The program was based on the work of science fiction writer and illustrator Wayne D. Barlowe, specifically the alien lifeforms presented in his 1990 speculative fiction book "Expedition: Being an Account in Words and Artwork of the 2358 A.D. Voyage to Darwin IV". The main difference is that the book is presented from the writer's point of view, as if he were an explorer on an alien planet, whereas this documentary focuses on robotic exploration probes.