The auto-destruct system (also known as self-destruct or destruct sequence) was a starship system that allowed the total destruction of the vessel. This was typically activated as a last resort, usually to prevent a ship from falling into enemy hands.
On Starfleet vessels, the activation sequence varied from class to class but usually required authorization with the use of command authorization codes. Once the countdown was activated, the ship's computer could give audio warnings and/or displayed countdown warning graphics on viewscreens and terminals, though this featured could be disabled when initiating the sequence. (Star Trek: First Contact) In the 23rd century, self-destruct was also known as Starfleet Order 2005. (Star Trek: The Motion Picture)
On Constitution-class starships, the captain or admiral (including rear admiral) and two senior officers (chief engineering and science officers/acting science officer) were required to initiate the destruct sequence, using the following, concurrent codes:
Each officer would state their name, rank and corresponding code:
- "Destruct sequence 1, code 1-1 A."
- "Destruct sequence 2, code 1-1 A-2B."
- "Destruct sequence 3, code 1 B-2B-3."
The computer would then reply:
- "Destruct sequence completed and engaged. Awaiting final code for (time interval) countdown."
The commanding officer would then state:
- "Code zero zero zero. Destruct. Zero."
The computer would than activate red alert and respond:
- "Destruct sequence is activated."
The sequence could be aborted at any time until T-minus five seconds by the captain or highest-ranking officer, with the command "Code 1-2-3-continuity, abort destruct order." Beyond that, the destruct order could not be cancelled. (TOS: "Let That Be Your Last Battlefield"; Star Trek III: The Search for Spock)
It was possible to set a remote auto-destruct for a Crossfield-class starship, allowing the crew to evacuate to another vessel. In 2257, Christopher Pike and Saru attempted this method with the USS Discovery, both of them providing handprint authorization. The crew was then evacuated to the USS Enterprise, but the attempt failed due to the Sphere data merging with the vessel's systems and protecting itself. (DIS: "Such Sweet Sorrow")
Originally, the auto-destruct sequence aboard Galaxy-class starships required the authorization and palm-print identification of both the commanding and executive officers from main engineering. The sequence could be aborted from the bridge by voice recognition and palm print identification by the same officers. The time interval could not be adjusted and was preset for a five minute countdown. (TNG: "11001001")
By 2365, the time interval could be pre-selected and the countdown aborted without the need of palm-print identification. The activation of the auto-destruct sequence also triggered a red alert. (TNG: "Where Silence Has Lease")
Upon providing palm-print identification, the captain would order the computer to initiate the auto-destruct. The computer would ask if the first officer concurred. Providing the first officer agrees, the computer would verbally confirm the order and begin the countdown with the appropriate time delay. Should the order be desired to be cancelled, the captain would order the computer to abort the sequence. The computer would question the first officer's agreement before cancelling the sequence. (TNG: "11001001", "Where Silence Has Lease")
The Defiant-class sequence was activated from the bridge, requiring the captain and first officer's consent and palm-print identification to activate. The time delay was left to the captain's discretion. Upon activation of the destruct sequence, a red alert would be triggered and all bridge computer terminals would display the remaining time left in the countdown. Cancelling the sequence would require the captain and first officer's orders without the need of palm-print identification or computer clarification. (DS9: "The Adversary")
Aboard the Intrepid-class, auto-destruct required the captain's sole authorization. In addition to selecting the desired time interval, the captain also had the option of ordering a silent countdown – a single voice prompt would occur at the commencement of the sequence, with no further audio warnings made. (VOY: "Deadlock", "Dreadnought")
The Sovereign-class required the authorization of the captain and two senior officers. Each would state their name and rank, confirming the sequence, and giving their authorization code. The captain would then select the destruct sequence type, sequence delay, and whether a silent countdown would be initiated.
- "Computer, begin auto-destruct sequence, authorization Picard 4-7 Alpha Tango."
- "Computer, Commander Beverly Crusher. Confirm auto-destruct sequence, authorization Crusher 2-2 Beta Charlie."
- "Computer, Lieutenant Commander Worf. Confirm auto-destruct sequence, authorization Worf 3-7 Gamma Echo."
- (The computer would ask for the final code to start the sequence.)
- "This is Captain Jean-Luc Picard. Destruct sequence Alpha-One. Fifteen minutes, silent countdown. Enable."
The auto-destruct need not be deactivated by the ship's captain, as Lieutenant Commander Data was able to deactivate the auto-destruct sequence by himself, however, this could be the result of Data hacking into main computer past normal operating parameters.
An "Omega" option for the auto-destruct was also available and only needed the captain's authorization to initiate.
- "Computer, stand-by auto-destruct sequence Omega. Recognize voice pattern Jean-Luc Picard, authorization Alpha-Alpha 3-0-5."
23rd century Romulan vessels used "old style" atomic weapons in their self-destruct system which were not integrated into the ship itself. These weapons could be removed and jettisoned into space as mines. (TOS: "Balance of Terror") Romulan scout ships were equipped with an Auto-destruct sequencer. (TNG: "The Defector")
During the Galen border conflict, Talarian observation craft equipped with self-destruct devices and subspace proximity detonators were responsible for 219 casualties over a three day period. (TNG: "Suddenly Human")
A Borg vessel's self-destruct mechanism forced the ship's power grid to feed back on itself, forcing an explosion that destroyed the ship. Lieutenant Commander Data was able to trigger such a destruction while being linked to the collective consciousness of the Borg ship that threatened Earth in 2367. The Borg Queen ordered the self destruction of several Borg ships that carried drones linked to Unimatrix Zero as well as a Borg tactical cube that had Captain Kathryn Janeway, Lieutenant Commander Tuvok, and Lieutenant B'Elanna Torres aboard. (TNG: "The Best of Both Worlds, Part II"; VOY: "Unimatrix Zero, Part II")
When a Borg vessel was critically damaged, all of its vital technology, such as the transwarp coils, self-destructed to prevent their use by other species. This process is autonomous and independent from the ship's self destruction. (VOY: "Dark Frontier")