Are there any plans to tone down the alien ships drone? if you don't have the means to fight it, you may as well start over, it's a complete wipe (to use MMO terminology). Fighting head on is the only coarse of action (because mortars are completely useless), and even if you do manage to kill it, the rest of your crew (usually like 1-2 people that) are basically dead and will die or go nuts within the day.
I am looking for a way to wait it out if you are soooooo ridiculously outgunned on their turf. Allow ways for your group to hold out and fight the aliens when in your base where you have defenses. I think it's just absolutely weak sauce game play to have only 1 way to defeat them.
Idk, maybe I am just unaware of a good way to combat that scenario.
psyshic deaf trait?
If i've a weak/lacking colony, normally i take one "expendible" out to attack the ship and then run to my defences once the mechs appear. While the mechs chase the "expendible" i'll send a melee strong type to run around back and take out the ship part quickly.
Also using a sniper to attack long range and a pistol guy to move back a forth between cover can take time but, saves your guys from taking too many hits.
I usually set up turrets and walls for cover before attacking. You have 5 days before the psychic drone increases, use that time to build near it and prepare for your assault, and maybe the 5 days after that if you can handle medium psychic drone and need the extra time. If you have just one or a few colonists (too smart or depressive, or under worse circumstances, any morale-problem trait) that are going to mental break, you can stick them in a cryptosleep casket.
Also, if the crashed ship part gets to low enough health (somewhere around 500, I think) the mechanoids will stop defending and attack the colony, letting you use whatever defenses or killbox you have there. If you build turrets right up against the ship part, not only will the eventual explosions damage it, some of the mechanoids' missed shots will hit the ship part too (especially helpful with minigun and HCB centipedes) and you can get it down to that point somewhat easily.