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Post by apophys on Mar 5, 2017 22:01:36 GMT
Also the variable optic mirror is made of Aluminum, but so is the default whipple shield, one melts but the other is fine. Why? I have a sneaking suspicion that the whipple shield should not be melting either. We need more transparency regarding damage calculations.
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Post by Enderminion on Mar 5, 2017 22:28:24 GMT
I agree with apophys we would like to know damage calculations
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Post by deltav on Mar 6, 2017 4:11:03 GMT
The incoming laser intensity at the aperture (big mirror) is much, much less than outgoing laser intensity at the same aperture. They are both proportionally more concentrated at the smaller focusing mirror (thanks for pointing out its location, deltav ). The outgoing beam is still much, much stronger at that location. For there to be any damage to any component, such as the focusing mirror, the combined intensity of incoming and outgoing beams would have to be greater than a certain number, " Lasing Damage Threshold." For Aluminum the threshold is 1.27 GW/m 2. For silver that is 4.46 GW/m 2. For titanium dioxide that is 129 TW/m 2. This is accounted for when producing the outgoing beam. This does not appear to be accounted for when receiving an incoming beam. Thus, the bug. But we are not hitting the working optics of the laser with our counter lasers. We are aiming at the "back" of the prefocusing laser, which is not designed and cannot be designed to be optimal for reflecting a laser beam. Here's a pic of a real laser to get an idea. We are aiming for that chunk of metal right in the center with our counter lasers. Even if we were aiming directly for the optics, (the shiny golden plate at the back in the pic)... While the power of the outgoing beam is spread out over the entire focusing and refocusing beam, our counter lasers are focusing on a tiny point, stressing the material far beyond its capacities. So the laser resistance of the optics doesn't come into play. The part we are targeting is neither mirrored nor armored, and probably cannot be.
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core2
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Post by core2 on Mar 6, 2017 4:42:25 GMT
"When 1361 W/m^2 is arriving above the atmosphere (when the sun is at the zenith in a cloudless sky), direct sun is about 1050 W/m^2, and global radiation on a horizontal surface at ground level is about 1120 W/m2." wikipedia So everything under ~1kW/m^2 is less than a sunny day on earth and shouldnt damage anything. I got lasers to insta pop with 100w/m^2, so there is clearly something bugged/modeled incorrectly.
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Post by apophys on Mar 6, 2017 4:52:11 GMT
But we are not hitting the working optics of the laser with our counter lasers. We are aiming at the "back" of the prefocusing laser, which is not designed and cannot be designed to be optimal for reflecting a laser beam. Here's a pic of a real laser to get an idea. We are aiming for that chunk of metal right in the center with our counter lasers. Even if we were aiming directly for the optics, (the shiny golden plate at the back in the pic)... While the power of the outgoing beam is spread out over the entire focusing and refocusing beam, our counter lasers are focusing on a tiny point, stressing the material far beyond its capacities. So the laser resistance of the optics doesn't come into play. The part we are targeting is neither mirrored nor armored, and probably cannot be. That can very easily be armored. Or mirrored. If that laser is firing at you, the orientation is very straight; you aren't seeing its edges or back. And that doesn't even matter here, because in the current bugged simulation, effective counter lasers can have intensities on the order of watts per square meter at target, which is not enough to damage even silica aerogel. Any material that backing is made of can easily shrug off such a weak intensity. The intensities we are talking about are similar to the light illuminating that picture. Or the light emanating from your computer screen. "the average intensity of solar energy reaching the top of the atmosphere directly facing the Sun is about 1,360 watts per square meter" www.google.com/#q=sunlight+intensity&*EDIT: Dang space ninjas.
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Post by newageofpower on Mar 6, 2017 5:17:53 GMT
Hmm. If the lasing damage threshold does rise to multiple GW/m^2, then our ludicrous 900km/s hypervelocity kinetics and gigantic 100m main mirror lasersats might actually be viable.
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dv2
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Post by dv2 on Mar 6, 2017 8:47:57 GMT
Edit:Maybe if they curve outward and downward in 3 dimensions somehow. But no current iris design works that way... as far as I know. Let me Google that for you: This is great I wish I had found it... it's perfect. The reason I think it's an iris portal instead of a flip up top, is the mechanics of it all. The iris door would be a pretty sturdy mechanism, and could be closed or opened relatively quickly. But a flip up door would be very heavy, need a hinge, and would be slow to open or close by comparison. Could be either but I think the iris door fits the ingame COADE behavior more. The only problem with the iris theory is that the armor of the iris would have to be thinner than the rest of the armor.
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dv2
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Post by dv2 on Mar 6, 2017 9:07:02 GMT
That can very easily be armored. Or mirrored. If that laser is firing at you, the orientation is very straight; you aren't seeing its edges or back. And that doesn't even matter here, because in the current bugged simulation, effective counter lasers can have intensities on the order of watts per square meter at target, which is not enough to damage even silica aerogel. Any material that backing is made of can easily shrug off such a weak intensity. The intensities we are talking about are similar to the light illuminating that picture. Or the light emanating from your computer screen. "the average intensity of solar energy reaching the top of the atmosphere directly facing the Sun is about 1,360 watts per square meter" www.google.com/#q=sunlight+intensity&*EDIT: Dang space ninjas. Let's put aside the idea for a sec of aiming for housing of the prefocusing mirror in the center of face of the laser turret. How much power would be needed to attack the focusing mirror directly? Starting with guidelines from credible sources who have discussed the issue at length... www.projectrho.com/public_html/rocket/spacegunconvent.php#id--Laser_Cannon--OpticsThe optics of our lasers would act like binoculars in reverse. As if we looked at the sun, that would be bad. But if we looked at the sun with binoculars, that would be double extra bad. According to PRHO, it would be 50x-100x as bad. So hitting the focusing laser with another laser beam, might end up being 50-100 times boosted by the optics inside the turret. "Well, for the same reason it is bad to unshutter your laser cannon optics and point them at a hostile ship which might zap you with its laser. Your cannon's optics would funnel their beam right down into the delicate interior of your cannon. The optics would also concentrate their beam to 10x or 100x the intensity. This means that if your lasers are unshuttered and your opponents are shuttered, you have the drop on them. The instant you detect their shutters trembling you give them a zap. Their shutters will still be opening when your bolt scrags their laser."Of course there is whole debate on the subject. Something I love about PRHO, is that he shares lot's of opinions, not just his own. And I think he personally disagrees with this. Just food for thought. Love to see where this debate goes.
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Post by darkwarriorj on Mar 6, 2017 22:51:52 GMT
How much power would be needed to attack the focusing mirror directly? Starting with guidelines from credible sources who have discussed the issue at length... www.projectrho.com/public_html/rocket/spacegunconvent.php#id--Laser_Cannon--OpticsThe optics of our lasers would act like binoculars in reverse. As if we looked at the sun, that would be bad. But if we looked at the sun with binoculars, that would be double extra bad. According to PRHO, it would be 50x-100x as bad. So hitting the focusing laser with another laser beam, might end up being 50-100 times boosted by the optics inside the turret. "Well, for the same reason it is bad to unshutter your laser cannon optics and point them at a hostile ship which might zap you with its laser. Your cannon's optics would funnel their beam right down into the delicate interior of your cannon. The optics would also concentrate their beam to 10x or 100x the intensity. This means that if your lasers are unshuttered and your opponents are shuttered, you have the drop on them. The instant you detect their shutters trembling you give them a zap. Their shutters will still be opening when your bolt scrags their laser."Here's a rough quantitative analysis of the situation. We have amorphous carbon to resist enemy lasers. Say it has a threshold intensity before damage of 50MW/m^2. I don't actually know if that's the number, but let us suppose so - it is representative of standard anti-laser armor aboard spaceships. We are using aluminum for our laser's output mirror. Say it has a threshold intensity before damage of 5MW/m^2 before melting/overheating - such mirrors are typically made of metal and tend to have lower threshold intensities, else they'd be used as said laser armor. From this, we have two cases: 1. Case one: The further focusing problem does not apply. Of which in this case, we may see that the intensity needed to zap an enemy laser is say, 10x less than the intensity needed to seriously damage armor or other modules. By the fact that laser intensity drops off with the square of the distance involved, this gives us the possibility of opening fire on an enemy's laser at root(10), or about 3 times longer range, than when this same laser may effectively open fire on enemy armor. Put in another way, a laser with a smaller aperture (by about 10x less surface area or 3x less aperture radius) can poke out the bigger laser just as the bigger laser gets into range to deal armor damage. 2. Case two: The further focusing problem applies. In this case, we cut the threshold intensity of the enemy laser down by the relevant factor - say 50. From 5 megawatts we get 100 kilowatts intensity needed to damage a relevant laser component. This also allows us to poke out an enemy laser from about root(500) times the range, or about 20-30 times the range that it'd take for the same laser damage to deal armor damage. Put in another way, a laser of same power but with 500x less surface area, or about 22x less radius, can poke out the bigger laser. The numbers are rough, but the idea is the general relations and scale. In all cases, note that we never get down to 1kilowatt/m^2, much less the absurd 100w/m^2. Now, I do not know if there are particularly sensitive components which would drive down relevant intensities even further, or if my estimate for say, aluminum is far too high, but given the scenarios described above, I would say hundreds of kilowatts per meter squared at the low end seems reasonable - while sunlight or torchlight vaporizing your laser does not. Also yeah, I recall Atomic Rockets followed that debate to its relative end where laser experts such as Luke Campbell weighed in and suggested that while possible, the whole focus all the way back to the laser emitter idea requires incredibly lucky shooting, as more likely one's laser beam will be hitting the relevant mirror at a very different angle than the beam going out would use, and thus would normally damage the focusing mirror and nothing more. May have recalled wrong, but it seems reasonable with my rough knowledge of optics from high school. The angles required seem very, very precise.
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Post by nerd1000 on Mar 6, 2017 23:22:49 GMT
How much power would be needed to attack the focusing mirror directly? Starting with guidelines from credible sources who have discussed the issue at length... www.projectrho.com/public_html/rocket/spacegunconvent.php#id--Laser_Cannon--OpticsThe optics of our lasers would act like binoculars in reverse. As if we looked at the sun, that would be bad. But if we looked at the sun with binoculars, that would be double extra bad. According to PRHO, it would be 50x-100x as bad. So hitting the focusing laser with another laser beam, might end up being 50-100 times boosted by the optics inside the turret. "Well, for the same reason it is bad to unshutter your laser cannon optics and point them at a hostile ship which might zap you with its laser. Your cannon's optics would funnel their beam right down into the delicate interior of your cannon. The optics would also concentrate their beam to 10x or 100x the intensity. This means that if your lasers are unshuttered and your opponents are shuttered, you have the drop on them. The instant you detect their shutters trembling you give them a zap. Their shutters will still be opening when your bolt scrags their laser."Here's a rough quantitative analysis of the situation. We have amorphous carbon to resist enemy lasers. Say it has a threshold intensity before damage of 50MW/m^2. I don't actually know if that's the number, but let us suppose so - it is representative of standard anti-laser armor aboard spaceships. We are using aluminum for our laser's output mirror. Say it has a threshold intensity before damage of 5MW/m^2 before melting/overheating - such mirrors are typically made of metal and tend to have lower threshold intensities, else they'd be used as said laser armor. From this, we have two cases: 1. Case one: The further focusing problem does not apply. Of which in this case, we may see that the intensity needed to zap an enemy laser is say, 10x less than the intensity needed to seriously damage armor or other modules. By the fact that laser intensity drops off with the square of the distance involved, this gives us the possibility of opening fire on an enemy's laser at root(10), or about 3 times longer range, than when this same laser may effectively open fire on enemy armor. Put in another way, a laser with a smaller aperture (by about 10x less surface area or 3x less aperture radius) can poke out the bigger laser just as the bigger laser gets into range to deal armor damage. 2. Case two: The further focusing problem applies. In this case, we cut the threshold intensity of the enemy laser down by the relevant factor - say 50. From 5 megawatts we get 100 kilowatts intensity needed to damage a relevant laser component. This also allows us to poke out an enemy laser from about root(500) times the range, or about 20-30 times the range that it'd take for the same laser damage to deal armor damage. Put in another way, a laser of same power but with 500x less surface area, or about 22x less radius, can poke out the bigger laser. The numbers are rough, but the idea is the general relations and scale. In all cases, note that we never get down to 1kilowatt/m^2, much less the absurd 100w/m^2. Now, I do not know if there are particularly sensitive components which would drive down relevant intensities even further, or if my estimate for say, aluminum is far too high, but given the scenarios described above, I would say hundreds of kilowatts per meter squared at the low end seems reasonable - while sunlight or torchlight vaporizing your laser does not. Also yeah, I recall Atomic Rockets followed that debate to its relative end where laser experts such as Luke Campbell weighed in and suggested that while possible, the whole focus all the way back to the laser emitter idea requires incredibly lucky shooting, as more likely one's laser beam will be hitting the relevant mirror at a very different angle than the beam going out would use, and thus would normally damage the focusing mirror and nothing more. May have recalled wrong, but it seems reasonable with my rough knowledge of optics from high school. The angles required seem very, very precise. I think the part that's in the most danger is the beam expander mirror: being at the focal point of the primary mirror, it's going to get any incoming laser beams focused onto its surface at much higher intensity than the primary itself is experiencing. It's also close enough that the small misalignment in the beam won't stop it from being hit. We could probably get ballpark figures for the intensity needed to kill a laser by comparing the area of primary and secondary.
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Post by Durandal on Mar 18, 2017 20:40:36 GMT
Late to the party, but I had a thought. What if it's the IR seeker that's being burnt out on the laser, not the optic itself? Perhaps the seeker is placed on the focusing mirror that extends over the lading cavity and this is what is being damaged, mission-killing the laser.
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Post by darthroach on Mar 18, 2017 20:45:52 GMT
Late to the party, but I had a thought. What if it's the IR seeker that's being burnt out on the laser, not the optic itself? Perhaps the seeker is placed on the focusing mirror that extends over the lading cavity and this is what is being damaged, mission-killing the laser. One would think there would be significant amounts of sensor redundancy and datalinking.
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Post by bigbombr on Mar 18, 2017 20:46:57 GMT
Late to the party, but I had a thought. What if it's the IR seeker that's being burnt out on the laser, not the optic itself? Perhaps the seeker is placed on the focusing mirror that extends over the lading cavity and this is what is being damaged, mission-killing the laser. A few W/m² should be too low for this, but works just fine for annihilating our precious doomlasers of doom. And if it really burned out sensors, than this should also be able to neutralise cannons, railguns and coulguns, as these have to be aimed carefully too.
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Post by deltav on Mar 19, 2017 5:22:20 GMT
Late to the party, but I had a thought. What if it's the IR seeker that's being burnt out on the laser, not the optic itself? Perhaps the seeker is placed on the focusing mirror that extends over the lading cavity and this is what is being damaged, mission-killing the laser. Durandal I think you are onto something. Lasers used in lightshows or special effects (not even weaponized) are known to burn out camera sensors. photofocus.com/2013/09/14/beware-lasers-can-kill-your-cameras-sensor/Plus lasers would use a different targeting system than guns would. Guns seemed to be sighted visually perhaps using ships cameras+sensors mounted separately from the weapon itself, hence the need for all the tracers. But weaponized lasers (at least in 2017) use small mini lasers beams+sensors built inline with the main laser inside the turret to target enemies, needed because laser beams are hard to track until they hit the target itself.
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Post by Durandal on Mar 19, 2017 6:15:18 GMT
Late to the party, but I had a thought. What if it's the IR seeker that's being burnt out on the laser, not the optic itself? Perhaps the seeker is placed on the focusing mirror that extends over the lading cavity and this is what is being damaged, mission-killing the laser. A few W/m² should be too low for this, but works just fine for annihilating our precious doomlasers of doom. And if it really burned out sensors, than this should also be able to neutralise cannons, railguns and coulguns, as these have to be aimed carefully too. Totally agree on a few watts being too weak to cause damage, but a few kW and up should be able to hurt something. As for destributed sensors that may be a factor, but as DeltaV said lasers may require different targeting sensors than KE or missiles. If that were true, perhaps they too would be vulnerable to counter-battery lasers...which would make sense. This would devolve combat into who has the most counter battery turrets. While possibly boring or tedious the game's objective *is* for realism. Missiles could still be guided by inertial navigation, and KE with tracers could still be guided optically. Maybe these sensors can be shuttered or or wouldn't need certain sensativity that a laser sensor would. But given the precision required with lasers they may require individually dedicated sensors. Here's how I see combat going down (assuming a reasonable damage threshold for laser optics): Two ships engage at 1Mm. ~1 MW Counterbattery lasers (CB) engage while ~100MW+ main batter lasers (MB) are shuttered. Whichever side either has the most CB turrets or is able more effectivly target enemy CB turrets wins laser superiority. The losing side must keep their MB shuttered and only fire when opportunity arises. Though KE and missile weapons could be fired, they would be vulnerable to enemy MB. The winning side can target soft targets with MB (like launchers, KE turrets, engine bells) to attempt a quick mission kill. Precision KE turrets (such as Concretedonkey's railgun) can engage as well, and ordinance can of course be launched frm the start. Both ships should be manuevering. Presuming the losing ship can still be suppressed, friendly MB can shift targets rapidly between incoming ordinance and targets of opportunity on the loser. The loser meanwhile, if able to unshutter their MB for a few seconds, may well be occupied by dozens to hundreds of inbound missiles. At about 500km, kenetics should have killed one ship or the other. The ship with the most lasers should be at an advantage, as the loser of the laser duel is vulnerable to stronger enemy lasers and enemy ordinance.
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