Star Trek (1966–1969)
34 user 7 critic

The Doomsday Machine 

The USS Enterprise encounters the wrecked USS Constellation and its distraught commodore who's determined to stop the giant planet-destroying robot ship that killed his crew.


Marc Daniels


Gene Roddenberry (created by), Norman Spinrad

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Episode complete credited cast:
William Shatner ... Capt. Kirk
Leonard Nimoy ... Mr. Spock
DeForest Kelley ... Dr. McCoy
William Windom ... Commodore Decker
James Doohan ... Scott
George Takei ... Sulu
Elizabeth Rogers Elizabeth Rogers ... Lt. Palmer
John Winston John Winston ... Lt. Kyle
Richard Compton Richard Compton ... Washburn
John Copage John Copage ... Elliott
Tim Burns Tim Burns ... Russ
Jerry Catron ... Montgomery


The U.S.S. Constellation and its crew were destroyed by a giant robot ship which consumes planets for fuel, leaving only a guilt-ridden Commodore Decker aboard the crippled ship. Kirk beams over to begin repairs while Decker beams aboard the Enterprise. After Kirk loses radio contact with the Enterprise, the obsessed Commodore seizes command of the starship, determined to destroy the planet-killer, even at the cost of Kirk's ship and the entire crew. Written by

Plot Summary | Plot Synopsis


TV-PG | See all certifications »


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Release Date:

20 October 1967 (USA) See more »

Company Credits

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Technical Specs


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Did You Know?


Norman Spinrad has expressed disappointment that the actor whom he envisioned playing Decker, Robert Ryan, was not cast. Ryan was a fan of the series and wanted to do the episode. Scheduling conflicts prevented this, so William Windom was cast. See more »


As is typical in "space opera", when the Enterprise changes direction, it dips and turns as an aircraft would, interacting with the atmosphere surrounding it. There is no atmosphere in space, and a spacecraft can change direction freely, without having to consider aerodynamics. Of course, the dipping and turning look a lot nicer. See more »


Spock: Random chance seems to have operated in our favor.
Dr. McCoy: In plain non-Vulcan English, we've been lucky.
Spock: I believe I said that, Doctor.
See more »

Alternate Versions

Special Enhanced version Digitally Remastered with new exterior shots and remade opening theme song. Highlights include Decker's shuttle impatiently taking off before the hangar doors had fully opened. See more »


Featured in For the Love of Spock (2016) See more »

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User Reviews

One of the best
25 June 2017 | by john-1451See all my reviews

One of the reasons the original series is thought of so highly is that certain individual episodes (City on the Edge of Forever, Journey to Babel, Balance of Terror and this one) are as good as anything you will see on movies or TV. This episode highlights some the things that made TOS great: Lighting, set design, and the acting. For all the grief Shatner receives as an actor, in this episode he really nails what makes Kirk a great captain. He is confident, forceful, able to think on his feet and fully in command. The color scheme, which employs bright primary colors, and the eye light they use on Kirk to highlight his sense of command are excellent. And don't forget the writing and directing that fully makes use of the tension inherent in the situation. You will never see a better straight ahead action episode on TV than The Doomsday Machine.

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