Merlin 1г—1 -

: One center Merlin engine is fired during the final landing burn to enable first-stage vertical landings.

: The first to feature a regeneratively cooled nozzle and combustion chamber. It powered the first privately developed rocket to reach orbit (Falcon 1 Flight 4) and early Falcon 9 flights. Merlin 1Г—1

: 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. : One center Merlin engine is fired during