. . . "The Reusable Booster System (RBS) was a United States Air Force research program, circa 2010 to 2012, to develop a new prototype vertical-takeoff, horizontal-landing (VTHL) reusable booster and a new prototype expendable second stage to replace the existing Evolved Expendable Launch Vehicles (EELV) after 2025. The program was discontinued in 2012."@en . . "Reusable Booster System"@en . . . "The Reusable Booster System (RBS) was a United States Air Force research program, circa 2010 to 2012, to develop a new prototype vertical-takeoff, horizontal-landing (VTHL) reusable booster and a new prototype expendable second stage to replace the existing Evolved Expendable Launch Vehicles (EELV) after 2025. The program was discontinued in 2012."@en . . .