and they don't target a specific shield section, then the amount of energy that the ship can dissipate is 16 TTs/sec. However, if they do target a specific section/arc, then it's possible to weaken that area with less firepower. Or conversely, it's also possible if the energy delivered is done so in a fraction of a second. OTOH, the ship being attacked can also shunt power from other arcs to boost the weakened arc.

However though, this isn't even factoring in the effect of the heat sinks and radiators like you mentioned Conner. And IIRC this is where the neutrinos are mentioned. Now, let's say heat sink was twice the shield dissipation rate. (I know it's greater, but just for my own ease) An Acclamator could then withstand an additional 32 TTs of waste heat from the shields?

I appreciate everyones' help. It's turning out to be a lot more complicated than I realized.

[McC]

The Acclamator's mots powerful guns are rated at 300GT/shot, aren't they? How, exactly, then, is even one Acclamator ever supposed to be capable of defeating another if they're both possessed of shields that can dissipate 53 of the ships' heaviest rounds per second? Something is decidedly not clicking for me with the explanations provided yet.

[Companion Cube]

The Acclamator's mots powerful guns are rated at 300GT/shot, aren't they? How, exactly, then, is even one Acclamator ever supposed to be capable of defeating another if they're both possessed of shields that can dissipate 53 of the ships' heaviest rounds per second? Something is decidedly not clicking for me with the explanations provided yet.

I assume the main batteries are more for performing bombardments against non-shielded ground targets in support of their troops.

[apocolypse]

The Acclamator's mots powerful guns are rated at 300GT/shot, aren't they? How, exactly, then, is even one Acclamator ever supposed to be capable of defeating another if they're both possessed of shields that can dissipate 53 of the ships' heaviest rounds per second? Something is decidedly not clicking for me with the explanations provided yet.

The way I'm understanding it so far, is that if you target all your weapons on a specific point (or if the weapons are quick enough) then it's possible to cause stress in that specific section. Although I'm not the best person to answer it since I'm still working on it myself. Keep in mind too that Acclamators aren't true warships, they're troop transports.

[McC]

The way I'm understanding it so far, is that if you target all your weapons on a specific point (or if the weapons are quick enough) then it's possible to cause stress in that specific section. Although I'm not the best person to answer it since I'm still working on it myself. Keep in mind too that Acclamators aren't true warships, they're troop transports.

True, but it still strikes me as horrifically unrealistic (not to mention entirely counter to what we see on-screen) that a ship will sport shields that can indefinitely stand up to its own guns.

[Illuminatus Primus]

The way I'm understanding it so far, is that if you target all your weapons on a specific point (or if the weapons are quick enough) then it's possible to cause stress in that specific section. Although I'm not the best person to answer it since I'm still working on it myself. Keep in mind too that Acclamators aren't true warships, they're troop transports.

True, but it still strikes me as horrifically unrealistic (not to mention entirely counter to what we see on-screen) that a ship will sport shields that can indefinitely stand up to its own guns.

Why? Are amphibs in real life typically equipped with AShMs? They are for self-defense from smaller craft and for supporting ground operations.

[Connor MacLeod]

The way I'm understanding it so far, is that if you target all your weapons on a specific point (or if the weapons are quick enough) then it's possible to cause stress in that specific section. Although I'm not the best person to answer it since I'm still working on it myself. Keep in mind too that Acclamators aren't true warships, they're troop transports.

True, but it still strikes me as horrifically unrealistic (not to mention entirely counter to what we see on-screen) that a ship will sport shields that can indefinitely stand up to its own guns.

Acclamators are designed for military insertions and supporting ground assaults. Their guns (and missiles) are primarily for ground bombardment, not capital ship battles (though they can fight off the enemy's smaller warships if need be) Their shields are designed likewise to protect them against enemies of a like size or smaller.

[Connor MacLeod]

The Acclamator's mots powerful guns are rated at 300GT/shot, aren't they? How, exactly, then, is even one Acclamator ever supposed to be capable of defeating another if they're both possessed of shields that can dissipate 53 of the ships' heaviest rounds per second? Something is decidedly not clicking for me with the explanations provided yet.

Simple. The Acclamator is a troop transport, not a dedicated warship. If you want a warship, look at the Venator.

[Connor MacLeod]

Each shield generator feeds to shield projectors, and the shields themselves are segmented.

More or less. Shields are designed for both "skin-tight" coverage as well as "bubble" coverage, but they can also be extended to overlap or cover other warships, ,and whatnot. That, and the ability to open "gaps" in the shields, neccesitates that shields be composed of a number individually overlapping segments. Also keep in mind that shields have volume (not just area), like any good force field.

Now, if a ship attacks an Acclamator, and they don't target a specific shield section, then the amount of energy that the ship can dissipate is 16 TTs/sec.

I presume by "target a specific shield section" you mean "If the enemy doesn't try to concentrate its fire so that it hits all the same spot at the same time (like with the X-wings in Bacta war or Isard's Revenge.)."

I'm not 100% sure just how large a shield section is or how many sections compose it (I can guess, but that's about it.) In a very simple sense, virttually all ships have at least 6 arcs (fore, aft, port, starboard, dorsal and ventral.) but each of those arcs can be composed of smaller overlapping segments as well (think of the smaller beams in the DS superlaser combining to form a large one.)

And at "peak" capacity (which is listed in the ICS) it can dissipate 7e22 watts (equivalent to 16 TT/second.. I sorta stopped thinking in terms of "-tons/second" because its misleading.) But assumign the attack was delivered over a second.. yes, the shields would be able to dissipate 16 TT's worth of enegy. I'm still not sure whether "peak" capacity refers to an individual segment, or for all segments together. But since shields can "reinforce" one another, I don't consider it that great an issue (it only drops the figure by about 1/6th, as long as you keep it simple.)

However, if they do target a specific section/arc, then it's possible to weaken that area with less firepower. Or conversely, it's also possible if the energy delivered is done so in a fraction of a second. OTOH, the ship being attacked can also shunt power from other arcs to boost the weakened arc.

Well yes. Since the dissipation rate is rated in "watts", time plays a huge factor in just how much energy can get dumped away. The idea of concentrating your fire on a single area has more to do with intensity (the amount of energy per square unit.. square cm for example.) rather than wattage, but concentrating alot of energy on a very small area makes it harder for the shields to dissipate. I just cna't tell you much more than that without knowing the numbers behind it

However though, this isn't even factoring in the effect of the heat sinks and radiators like you mentioned Conner. And IIRC this is where the neutrinos are mentioned. Now, let's say heat sink was twice the shield dissipation rate. (I know it's greater, but just for my own ease) An Acclamator could then withstand an additional 32 TTs of waste heat from the shields?

I believe the "dissipation rate" already refers to the radiators (thats how much energy they can dispose of in a given amount of time.) Think back to Mike's sink analogy The heat sink is how much "water" can be held, while the dissipation rate is analogous to how fast the water drains out of said sink.)

So in other words, if the sinks can absorb 32 TTs total. If the Acclamator is hit with 16 TT in a single second, this energy goes into the heat sink (meaning its absorbed half of what it could.) But the energy input is also equal to the dissipation rate, so that energy in the heat sink gets dumped back out, meaning the capacity of the heat sink goes back up to 32 TT.

However, if the Acclamator was hit with (say) 36 TTs, the heat sink would only be able to stop 32 TTs worth.. the other 4 TT (I believe) going into the hull.

I appreciate everyones' help. It's turning out to be a lot more complicated than I realized.

i should have remembered earlier. Curtis has a section on shields on his "power technologies" page that explains how shields work.. you might find that useful:

Power tech page

[Meest]

Also have to remember that the shield to heatsink connections and such probably aren't 100% efficient, so it could explain how you can pound away at shields slowly building up excess energy over time. Not sure if that would make pounding away with any light to heavy guns(maybe the roll of fighter/bomber support) a good strategy just to keep those systems working and busy till gaps or holes get rotated/compensated, then precision strikes.

[apocolypse]

A couple more questions that came to mind while reading the information Connor posted. Am I correct in thinking that the way I've been using the shield dissipation rate (as a measure of shield strength) isn't really proper? Is it better to think of the dissipation rate as the amount of power the heat sinks can safely handle?

[Connor MacLeod]

A couple more questions that came to mind while reading the information Connor posted. Am I correct in thinking that the way I've been using the shield dissipation rate (as a measure of shield strength) isn't really proper? Is it better to think of the dissipation rate as the amount of power the heat sinks can safely handle?

Well, you *could* use it as a measure of shield strength in a low-end sense. Logically the heat sinks have to be capable of absorbing at LEAST one second's worth of the dissipation rate (not much good if they are - since you sortta need the sinks in order ot have anything to dissipate away to begin with.)

The best way to think of the dissipation rate is simply how much energy can be removed from the heat sinks in a given period of time. The heat sink capacity would be the amount of energy the sinks can safely handle. (Which would be at least several times the dissipation rate. Given that even in the EU warships can withstand around a minute or so of battle, they probably can 10 or even 100x the dissipation capacity.

A safe way to go about it is to take the dissipation rate, divide it by the duration of a TL blast (usually 1/8 to 1/15th a second.), and then multiplying by about 50-100 times (about a minute or two of endurance.)

That's at least a reasonable guesstimate, but its a not too solid so it can be open to nitpicking by others (and they probably would.)

[McC]

Based on the 1/15th second pulse dwell time, and assuming the visible pulse dwell time of a TL is consistent with the c-beam dwell time (grr...I still hate using that system):

Acclamator Specifications (E2ICS):
Peak Shielding Power = 7x10^22 W
Main Cannon Energy = 200 GT/shot

Relevant Constants:
Gigaton = 10^9 tons
Ton = 4.2x10^9 J

Calculated Values:
200 GT * 10^9 ton/GT * 4.2x10^9 J/ton = 8.4x10^20 J/shot
8.4x10^2 J / (1/15 second) = 1.26x10^22 W/shot
7x10^22 W / 1.26x10^22 W = 5.56 ~ 6

In other words, six simultaneous hits from an Acclamator turbolaser would be sufficient to overcome its own shields. This is much more in line than I originally thought.

I am now at ease regarding this topic

[Connor MacLeod]

Based on the 1/15th second pulse dwell time, and assuming the visible pulse dwell time of a TL is consistent with the c-beam dwell time (grr...I still hate using that system):

Acclamator Specifications (E2ICS):
Peak Shielding Power = 7x10^22 W
Main Cannon Energy = 200 GT/shot

Relevant Constants:
Gigaton = 10^9 tons
Ton = 4.2x10^9 J

Calculated Values:
200 GT * 10^9 ton/GT * 4.2x10^9 J/ton = 8.4x10^20 J/shot
8.4x10^2 J / (1/15 second) = 1.26x10^22 W/shot
7x10^22 W / 1.26x10^22 W = 5.56 ~ 6

In other words, six simultaneous hits from an Acclamator turbolaser would be sufficient to overcome its own shields. This is much more in line than I originally thought.

I am now at ease regarding this topic

It will overcome the instantneous dissipation capacity. Any energy that isn't dissipated away immediately remains stored in the heat sink (to be dissipated subsequently, assuming no further bombardment is made.)

And the 1/15 second duration might be a bit much.. DVD FPS is only 24, so that means only 1/12 to 1/8th

[McC]

It will overcome the instantneous dissipation capacity. Any energy that isn't dissipated away immediately remains stored in the heat sink (to be dissipated subsequently, assuming no further bombardment is made.)

How do you figure? See the below re-calculations.

And the 1/15 second duration might be a bit much.. DVD FPS is only 24, so that means only 1/12 to 1/8th

Good point. Recalculated below:

Acclamator Specifications (E2ICS):
Peak Shielding Power = 7x10^22 W
Main Cannon Energy = 200 GT/shot

Relevant Constants:
Gigaton = 10^9 tons
Ton = 4.2x10^9 J
T = 1/12th second

Calculated Values:
200 GT * 10^9 ton/GT * 4.2x10^9 J/ton = 8.4x10^20 J/shot
7x10^22 J /s / 12 = 5.8x10^21 J / T
(5.8x10^21 J / T) / (8.4x10^20 J / T) = 6.9 ~ 7

Looks to me as though it more or less comes out the same...unless you meant instantaneous in the Calculus-physics sense? In which case, can we even calculate that with the information available?

[The Silence and I]

It will overcome the instantneous dissipation capacity. Any energy that isn't dissipated away immediately remains stored in the heat sink (to be dissipated subsequently, assuming no further bombardment is made.)

How do you figure? See the below re-calculations.

<snip>

Looks to me as though it more or less comes out the same...unless you meant instantaneous in the Calculus-physics sense? In which case, can we even calculate that with the information available?

If I understand this shield theory rightly (and that is not a given ) then what Connor means, to use the sink analogy, is the "drain" can drain away 6.9 of those turbolaser hits in 1/12 th a second and the 0.1 turbolaser shot left will remain in the sink--which probably can hold far, far more than 0.1 of a shot. So unless you maintain firing at least 7 shots every 1/12 th a second long enough for those 0.1's to fill the sink the shields will hold. So no, 7 shots is not enough to breach the shields (if I made an error somewhere Connor feel free to point it out).

*******************************

Now for my own problem with this shielding theory: ANH and ROTJ. More usefully, the Tantive IV, armed with spit ball guns and running for its life from a vastly more powerful vessel powers and fires its guns at the far larger ship. My problem with this is 'why do it?' According to this theory as I know it those little guns could fire until the main reactor burns out without so much as ruining the paint job on the stardestroyer, and in fact I'd expect the extra power could be better used to recharge the hyperdrive or supercharge the engines or something, anything, to facilitate escape. Yet they fire anyway. Why? If we think the commander was logical then firing the weapons must have had some purpose, some point to it, even if small, otherwise it is a waste of power that might have given them an edge in sublight.

Then in ROTJ we see the oddly scaled Nebulon B frigate pounding away at the much, much more powerful Executor--with small caliber weapons! And get this, the Executor sustained very minor hull damage (think ruined the paint job kind of deal) from one or two shots. The Executor also returned fire with similar caliber weapons. So what I want to know is how did the Executor sustain any bleedthrough from the secondary guns on a moderately sized warship if it never lost main hull shielding (and indeed several other shots were blocked by the shields so they were still up)? Perhaps more to the point, why is the rebel ship even bothering to attack the friggin super stardestroyer with anything less than its most powerful weaponry--which is still so far outclassed by the shielding it is kind of funny--?

If I had been left to my own devices I'd have said the shields are fickle devices that must be angled against incoming fire to maximize effectiveness and even powerful shields can let a weaker shot slip by if the angling isn't correct. This explains why the equivalent of hand guns are sometimes used against main battle tanks, in terms of absolute power difference, and why those hand guns can sometimes cause damage. It also does just as good a job of explaining the angle main deflectors we hear every so often. But the other theory is main stream and this is not, and I am interested in any explanation out there.

[Stark]

Ever consider they fired to stop the ISD lowering the ventral shield to launch fighters?

The frigate didn't seem to do shit to me, but the fireballs suggest that shield was down. So what?

Christ the 'reroute power to the scooby dooby' thing is so LAME.

[SCVN 2812]

The Executor presumably was also under heavy fire from other ships so the Nebulon-B wouldn't have been single handedly trying to down Executor's shields but making its own meager contribution to the entire assault.