In 2268, the USS Enterprise conducted a planetary survey of Argus X, discovering a large vein of tritanium ore. Captain James T. Kirk sent a recommendation to Starfleet for a survey vessel to be dispatched to this planet as a result of the rich find.
For the original production of the episode, the planet model for Argus X was first used for Delta Vega ("Where No Man Has Gone Before"). It was used again for Alfa 177 ("The Enemy Within", Tantalus V ("Dagger of the Mind"), Planet Q ("The Conscience of the King"), Benecia ("The Conscience of the King"), Gothos ("The Squire of Gothos"), Lazarus' planet ("The Alternative Factor"), Beta III ("The Return of the Archons"), Janus VI ("The Devil in the Dark"), Organia ("Errand of Mercy"), and Mudd ("I, Mudd"). It was later used for Ardana ("The Cloud Minders").
According to Star Trek: Star Charts ("United Federation of Planets I") and Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"), the Argus system was located in the Alpha Quadrant. The system's primary was a M-class star.