A corner cube prism, also known as a retroreflector, a CCR, or a trihedral prism, is an optical prism that sends an incoming beam of light directly towards its point of origin while translating it spatially. It does this regardless of the angle of entry, which makes it very useful for applications in spectroscopy, satellites, or battlefield technology.Corner cube prisms are also used in land surveying, laser resonator cavities, electronic distance measurement, and space vessel docking.