I had problems with the autosave that triggeers when going to FTL. Manually saving didn't work anymore either. That, and things disappearing from letters to ship parts where a prelude to memory issues. This was because I was running multiple weapon mods and appearantly they eat a lot of memory because of the png files involved. The solution? Disable some mods and see if the memory issues subside. I also downscaled from "Huge Galaxy" to "Normal Galaxy." I don't know if that fixed any memory related stuff, but I haven't encountered it as such anymore.
Note that memory problems often don't start immediatly. Code often produce "memory leaks" meaning they don't release all the memory when done, and this will build up over time, and this causes more and more issues untill the game crashes.
Short story: Disable a mod, see what happens.
