(covers information from several alternate timelines)
Helmets were a device made of a material much harder than that of a hat. They were generally worn strictly for protective reasons, although they could also be worn for decoration.
The helmets included with United Earth Starfleet EV suits, according to Malcolm Reed, after wearing his suit for three days, felt as if it would have fused to his skull, leading him to threaten to "find the designer of this suit make him wear it for three days." (ENT: "United")
In Timothy's fictional account of the attack on his ship, the SS Vico, he claimed that an unidentified species came out of nowhere, fired at their ship, before boarding it. His description of the unknown forces was "they had purple helmets on and phaser rifles." (TNG: "Hero Worship")
After Chief Miles O'Brien punched a Hunter, he stated, "Glass jaw. Now I know why you wear a helmet." (DS9: "Captive Pursuit")
Types of helmets
Army helmet
Several of the Onlies on Miri's planet wore helmets resembling those of United States Army soldiers. (TOS: "Miri")
Romulan helmet
Crew members aboard Romulan Birds-of-Prey during the 2260s wore helmets. Some exceptions included the ship's commanding officer and his centurion. (TOS: "Balance of Terror", "The Enterprise Incident")
Starfleet security helmet
Introduced in the 2270s, these helmets were a part of a Starfleet Security officer's uniform, due to the sometimes hazardous nature of their work. (Star Trek: The Motion Picture; Star Trek III: The Search for Spock)
Klingon helmet
Light helmets were donned by workers in the underground Klingon dilithium mines of Rura Penthe in the 2290s. They were not in evidence during dilithium mining on Rura Penthe during the 2150s. (Star Trek VI: The Undiscovered Country; ENT: "Judgment")
In the alternate reality, all members of the Klingon Defense Force wore helmets that gave everyone the appearance of cranial ridges. (Star Trek Into Darkness)
Hunter helmet
The Hunters, a species from the Gamma Quadrant, wore these high-technology helmets during their hunt for a Tosk. The helmets allowed the Hunters to see even the cloaked Tosk. (DS9: "Captive Pursuit")
Ekosian Nazi helmet
Within their military, Ekosian soldiers wore helmets identical to those of the National Socialist Party in 1930s-1940s Earth. (TOS: "Patterns of Force")
Mokra Order helmet
The soldiers of the Mokra Order wore black helmets matching their uniforms. Inside the detention facility they took them off. (VOY: "Resistance")
World War III-era helmet
During World War III, soldiers were seen wearing combat helmets equipped with cameras in order to record events that occurred on the battlefield. One of these helmets managed to record the Red Angel transport the members of the East Fork Presbyterian Church to the planet Terralysium. (DIS: "New Eden")
See also
- Football helmet
- Hard hat
- Kabuto
- Pith helmet
Appendices
Background information
An early version of the nonsense poem "Saturn Rings", from the final draft script of TOS: "Charlie X", included the line, "Vulcan's helmet on my head."