Each Techeun found, each clearing of the Ley Lines brings Mara Sov's plan closer to fruition. Continue collecting Parallax Trajectory, conducting Astral Alignments, and charting the Ley Lines of the Shattered Realm. Eventually, Savathûn's worm will be exorcised and the real Osiris will be returned.
The Ley Lines are degrading, polluted with Taken corruption and Hive spellcraft. This causes them to mirror aspects of the material world. Primal cosmic forces govern the Ley Lines. Conditions must be perfect to open a pathway for the next rescue mission.