The Man Trap - Wikipedia

On September 8, 1966 "Star Trek" premiered on NBC-TV. From the article:

"The Man Trap" is the first episode of the American science fiction television series Star Trek to be broadcast. It aired on NBC on September 8, 1966, and two days earlier on Canadian network CTV. Set in the 23rd century, the series follows the adventures of Captain James T. Kirk (William Shatner) and his crew aboard the Starfleet starship USS Enterprise. In the episode, the crew visit an outpost to conduct medical exams on the residents, only to be attacked by a shapeshifting alien creature seeking to extract salt from their bodies. "The Man Trap" was written by George Clayton Johnson and directed by Marc Daniels. This episode was the first to be broadcast, but was not the pilot; the original series had two pilots, "The Cage" and "Where No Man Has Gone Before".