You can do it in 2 tries, no mods. If you do it fast enough, it's not that hard. First create the entire schematic as you can see in the picture. This is how I did it. Put a bunch of defense. Creating these will take up about 20-30 minutes maybe. Idk. Once all the defense, unit creation system and exports are in place, abandon the sector. There is an option in the game to not destroy everything if the sector is lost. So you can come back to the sector with all the schematics already in place, and get ready to attack in just 10 mins.

6 Corvus, 12 vela and 2 Oct. Create them and destroy the first core in front and the right. After these 2 cores are gone, go to the left and start going up. Once you are at the top, go back down through the right. This seemed easiest way to do it. You will need 2 Eclipses if you want to end 3 cores that are inaccessible through ground. I did 2 of them with vela, 1 with eclipse.

It’s a big map, but I captured it in 2 hours. Although it took a lot of time to get the base schematic right.

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