|Tomorrow is Yesterday|
|Season 1, Episode 19|
|Air date||January 26, 1967|
|Written by||D.C. Fontana|
|Directed by||Michael O'Herlihy|
|Star Trek episodes|
The Enterprise is sent back in time to the 1960s.
Stardate 3113.2 - 3114.1 Air base detects EnterpriseThe Enterprise is pulled into a black hole and travels back in time to the 20th century. When they enter the Earth's atmosphere, they are detected by the Omaha Air Base. The air base sends a jet controlled by a man named Captain Christopher to investigate what they had found. To prevent the plane from attacking the ship, the Enterprise tries to bring aboard using the tractor beam, but ends up destroying it. Luckily, Montgomery Scott is able to beam aboard the pilot. Unfortunately for the pilot, he cannot come back to Earth because he had learned too from his stay on the ship. If Captain Christopher were to return to Earth, he could change the course of history. However, Spock soon learns that Captain Christopher will one day father a son who will be important to history of space exploration. To complicate thing further, Captain Christopher had turned on his instruments and was recording what he had seen and heard. Kirk decides that they need to head down to the airbase to retrieve the records containing footage of the Enterprise. Kirk is intorrogatedKirk and Sulu beam to the air base. While looking for the recordings, they are spotted by the air police sergeant. The police sergeant takes one of their communicators and accidentally activates an emergency signal. Spock picks up on the signal and beams up the sergeant. Upon seeing the inside of the starship appear before his eyes, the sergeant becomes fearful and decides to stay in the transporter. Sulu finds the recordings in the dark room of the air base. Their entry into the room trips an alarm and alerts the air force personnel. Soon, they arrive to arrests Kirk and Sulu. However, Kirk distracts them while Sulu beams up with the recordings. Kirk is taken prisoner and interrogated for information. Kirk's interrogation does not last long when Spock and Sulu beam down to free Kirk. On the ship, Spock purposes that the Enterprise should recreate the conditions that brought them back in time. He believes that if they slingshot around the sun, it will allow them to time travel and return Captain Christopher to Earth without him having any knowledge of what he had seen. Enterprise near the SunWhen they go through with the plan Christopher and the air police sergeant are transported back to the Earth without any memory of being aboard the ship. Meanwhile, the Enterprise continues to accelerate until it brakes and ends up in the 23rd century.
This episode was based on a project that was done by the United States after World War 2. During that time, the United States air force launched a project called Project Bluebook, which sought to prove or disprove the UFO sightings reported every year. However, the project was canceled because they were unable to produce any conclusive evidence. "Tomorrow is Yesterday" was created based on the idea that aliens aboard a spaceship had stolen the evidence.