Star Trek: Season 1, Episode Nineteen “Tomorrow Is Yesterday”

Stardate: 3113.2 (2267)
Original Air Date: January 26, 1967
Writer: D.C. Fontana
Director: Michael O’Herlihy

“If I remember my history, these things were being dismissed as weather balloons…”

Rating: 5 out of 5.

Stationed in Nebraska, U.S. Air Force analyst Webb picks up a strange blip on his radar screen –an unidentified flying object seems to have just fallen out of the sky. Currently, the craft is sitting in the sky above Omaha Station. Webb alerts his Captain who then radios for aircraft support to investigate the situation. The Air Force decides to send a lone pilot, Captain Christopher, to investigate (played by Roger Perry, who actually served as an intelligence officer in the United States Air Force during the early 1950s).

Meanwhile, per Kirk’s log, the Enterprise, while en route to Starbase 9, has been suddenly pulled into the orbit of a black star of high gravitational attraction. Using the full power of warp speed, the Enterprise managed to snap away from the star’s pull, but like a rubber band snapping into place, the force sent the Enterprise plunging through space only to stop here, in the atmosphere of this strange place…

In fact, the dramatic warp speed launch has apparently sent the Enterprise backward in time to late 1960s Earth (apparently the year is 1969, two years after this episode was originally released). Note: Earth is located near Starbase 9 hence why it makes sense for the Enterprise to arrive at Earth. At any rate, Air Force pilot Captain John Christopher chases the Enterprise through Earth’s atmosphere. A tractor beam is then sent out but the beam is simply too strong so the Enterprise transports the lone pilot aboard the Enterprise just as his shuttle disintegrates. Now aboard the ship, he marvels at this strange situation. The Enterprise reaches an orbit-level and brings up its deflectors to prevent further detection as a “U.F.O.” by. the U.S. Air Force, but Spock privately suggests to Kirk that they now have a problem on their hands. Capt. John Christopher cannot simply be returned to Earth without risking a change to time, itself.

“We cannot return him to earth, Captain. He already knows too much about us and is learning more. I do not specifically refer to Captain Christopher, but suppose an unscrupulous man were to gain certain knowledge of man’s future? Such a man could manipulate key industries, stocks, and even nations. And, in so doing, change all that must be. And if it is changed, Captain, you and I, and all that we know, might not even exist.”

While the Enterprise requires repairs from its own debacle, it is also soon revealed that Captain Christopher has been sending clear images he took of the Enterprise from his plane back to base, so Kirk and Sulu beam directly into the base in an effort to retrieve Captain Christopher’s data before it can be viewed by the Air Force. Kirk is captured while Sulu secretly beams back aboard the Enterprise. The group is saved for the time being. Now, how to fix the situation with Capt. Christopher (along with another Air Force security guard who is accidentally beamed aboard)? And how to return to the 23rd century?

Spock suggests a new “slingshot” effect by rapidly moving toward the sun in order to bend time backwards and recreate the effect they accidentally stepped into. Thankfully, it works. The Enterprise manages to return the two men to their appropriate moment on earth, before they ever saw the Enterprise, by beaming them back without creating a doppelgänger effect. The arrival of the Enterprise in the late 1960s has now been corrected, and they speed away into the 23rd century as if they had never arrived just as the familiar voice of Starfleet is heard over the speaker.

My Thoughts on “Tomorrow Is Yesterday”

While certainly a fun classic episode, “Tomorrow Is Yesterday” is a bit of a contrived story. To be sure, time travel episodes of Star Trek are compelling, but they also have a tendency to unleash pandora’s box. It is apparently quite an easy albeit accidental achievement for the Enterprise to travel through time. Also, if the Enterprise has the capacity to turn back time using Spock’s “slingshot” maneuver, why waste time recovering the tapes from Omaha? Wouldn’t the tapes no longer exist if time goes backward? And how is it physically possible to beam a person back into their own body during a time warp? And how is it that Captain Christopher’s memory is erased if he travels backward, but not the same is not true for the Enterprise crewmen? At any rate, “Tomorrow Is Yesterday” is a great episode that opened a world of possibilities for Star Trek despite certain questionable plot-holes.


The writer of this episode, Dorothea Catherine “D.C.” Fontana (1939-2019), also worked as a writer for a few different television programs prior to Star Trek, and then she briefly worked as Gene Roddenberry’s secretary before becoming a writer on the show. At the age of 27, Fontana became the youngest story editor in Hollywood at the time, and she was also one of the few female staff writers. She remained a Star Trek writer until the end of the second season. Fontana had the notable distinction of being one of the few people to have worked on Star Trek: The Original Series, as well as Star Trek: The Animated Series, Star Trek: The Next Generation, and Star Trek: Deep Space Nine. Of them all, Deep Space Nine was her favorite Star Trek series.

Michael O’Herlihy (1929-1997) was an Irish television producer and director of shows like Gunsmoke, Mission Impossible, MAS*H and many others. This was the only episode of Star Trek he directed.

Star Trek Trivia:

  • This was the first full episode to be written by a woman, D.C. Fontana had previously written the teleplay for “Charlie X” but the story was the original product of Gene Roddenberry.
  • In this episode, Kirk notes there are 12 ships like the Enterprise under the “United Earth Probe Agency.” This fact is apparently contradicted in later series lore and literature.
  • The episode was originally conceived as a sequel to “The Naked Time” however when the ending to that episode was revised, “Tomorrow is Yesterday” was reworked as a stand-alone story. Associate producer Robert Justman devised the original idea for this story, and it was then handed to Dorothy Fontana to create the teleplay. Justman received neither credit nor payment for doing so, whereas Roddenberry’s agent charged the studio up to $3,000 for his own stories and rewrites.
  • There is an amusing scene in which Captain John Christopher notices a woman aboard the Enterprise. He looks at Kirk and asks, “A woman?” To which Kirk corrects him, “A crewmen” –highlighting the changing nature of the times.
  • Kirk’s recording computer has an amusing malfunction after the accidental time travel in this episode: it continually addresses him as “dear,” much to his chagrin. According to Spock, the computer was recently overhauled on the female-dominated planet called Cygnet XIV.
  • The “slingshot maneuver” was employed again by the crew in the motion picture Star Trek IV: The Voyage Home.
  • Actor Roger Perry who plays Capt. Christopher actually served as an intelligence officer in the United States Air Force during the early 1950s. Several other background characters in this episode also served in the military.
  • In this episode, the Air Force security guard reveals that an emergency button on a communicator automatically beams up a crewman.
  • This is the only episode which ends on a close-up of George Takei before the final Enterprise flies away.
  • This is the first episode where the Enterprise visits Earth during its five-year mission.

Click here to return to my survey of the Star Trek series.

1 thought on “Star Trek: Season 1, Episode Nineteen “Tomorrow Is Yesterday”

  1. Curious that the Enterprise in the classic series would only visit Earth in the past thanks to the sci-fi wonders of time travel. The movies would change all that and all the updated production values by then were obviously a blessing. There was of course the vision of 23rd-century home for Chris Pike in The Cage/Menagerie. Thank you for your review and trivia.

    Liked by 2 people

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