Working toward their goal of making humanity multi-planetary. SpaceX needed a high-performance, affordable, and reusable engine for its Falcon family. They delivered Merlin. Using a gas-generator cycle with refined kerosene (RP-1) and liquid oxygen (LOX), each Merlin is capable of producing 86 tons of thrust. Along with its record thrust-to-weight ratio, deep throttling, and low-cost design, Merlin is built for mass production and rapid reuse. Nine Merlins power the Falcon 9 first stage, making it the most reliable and frequently flown orbital rocket in history, the undisputed workhorse of commercial spaceflight.