- See Masada for other articles with titles that contain, either by relationship or by coincidence, this character's surname.
Guillermo Masada was a male human who served in the Federation Starfleet in the 23rd century.
By 2263, Masada held the rank of lieutenant, and served as science officer and second officer of the USS Constellation under Commodore Matthew Decker. In that year, during the survey of Ravanar IV in the Taurus Reach, he discovered a mold containing an anomalously high count of chemical base pairs. Masada determined, that the Constellation's lab facilities were inadequate to pursue the matter, so Commodore Decker decided to transmit their findings to Starfleet Command. (VAN novel: Harbinger)
In 2266, he still served on the Constellation in the same capacity during the Alpha Proxima II crisis. (TOS - The Brave and the Bold, Book One novella: The First Artifact)
Masada perished, along with the rest of the Constellation crew, during that ship's encounter with an alien "planet killer" in 2267. (TOS episode: "The Doomsday Machine")
In an alternate timeline, Masada was assigned to the UESS Enterprise as science officer in 2264. (Star Trek: Myriad Universes novel: A Less Perfect Union)