Are you a defensive player
(who uses MarkI ships till mid/end game(like me)) and want to capture a heavily defended AI planet? Is there an MRLS Guard Post and (Zombie/Laser) Guardians camping under a MarkIII Force Field? MarkIII Fort protected by Force Fields? Or just a lot of AI ships refusing to die
(Tackle Drones tackling ships whose engines are blow up by Riots)?
No problem! Just build a beachhead like in the screenshot, destroy the AI Command Center, build your own CS in middle of the beachhead and build long range turrets to slowly
(but surely) destroy the remaining ships and guard posts! MarkII Basic and Laser Turrets work too now that they have radar dampening
(well I guess they did before too but now they're even better)! Don't forget to manually build the Harvesters! This saves time and ships.
Now you have captured the planet and your beachhead turrets are cleaning and defending the planet and you can use your fleet for something else!
BOOM! Problem Solved!