On this day in the Star Trek universe:

Star Trek (1966 & 1967)

Star Trek

Season 1. Episode 14.

Episode entitled: Balance of Terror.

Released December 15, 1966.

Directed by Vincent McEveety.

Written by Paul Schneider.

Created by Gene Roddenberry.

Music by Alexander Courage, Fred Steiner.

Cast: William Shatner, Leonard Nimoy, Nichelle Nichols, DeForest Kelley, Mark Lenard, Paul Comi, Lawrence Montaigne, Grace Lee Whitney, George Takei, James Doohan, Stephen Mines, Barbara Baldavin, Garry Walberg, John Warburton, John Arndt, Bill Blackburn, Robert Chadwick, Frank da Vinci, Walt Davis, Vince Deadrick Sr., Jeannie Malone, John Hugh McKnight, Sean Morgan, Eddie Paskey, Anthony Larry Paul, Ron Veto.

Star Trek

Season 2. Episode 13.

Episode entitled: Obsession.

Released December 15, 1967.

Directed by Ralph Senensky.

Written by Art Wallace.

Created by Gene Roddenberry.

Music by Alexander Courage.

Cast: William Shatner, Leonard Nimoy, Nichelle Nichols, DeForest Kelley, James Doohan, George Takei, Majel Barrett, Walter Koenig, Jerry Ayres, Bill Blackburn, John Blower, Frank da Vinci, Jeannie Malone, Eddie Paskey, Basil Poledouris.