The giant spider costume was nicknamed "Brian the Spider" by make-up designer Sheelagh Wells, in an effort to counteract her arachnophobia. She thought that if the spider had a name, it couldn't be very frightening. Her approach worked.
The protostage landing module is in fact a Lunar Module (LM) from the Apollo Program, the ship that landed on the Moon.
There are rumours that Jan Chappell made her decision to leave at the end of the season after seeing the giant ant in this story.
Tarrant states that there isn't a Federation anymore. The accuracy of the statement is unclear but the Federation is clearly functioning again by Rumours of Death (1980).
Avon's line, "I understand that this ship is the most powerful in the galaxy, and you are the most astute space warfare commander" is dubbed, with the word "astute" replacing whatever was originally said.