For example, let's take the Death Star.
Space Opera - The Death Star can destroy planets! We must stop it!
Science Fiction - The Death Star operates using an anti-graviton beam. This cancells the gravity in an area of space. After that, the planet's centrifical forces just rip it apart.
??? Fiction - The Death Star was designed by the Geonosians just before the Clone Wars. It was researched at X facility by Y scientist. The keel was laid down in Z year. One bazillion tons of steel was used in its construction. The entrance foyer was Nabooan marble. The decor was military gray.
More examples include the cut-away books, Enterprise blueprints, and the inventory of the warp drive.
Right now, I want to call this techno-fiction, because I don't have another word for it. But is there a word for this style of fiction?