When HBO (Home Box Office) first started, it was purely a movie channel. This was the channel's first original series.
The Gorgs required two performers each: an actor to perform in the costume, and a puppeteer to do the voice and operate the face by radio controls. Previously, full-body Muppet characters (e.g., Big Bird) required the performer to operate the head with one hand, leaving the character with only one functional arm. Operating the face from outside allowed for a more expressive performance from the characters. Furthermore, video cameras installed inside the eyes allowed the performer to see from the Gorg's point of view.
After ceasing production on The Muppet Show, Jim Henson asked writers Jerry Juhl and Jocelyn Stevenson and conceptual designer Michael K. Frith to 'create a show for kids that will save the world'. He gave them access to his house in London, England to develop what would become Fraggle Rock.
The names "Gobo" and "Traveling Mat" are film-industry in-jokes. Gobos are used to control the shape of light emitted from a source and traveling mattes are used to combine two or more image elements into one final image.
Michael K. Frith originally conceived the Trash Heap character for the tenth season of Sesame Street. His reasoning was that archaeologist always gather the most useful information about ancient civilizations by going through its trash. When the Sesame Street producers decided not to use the character, Frith was able to resurrect her while developing Fraggle Rock.