Alien Missions (LWR)

Back To Main Page

In General

During the long war against the alien threat, the skies are also part of the battlespace. Aliens will dispatch UFOs to further their goals during the war, and XCOM may respond in kind by sending out interceptors and the Skyranger to foil their missions in the air or on the ground. In other words, an alien mission always starts with a UFO.

There are eight types of regular alien missions scheduled on the fly. The type of each mission is determined by the resources the aliens have, and how threatening XCOM is perceived to be. There are also two special mission types that occur irregularly. All ten mission types are listed and discussed below.

The aliens' choice of UFO is limited by their level and resources, with the actual ship sent on a mission being chosen randomly - with equal probability for each - from the available pool. For example, if the aliens are weak then they will randomly send either a Scout or Raider for research; if they are strong however, then the large Abductor and Terror Ship will be added to the pool for the same mission.

Conversely, any damage and casualties sustained by the UFOs will cut into the aliens’ resources, likely limiting their options.

The aliens have a strategy in Long War, and tend to focus on geographic locations. Expect to fight them the most in the continent where they build their first base.

Failing to damage a UFO on its mission at all will result in 1 panic to the target country, in addition to any of its normal effects.

All mission frequencies are reduced on shorter campaigns and increased on longer campaigns: NSLW (50%), LW (100%), VLW (200%), ELW (400%).

Resource Costs

Missions themselves do not require Alien Resources to run if left unchallenged, but shooting down or damaging the UFOs conducting them does cost the aliens resources. Crucially, though, which UFOs are deployed depend indirectly on the alien resources as well as the Alien Level at the time the mission is scheduled. Specifically, Aliens add stronger UFOs to a pool if they have sufficient resources, choosing randomly from the pool when the mission is scheduled (with equal probability for each UFO type); Alien Level reduces the amount of resources the Aliens must have for the stronger UFOs to be added to the pool.

• If Alien Level 1-7, new types require 100-73% of their base required resources.
• If Alien Level 8-14, new types are possible at 72-41% of required resources.
• If Alien Level 15+, new types are possible at 40% of required resources.

XCOM satellite coverage will increase the resources the aliens have when deciding which UFO to send out:

• 1 Continent has some coverage: No Increase
• 2 Continents: +10% Resources
• 3 Continents: +20% Resources
• 4 Continents: +30% Resources
• 5 Continents: +40% Resources

Note: Even a single satellite in a continent counts as coverage in that continent

Mission Frequency

Each mission type requires a score of 1.0 to trigger a mission. In the chart below is on average how much of that score is gained each month. When a mission type gets a score of 1.0 it is triggered and the score is set back to 0. As an example, if you have 3 months of 0.33 of a mission, on average it will trigger at the end of month 3 - but could trigger weeks earlier or later.

Resources	Aggression
	0	25	50	75	100
0	1.2 Abduction 1.9 Harvest 0 Hunt* 1.5 Scout	1 Abduction 0.3 Bomb 1.9 Harvest 0 Hunt* 1.6 Scout 0.1 Terror	0.9 Abduction 0.6 Bomb 1.9 Harvest 0.3 Hunt* 0.15 Retaliate 1.8 Scout 0.4 Terror	0.7 Abduction 1 Bomb 1.9 Harvest 0.7 Hunt* 0.15 Retaliate 1.9 Scout 0.7 Terror	0.6 Abduction 1.3 Bomb 1.9 Harvest 1 Hunt 0.29 Retaliate 2 Scout 1 Terror
25	1.5 Abduction 0.1 Bomb 1.8 Harvest 0.3 Hunt* 0.15 Research 1.6 Scout 0.6 Terror	1.3 Abduction 0.4 Bomb 1.8 Harvest 0.7 Hunt* 0.15 Research 1.8 Scout 0.9 Terror	1.2 Abduction 0.9 Bomb 1.8 Harvest 1 Hunt* 0.15 Research Retaliate 0.15 1.9 Scout 1.2 Terror	1 Abduction 1.2 Bomb 1.8 Harvest 1.3 Hunt* 0.15 Research 0.15 Retaliate 2 Scout 0.6 Terror	1 Abduction 1.6 Bomb 1.8 Harvest 1.6 Hunt* 0.15 Research 0.29 Retaliate 2.2 Scout 1.6 Terror
50	1.9 Abduction 0.4 Bomb 1.6 Harvest 1 Hunt* 0.29 Research 1.6 Scout 1.3 Terror	1.8 Abduction 0.7 Bomb 1.6 Harvest 1.3 Hunt* 0.29 Research 1.8 Scout 1.5 Terror	1.6 Abduction 1 Bomb 1.6 Harvest 1.6 Hunt* 0.29 Research Retaliate 0.15 1.9 Scout 1.8 Terror	1.5 Abduction 1.5 Bomb 1.6 Harvest 1.9 Hunt* 0.29 Research 0.15 Retaliate 2 Scout 2 Terror	1.3 Abduction 1.8 Bomb 1.6 Harvest 2.3 Hunt* 0.29 Research 0.29 Retaliate 2.2 Scout 2.3 Terror
75	2.2 Abduction 0.6 Bomb 1.5 Harvest 1.6 Hunt* 0.44 Research 1.8 Scout 1.9 Terror	2 Abduction 0.9 Bomb 1.5 Harvest 1.9 Hunt* 0.44 Research 1.9 Scout 2.2 Terror	1.9 Abduction 1.3 Bomb 1.5 Harvest 2.3 Hunt* 0.44 Research Retaliate 0.15 2 Scout 2.5 Terror	1.9 Abduction 1.6 Bomb 1.5 Harvest 2.6 Hunt* 0.44 Research 0.15 Retaliate 2.2 Scout 2.6 Terror	1.8 Abduction 2 Bomb 1.5 Harvest 2.9 Hunt* 0.44 Research 0.29 Retaliate 2.3 Scout 2.9 Terror
100	2.6 Abduction 0.9 Bomb 1.3 Harvest 2.3 Hunt* 0.58 Research 1.9 Scout 2.6 Terror	2.5 Abduction 1.2 Bomb 1.3 Harvest 2.6 Hunt* 0.58 Research 2 Scout 2.8 Terror	2.3 Abduction 1.5 Bomb 1.3 Harvest 2.9 Hunt* 0.58 Research Retaliate 0.15 2.2 Scout 3.1 Terror	2.2 Abduction 1.9 Bomb 1.3 Harvest 3.2 Hunt* 0.58 Research 0.15 Retaliate 2.3 Scout 3.4 Terror	2 Abduction 2.2 Bomb 1.3 Harvest 3.5 Hunt* 0.58 Research 0.29 Retaliate 2.5 Scout 3.7 Terror

\* Hunts are significantly increased by # of Satellites and UFOs raided scaling by aggression - #s above are the *lower bound* for a single satellite and 0 UFOs raided. At 100 Aggression, each satellite and raided UFO adds .12 Hunts per month on top of these numbers. \*\* Abductions and Terror #s do not take into account reductions from passing months.

Mission Types

Recon

A UFO will fly at low altitude over the target country, attempting to confirm the existence of XCOM satellites there. Successful recon missions will be followed up by a new UFO to hunt the compromised satellite. It is possible that the hunting UFO will be stronger or weaker than the recon one, so the priority to intercept this mission can vary.

A recon mission can fail in four ways with varying chances of failure:

• Downed: The UFO is shot down. 100% chance of failure - if it's shot down they will always get nothing.
• Damaged: The UFO botches the mission from sustained damage. (2 × (100 - RemainingUFOHP%))% chance of failure - this means XCOM can commit less and gamble on merely damaging the UFO.
• Defended: The target country fends off the mission by itself. (CountryDefense/2)% chance of failure - the shield representing a country's defense is shown in the Situation Room and is improved by fulfilling their requests; maximum chance is 50% with 100% CountryDefense.
• Damned: The UFO could simply get unlucky. (60 - AlienResearch/15)% chance of failure - when the aliens have 900 research points, an unfettered recon mission will always succeed.

For recons, hunts, and bombings, a 50% HP UFO will start flaring up in the aerial combat screen, as if it was being hit by multiple missiles continuously. When this happens, XCOM can order their interceptor to disengage, preventing further risks while still stopping the recon mission, as the mission is guaranteed to fail.

UFO Pool:

• Scout: Always in pool
• Raider: Aliens must have > 17% / 12% / 7% resources & Alien Level > 3
• Destroyer: Aliens must have > 75% / 54% / 30% resources
• Battleship: Aliens must have > 100% / 72% / 40% resources

Hunt

A UFO will fly at high altitude over a previously reconned satellite-covered country, seeking to destroy the satellite.

The aliens will prioritize getting rid of satellites over withdrawn ex-council-members, as they have bases in such countries and without a satellite over them XCOM cannot assault it. Next, the aliens prefer satellites that protect panicking nations, and in doing so potentially forcing said nations to withdraw XCOM support, and to be controlled by them.

Successful hunts will destroy the satellite in question. Hunts have a base chance of success of 100% (50% if Stealth Satellites is researched). Damage sustained by the UFO will reduce this chance further, with 50% or less HP leading to an automatic failure (including failure of an initial observation).

For recons, hunts, and bombings, a 50% HP UFO will start flaring up in the aerial combat screen, as if it was being hit by multiple missiles continuously. When this happens, XCOM can order their interceptor to disengage, preventing further risks while still stopping the hunt mission, as the mission is guaranteed to fail.

The aliens will send out more hunt missions for each satellite that XCOM has in orbit. Also, each UFO XCOM raided earlier in the current month further increases hunt missions sent out for the remainder of the month.

As well, the more coverage XCOM has the more likely the aliens are to send out stronger UFOs to challenge XCOM's coverage of the planet.

Note that the aliens can dispatch hunt missions directly, without needing to scout first; although this will only occur if alien aggression is high. The more aggression and resources the aliens have, the more direct hunt missions are sent.

UFO Pool:

• Fighter: Always in pool
• Destroyer: Aliens must have > ?% / ?% / ?% resources
• Battleship: Aliens must have > ?% / ?% / ?% resources

Research

A UFO will fly NOE, land for a while, and then fly off. This mission will grant the aliens research if successful, increasing their level. This will slowly but permanently increase the capabilities of their ground troops and UFOs.

If the aliens have no resource (0% resources), the aliens will never undertake research missions; conversely, if they have many resources (100% resources), then the maximum amount of research missions will be performed.

UFO Pool:

• Scout: Always in pool
• Raider: Aliens must have > 25% / 18% / 10% resources
• Abductor: Aliens must have > 42% / 30% / 17% resources
• Terror Ship: Aliens must have > 83% / 60% / 33% resources
• Assault Carrier: Aliens must have > 100% / 72% / 40% resources

Harvest

A UFO will fly NOE and land in a randomly selected country. An unimpeded harvest grants the aliens resources, which will allow the aliens to field UFOs in greater quantity and quality.

If the targeted country has a satellite, there is a Alien Aggression / 2 chance that the aliens will re-roll its target once and will pay a price in the process. This represents the power projected by a strong XCOM forcing the aliens to settle for sub-optimal harvests. As the aliens' first choice for harvest is randomized, more satellite coverage means a higher chance that the aliens need to waste resource to even start a harvest mission.

The aliens' tendency to perform harvest missions is the exact reverse to their tendencies to send out research missions. If the aliens have minimal resources (0%), then a maximum amount of harvest mission is attempted (three per month); if they have too many resources (100%), then less harvests will occur.

UFO Pool:

• Transport: always in pool
• Harvester: Aliens must have > 25% resources
• Raider: Aliens must have > 42% resources
• Scout: Aliens must have > 75% resources

Note that the UFO pool for harvest missions becomes less threatening the more resources the aliens have, and isn't affected by higher Alien Research as others do.

Bomb

A UFO will fly NOE and around the target area bombing civilians. This mission will cause a lot of panic if successful. This is one of the few NOE mission types that never lands, and the only way to completely foil its panic increase is to damage the bombing UFO by at least 50%. However, damaging the UFO at all will still reduce the amount of panic created at the end of its mission. A successful bombing mission generates 6 panic in the country raided (reduced proportionally by amount of damage received down to 0 panic at 50% health) in addition to the standard 1 panic if the UFO has received no damage.

For recons, hunts, and bombings, a 50% HP UFO will start flaring up in the aerial combat screen, as if it was being hit by multiple missiles continuously. When this happens, XCOM can order their interceptor to disengage, preventing further risks while still stopping the bombing mission, as the mission is guaranteed to fail.

The aliens will send out more bombing missions if they have spare resources and a higher aggression level. With maximum resource and aggression level they will conduct multiple bombing missions per month.

UFO Pool:

• Fighter: Always in pool
• Destroyer: Aliens must have > ?% / ?% / ?% resources
• Battleship: Aliens must have > ?% / ?% / ?% resources

Abduction

Multiple Abductors (2, 3 after 6 months) will fly NOE to multiple target areas and generate Abduction sites. A successful abduction will increase panic in the country and across the continent. Thwarting the abduction will decrease panic in the country and continent, but by a lesser degree. After the first round of abductions a second will occur 1 day later.

Only 1 abduction can be dealt by XCOM as the others will expire after the first abduction is attempted with so the commander must choose carefully.

Each successful abduction (a failed abduction for XCOM) grants alien research which leads to an increase in Alien Level. The council will offer rewards to XCOM for successfully completing an abduction which can include: credits, scientists, engineers, or new soldiers. The difficulty of the abduction will increase the quantity or quality of the reward.

In many ways abduction is the least aggressive mission type; perhaps due to this, the aliens will scale back on abduction attempts if they are being aggressive. But the aliens still dispatch more abduction missions if they have more resources when they are not being aggressive with max resources. Conversely, if the aliens are short on resources, and are being highly aggressive (high aggression level), fewer abductions per month is attempted.

Terrorize Populace

This is a double UFO mission: At first, a Terror Ship will fly NOE and hover over the target nation scouting and planning for the actual mission. Shortly after, an Assault Carrier will fly NOE to the target area and finally generate a Terror site. This means anyone with satellite coverage and interested in stopping the mission will have plenty of time to set up, though actually executing that is a different matter entirely.

The aliens will terrorize the most panicked nation adjacent to an alien base roughly 85% of the time, seeking to push them over the edge. Terror missions increase panic in the targeted country and continent per civilian killed.

Saving the vast majority of the civilians can actually lead to a decrease in panic. 
Losing or ignoring the mission will cause immediate country defection and an increase in panic continent-wide.
Each civilian saved in a country that has not left the council will grant XCOM a 40 credit reward from the affected country (Modified by Campaign Length) (Increases by 5% per month).

There are only two ways to completely foil this kind of terrorism: by saving the vast majority of civilians during the engagement, or by shooting down the Assault Carrier before it could even deploy. Neither of these scenarios are predictable, and will probably be cost prohibitive to even try the latter. Only an exceptionally advanced and exceedingly experienced XCOM can pull either option off consistently. Otherwise the best a commander can do is to minimize the damage and make up for it elsewhere.

When Alien Aggression and Resources are higher, the aliens will try to launch more terror missions each month.

Shooting down the forward scouting Terror Ship doesn't actually hinder the scheduled mission in any way. However, it's a lot easier to achieve, and it forces the aliens to pay dearly in resource cost for each such Terror attack they perform. In addition, it will grant XCOM a lot of looted resource and battlefield experience if the downed terror ship is successfully raided. It may not stop the looming terror attack, but it may very well help in the future.

Infiltrate

A Battleship or Transport will fly around the target area, followed by an Overseer inserting in to the target city. This mission will cause the target country to leave XCOM immediately if successful. Note that the final Overseer can only be detected if XCOM has the Hyperwave Decoder, so without one the country will appear to leave for no reason.

These missions are not common.

Retaliate

This is a special mission. A UFO will fly to your main base or to one of your interceptor bases and immediately start an XCOM Base Defense mission or an Air Base Defense mission.

Aliens usually send an Assault Carrier to main base assaults. The aliens take a look time to build up to XCOM Base Defenses, faster if they have a lot of resources and high aggression. If a base defense does not spawn before the new year it will automatically spawn at the end of the first year. You can only have 1 XCOM base defense mission.

If the aliens win a base defense it will damage resources and kill personnel - but it is not the end of the game, and can be recovered from.

For Air Base assaults, aliens will send an Overseer. The cost of failure of these missions is the destruction and/or severe damage of all stationed interceptors. Air Defenses missions only begin spawning after XCOM constructs its first Firestorm interceptor.

Command Overwatch

This is a special mission. An Overseer will fly low around the target area. This mission is how the aliens communicate and coordinate their activities and is normally hidden to XCOM.

Before XCOM has successfully raided an overseer, overseers will spawn preferentially over countries with satellite coverage to aid in coordinating their activities. However, if an overseer is successfully raided, the aliens will conduct future overseer missions exclusively in countries with alien bases in order to minimize exposure and risk.

The aliens have many Overseers and shooting 1 down has no special strategic value.

See also

Long War Rebalance: Aliens
	Alien Life Forms • Alien Missions • UFOs • Alien Artifacts • Alien Level • Alien Resources • Alien Aggression