- Milky Way - the galaxy
- Clusters - an individual cluster within the galaxy
- Systems - an individual star system within a cluster
- Planets - a single planet or object within a star system
The Galaxy Map also has details of individual planets once one has been selected, including relevant statistics (temperature, gravity, orbital period etc.) and any historical points of interest relating to that world.
Since mass relays function as a network, ships must change relays repeatedly to cross to the far side of the galaxy. The Galaxy Map automatically calculates the paths necessary to reach the desired location.
Mass Effect Edit
In Mass Effect, even if a planet is too dangerous to land on, many can be surveyed to search for valuable resources and assignment-relevant items. Systems may also contain asteroids, which can be scanned by sweeping an asteroid belt with the cursor, and points of interest like derelict spacecraft. Over one hundred planets can be examined, yet only a few can be explored on foot due to most being non-terrestrial or too inhospitable.
Mass Effect 2 Edit
In Mass Effect 2, planets can be scanned for resource deposits and mined by probes. Scanning and deploying probes can also locate assignments. In addition, traveling between the various systems of a cluster requires fuel, which can be purchased at Fuel Depots. If the Normandy SR-2 expends all of its fuel, a quantity of a resource (element zero, platinum, palladium, or iridium) is consumed and the Normandy is returned to the cluster's gateway system. If the Normandy has no resources and expends all of its fuel, EDI simply engages emergency FTL thrusters to return the ship to the gateway system without any penalty.
Mass Effect 3 Edit
In Mass Effect 3, the Galaxy Map experiences significant changes: first, some star clusters now have an icon above them which indicates the clusters are currently being invaded by the Reapers. In addition, resources are now obtained by activating a scan while exploring individual star systems and subsequently investigating red 'blips' from the scan. Scans only cover a limited area around the Normandy, so it may be necessary to scan several locations in a star system to locate all available loot. Resources now include possible fuel or credit rewards, as well as certain assignment objectives and War Assets (see Mass Effect 3: Galaxy at War).
If the player scans multiple times in systems which are being invaded, they may eventually attract the attention of Reaper ships, which will chase the player around the star system. Leaving the star system or activating a mass relay is sufficient to evade the Reaper ships. Reaper ships will continue to patrol a star system in which they detected the Normandy, chasing them again if they re-enter the system, until a certain amount of time (completed missions) has passed. Note that if Reapers are currently chasing the Normandy and the player investigates a planet or other feature, time effectively stops and the Reapers won't get any closer until the player zooms out again.
Fuel is required to travel between the various systems of a cluster and if all the fuel has been expended, you will be returned to the gateway system.
- Standing close to the Galaxy Map reveals that the pop-ups on the display read PLANET 42-518P-111. This designation appeared in early footage of the Galaxy Map, referring to "a small, icy planet orbiting the STAR 42-518P." However, numerical designations are not used in-game; planets and stars are referred to by their names.
- In Mass Effect 2, sometimes when flying through a system in the Galaxy Map, the game will emit a sound indicating that the player may interact with a planet, but no planet or object is visible, nor can the player interact with it in any way. The cause of these "ghost planets" is unknown.