last long," and they ploughed through her fifteen pages of work in an unprecedented two days. The final shooting script contains unaired dialogue between Arra and Koenig. Cut for time, it had Arra explaining to the Alphan that if he were to consider the Universe as a microscopic cell, his galaxy could be thought of as a single chromosome, the solar system as one gene and himself as a minuscule fragment of that gene. This missing sequence made sense of Arra's later line that the gene of which she and her people were part would mutate. Also lost was the end of the epilogue, where Koenig would leave Helena alone at the window. Gazing out into space, she was to suddenly assume an enraptured expression and utter "Arra..." Martin Bower constructed the Atherian spaceship and nuclear charge miniatures. Both would reappear in later spaceship graveyard sequences in "Dragon's Domain" and "The Metamorph". Novelisation The episode was adapted in the fourth Year One Space: 1999 novel Collision Course by E.C. Tubb, published in 1975. While being true to the script, Tubb would attempt to address the scientific criticism that shock waves cannot propagate through the vacuum of space. Bergman would theorise that the atomic blast would divert the Moon and Atheria by the creation of a 'sub-etheric' shock wave; the creation of a 'sub-atomic vortex' would act on not actual particles of matter, but on the 'sub-spatial matrix' confining them. It would be like moving bricks by moving the mortar binding them. References External links Space: 1999 - "Collision Course" - The Catacombs episode guide Space: 1999 - "Collision Course" - Moonbase Alpha's Space: 1999 Page 1975 British television episodes Space: 1999 episodes