Those are class M Deimos parts. They are made available by this mod "Ultimate Shipyards Unlocked" at https://www.nexusmods.com/starfield/mods/4723
Only a few M parts can be mixed up with vanilla part (due to attachment points system).
I have also this entry in my StarfieldCustom.ini to allow slighlty colliding parts (i.e. you can superimpose parts on the same spot as long as they use distinct attachment points) : [Spaceship] fShipBuilderModuleOverlapTolerance=-5.0000
2 comments
"Ultimate Shipyards Unlocked" at https://www.nexusmods.com/starfield/mods/4723
Only a few M parts can be mixed up with vanilla part (due to attachment points system).
I have also this entry in my StarfieldCustom.ini to allow slighlty colliding parts (i.e. you can superimpose parts on the same spot as long as they use distinct attachment points) :
[Spaceship]fShipBuilderModuleOverlapTolerance=-5.0000