BE-4

The BE-4 (Blue Engine 4) is a liquid rocket engine developed by Blue Origin. It uses liquefied methane fuel and operates on an oxygen-rich staged combustion cycle. The BE-4 produces 2,800 kN (640,000 lbf) of thrust at sea level.

Development of the BE-4 was funded through a combination of private investments and public contracts.

Although initially intended solely for use on Blue Origin's proprietary launch vehicle, the New Glenn, the engine was also selected in 2014 by United Launch Alliance (ULA) for its Vulcan Centaur rocket, which replaces the Atlas V and Delta IV. ULA finalized the BE-4 as its choice in September 2018.

The BE-4 made its first flight aboard the Vulcan Centaur rocket on January 8, 2024. It was later launched on New Glenn for the first time on January 16, 2025.