Leigh Brackett 
The Blue Behemoth [EPUB ebook] 

Shannon’s Imperial Circus was a jinxed space-carny leased for a mysterious tour of the inner worlds. It made a one-night pitch on a Venusian swamp-town—to find that death stalked it from the jungle in a tiny ball of flame.
Leigh Brackett was the undisputed Queen of Space Opera and the first women to be nominated for the coveted Hugo Award. She wrote short stories, novels, and scripts for Hollywood. She wrote the first draft of the Empire Strikes Back shortly before her death in 1978.