The RD-8 is a Soviet / Ukrainian liquid propellant rocket engine burning LOX and RG-1 in an oxidizer rich staged combustion cycle. It has four combustion chambers that provide thrust vector control by gimbaling each of the nozzles in a single axis ±33°. It was designed in Dnipropetrovsk by the Yuzhnoye Design Bureau as the vernier thruster of the Zenit second stage. As such, it has always been paired with the RD-120 engine for main propulsion.