Invasion

Invasion is a mission type that allows players to team up together with the Corpus or the Grineer to work against the opposing factions, as a faction invades a specific mission node. It was first introduced in The Gradivus Dilemma and officially added to the game in Update 11.3. The Infested also are able to invade, although players cannot side with them.

Mechanics
Invasion Missions are essentially a modified version of Exterminate where players are ordered to clear out the level of an enemy faction, depending on who the player chooses to side with. During the mission the player is aided by the faction they sided with (i.e. siding with the Grineer will give you Elite Lancers and Heavy Gunners, among others) as they attack the enemy. Any ongoing invasions are listed in the menu UI, just below the Alert section. Both sides offer payment for supporting them in contested locations. Selecting a conflict location presented a choice of sides and their respective battle pay (ranging from large Credit sums, to rare Blueprints and Resources). You will need to commit to a single side to earn battle pay by completing 5 missions, with switching sides eroding your rating with the opposition and denying players either reward.

The attacking faction is represented on the left, with a percent of capture. The faction being attacked is represented on the right. Once it reaches 100% for the attacking faction, that faction will now control the level, replacing the enemies of that level with their type. Once it reaches 0% however, the attacking faction will be beaten back and it will remain the same. It will be marked either [DEFENDED] if the staying faction survived, and [CONQUERED] if the attacking faction won.

Corpus and Grineer invasions are only Exterminate. The mode will be called Invasion though, while Infested has Exterminate, Defense, Survival, Mobile Defense, Assassination.

Tile Sets
Invasions feature more unique tile sets, mostly being battle ravaged ships of both Corpus and Grineer factions. There is also a tile set featuring a Grineer asteroid base being assulted by a Corpus frigate, with the Tenno that supported the Grineer being brought in by a ship to counter the attacking forces.

Infestation Outbreaks
Infested missions were cleared from their solar map locations with Update 11.3 and replaced with Operations using the Invasion mission mechanic. During which, the faction being invaded will assist you in dealing with the Infested threat. Unlike standard Invasions, the threshold for rewards is completing 3 battles instead of 5.

Infested Invasions will always inherit node mission type if the pre-existing node was Exterminate, Defense, Mobile Defense, or Survival. If the node being Infested was not one of those, game will decide randomly out of those 4. Assassination mission types use Phorid as the assassination target.

Aftermath
Once a victor for a node has been decided, the player will receive his reward in the inbox regardless who won the node. However, the player will attract the attention of either the Harvester or The Grustrag Three depending on who he sided with (The Harvester will attack players who supported the Grineer and vice versa) and may be ambushed during their next mission. Players may also get the Stalker's attention by defeating Phorid.