Of the four main factions in Starfield, two are associated with the Freestar Collective. However, while Ryujin Industries only looks after its own interests, the Freestar Rangers put their lives on the line to try and defend Freestar citizens.
Starfield: Deputized (Freestar Rangers) Walkthrough
Players who want to join the Freestar Rangers must start out by getting Deputized.