Originally broadcast as a two-hour episode. Separated into two parts for syndication.
The street scenes in the abandoned capitol city on Paradeen were filmed in Montreal, Canada in the leftover pavilions from Expo '67. The footage was later reused on Buck Rogers in the 25th Century (1979) and Quantum Leap (1989).
The art used to depict the city on Paradeen in this episode was later used for New Chicago and the Directorate building from Buck Rogers in the 25th Century (1979), starring Gil Gerard. Both series were created and produced by Glen A. Larson.
Those from Terra use seconds, minutes etc. to measure time not centons etc.
This was the last episode to feature Athena.