script dated 18 May 1976, Koenig's co-pilot, Bill, was supposed to be Astronaut Bill Fraser. Budgetary limitations led to John Hug's replacement with one-off actor Alan Hunter. Early drafts of the script had Helena and Ben Vincent referring to their prosthesis as the 'Bergman' heart, as it was identical to the mechanical heart implanted in the late Victor Bergman. One line of dialogue read 'Victor might have lived forever—given the chance.' Novelisation The episode was adapted in the second Year Two Space: 1999 novel Mind-Breaks of Space by Michael Butterworth and J. Jeff Jones published in 1977. The authors made minor changes in the story, the most obvious being the two Maya transformation sequences feature decidedly extraterrestrial animals: a long-bodied beast with natural armour plating and trap-like mouth would come to Verdeschi's aid in the explosives storeroom and later, a headless, bipedal bat-creature would use its sonar to navigate the Security team through the darkness of the catacombs. The novel would also give Koenig and Maya more exposure than did the actual shooting script and transformed the character of 'Sahn' into a young Indian man. References External links Space: 1999 - "Catacombs of the Moon" - The Catacombs episode guide Space: 1999 - "Catacombs of the Moon" - Moonbase Alpha's Space: 1999 page 1976 British television episodes Space: 1999 episodes