NBC was given four pilots of Star Trek: The Original Series to choose from

"The Cage" was the original pilot of Star Trek: The Original Series. It completed filming in January 1965 and was offered to NBC for screeing in February 1965. All Star Trek fans know how that went down. Though now, the episode is one of the highest-ranked episodes by sites like Den of Geek and Syfy, back in 1965, the NBC executives rejected it for the pilot of the brand new sci-fi series.

Oscar Katz, who was the head of production at Desilu, which produced the first two seasons of The Original Series, didn't understaned why the network had turned it down, and the explanation didn't really help. Executives responded with "we can't sell this show; it's too atypical." Katz reminded NBC that they'd chosen "The Cage" to review as the pilot out of four potential offerings as Gene Roddenberry had written three additional script pilots.

"When they rejected "The Cage," I asked NBC, "Why are you turning it down?" and I was told. "We can't sell it from this show, it's too atypical." I said, "but you guys picked this one. I gave you four choices." NBC said, "I know we did and because of that, right now, we're going to give you an order for a second pilot next season.""

- Oscar Katz

According to Stephen Kandel, the writer of Mudd's Women, as reported in The Fifty-Year Mission The First 25 Years by Edward Gross and Mark A. Altman, "The Cage" frightened the network because they thought the audience wouldn't understand it.

But it was because NBC had chosen "The Cage" out of the four potential scripts that they decided to give Star Trek another shot. Perhaps they were thinking they just chose the wrong script. At any rate, being given a second pilot was extremely rare, and while we don't know if Roddenberry chose one of the additional three scripts he'd written to film for NBC's second perusal, we do know that the second time around was the charm. That was "Where No Man Has Gone Before," but it didn't air as the first episode of Star Trek in September 1966. That honor when to "The Man Trap." Still, it would be interesting to know if the second pilot came out of Roddenberry's first scripts, or if he decided to shelve them all and go for a different one given the second chance.