America's next Rocket Engine

We chose LNG because it is highly efficient, low cost and widely available. Unlike kerosene, LNG can be used to self-pressurize its tank. Known as autogenous repressurization, this eliminates the need for costly and complex systems that draw on Earth’s scarce helium reserves. LNG also possesses clean combustion characteristics even at low throttle, simplifying engine reuse compared to kerosene fuels.

BE-4 was designed from the beginning to be a medium-performing version of a high-performance architecture. It’s a conscious design choice made to lower development risk while meeting performance, schedule and reusability requirements. With our hardware-rich approach, multiple developmental units and redundant test stands enable a high test tempo and rapid learning.