SolCore

SolCore was the original name for the central human government in the Halo universe, rather than the Unified Earth Government and its United Nations Space Command. By the time it encountered the Covenant it had colonized seven worlds and discovered four "lost colonies" of humans. The Pillar of Autumn's original hull classification symbol, SCS, presumably stood for SolCore Ship.

Though SolCore has long been abandoned, the concept of lost human colonies was canonized in 2009 with the release of "The Babysitter", one of several short films from the Halo Legends anime anthology.