Which is better for point defense?

[Zeebie (OP)]

I find myself 37 years into a game and finally needing to shoot down missiles (just been fighting raiders so far).  Through some randomness, I find myself with two readily available options for point defense:

1. A twin 10cm C3 Infrared laser turret, 30000km range, 5sec interval, 12000 km/s tracking speed, taking up 380 tons of space

2. A 10cm Railgun V20/C4, 4 shots/5 sec, taking up 150 tons

Both would be using a R96-TS12000 fire control, and mounted on a ship with 5300 speed (I could nudge it up to 6000 if needed). Looks like enemy anti-ship missiles go 14000 km/s.  I've done no gauss cannon research.

Thoughts on which will be more effective? Does the increased number of shots on the railgun make up for the lack of turret tracking speed?

[Demonius]

10 cm Rail would be the "meta" answer.

[nuclearslurpee]

A short summary of point defense options:

• Anti-Missile Missiles (AMMs): Typically these will end up costing you a lot more over time since once you shoot a missile it is gone, while beam guns live forever. However, the volume of fire possible with AMMs can be necessary to defeat very large salvos if you have a good sensor coverage. AMMs are also a useful secondary weapon, especially against NPRs that use AMM spam to distract their AMMs while you close in.
• Gauss cannons are the most effective beam PD but have a high upfront cost in research to be effective and are only useful as defensive weapons, very specialized.
• 10cm railguns are reasonably effective due to sheer volume of fire and require no research (in a TN start), but they don't get any better as PD weapons over time while Gauss cannons do. Okay as secondary weapons due to having the highest volume of fire per ton in the game.
• Turreted lasers or mesons are the worst beam PD you can get, in most cases they cannot even beat 10cm railguns unless you have done something very weird with your research programme. In order to beat a 10cm railgun you need a tracking speed more than 4x higher than your ship's speed, and the turret is heavier to boot so really more like 5x or 6x depending on your BFCs. The advantage of using these is that they will be stronger as secondary weapons than the above options, which means that if you go up against beam-only opponents you will still be fairly effective.

In your case I would probably use the 10cm railguns, as infrared lasers are not really worth it as secondary weapons. If you invested a lot into your laser techs then having the useful secondary weapon could be helpful.

[smoelf]

There is a rule of thumb for point defence, which is that you look at the total amount of "tracking speed" possible/required for each salvo, since there is (AFAIK) a linear relation between tracking speed and accuracy. Against a missile flying at 20.000 km/s, you could either have a single laser turret with tracking speed 20.000 km/t (100 % accuracy) or a twin turret with tracking speed 10.000 km/s (50% each for two shots) or a quad turret of 5.000 km/s (25% accuracy for each shots). Of course there are other factors and specific cases, but it is a general rule of thumb. This means we can calculate the PD capability per ton for your example:

1) 2 shots * 12000 km/s / 380 tons = 63 km/s/ton

2) 4 shots * 5300 km/s / 150 tons = 141 km/s/ton

So as Demonius suggests the railguns are actually more than twice as good for PD than your lasers, especially because you can fit two of them in the same space, so you get 8 shots at lower accuracy.

[Jorgen_CAB]

Unfortunately it is not that easy... it all depends. If you have to put more engines into the ship to get a good PD effect of the railguns then the laser might actually be the better choice as they normally are either cheaper or have much better range, depending on tech levels used

A turreted weapon is decoupled from the ships speed, this matter allot. This can make the laser both more effective and cheaper option by far.

Beam combat potential can also matter allot too.

Then you have counter measures... a railgun that shoots four shots and hits on 20% or a twin laser cannon that hits on 50%, then the laser are susceptible to countermeasures as it is a direct deduction of the to hit rate. If the opponent have say 20% better ECM than your ECCM the railgun hit on 0% and the lasers on 30%... which is a considerable difference. If you happen to be up against a more technologically superior enemy the railgun might prove to be just pointless while the laser actually would have some effect.

But generally railguns are the best early PD that you have. Lasers are better for dual purposes and in some special circumstances better than railguns.

[nuclearslurpee]

Unfortunately it is not that easy... it all depends. If you have to put more engines into the ship to get a good PD effect of the railguns then the laser might actually be the better choice as they normally are either cheaper or have much better range, depending on tech levels used

A turreted weapon is decoupled from the ships speed, this matter allot. This can make the laser both more effective and cheaper option by far.

I don't think this is usually true in practice. In order for a single 10cm laser in a turret to be as effective on a per-weapon basis as a 10cm railgun on a ship hull, the racial tracking speed needs to be 4x the ship speed. Add in the tonnage overhead, which is something like +40% so in this case +60 tons, and you need to be more like >5x the ship speed with the turret to break even on a tonnage basis. Unless you are using extremely slow ships (i.e. commercial engines, basically -- for most players I think very much an edge case) this isn't really feasible unless you hugely rush BFC techs, and most players I think rush the propulsion techs, not the BFC techs. Which brings up another factor, the 4x tracking speed for a laser turret BFC is an additional extra cost against the railgun PD.

Beam combat potential can also matter allot too.

This has to be the primary reason to prefer laser turrets IMO. It is a good one though.

Then you have counter measures... a railgun that shoots four shots and hits on 20% or a twin laser cannon that hits on 50%, then the laser are susceptible to countermeasures as it is a direct deduction of the to hit rate. If the opponent have say 20% better ECM than your ECCM the railgun hit on 0% and the lasers on 30%... which is a considerable difference. If you happen to be up against a more technologically superior enemy the railgun might prove to be just pointless while the laser actually would have some effect.

This is a true point. If you are using railguns for PD to save on tech spending, you should be investing to keep up in ECCM tech, but if this isn't always feasible then lasers (or Gauss) become relatively stronger by comparison.

[Jorgen_CAB]

I don't think this is usually true in practice. In order for a single 10cm laser in a turret to be as effective on a per-weapon basis as a 10cm railgun on a ship hull, the racial tracking speed needs to be 4x the ship speed. Add in the tonnage overhead, which is something like +40% so in this case +60 tons, and you need to be more like >5x the ship speed with the turret to break even on a tonnage basis. Unless you are using extremely slow ships (i.e. commercial engines, basically -- for most players I think very much an edge case) this isn't really feasible unless you hugely rush BFC techs, and most players I think rush the propulsion techs, not the BFC techs. Which brings up another factor, the 4x tracking speed for a laser turret BFC is an additional extra cost against the railgun PD.

When I meant more effective I did not just mean in a PD capacity directly, but as a complete weapons system.

I would normally think that your BFC is about three times faster than you "normal" ships, roughly.... but that obviously depends allot on your doctrine as well as technology. In the new version of the game if you run with the new limitation to technology you might actually have better sensor technology than engine technology, at least it is a bit more likely than before.

If you start to compensate ship speed for accuracy your PD railguns will come at a very high price... both in tons and cost of the ship. At least from a PD perspective. But if the ships is used for other purposes too it can still be worth it, then the biproduct are just an increased PD efficiency too.

But anyhow I do agree that railguns are generally better PD weapons, at least early on. Lasers do work good as hybrid weapons when and if you have good laser and sensor technologies. You also can use reduced size lasers too... if you are more concerned about large volleys rather than smaller volleys fired in short bursts.

But if I go Laser focused PD I probably go with 12cm or even 15cm PD lasers as they are better hybrid weapon systems than the 10cm ones and simply add some 10cm railguns as close in PD weapons. The railguns require so little research that you can have both.

But the ECM effect on railguns can be very extreme in some cases, that is an important achilleas heel of the railgun. Fortunately the AI don't seem to use ECM on their missiles... but factions in my game does so I need to consider it.

In the new version of the game you also can lack Missile/Kinetic scientists or have bad ones, that leave you with using them either for missiles, railguns or gauss. This can make 10cm railguns good as a "poor" mans close in weapon system rather than use Gauss weapons. if you have good energy scientists you might go down the laser path and might as well use laser turrets for PD and ship to ship combat.

You need 2000RP to get basic Railguns but you only need about 6500RP to get decently good Gauss which are way less susceptible to ECM than railguns. The Gauss just escalate in efficiency over railguns from there. So, heading in that direction and use lasers turrets until then can be a decent option too... that is skip the railgun technology and save the 2000RP. If you play with slow technology progression like I do, this actually matter... trust me it does.

My general advice is... if you don't intend to use gauss weapons I would always find the 2000RP to at least get 10cm railguns. But they might not always be needed as you might be more interested in the hybrid effect of the laser.

[Jorgen_CAB]

Another thing to note is that hybrid laser systems can also potentially hit incoming missiles more than once as well, depends on how you are able to use them and technology differences.

Larger long range missiles seem to be slower than what they used to be, especially if they also carry ECM and ECCM in them. I don't build PD to defend against AMM missiles, I have my own missiles to saturate enemy AMM with and supress them. This means that rapid firing PD is generally not very important.

[nuclearslurpee]

Larger long range missiles seem to be slower than what they used to be, especially if they also carry ECM and ECCM in them. I don't build PD to defend against AMM missiles, I have my own missiles to saturate enemy AMM with and supress them. This means that rapid firing PD is generally not very important.

Worth noting that if you do have sufficient PD to defeat AMM spam, it is substantially cheaper than using missiles as railgun ammo or laser power is free for point defense purposes, once the weapon is built. Particularly if gallicite is short or in high demand, which it usually is.

The downside of course is that you can easily overbuild PD ships to accomplish this which reduces how many resources you can put into offensive firepower.

That being said, I've yet to find a situation where area defense PD is the most effective solution against enemy missiles by any sensible metrics, unless you have such a tech advantage that it makes no difference how you solve your PD needs. In theory an area defense laser is a decent hybrid weapon but I think to deploy it effectively you need a super-specialized ship, to the point where it is better overall to just use regular final fire PD and main weapons instead of spending the resources on such a narrow specialist ship.

[Droll]

Larger long range missiles seem to be slower than what they used to be, especially if they also carry ECM and ECCM in them. I don't build PD to defend against AMM missiles, I have my own missiles to saturate enemy AMM with and supress them. This means that rapid firing PD is generally not very important.

Worth noting that if you do have sufficient PD to defeat AMM spam, it is substantially cheaper than using missiles as railgun ammo or laser power is free for point defense purposes, once the weapon is built. Particularly if gallicite is short or in high demand, which it usually is.

The downside of course is that you can easily overbuild PD ships to accomplish this which reduces how many resources you can put into offensive firepower.

That being said, I've yet to find a situation where area defense PD is the most effective solution against enemy missiles by any sensible metrics, unless you have such a tech advantage that it makes no difference how you solve your PD needs. In theory an area defense laser is a decent hybrid weapon but I think to deploy it effectively you need a super-specialized ship, to the point where it is better overall to just use regular final fire PD and main weapons instead of spending the resources on such a narrow specialist ship.

The problem with beam area PD is the physical limitations that aurora has on beam weapon range. At 1.4m km you just don't have the time to get a second shot in, which is really the only incentive for area PD given how fleets work.

One of the things I do wish is for missiles to not always rely on active locks and be able to lock on thermal/EM signatures and guide themselves to a target that way. This would perhaps allow the player to "decoy" the missiles using ships that are flying formations with a parent fleet some distance away and draw fire away from sensitive targets. Would give another use in combat for formation orders beyond just spreading out sensor scouts.

[nuclearslurpee]

The problem with beam area PD is the physical limitations that aurora has on beam weapon range. At 1.4m km you just don't have the time to get a second shot in, which is really the only incentive for area PD given how fleets work.

One of the things I do wish is for missiles to not always rely on active locks and be able to lock on thermal/EM signatures and guide themselves to a target that way. This would perhaps allow the player to "decoy" the missiles using ships that are flying formations with a parent fleet some distance away and draw fire away from sensitive targets. Would give another use in combat for formation orders beyond just spreading out sensor scouts.

Usually the best way to get area PD to work, possibly even the only efficient way in many cases, is to use smaller ships under the enemy sensor resolution and deploy them ~1.4m km (scaled for tech level, of course) from the main fleet. Then they can take a shot as the missiles come in and another shot as the missiles pass through the advanced formation.

The trouble being that this is rarely going to be more effective than just mounting two smaller weapons in final fire mode in the main fleet ball, if ever - and of course those detached PD ships will be vulnerable if the enemy is able to target them while they are outside of the main fleet final fire umbrella. Maybe an interesting tactical situation would be deploying area defense ships even further forward to intercept slow MIRV missiles but I think even in multiple player faction games this is an uncommon edge case, as MIRVS simply don't do much that box launchers or fighters, depending on use case, don't do better.

[Jorgen_CAB]

The problem with beam area PD is the physical limitations that aurora has on beam weapon range. At 1.4m km you just don't have the time to get a second shot in, which is really the only incentive for area PD given how fleets work.

Not sure why you think that is, their range is not good enough... this happen all the time in my games... long range missiles are quite slow given same technologies so that happens all the time. You can also use the range as the radius as escorts rush forward to protect a group from a missile attack.

I basically have never played a game thus far where I ever managed to even get to 1.4 million beam range fire-controls, so that is pretty much of no concern for me at all.

The point is that you use the lasers in this case as hybrid weapons... they work very well in regular beam combat too. It is about having one system do two things at once... it does not have to be the best PD of all time just good enough.

In my opinion building your fleet to the point you can just wade through AMM spam (as a design choice) seem very inefficient and you use allot of resources to accomplish this. When I talk about missiles to accomplish it, these systems are not primarily for this purpose but can be used for it quite effectively in conjunction to whatever PD you also have. What I mean is that you don't need a dedicated system to deal with AMM spam, you just use the resources you already have to achieve the same results.

[Jorgen_CAB]

That being said, I've yet to find a situation where area defense PD is the most effective solution against enemy missiles by any sensible metrics, unless you have such a tech advantage that it makes no difference how you solve your PD needs. In theory an area defense laser is a decent hybrid weapon but I think to deploy it effectively you need a super-specialized ship, to the point where it is better overall to just use regular final fire PD and main weapons instead of spending the resources on such a narrow specialist ship.

I don't understand this mentality at all... it is just a beam ship with a slightly different design philosophy. It works very well in both general escort and direct beam combat. To be honest it probably is better than most beam ships as it is better at PD (unless a railgun beam ship that is) which you probably will use more than direct beam combat anyway. So... it is not a super specialized warship... it is a dual purpose ship. It is more of a defensive beam ship than an offensive one as it does not have to rely on speed as much as other beam ships, just a different design philosophy.

[Jorgen_CAB]

Usually the best way to get area PD to work, possibly even the only efficient way in many cases, is to use smaller ships under the enemy sensor resolution and deploy them ~1.4m km (scaled for tech level, of course) from the main fleet. Then they can take a shot as the missiles come in and another shot as the missiles pass through the advanced formation.

The trouble being that this is rarely going to be more effective than just mounting two smaller weapons in final fire mode in the main fleet ball, if ever - and of course those detached PD ships will be vulnerable if the enemy is able to target them while they are outside of the main fleet final fire umbrella. Maybe an interesting tactical situation would be deploying area defense ships even further forward to intercept slow MIRV missiles but I think even in multiple player faction games this is an uncommon edge case, as MIRVS simply don't do much that box launchers or fighters, depending on use case, don't do better.

The thing is, that this is just the way you can split large salvoes into smaller chunks... as long as you have good sensor coverage to detect incoming missiles. Done through smaller scouts. This is also why you can deploy escorts further forward to, to entice the opponent to split their fire. One single ball of ships are very vulnerable to large box launched salvoes and or fighter attacks.

I have experimented allot with this in my campaigns and it is allot harder to target these escorts, even if they are large, than what you think... you usually have time to do significant manoeuvring of the escort, split the main force etc. Unless the opponent don't target all their missiles against one ship (which happens sometimes on a high value target) there are good strategies for dealing with large salvoes this way.

I do have some restrictions on box launchers in my games though on normal ships... so I can't spam huge amount of them in larger ships. But large salvoes are still the primary way to deal with ships using missiles... small missile salvoes are just too inefficient.

In one game I also had a few small beam FAC that was used for protection of fighter squadrons but could also be deployed in forward position to act as area PD. These FAC had either 12cm or 15cm lasers. As they were really fast... almost as fast as my fire-controls they could fire ALLOT on incoming missiles as they would move towards the fleet  (chasing the missiles) and keep shooting every five seconds on every missile. As their speed was so high the missiles where in their envelope for a very long time. This was not the fleets main PD effort, but just one additional job for these FAC. Escort PD do the same thing... they start chasing the missiles thus keeping them in their envelope for longer time.