"Star Trek" was on the
brink of cancellation following this episode. A major letter writing
campaign proved to NBC how popular the show really was, in spite of
the ratings system of the time. Convinced, NBC granted the show
This episode was
originally written as a pilot episode for a completely new series.
When it wasn't picked up, Gene Roddenberry adapted it as a "Star
There are absolutely no
clouds visible in the shots of the Enterprise orbiting Earth.
During the early
briefing Scotty chips in on the viewscreen from Engineering, but the
image fades out before Kirk turns off the viewer (and there's no
indication Scotty does it at his end either).
This is the only episode
of the series that credits the guest star after the episode title.