Geordi's VISOR was originally improvised from an automotive air filter and a hair band.

The Tantalus field was a 23rd century device found aboard the I.S.S. Enterprise in the mirror universe, which could be used to monitor and eliminate enemies from existence with the touch of a button.

In "Relics", the crew of the U.S.S. Enterprise-D discovers Montgomery Scott alive in a transporter buffer while investigating the 75-year-old wreck of a Federation transport vessel.

DeForest Kelley appeared as 137-year-old Leonard McCoy in "Encounter at Farpoint", the pilot episode of Star Trek: The Next Generation, reprising his role from the original series. As he inspects the Enterprise-D, he tells Data, "You treat her like a lady ... and she'll always bring you home."

In "The Naked Now", Tasha Yar asks Data if he is "fully functional". He replies that he is not only functional "in every way", but also "programmed in multiple techniques." "Oh you jewel," Tasha says, "that's exactly what I hoped!"

Martin Landau was originally offered the role of Spock, but declined. Later, Leonard Nimoy, who did accept the part, took over the role of the disguise-expert on "Mission: Impossible" when Landau left that show. Landau later headed his own sci-fi series, "Space: 1999" (1975).

A 22nd-century beagle, Porthos, is Captain Archer's closest companion and confidant.

Star Trek: Deep Space Nine stars Alexander Siddig (Dr. Julian Bashir) and Nana Visitor (Maj. Kira Nerys) were married in real life in 1997 (after the show's fourth season).

Mae C. Jemison was the first real astronaut to appear in any Star Trek show. She played "Lt. Palmer" in a Star Trek: The Next Generation episode entitled "Second Chances" (May 22, 1993).

In "Slaver Weapon", an episode of Star Trek: The Animated Series, writer Larry Niven introduced the cat-like alien race, the Kzinti, from his "Known Space" novels into the Star Trek universe.