In Michael Kandel’s satiric short story, “Space Opera,” which is written as a libretto for a science fiction opera, the curtain rises in a provincial spaceport on the Planet Creeth orbiting the sun Alpha Cygni.The opera’s hero, Bobby “Rocket” DeVries, and his fellow grease monkeys are banging the dents out of a rickety space junker, singing “Let’s return this old bucket to the stars,” to the din of their hammer blows.Then Bobby’s friend Fred runs in with the news that Darg Bahr, the governor of the astero