foster's contract also required a second novel, to be used as a basis for a low-budget sequel to "star wars" in case the film was not successful. though foster was granted a great deal of leeway in developing the story, a key requirement was that many of the props from the previous production could be reused when shooting the new film. foster's decision to place his story on a misty jungle planet was also intended to reduce set and background costs for a film adaptation. han solo and chewbacca were also left out as harrison ford had not signed a contract to film any of the sequels at the time of the novel contract. lucas's only request upon inspecting the manuscript was the removal of a space dogfight undertaken by luke and leia before crash-landing on the planet, which would have been effects-heavy and expensive to film.