Star Trek Expanded Universe

The security chief, also known as the chief of security or the chief security officer, holds responsibility for the safety, protection and defence of the crew and others aboard a starship or starbase.

22nd century[]

Prior to the Federation Starfleet, Earth's Starfleet called this position the armory officer. The term tactical officer was also used interchangeably. (ENT: "Singularity")

23rd century[]

By the mid-23rd century, Federation starships and starbases used the term "security chief". On some ships, like the USS Enterprise (NCC-1701), the security chief did not hold a bridge officer's position. (TOS: "The Devil in the Dark")

In the TOS novel: Errand of Vengeance trilogy, published by Pocket Books, the many security chiefs seen during the five-year mission were reconciled by the use of the billet title security section chief, noting that the billet was also known as squad leader. In 2266, the three assigned to Enterprise were Fuller, Ordover and Brantley. (Errand of Vengeance trilogy: The Edge of the Sword)

Starfleet merged the security chief and chief tactical officer positions sometime in the 2270s. Often, the helmsman or navigator would double as tactical officer during a given situation. (Star Trek: The Motion Picture, Star Trek V: The Final Frontier, Star Trek VI: The Undiscovered Country)

At least in the Orion Press continuity, Chekov's billet was chief of security and personnel on the Enterprise-A in 2287 (The Dianasian Gift), adding a responsibility to a security chief's portfolio that would have been a separate billet, personnel officer, in the 2260s. (TOS: "Court Martial")

24th century[]

By the 24th century, Starfleet reconsidered the helmsman and navigator positions, combining them into a new position called the flight controller aka conn. They removed the tactical and security duties, giving these duties to a dedicated tactical officer, who normally held a position as a bridge officer. (TNG: "Encounter at Farpoint")

As well, with helm and navigation consolidated in the new conn position, the chief tactical officer fulfilled the role of security chief ("Encounter at Farpoint").

On some starbases and space stations, the roles of security chief and tactical officer were separate. Odo was the security chief (albeit with the Bajoran billet title of constable), but not tactical officer, aboard Deep Space 9. (DS9: "Emissary")

Notable security chiefs[]

External links[]