Rigel VII was the inhabited seventh planet of the Rigel system. The planet had one moon. This was the homeworld of the Kalar, a pre-warp humanoid species. The Rigel VII Lagrange colony was associated with it. (TOS: "The Cage", "The Menagerie, Part I", "The Menagerie, Part II"; TNG-R: "Inheritance")
In 2254, a landing party from the starship USS Enterprise, led by Captain Christopher Pike, visited Rigel VII. While inside an apparently abandoned Kalar fortress, Pike and crew were attacked by the native Kalar warriors. Three crew members, including Pike's personal yeoman, were killed. Seven more were injured (including Spock, Navigator Tyler and a ship's geologist); some of these were so severely wounded that they required treatment at the Vega colony. Pike later regretted his decision to enter the fortress, stating that "the swords and the armor" should have alerted him to the possibility of a trap. (TOS: "The Cage", "The Menagerie, Part I", "The Menagerie, Part II")
There was a song called "Moon over Rigel VII". Captain Kirk proposed singing it around a campfire while taking shore leave at Yosemite National Park on Earth with Captain Spock and Doctor McCoy in 2287. (Star Trek V: The Final Frontier)
During the 2360s, Kobliad fugitive Rao Vantika used a subspace shunt to access and purge everything in the active memory of computer systems on Rigel VII. He later attempted the same on Deep Space 9 in 2369. (DS9: "The Passenger")
In the 2370s, a view of the surface of Rigel VII was depicted on several viewscreens on Deep Space 9's Promenade and replimat, (DS9: "The Muse") advertising a visit to the "spectacular castles of Rigel VII". (DS9: "What You Leave Behind")
|Rigel II • Rigel III • Rigel IV • Rigel V • Rigel VI • Rigel VII • Rigel X • Rigel XII • Asteroid Belt|
According to StarTrek.com, Rigel VII was in a double planet system.
In the story outline for "The Cage" (as reprinted in The Making of Star Trek, pp. 47-65), this planet's name was given as Endrex II. (The Making of Star Trek, p. 51) Analysis of the script for "The Cage" indicated that the planet's name was then changed to Rigel 113. Before it finally became Rigel VII, Harvey P. Lynn – a physicist from the RAND Corporation who served as an unofficial adviser on both "The Cage" and, later, the first season of Star Trek: The Original Series – suggested to Gene Roddenberry that he consider changing Rigel 113 to Vega 113, due to Rigel being "mighty far away." (The Making of Star Trek, p. 95)
In the second revised final draft script of "The Cage", it was notated that the Rigel fortress "suggests a medieval civilization, but carrying strange symbols and odd décor which suggests things quite alien from Earth." The script similarly described the fortress' courtyard; "The feeling here is as outside, a feudal-level civilization but with its weapons and architecture somewhat different from Earth."
In "The Cage" and "The Menagerie, Part II", the surface of Rigel VII, including the exterior of the Rigel fortress, was depicted with a matte painting that was created by Albert Whitlock. The Rigel fortress' exterior also involved live-action footage that was filmed on the Metro-Goldwyn-Mayer backlot and the fortress' interior was a set. (TOS: "The Menagerie, Part II" text commentary, TOS Season 1 DVD) The latter was actually the interior of Desilu 40 Acres back-lot.  The matte painting used to depict Rigel VII was re-used, unaltered, for Holberg 917G in the original version of TOS: "Requiem for Methuselah" (though it was replaced by a new CG matte painting for that episode's remastered version).
In the short story version of "The Cage" (titled "The Menagerie" and published in Star Trek 4), this planet was Rigel VIII.
According to Star Trek: Star Charts (p. 54; "United Federation of Planets III"), Rigel VII (Beta Orionis A VII) was a quarantined planet. The planet was an M-class world. The planet was non-aligned, with its status pending the development of warp drive. The dominant species was the Kalar. There was a conjectural count of 725,000 Kalar in 2370. First contact with this world was made by the Enterprise in 2254. This planet was in the Beta Quadrant, in the "true" Rigel (Beta Orionis) system.
According to the comics series Star Trek: Early Voyages, the building was named the Zemtar fortress, and the Kalar warriors attacked because of their reluctance to see their homeworld join the peaceful Federation.