Fifty years ago – on Sept. 8, 1966 – TV viewers were transfixed by the appearance on screen of a green-hued, pointy-eared alien called Spock. But beneath the makeup, actor Leonard Nimoy fretted that this would be the end of his promising career.

“How can I play a character without emotion?” he asked his boss, Gene Roddenberry. “I’m going to be on one note throughout the entire series.”

Nimoy thought he looked silly wearing the prosthetics that turned him into a Vulcan, at one point issuing an ultimatum: “It’s me or the ears.”

Nimoy’s misgivings were just one of many problems the writers, producers and cast faced during “Star Trek”’s troubled journey to the screen. Culled from their recollections, this is the story of how “Star Trek”’s mission to explore strange new worlds was almost over before it began.

Seeds of inspiration

The ingredients of “Star Trek” had been slow-cooking in creator Gene Roddenberry’s brain for years. At first he wanted to write a show about a 19th-century blimp that journeyed from place to place, making contact with distant peoples.