UFO Power Source
The power source of UFOs is an anti-matter reactor which uses Elerium-115 (element 115) to generate powerful gravity waves as well as other forms of energy. The conversion of matter to energy produces an incredible amount of power (E=mc2); even the tiniest amounts of Elerium produce huge amounts of power. Power Sources can be manufactured easily using Alien Alloys.
A UFO Power Source requires 1400 man-hours to build, $130,000, and the materials Elerium-115 and Alien Alloys. You can obtain these materials from Alien Bases and UFOs. Power Sources can be sold for $250,000.
|Hint: Don't bother building them. Salvage them from UFOs. If you choose to sell power units, keep a supply sufficient for any aircraft that you wish to build. A minimum of two PSs are required for an Avenger, and one for a Firestorm or Lightning.|
Extracting Elerium from Power Sources ("Milking")
Every UFO Power Source that is intact at the beginning of a mission will have Elerium, with the exception of one UFO Power Source found in a particular Alien Base module. If a UFO crashes, you will often find that the UFO Power Source(s) stored inside have exploded with great force; for the probability of recovering Elerium from a crashed UFO, see UFO Crash Recovery. Note that PSs destroyed during play do not detonate.
A UFO Power Source has 50 armour, which means that an explosive needs a damage rating of 100+ HE to destroy it. Weapons that will kill a PS are: the Large Rocket, High Explosive, Hovertank/Launcher, or Blaster.
However, this is NOT the right way to get Elerium out of a Power Source, because explosions affect everything in their square equally, and Elerium itself (an object on the ground) is destroyed by any explosive blast over HE 20. (Elerium is not created when the PS dies - it's actually sitting right there and can be seen in the overhead map; you just can't get to it until the Power Source is gone.) The PS is much more resistant to explosions than its Elerium. Compare how you can destroy the Elerium with a standard human Grenade exploding two tiles away, but a standard grenade can't hurt the Power Source even if right on top of it. Clearly, the designers made Elerium a tough nut to get to.
Because of this, you have to use firearms to take out the UFO Power Source surgically, leaving the Elerium behind. PSs have the usual terrain damage resistance to conventional ammunition types (AP, Laser, and Plasma; a.k.a. firearms only do 25%-75% of listed Strength/Damage, so you need a listed weapon strength of at least 67 (50/.75) to destroy it). The following weapons can breach a PS:
Damage Breach Weapon Range Chance ------ ----- ------ Plasma Rifle 20-60 26.8% Heavy Laser 21-63 32.6% Tank/Laser Cannon 27-82 58.9% Hovertank/Plasma 27-82 58.9% Heavy Plasma 28-86 62.7%
This is usually only a concern if you are "milking" an alien base - deliberately not destroying it, so you can revisit it time and time again, and pull out Elerium and other goodies. On the usual UFO or Base raid, you simply kill all aliens, and recover any and all Elerium present anywhere on the map, at the end of the mission.