Star Trek Galactic Barrier

[Ender]

What episode had the Galactic Barrier in it?

[Ghost Rider]

I believe it was "Where No Man Has Gone Before"

The Gary Mitchell one.

[consequences]

Wasn't there at least one other episode that mentioned it? It was the one where the one woman was turned into a cube and crushed if I remember correctly.

[Patrick Degan]

• "Where No Man Has Gone Before" —the original, with Gary Mitchell, of course.
• "By Any Other Name" —the one with the Kelvans; mentioned by name. And yes, this is the one with the female yeoman turned into a cube and crushed.
• "Is There In Truth No Beauty" —certainly using the same visuals as the Barrier (except for when the Enterprise is depicted adrift); not specifically mentioned as such in the actual episode. It is assumed however that it was the Barrier.

The Galactic Barrier does not survive conceptually past TOS. The TNG episode "Where None Have Gone Before" invokes the memory of the Barrier in the alternate space the E-D winds up in but of course is not related to the TOS artefact in any way.