First episode to establish the United Federation of Planets as the principal service to which the Enterprise operated under. In previous episodes, vague and often conflicting references were made to this service. Such references included "Space Command", "Space Central", the "Star Service", and "United Earth Space Probe Agency" (the latter even abbreviated as UESPA, pronounced by Captain Kirk as "you spah" in Star Trek: Charlie X (1966)). UESPA would later go on to be the principal service to which the Enterprise NX-01 operated under on Star Trek: Enterprise (2001), which is set in a time when the Federation has not been firmly established.
In his memoir, "Beam Me Up, Scotty," James Doohan described Gene Lyons (Ambassador Robert Fox), as being "out of his element" and "completely discombobulated" during filming. He added that it took Lyons many takes to get his lines right, and that they finally "went to having him speak off-screen." Doohan speculates that Lyons, who was an experienced actor, may have been thrown off by the science fiction element, as such shows were relatively rare at the time.
When Mea 3 escorts the landing part from the beam-down area to the council chamber, the transition of scenes is conveyed not through a cut or a dissolve, but through a wipe-the only time such an effect was used in the original series.
Spock refers to himself in this episode as a "Vulcanian" rather than a Vulcan, one of very few times in the series where the longer synonym is spoken. Also, the Enterprise's protection is called screens rather than shields.
The inner slipcase, along with the fold-out episode guide, from the 2004 DVD release of Star Trek: The Original Series - Complete Season One, featured a large still image on the front cover of Captain Kirk and Mr. Spock which is taken from the ending of this episode.