Atlas V is an active expendable launch system in the Atlas rocket family. Atlas V is operated by the Lockheed Martin-Boeing joint venture United Launch Alliance. Each Atlas V rocket uses a Russian-built RD-180 engine burning kerosene and liquid oxygen to power its first stage and an American-built RL10 engine burning liquid hydrogen and liquid oxygen to power its Centaur upper stage. The RD-180 engines are provided by RD AMROSS, while Aerojet Rocketdyne provides both the RL10 engines and the strap-on boosters used in some configurations. Launch window is between 15:00 GMT - 19:00 GMT.