S-thread boosters were a type of technology used to create and maintain hyperspace routes, such as the Sanctuary Pipeline. They were extremely expensive, enough to "bankrupt whole star systems," yet considerably less than the cost of building a Death Star.
Shortly before the Battle of Endor, Major Capin Harinar wrote a report to General Crix Madine explaining how the Empire had corrected for galactic drift and used s-thread boosters to create a hyperlane directly to the Moddell sector.
- Star Wars Helmet Collection 14
- Star Wars: The Rebel Files