: Uses a triple-redundant flight computer system on each engine to ensure high reliability during launch.
: Based on the Apollo Lunar Module landing engine, this provides excellent stability and allows for deep throttling. Merlin 1Г—1
: The initial version used an expendable ablatively cooled carbon-fiber nozzle. It flew only twice on the Falcon 1 (2006–2007). : Uses a triple-redundant flight computer system on
: One center Merlin engine is fired during the final landing burn to enable first-stage vertical landings. Merlin 1Г—1