Hadley engine
The Ursa Major Technologies Hadley is a  thrust Kerosene/LOX oxidizer-rich staged combustion cycle rocket engine. Hadley is the first engine developed by Ursa Major Technologies. It started development in 2015, and prototypes were test fired in 2018. , qualification of the engine is complete and flight-ready engines have been delivered to customers. Initial customers of the Hadley engine include Stratolaunch Systems, which has announced that they will use the Hadley engine on their Talon-A hypersonic test vehicle, and Phantom Space Corporation, who will use it on their Daytona small-lift rocket. ABL Space Systems initially announced they would use the Hadley engine for the upper-stage of their RS1 rocket, but have subsequently decided to use an internally-developed engine called E2. In April 2023, Astra revealed that the vacuum variant of the Hadley engine would power the second stage of their Rocket 4.0. References

External links 

 Ursa Major Technologies Hadley webpage

Rocket engines using kerosene propellant
Rocket engines using the staged combustion cycle