Infiltrating missions require you to dispatch a squad several days before the mission so they can study the target and make plans. This is represented by an in-game "infiltration" value which accumulates as the squad spends more time at the mission location. The speed at which a squad infiltrates depends primarily on its size, and to a lesser degree on its equipment. The final infiltration value, at the time you launch the mission, affects several aspects of tactical gameplay. This includes the quantity of enemies, their detection radius, and the delay before the Skyranger arrives for evac. Mission rewards and objective timers are not affected by infiltration.
The infiltration mechanic is the method by which most, but not all, missions are launched. The system is designed to provide a balance between the assignment of your haven personnel on intel gathering, the number of troops and equipment you bring on the mission, and the danger you will encounter on the mission.
When a mission is discovered you can deploy a squad, selecting soldiers and their loadout just like in the base game. Soldiers and equipment are unavailable while deployed to a mission. Once in place they will begin infiltrating. You can see their progress on the geoscape and you can click the mission bar to view details. From that screen you have the option to launch the mission immediately or to abort infiltration and recall your squad. The only penalty for aborting early is losing the squad's accumulated infiltration progress; you do not forfeit the mission. You can try to re-infiltrate with a newly selected squad if there is enough time left.
Most infiltration missions have a limited duration. You must launch the mission before it expires, but you don't have to watch the clock: if you have a squad deployed to infiltrate then the game will prompt you to launch or abort just before the mission expires. The time remaining for a mission is shown in the geoscape and in the top left of mission load-out screen. The load-out screen also displays the time to infiltrate, updated as you add or remove soldiers and equipment. This is how long the squad needs to reach 100% infiltration and eliminate all tactical penalties. If the squad's infiltration time is greater than the mission's time remaining then you won't be able to fully infiltrate. You can still deploy, but the mission will be more difficult.
A mission's expiration timer starts when it is created; the mission is not visible at this time. The local haven must collect enough intel to reveal the mission. Assigning more resistance members to the "intel" job can make missions considerably easier by discovering missions earlier and allowing more time to infiltrate. Most infiltration missions have a base duration of 18 days, which is randomized by a few days each time a mission is created. For more information on generating missions, see the Missions page.
Effects of Infiltration
Infiltration is measured as a percentage with a maximum of 200%. An infiltration value of 100% gives no bonuses or penalties. Lower infiltration aids the aliens and higher infiltration aids XCOM, but these effects are not equal: the penalties for a low infiltration level are much worse than the bonuses for an excessive infiltration.
Each breakpoint below or above 100% corresponds to an increase or decrease in Enemy Activity Level, respectively. Being between two breakpoints gives you a percent chance to upgrade to the next breakpoint and reduce enemy activity level accordingly, with the chance increasing proportionally as you approach the next breakpoint.
For example, consider a mission with Very Light baseline enemy activity. Above 92% infiltration you are guaranteed to receive at worst Light enemy activity, with an increasing chance to get Very Light enemy activity as you approach 100% infiltration.
There are many more breakpoints below 100% than there are above it; missions will quickly become significantly more difficult at under 100% and you should try your best to reach this percentage. Similarly the difference between 150% and 200% is very small and may not be worth the squad strength cuts needed to attain 200%.
Skyranger Evac Delay
Infiltration rate adds a modifier to the Skyranger evac delay timer. In addition, having a large number of infiltrations active at any given time adds an additional penalty. For more information on Skyranger evac time, see Skyranger Evac Mechanics.
- 0-29%: +3 turns
- 30-59%: +2 turns
- 60-99%: +1 turn
- 100-149%: no change
- 150-199%: -1 turn
- 200%: -2 turns
7 or more infiltration missions including the current mission: +1 turn.
Enemy Detection Range
The radius at which enemies can detect you in concealment is affected by your infiltration rate. At baseline 100% infiltration, enemies will have their normal detection range. At infiltration rates below 100%, the enemy will have between between x1 and x1.25 of normal detection radius (i.e up to 1/4th more); conversely, at infiltration rates above 100%, the enemy will have between x1 and x0.8334 of normal detection radius (i.e. up to 1/6th less). The effect scales linearly; for example, at 50% Infiltration, enemy detection range gets a 1/8 bonus (half the maximum bonus of 1/4).
- <100% Infiltration: Base * [1 + ((100% - Infil%) x 1/4)]
- >100% Infiltration: Base * [1 - ((Infil% - 100%) x 1/6)]
Detection Radius is also affected by other factors, including the type of enemy. For more information, see Detection Radius Mechanics.
- Remaining Distributions (JoINrbs)