Artifacts are mechanical parts of the Humanity's Greatest Fan, which were scattered around the Milky Way Galaxy to not let the device's power be in the wrong hands.
So far they only appeared in Chicken Invaders: Cluck of the Dark Side.
There are three of them:
Blade of Revolution
It's consisting of three circles with blades in them. It lets the fan work.
It is located within Epsilon Thalassus (Chapter 4).
Source of Power
It's a potato battery, which works as the fan's source of power.
It is located within Gamma Chthon (Chapter 6).
Thingamajig of Vagueness
It's a button which lets you turn the fan on and off.
It is located within Eta Astropelecae (Chapter 8).