The original STSSTCS was produced by role-playing game manufacturer FASA back in the early to mid 1980's, in the time period between the release of the motion picture Star Trek II: The Wrath Of Khan, and the release of the motion picture Star Trek V: The Final Frontier.  It was a traditional counters/miniatures wargame, and unlike Star Fleet Battles (which I also play and enjoy) it didn't have a rulebook the size of the Gutenberg Bible nor did it require a West Point education to play.

 Unfortunately, FASA and Paramount failed to come to terms with their license agreement. Paramount failed to integrate and support the FASA material with their film projects (the original agreement called for FASA material to be an official part of the Star Trek Universe)

Add to the mix the fact that Gene Roddenberry, who had become something of an empty-headed leftist in his later years opposed renewal of FASA's Star Trek license. Having become a self-proclaimed pacifist, he claimed he never comfortable with the military aspect that his self-created "starfleet" implies, Gene apparently became unhappy with the "militarized" nature of the FASA role playing universe.  (Side note: how Gene expected to film a whole SF television series set on an armed star vessel--populated by folks with titles like "Captain" and "Lieutenant", doing galactic battle in the name of the Federation--and not have it seem "militaristic", is truly beyond me. But then no one ever accused leftists of making sense)

By 1990, FASA had lost it's license to Star Trek and the game went out of print. FASA, itself, ceased operations in 2002 and there is no chance of the Star Trek d% system returning to print. More is the pity because it was one of the best Trek RPGs ever published.