BE-4
The Blue Engine 4 or BE-4 is an oxygen-rich liquefied-natural-gas-fueled staged-combustion rocket engine under development by Blue Origin. The BE-4 is being developed with private and public funding. The engine has been designed to produce 2.4 meganewtons of thrust at sea level. It was initially planned for the engine to be used exclusively on a Blue Origin proprietary launch vehicle New Glenn, the company's first orbital rocket. However, it was announced in 2014 that the engine would also be used on the United Launch Alliance Vulcan Centaur launch vehicle, the successor to the Atlas V launch vehicle. Final engine selection by ULA happened in September 2018. Although previously planned to fly as early as 2019, the first flight test of the new engine is now expected no earlier than 2022 on the Vulcan rocket.