Here’s what I’ve got, it’s a bit vague so it needs more clarification
Settlement City Requirements
Visually impressive and abundant background scenery. Must be man-made, such as buildings.
Must be big enough to fit many small to medium ships.
Must be able to fit at least a dozen or two large ships.
Needs easy access to the landing/docking areas. Needs space for NPCs to export by offering shipping missions to players. Needs a place for importer NPCs to receive missions.