Find a way into the Arcology and locate the Central Processing Unit network.
- Go forward and through the open doorway in front of you.
- Head over to the right to cross the remains of the bridge.
- This will bring you to Solarium.
- Go on up the stairs and confront the Dregs, Vandals and a Servitor.
- Defeat the Fallen to clear out the room and allow Ghost to scan the area.
- Go over to the highlighted portion of the purple and blue wall.
- Break it buy shooting it or melee it.
- Go through the resulting opening to enter the Arcology itself.