Star Trek's First Holodeck Episode Aired Over A Decade Before The Next Generation Debuted

"Star Trek: The Next Generation" may be known for its frequent use of the holodeck, but it didn't introduce the concept.

In fact, the first appearance of something like the holodeck — a room on a starship that can create realistic holographic simulations of various locations and beings — came in Season 2, Episode 3 of "Star Trek: The Animated Series," around 13 years before "TNG" debuted.

Airing in September 1974, "The Practical Joker" saw the computer of the starship Enterprise descend into practical-joke mode after passing through a mysterious space cloud. Dr. McCoy, Lieutenant Sulu, and Lieutenant Uhura use the holodeck as a hideout during the ensuing chaos, and they soon end up trapped inside. The main difference between this initial appearance and later holodecks is that, here, the area is known as the "rec room." Nevertheless, it functions very closely to how it would be used throughout "TNG" and other "Star Trek" shows.

Clearly, the "rec room" name didn't stick — but holodecks and holosuites soon became commonplace in the greater "Star Trek" universe. 

Initially, "Star Trek" creator Gene Roddenberry had planned to debut holo-tech in Season 3 of "Star Trek: The Original Series," but budget constraints forced the concept to move to "Star Trek: The Animated Series." In an issue of Star Trek: The Magazine, franchise stalwart D.C. Fontana claimed that, when they first used the idea, the "Star Trek: The Next Generation" writing team had forgotten that the concept of holo-tech had been previously introduced.

Arguably, though, few "Star Trek" properties have utilized holodecks quite as successfully as "TNG," which was recognized with a Peabody Award for Season 1's holodeck-set episode "The Big Goodbye." Mere months after "TNG" premiered, the series had already made its mark on the legacy of this iconic sci-fi concept — one that began as far back as "The Animated Series."