Ardana was an inhabited planet orbiting the primary Ardana, in the Beta Quadrant. This was the homeworld for the Ardanans, a warp-capable species. The planet was a Federation member. It was in the same quadrant as Merak II.
Prior to stardate 5818, this planet was united under an uniglobal government. The capital city of this world was the elevated metropolis Stratos. The civilization of Ardana was divided into two castes, a labor class of Troglytes and an intellectual ruling class of Stratos city-dwellers. The caste system was riven with conflict.
This world was admitted to the Federation. Upon being admitted as a member, it was expected that Ardana would live up to its obligations in helping another member. Despite its membership in the Federation, Ardana employed torture and capital punishment.
In 2269, Ardana's obligations as a member were threatened by a rebellion. In that year, the USS Enterprise came to obtain zenite for use to prevent a bacterial botanical plague on Merak II. Captain James T. Kirk of the Enterprise successfully quelled a rebellion by the Troglytes against the city-dwellers on the planet, while at the same time procuring a consignment of zenite for transport to Merak II. (TOS: "The Cloud Minders"; DIS: "Magic to Make the Sanest Man Go Mad")
For the pre-remastered episode, the planet model for Ardana was first used for Delta Vega. ("Where No Man Has Gone Before") It was used again for Alfa 177, ("The Enemy Within" M-113, ("The Man Trap" 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") Mudd, ("I, Mudd") and Argus X. ("Obsession") For the remastered episode, a new planet model was created by CGI artist Max Gabl. The planet's appearance was based on a NASA satellite photograph of Wadi Hadramawt.
According to DS9: "Accession", Ardana's policies of caste system oppression, executing political dissidents, and public torture would be in direct contradiction to Federation guidelines that would be established by the 2370s for member worlds.
According to the Star Trek: Star Charts (p. 53), Ardana (Mu Leonis A III) was governed by the Plutocracy of Ardana from the capital city of Stratos. The dominant species were the humanoid Stratos dwellers and the Troglytes. Major points of interest were Stratos City and the Troglyte Mining Museum. After achieving warp capability in 2259, Ardana was admitted to the Federation in 2263. Six years later, reunification of the society began with the aid of the crew of the USS Enterprise. In the census of 2370, there were 58.7 million Stratos dwellers and 9.2 billion Troglytes living on the planet. This planet was located in the Ardana (Rasalas, Mu Leonis) system.
From the Star Trek Encyclopedia (4th ed., vol. 2, p. 338), "The view of the Ardanian landscape directly below Stratos was a NASA photograph of the Hadramawt Plateau dry river basin in southern Saudia Arabia as seen from space, taken by the crew of Gemini 4 in 1965. Many years later, when CBS remastered the original series, space historian Dwayne Day went to NASA headquarters in Washington, DC, to locate the original image so that the scene could be properly re-created in HD. (Thanks, Dr. Day!)"
According to the mirror universe novel The Mirror-Scaled Serpent, Ardana was a Terran Empire planet until it was conquered by the Klingon-Cardassian Alliance in the late 23rd century. The half-Klingon, half-Terran B'Elanna was the Intendant of Ardana in 2371.