Gilligan's Planet Gilligan's Planet is a spin-off of The New Adventures of Gilligan, based on the premise that the Professor had managed to build an operational interplanetary spaceship to get the castaways of the original cartoon series off the island. True to the castaways' perpetual bad luck, they rocketed off into space and crash-landed on an unknown planet that supported human life. In many ways, the planet was like the island, but with a strangely colored and cratered surface with more land to get around. The rocket was severely damaged in the crash; thus, the castaways were still stranded and the Professor resumed his attempts to repair their only way home.