Warframe - What Are Invasion Missions?
In Warframe, Invasion Missions see you temporarily becoming an ally with a faction that is normally your enemy. The balance of power is delicate, so sometimes you will need to intervene in battles between your foes to ensure one of them does not win, and become too powerful. In Invasion Missions you pick a side between the Corpus and the Grineer, then help them to achieve their goal.
Where To Find Invasion Missions
You can easily find Invasion Missions by using your Navigator. Just select it from the menu or module in your ship, then have a look in the top left at the row of icons. You will see a small fist icon, click on this to see a list of currently active Invasion Missions. You can click on any of the missions in the list, and it will bring you directly to the relevant planet. The missions will be marked on the Star Map by the same fist icon.
The list will show you where the mission is located, which of the factions is involved, and what percentage of control each faction exerts in the area. When the percentage reaches 100%, that faction is deemed to have won.
The factions will offer you different rewards to help them, and you need to complete the mission three times on the same node to get your reward. The reward is then sent to your inbox when the Invasion is complete. Rewards, or Battle Pay, can consist of things like blueprints, or parts for the Wraith and Vandal weapon variants. The only time you don't need to pick a side is if the Invasion involves the Infested because they are always your enemy.
It should also be noted; you can only see the Battle Pay when you click on the mission node on the Star Map and have to pick between both sides. From a narrative point of view, it doesn't matter who you pick, go with the faction offering the most attractive reward.
What Are Invasion Missions?
Mission types include Capture, Defense, Exterminate, Interception, Rescue, Sabotage, and Spy missions. They can often change as you play through all three, so you might end up doing two Exterminate missions, then a Spy. After you load into the mission, you play through it as normal, achieve the objective, then extract.
The main difference is that the friendly faction will be fighting alongside you, and will attack your enemies. It is very similar to a Crossfire mission in this way, except that one of the factions will not aggro to you.
Invasion Missions In Nightwave
If you are playing Invasion Missions are part of Nightwave, then each complete mission will count towards your target. You do not need to complete all three missions on the same node for Nightwave, but you will need to do it if you want to get your standard Invasion Mission rewards. There is no reason not just to do the three missions; this is just some good knowledge to have in case your play session is interrupted for any reason. If you only do one or two missions, Nightwave will still count them.