A Piece of the Action - S2-E17
Trivia: According to the script and audio of this episode, the first Boss is named Bella Oxmyx. But all posters of Oxmyx have the last name spelled "Okmyx." The reason is the as originally written, Okmyx would have been correct, but all material with Okmyx had already been made. Since it was a tight budget, the name was only changed at the time of filming.
Trivia: All the action in this episode revolves around McKinley Rocket Base. All footage around the base is actually of Cape Canaveral, Florida, provided to Roddenberry by NASA.
Trivia: When Scotty orders the blackout on the planet, the camera looks at Chekov's hands. It is a re-used shot of his hands from Season 2 Episode 4 "Mirror, Mirror."
Trivia: The painting on the wall in the office is an actual painting by Reginald Pollack.
The Ultimate Computer - S2-E24
Trivia: James Doohan provides the voice of the computer M-5.
Who Mourns for Adonais? - S2-E2
Trivia: Originally they wanted Jon Voight for Apollo.
Trivia: Banned in Germany until mid 1990.
Trivia: Stock footage of the White Rabbit's footprints from "Shore Leave" were used for the mugato footprints.
Trivia: This was the first time in the original series that Captain Kirk does not appear on board the Enterprise at any point.
Trivia: All the footage of the shuttlecraft in outer space was reused from Star Trek: The Galileo Seven.
Trivia: Nancy Crater's scream from "The Man Trap" is reused as Kara's scream when she is killed.
The Trouble With Tribbles - S2-E15
Trivia: This is the first time in the series the Klingon language is mentioned.
A Piece of the Action - S2-E17
Trivia: This is the only episode that ends with a freeze-frame.
A Piece of the Action - S2-E17
Trivia: James Doohan provided the voice of the radio announcer.
Trivia: Neither Nichelle Nichols nor Walter Koenig appear in this episode.
Answer: Kirk was getting his physical and Dr. McCoy probably turned off communications, because if he hadn't, Kirk would have left and headed straight for the bridge, leaving McCoy irritated.