On this day in the Star Trek universe:

Star Trek (1966 & 1967)

Star Trek: The Next Generation (1990)

Star Trek: Voyager (1999)

Star Trek

Season 1. Episode 5.

Episode entitled: The Enemy Within.

Released October 6, 1966.

Directed by Leo Penn.

Written by Richard Matheson.

Created by Gene Roddenberry.

Music by Alexander Courage, Sol Kaplan.

Cast: William Shatner, Leonard Nimoy, DeForest Kelley, Grace Lee Whitney, George Takei, James Doohan, Nichelle Nichols, Ed Madden, Garland Thompson, Jim Goodwin, Eddie Paskey.

Star Trek

Season 2. Episode 4.

Episode entitled: Mirror, Mirror.

Released October 6, 1967.

Directed by Marc Daniels.

Written by Jerome Bixby.

Created by Gene Roddenberry.

Music by Alexander Courage, Fred Steiner.

Cast: William Shatner, Leonard Nimoy, Nichelle Nichols, DeForest Kelley, James Doohan, George Takei, Walter Koenig, BarBara Luna, Vic Perrin, John Winston, Garth Pillsbury, Pete Kellett, Bobby Bass, Bill Blackburn, Bobby Clark, Roger Holloway, Johnny Mandell, Robert Metz, Eddie Paskey, Russ Peek, Paul Prokop.

Star Trek: The Next Generation

Season 4. Episode 3.

Episode entitled: Brothers.

Released October 6, 1990.

Directed by Rob Bowman.

Written by Rick Berman, Ronald D. Moore, Joe Menosky.

Created by Gene Roddenberry.

Music by Ron Jones.

Cast: Patrick Stewart, Jonathan Frakes, LeVar Burton, Michael Dorn, Gates McFadden, Marina Sirtis, Brent Spiner, Wil Wheaton, Cory Danziger, Colm Meaney, Adam Ryen, James Lashly, Majel Barrett, Joe Baumann, Michael Braveheart, George B. Colucci Jr., Debbie David, Jeremy Doyle, Elliot Durant III, Margaret Rose Flores, Carrie Henger, Jerry Spicer, K. Uchizono.

Star Trek: Voyager

Season 6. Episode 3.

Episode entitled: Barge of the Dead.

Released October 6, 1999.

Directed by Michael/Mike Vejar.

Created by Rick Berman, Michael Piller, Jeri Taylor.

Written by Bryan Fuller, Ronald D. Moore, Michael Taylor, Robert Doherty.

Based on Star Trek, created by Gene Roddenberry.

Music by David Bell.

Cast: Kate Mulgrew, Robert Beltran, Roxann Dawson, Robert Duncan McNeill, Ethan Phillips, Robert Picardo, Tim Russ, Garrett Wang, Jeri Ryan, Eric Pierpoint, Sherman Augustus, Karen Austin, John K. Shull, David Lewman, Dennis Madalone, Nichole McAuley, Tom Morga, Mark Tobin.