The problem is that these aliens will out-tech you for a looong time. They spot you at ridiculous ranges, they shoot at you from ridiculous ranges and they are much faster than any ship you can build (fighters notwithstanding). Most fleets they field will also shrug off a salvo of three (or ten or twenty) missiles without breaking a sweat, shooting them down with point-defense guns.
Thing is though that to my surprise they don't seem that much superior to me in tech. I mean I don't know if perhaps their civilian tech is far ahead but navy wise they seem to be only slightly ahead and that's only in terms of their weaponry (they are actually slower than most my ships), they don't shoot at me from ridiculous ranges (at least the sensor ships I've sent them so far) but instead opt in to get close and blast me with gauss guns (I've seen missiles from them but in general they only tickled), and those are quite definitely more advanced than mine since I don't HAVE gauss cannons and I'm instead working on the laser tech.
I don't know about their point defense but it most probably is capable, since they're focused on the gun tech. That's one of the reasons I'm intending to rely on the element of surprise, attack from stealth possibly beyond their sensor range. Additionally in a perfect world where I have all the tech Minervas would be filled with size 1 missiles that would have the highest chance of hitting and would probably get there fastest.
And if it turns out that I was being harassed by their ships from 20 years ago and now they have better stuff than I'll just lock myself up behind a wall of mines and sensors and hope for the best while the tech gets to where it needs to be.
That means your fleet must be able to:
1) survive anything they can throw at you, and that implies shooting down thirty or forty missiles every 10 seconds. Numbers vary, but if your fleet isn't comfortable with that number of missiles coming its way at 30k km/s, you'd better wait a few more years, and
2) fire enough missiles per 5-sec turn to overcome massive PD or anti-missile-missile fire itself *and* do enough damage to kill what's behind that wall of fire.
I'm working on both these, Again the ship I made is merely a blueprint for a more advanced unit that will basically fill the same role but with "slightly" more punch. As for avoiding the 30k km/s the missiles since my laser and turret tech is kind of in the barn right now I'll probably have to rely on AMM's, and that might not be so bad since the fleet is supposed to be the one surprising people with missiles, not the other way around.
2b) Optionally you can hope that particular fleet relies mostly on AMMs instead of guns for defense. Then you can try to exhaust their missile magazines.
I would probably loose at that but we'll see.
Fighters might do the trick, but you *need* reduced-size launchers (that branch of the tech tree finally leads to box launchers). Four size-6 launchers on a 300-ton fighter and three 8000-ton carriers full of these should give you about 150 missiles. Don't forget to click "synchronize fire" before you launch. If your fighters can get close enough before getting spotted, you can enjoy the fireworks. If not, all you've risked is 70 or 80 fighters, hopefully flown by volunteers who had no navy life insurance.
Yeah I did get box launchers the last time and seeing them on fighters was fantastic. I was planning to make a carrier in the fleet anyway, but mostly as a prevention measure for when the bad guys are actually trying to intercept us.
EDIT:
OK I got some tech and made some changes to the ship.
Royal class Missile Frigate 5 000 tons 397 Crew 974 BP TCS 100 TH 72 EM 300
3000 km/s Armour 4-26 Shields 10-300 Sensors 8/1/0/0 Damage Control Rating 2 PPV 40
Maint Life 2.79 Years MSP 244 AFR 100% IFR 1.4% 1YR 46 5YR 683 Max Repair 160 MSP
Magazine 160
Military Ion MK.II (5) Power 60 Fuel Use 70% Signature 14.4 Armour 0 Exp 5%
Fuel Capacity 200 000 Litres Range 102.9 billion km (396 days at full power)
Gamma R300/18 Shields (5) Total Fuel Cost 90 Litres per day
Minerva Launcher MK.2 (8) Missile Size 20 Rate of Fire 20000
Missile Fire Control FC217-R50 (70%) (1) Range 217.2m km Resolution 50
Minerva MK.2 (8) Speed: 12 000 km/s End: 416.6m Range: 300.1m km WH: 0 Size: 20 TH: 20 / 12 / 6
Active Search Sensor MR10-R65 (70%) (1) GPS 1040 Range 10.3m km Resolution 65
Thermal Sensor TH1-8 (70%) (1) Sensitivity 8 Detect Sig Strength 1000: 8m km
Missile to hit chances are vs targets moving at 3000 km/s, 5000 km/s and 10,000 km/s
This design is classed as a Military Vessel for maintenance purposes
Before I proceed I have a question. Initially I had a magazine able to fit 8 more Minervas in the ship but I noticed the launchers also provide magazine capacity. Is that capacity for the second salvo or does it count as the missiles actually IN the launchers from the start?
Anyway, while this is still not entirely finished I'm rather happy (gotta get new engines and missile fire control on it) with how it's turning out. So the main change is I got the box launcher tech, and right before it I got the 0.25 size tech and decided to use it instead. This way with the lvl 3 reload tech for launchers I can actually fire a second salvo before the original drone gets to it's target (reload time is about 5 and a half hours and the drone can go for about 7 assuming target at max range).
Additionally because of the now smaller size I decided to have 8 of the damn things on the ship meaning that one simultaneous salvo shoots out 8 Minerva drones carrying 6 Archangel Missiles each.
Each archangel does 4 damage (enough to damage 2 layers of armor if the wiki is correct) so assuming all of them hit that's 8x6x4=192 damage. A reasonable increase from the original 1x3x4=12 damage.
All I'm going to do now is get all the tech on it up to date and start producing these things. Originally I planned to have only a few of them in a fleet but I think for proper offensive operations I might actually mass produce them to do the bulk of the damage. (They would ofc have to be covered because they're useless if ambushed).
I don't have many plans in terms of upgrading them. Eventually I might put some cloaking on them and reduce the thermal emissions so they can serve as proper hidden hit and run ships, not to mention upgrading the tech in general.
EDIT2:
Allright I'm not sure about the magazine thing so I opted out to just add one anyway. The final build is something like that:
The ship
Royal MK.2 class Missile Frigate 5 500 tons 415 Crew 1245.8 BP TCS 110 TH 64 EM 300
3636 km/s Armour 3-27 Shields 10-300 Sensors 33/11/0/0 Damage Control Rating 2 PPV 40
Maint Life 2.19 Years MSP 283 AFR 121% IFR 1.7% 1YR 79 5YR 1190 Max Repair 175 MSP
Magazine 321
Military Magneto-Plasma (5) Power 80 Fuel Use 60% Signature 12.8 Armour 0 Exp 5%
Fuel Capacity 200 000 Litres Range 109.1 billion km (347 days at full power)
Gamma R300/18 Shields (5) Total Fuel Cost 90 Litres per day
Minerva Launcher MK.2 (8) Missile Size 20 Rate of Fire 20000
Missile Fire Control FC326-R50 (70%) (1) Range 326.7m km Resolution 50
Minerva MIRV MK.3 (16) Speed: 16 000 km/s End: 312.5m Range: 320m km WH: 0 Size: 20 TH: 26 / 16 / 8
Active Search Sensor MR10-R65 (70%) (1) GPS 1040 Range 10.3m km Resolution 65
Thermal Sensor TH3-33 (70%) (1) Sensitivity 33 Detect Sig Strength 1000: 33m km
EM Detection Sensor EM1-11 (70%) (1) Sensitivity 11 Detect Sig Strength 1000: 11m km
Missile to hit chances are vs targets moving at 3000 km/s, 5000 km/s and 10,000 km/s
This design is classed as a Military Vessel for maintenance purposes
The drone
Missile Size: 20 MSP (1 HS) Warhead: 0 Armour: 1 Manoeuvre Rating: 5
Speed: 16000 km/s Endurance: 312 minutes Range: 300.0m km
Cost Per Missile: 18.9085
Second Stage: Archangel MK.2 x6
Second Stage Separation Range: 20 000 000 km
Overall Endurance: 5 hours Overall Range: 330.0m km
Chance to Hit: 1k km/s 80% 3k km/s 25% 5k km/s 16% 10k km/s 8%
Materials Required: 6.25x Tritanium 12.1435x Gallicite Fuel x5000
The missiles
Missile Size: 2 MSP (0.1 HS) Warhead: 4 Armour: 0 Manoeuvre Rating: 17
Speed: 32000 km/s Endurance: 16 minutes Range: 30.0m km
Cost Per Missile: 2.2417
Chance to Hit: 1k km/s 544% 3k km/s 170% 5k km/s 108.8% 10k km/s 54.4%
Materials Required: 1x Tritanium 1.1767x Gallicite Fuel x500
Development Cost for Project: 224RP
That's about it for this ship. Now what I mainly have to do is design a sensor boat that's powerful enough to detect ships at the range of 200-300m km which is the operating range I've decided upon. Than I'll make about 3 of these + a sensor + a jump ship get them to the nearest system where the aliens are at and raid them to see if it was all worth anything.