During its expansion across the relay network, the Systems Alliance created a number of Outposts to serve as its centers of power within the new territories. These Outposts, of which there was usually only one per world or even colonized system, became centers of colonization, both due to being placed in areas ripe for it, and as protection against dangers both natural and man-made in the form of wildlife, natural disasters, and piracy.

In 2151, the Alliance standardized its Outposts, creating prefabricated structures to fulfill different roles and prepanning the phases of construction.

The first phase of an Outpost's construction is the exploration phase. During this time the only structures deployed are the Outpost Core, Fighter Squadron Hanger and Resupply Depots. Upon an Alliance exploration cruiser discovering a system believed to be worth colonizing, or that is strategically placed close to several unexplored systems, an Alliance transport will be deployed with the prefabricated Outpost Core and Depot. The Outpost Core is a large structure with a fusion reactor, command facilities, quarters for over 200 personnel, and all the equipment needed for the Outpost's operation. The Depot, which is deployed a decent distance from the Core to allow for expansion, holds all the supplies a Alliance military or exploration ship could need, providing a close resupply point for exploration cruisers and Alliance patrols. The Depot also has landing facilities for up to frigate size craft and hanger facilities for a UT-31 Atlas shuttle to facilitate the resupply of larger vessels. The Fighter Squadron Hangar has the facilities to support a full Independent Fighter Squadron to patrol and defend the planet. At this phase the Outpost is commanded by a Commander who holds the title of Outpost Commander.

The next phase comes when settlement planning for the system has begun. This phase sees the deployment of facilities for a number of corvettes. Additionally, barracks facilities for a Battalion of Marines will be constructed, though only a Company will be deployed in the beginning. Administrative and government facilities will also be added to allow for the enforcement of Alliance law and governance over planetary settlements, to the limited extent the Alliance does have its own laws and government. At this phase, the Outpost Commander is replaced by a Governor-General who governs the entire planet and all colonies on it in the name of the Alliance. Governor-General is more of a civilian position than military, but the holder of the office has military authority and Governor-Generals are often pulled from the ranks of the Alliance armed forces.

The final phase for an Outpost comes when the colony has greatly expanded, with hundreds of thousands of people dotting the planet in many settlements and colonies. At this point additional Outposts will be created near most large settlements, each with their own Outpost Commander who operate under the command of the Governor General, spreading the Alliance's reach as the population grows. At this point the Outpost turns into an Outpost Complex spread across the entire planet, consisting of the individual Outposts alongside Marine Bases and Fighter Wing Hangers.

Gateway Stations are a form of Outpost deployed around Mass Relays which are designed to support Alliance patrols in the area and deal with traffic through the Relay. They carry a contingent of Marines and Alliance customs officials alongside an Independent Fighter Squadron and a number of UT-29 shuttles. Some also play host to corvettes.

In 2155, the way the Alliance constructed Outposts changed dramatically with the introduction of self constructing Outposts. These Outposts starts out as small packages deployed by Alliance exploration cruisers, held externally on older cruisers, and fabricated on boars in the case of newer Francis Drake class ships. Once deployed on an asteroid, the package will unpack to unveil a modest sized industrial fabricator and all the equipment needed to allow its operation and for construction. The new Outpost continues to construct itself on its own, using materials gained from its parent asteroid and some rarer materials dropped off by the cruiser such as eezo to get started. While some traditional Outposts are still required as immediate resupply bases due to the long building time of the self constructing Outposts, they allow for the Alliance to spread its practical authority to countless mostly uninhabited systems that before it only controlled on paper, Alliance authority only truly extending within the mass accelerator range of the rare patrol ship.

There is currently some significant debate in relation to the automated Outposts, with some factions in Alliance commanders wishing for the combat abilities of these Outposts to extend beyond the handful of lasers and secondary mass accelerators existing on the current iteration, adding patrol fighters and even fully automated corvettes. This faction has been resisted by another that has concerns over the effectiveness of the VI controlling such assets without human assistance, and the positioning of so much military equipment (and the fabrication data to construct it) with limited protection and possibility for help. This concern is confounded by the already common attacks on the automated Outposts, their mining operations not stopping once all currently planned modules are completed, leading to them holding a large surplus of raw materials sitting preprocessed. While the Alliance is itself debating on what to do with the materials, with several interest groups trying to stop the Alliance from using it itself or selling it, many pirate groups have seen the opportunity to gain large amounts of materials to sell and use in their own fabricators, striking at the automated Outposts. The current stopgap measure in use is for Outposts to construct significantly more defenses, including independent defense platforms, dealing with both the pirates and much of the surplus materials, while further protecting Alliance systems, at least those assets nearby the Outposts. As the Alliance continues to be stretched the armament faction gains power within the Alliance, increasing necessity causing more of the Alliance's leadership to come to their side, though still not enough for more than a few tests of its viability to be done.

The Alliance operates over a hundred standard Outposts, of which nearly half are at phase 2 or beyond. The majority of systems have only a single Outpost, if they have one at all, but more populous systems often have more than one. The self constructing Outposts continue to increase in number exponentially, with most existing on the frontiers of Alliance Space, though that is quickly changing as unpopulated systems in the more settled areas are deployed in order to monitor pirate activities.