: One center Merlin engine is fired during the final landing burn to enable first-stage vertical landings.
: An upgraded variant of the 1A with a more powerful turbine; it was never used on a flight vehicle before SpaceX shifted to regenerative cooling. Merlin 1Г—1
: Drives both the LOX and RP-1 impellers. It also provides high-pressure fuel for hydraulic actuators , eliminating separate hydraulic systems. : One center Merlin engine is fired during
: Based on the Apollo Lunar Module landing engine, this provides excellent stability and allows for deep throttling. It also provides high-pressure fuel for hydraulic actuators
: The current active version, introduced in 2013. It is designed for rapid reusability and vertical landings. Core Specifications (Merlin 1D) Sea Level (SL) Vacuum (Vac) Thrust ~845 kN (190,000 lbf) ~981 kN (220,500 lbf) Specific Impulse (Isp) Chamber Pressure 9.7 MPa (1,410 psi) 9.7 MPa (1,410 psi) Thrust-to-Weight Ratio Sources: Design Innovations