Arteria are large, ground-based facilities that act as the Cradles' lifeline. Each Arteria facility contains Kojima generators and multiple large energy projection devices that broadcast power directly to the Cradles. Without the power that these facilities provide, the cradles are unable to sustain themselves and must make an emergency landing.

Armored Core: For Answer Edit

During Armored Core: For Answer, the Protagonist may decide to join the anti-league group, ORCA. In that case, two of the missions assigned take place at various Arteria facilities. In the first mission, the protagonist is called upon to destroy the energy projection devices, forcing the Cradles to switch to back-up facilities. In the second mission, the Arteria facility, Carpals, is the site of an ambush that the Protagonist sets for Gerald Gendlin.

The final mission of both main routes take place in yet another Arteria Facility, the Cranium, which seems to be the center of the Arteria system. The missions themselves appear to take place below the actual facility, as the Kojima Projectors can be seen hanging from the ceiling inside cylinder-like slots. Capturing this facility allows a person to control the flow of energy throughout the entire Arteria network, and in the ORCA ending allows the player to redirect said energy to power the Anti-Satellite Cannons.

If the Protagonist decides to join Old King in destroying the Cradles directly, the Arteria Carpals facility is the site of a large ambush, set by four (5 on hard) Lynx.