For the most part, the way the Galactic War metagame works in Arrowhead Game Studios' co-op shooter Helldivers 2 is pretty simple. Players both liberate enemy planets and defend Super Earth-controlled ones by completing series of missions called Planetary Operations, with each finished op contributing a small amount to the community's overall war effort — AKA, the blue bars that represent liberation percentage. If they can add to a world's liberation percentage faster than the Terminid bugs or Automaton bots drain it (reductions happen at hourly intervals), they'll eventually free/protect the world successfully.
Something Helldivers 2 doesn't tell you, though, is that there's actually another mechanic at work here. And without understanding it and factoring it into its strategies properly, the wider community may find itself wondering why some Major Order planets are unavailable, or could be stuck watching in shock as worlds it's actively fighting for suddenly get cut off.
The mechanic in question is the "supply lines" system, and while there's no information about it in-game, players have figured out how it works and how to track it, too. Below, you'll find a quick guide that goes over all of that information, including a full explanation on Helldivers 2 supply lines and how to keep tabs on them.
How Helldivers 2 supply lines work
Put simply, supply lines in Helldivers 2 are what determine if a specific planet is available to fight for or not. If a world is directly next to one controlled by Super Earth forces, Helldivers can attempt to liberate it; if it's not, it'll be grayed out. Note that if there's a Major Order telling us to free a planet, but it's unavailable to play on, it's not due to a bug or a glitch — this is the cause. I've seen a lot of confusion about this since the Major Order to liberate Zagon Prime and Fori Prime went live, which is actually what made me want to write up this explainer in the first place.
To successfully open a front on worlds that are behind enemy lines, players will need to take control of a planet near them so there's a supply line connected to it. For example, before the community can try liberating Fori Prime, it'll first have to kick the Terminid bugs off of Estanu or Crimsica.
It's important to keep in mind that planets in a supply line can be invaded by the Terminids or Automatons, and if Helldivers fail to ward off their assault, access to every world ahead of that one in the chain will be instantly cut off. When this happens, the liberation percentages of those worlds will slowly drain until players either regain control of the "staging area" planet or it reaches zero, wiping out all the community's progress; a few weeks back, this actually occurred on Mantes (documented in this post), stopping campaigns to take Draupnir and Malevelon Creek in their tracks.
Thus, it's extremely important that players pay attention to where Helldivers 2's Game Master has the bugs and bots attack (any world next to one under enemy control can be invaded) and defends planets keeping crucial supply lines open. If they fall during a pivotal moment during a Major Order, the consequences could be disastrous and guarantee defeat in that campaign.
Helldivers 2 supply lines map
Due to the importance of supply lines, having a clear understanding of how each planet connects to the ones around it is extremely valuable. Luckily, u/shalzuth built an amazing Helldivers 2 Galactic War map called Helldivers.io, and in addition to showing live liberation progress updates, it also has a toggle for displaying supply lines.
The toggle can be found in the map's top-right menu, and when checked, the connections between every planet on the galaxy map will be shown with yellow arrows. These make it easy to see which worlds are keeping specific battlegrounds open and which ones players need to free to reach important objective planets.
The current Major Order is the first one to majorly involve the supply lines mechanic, but undoubtedly, it won't be the last. In fact, I only expect supply lines to become more important as Helldivers 2's Galactic War metagame evolves, so make sure you keep them in mind and make good use of this tool while you play.
Helldivers 2 is available now for $39.99 on both PS5 and PC, and so far, it's one of the best PC games of the year. Notably, the game also supports cross-platform play between PS5 and PC.