As told by Robert Justman, Co-Producer of TOS, and presented in his book "Inside Star Trek: The Real Story" (Pocket Books, 1996) which was co-authored with Herb Solow, Desilu's executive in charge of production for Star Trek.
Although Gene Roddenberry was brilliant in creating unusual concepts and story ideas, he practiced every imaginable technique to avoid one of his primary responsibilities, that of rewriting scripts. His days were filled with story and script conferences, and he was always immediately available to approve costume designs, prop designs, hair designs, and whatever network and production matters "desperately" required his attention. At the eleventh hour, however, he'd finally begin rewriting, which almost always meant Roddenberry was still at his desk when the morning sun rose over Hollywood.
Star Trek's famous opening narration came about under the pressure of an approaching crucial deadline.
BOB: On August 1, 1966, with the season premiere set for September 8, only weeks away, I prodded Gene to write the show's opening narration. But as usual, he continued to procrastinate. With only a few days left to ship the premiere episode to NBC for broadcast, it was now or never. The episode was complete except for this necessary and long-promised element.
Finally goaded into action, Gene took a stab at writing it, incorporating Sam Peeples's pilot title, "Where No Man Has Gone Before." He sent his first version to John Black and me. Gene asked for our comments and contributions. After an exchange of memos, he incorporated some of the suggestions into what became Captain Kirk's famous opening narration.
Justman's memo asking Roddenberry to write the narration ...
Roddenberry's first rough draft ...
Roddenberry's revised draft ...
Black's suggested version ...
Black's shorter version ...
Justman's suggested version, with Roddenberry's handwritten annotations ...
Justman's demand that Roddenberry deliver his final draft ...
On the afternoon of August 10, 1966, literally minutes after Gene finished his final version, I phoned Bill Shatner on stage, where he was working on "Dagger of the Mind", our ninth episode to be filmed. I told him to "drop everything", and then I ran across the street to the dubbing stage. Bill raced to meet me and arrived a minute later, slightly out of breath. We rehearsed the dialogue several times and made a take. Due to Bill's classical training, his delivery was excellent -- but the narration sounded too contemporary. There was something lacking; it didn't seem to "ring out".
I asked the sound mixer to add reverberation to Shatner's voice. We made another take and the results were perfect. Bill had become Captain Kirk, the adventurous commander of a spacecraft of the future, when he declared:
Space ... the final frontier. These are the voyages of the Starship Enterprise, its five-year mission:
... to explore strange new worlds ...
... to seek out new life and new civilizations ...
... to boldly go where no man has gone before.