High Quality Content by WIKIPEDIA articles! The Space Shuttle Solid Rocket Boosters (SRBs) were the pair of large solid rockets used by the United States` NASA Space Shuttle during the first two minutes of powered flight. Together they provided about 83% of liftoff thrust for the Space Shuttle. They were located on either side of the rusty or orange-colored external propellant tank. Each SRB produced 80% more liftoff thrust than one F-1 engine, the most powerful single-chamber liquid-fueled rocket engine ever flown — five of which powered the first stage of the Saturn V "moon rocket". The SRBs were the largest solid-fuel rocket motors ever flown, and the first to be used for primary propulsion on human spaceflight missions. The spent SRBs were recovered from the ocean, refurbished, reloaded with propellant, and reused for several missions. The prime contractor for the SRBs and the manufacturer of the vital solid fuel rocket segments was the Thiokol Corporation of Brigham City, Utah.