Base management is the art of placing, maintaining, and defending the bases X-COM needs to counter the alien threat. This includes placing bases in a way that maximizes your chances of detecting and intercepting UFOs, building new base modules to supply necessary services, and arranging those modules in a way that gives the garrison an advantage over invaders.
There are several factors to consider when placing your bases. One of the most important is where the funding nations are located. Europe is home to the greatest concentration of funding nations: a base in the center of the Balkans with a Large Radar or Hyper-wave Decoder offers radar coverage of the UK, France, Germany, Italy, Spain, part of Russia, Egypt, and at the outer edge, Nigeria (see Geoscape (EU)#Countries). A base in North America will cover the US (X-COM's wealthiest sponsor) plus Canada. A base in China will span China, India, Japan, and most of Russia.
Another important factor is where the aliens tend to visit. A Chinese base can cover Southeast Asia, Central Asia, and Siberia; this extended region tends to see approximately 30% more alien activity than the Europe + North Africa region (see ZONAL.DAT). North America receives the most alien attention of any single region, although a base sited there can cover North American region only. The aliens will almost certainly try and infiltrate North America early, however, so even if your first base is not built there, your second or third definitely should be.
Another consideration is the price of the Access Lift. It can range from $500,000 for a base in Central Asia to $1,000,000 for a base in Europe. Your first base is free, so placing it in Europe can save you a few hundred thousand down the road. A properly outfitted base will end up costing millions more, however, so this is a relatively minor consideration.
One final consideration for your first or second base is the fact that Alien Supply missions always take place shortly after midnight GMT. If an alien base is located in Asia or Australia, and you can get there quickly, raids on their Supply Ships will always take place in daylight.
For your second and later bases, you should factor in where you have seen the most alien activity, by checking the UFO Activity Graph. Although the aliens focus on different regions from month to month, and it takes about a month for a base to become operational, there are still several types of alien activity that repeat over the long term. Aliens always send out scouts before sending in larger craft; some missions may involve a succession of scouts over a period of a couple of months. For instance, Alien Infiltration missions involve a series of scouts, followed by a four-UFO sortie that establishes an Alien Base, which then generates repeated Supply Ship missions.
Shooting down several UFOs in a given region will cause the aliens to send a series of UFOs carrying out Alien Retaliation missions. Building a base directly in that region is potentially dangerous -- the aliens may discover and invade the base before you can staff it, causing it to be automatically lost. It is good to build a base in an adjacent region, however, from which you can launch interceptions.
Terror Missions tend to generate a lot of alien activity that does not extend beyond a single month; you should discount terror activity when studying the UFO Activity Graph to decide where to place your bases.
Another consideration is to achieve good global Interceptor coverage. Having only two bases in nearby regions will leave a portion of the world undefended. For instance, bases in Europe and Asia will have difficulty defending South America. Bases in Europe and North America will not be able to defend Australia. As far as base pairings go, Europe and Australia offers good global coverage, as does China and central Africa. This consideration is especially important if you make extensive use of the UFO Activity Graph as an alternative to radar coverage.
Your first two bases should have Interceptors. You can get away with only one Skyranger if you plan to do mostly UFO Crash Recovery instead of UFO Ground Assaults -- crashed UFOs remain for several days and the Skyranger has a global range.
Maximizing Global Coverage
It is best to spread out your base placement to achieve maximal radar and interception coverage worldwide. A fairly standard base build order might be Europe, North America, China, Africa, South America, Australia, South Pole, and for the final base, either North Pole or Hawaii -- covering the major funding areas first and filling in all the remaining landmass at the end.
A base at the North Pole will cover more total land mass, and the poles are a common entry/exit point for UFOs, although most of the Arctic will already be covered by other bases in the Northern Hemisphere. A Hawaii base will give you the best coverage of the entire Earth's surface, filling in a huge tracking gap over the Pacific.
It is good to experiment with screenshots and the radar range overlay when studying the optimal distribution of bases. For instance, southern Europe is one of the best locations for a starting base, but it will have extensive overlap with a base in central Africa. A build order of China, Africa, North America, northern Europe, South America, Australia, South Pole, Hawaii, will allow almost complete global radar coverage, including the Arctic, while also giving good progressive geographic distribution and coverage of important regions.
There are three types of coverage you need to provide to areas of the globe. Detection (radar/hyperwave) coverage is the first and one you will need to consider most carefully when placing bases. Interception coverage is the second, and is still important particularly if you are using Firestorms. Recovery and Assault team coverage is the last, and usually least important consideration. There are also several utility bases that don't provide any of the above.
Detection bases have at least one radar installation, some people also call them listening posts. Most standard bases will start off as a detection base. As funds permit, its role will evolve as more facilities are added to it.
A listening post is base with an Access Lift, a radar (of any type) and little else. The low cost of the base and lack of valuable assets stored in the base means a cheaper bill for replacements if any are lost to retaliations. It is not recommended to build a pure listening post in any region where you have shot down multiple UFOs, as alien retaliation missions will ensue and the base will eventually be lost.
A listening outpost provides a decent chance of detecting UFOs operating in the area to an extent. If a passing UFO flies past in between a scan interval it will be missed. More bases mean a better chance to detect the fly-by UFOs as they move between coverage areas. Once you lock on to a UFO, it will remain visible within any of your radar tracking ranges. This range is quite large; a base in the Northern USA can keep a lock on a UFO to the northern coast of South America for example. You can detect most of the UFOs you need to with several well positioned detection bases in key areas.
Due to the paying for dirt bug there is little point selling off your old radars unless you immediately reclaim the space by building another facility over it.
For more information on radars in general, refer to UFO Detection.
Interception bases are extensions of radar bases with the addition of at least one hangar dedicated to aircraft that shoot down UFOs. A base garrison may be added to protect the aircraft and its supplies.
How you have the intercept outposts deal with UFOs will depend on what types of ships you have stationed at each base as interceptor speeds and operational ranges will vary. No matter the case, a good network of intercept outposts scattered around the globe can let you snare any UFOs that enter the atmosphere.
In general, for slower or shorter ranged intercept craft, it's best to wait for the UFOs to reach their destinations/area of operations before launching an attack.
An assault base has at least one hangar that houses one of any of the three troop transporters.
You can launch an assault or recovery from anywhere on earth, however if you take too long the downed or landed UFO may have taken off by then. Most UFOs either land twice or not at all. Those that do land will remain in their theater of operations for about six to ten hours. Just set a waypoint for your Skyranger and see how far it gets within eight hours: that's about the maximum effective range. You should be able to get there in time more often than not, but may be forced to fight at night – an assault craft that had been based closer could have picked the time of the battle.
Of the three possible choices of aircraft, Skyrangers and Avengers have terrific range, with the Skyranger offering amazingly extended flight hours while the Avenger has great acceleration. The Lightning on the other hand has shorter range but offers the rapid response time of hybrid aircraft. Avengers and Lightnings are also used as interceptors.
Utility bases are ones that specialize in filling a particular need. Supply depots, R&D centers, factories and psi training centers are all common base types. There is also the empty decoy base.
When a whole base is dedicated to one or two functions, all of the resources involved can be pooled together for a concentrated effort. Used in small numbers, they are often mixed in with other bases to provide additional functionality to them.
Empty bases can also be constructed near existing bases to function as decoys for alien retaliation teams. The more bases there are in the same location, the better the odds that the retaliation team might just pick the wrong one. Due to their temporary nature and the limited amount of space you have for bases, decoys can be quickly decommissioned to make room for new bases.
- After the Workshop, Stores, and Living Quarters are complete in your new base, then transfer your engineers and dismantle the old base's Workshop to make room for new facilities.
- Manufacturing Bases will need a spare hangar to build new Craft.
- Don't forget a garrison force of soldiers, and weapons for same.
- Also see the Robotic Factories exploit.
- See also: Base Layout Strategy
Base Defence is a primary consideration when choosing what to place where and when to build what. The higher the difficulty the more important a defensible base is, and your placement strategy also needs to account for at least 4 different known bugs.
The secondary consideration is the amount of time modules take to build. Apart from decoy bases and listening posts, all bases need General Stores and they are a fast module to build. Even if not needed yet,they can speed the construction of other modules by quickly opening up extra construction slots. Consider placing them first when you have to choose between them and something like a large radar that takes more than twice as long to complete.
For a structure to be useful it often needs to be matched with another. For example building 2 Laboratories and 2 Workshops but only 2 Living Quarters means you have approximately 175+ technical jobs to fill but only enough room to house 100 staff.
Money is the final arbiter of what you should build. Monthly income and expenses are not particularly relevant but you need to remember purchases that you have earmarked for later. Be sure you save enough money to staff your new structures or manufacture the goods you need. You may have $3 million spare now and spend it on new workshops but in 3 days the lab you started way back when becomes operational and you needed that money to staff it with scientists. You may be sitting on a pile of money now, but what happens when there are no UFO's to shoot down for a week or two? All that lab space and time you could have been researching will go idle.
All things considered, unused facilities are much cheaper (monthly) than unused staff or (rented) aircraft. The up front cost of facilities is usually cheaper than the cost of staff/craft to fill them. And facilities have a much longer lead time, by x8 - x10. So if you are unsure of future cash flow or your future plans, facilities are the safer bet.