SpaceX Stories: How Did SpaceX Rocket Engines Get Their Names

Tom Mueller (Credit: Popular Mechanics)

Tom Mueller has been designing rocket engines at SpaceX since the company was founded in 2002. He helped develop the Kestrel (Falcon 1), Merlin (Falcon 1, Falcon 9 and Falcon Heavy), Raptor (Starship) and more. Currently, he works part-time at SpaceX as a Senior Advisor.

You may already know that the Falcon rocket is named after the Millennium Falcon from Star Wars, but do you know how exactly the SpaceX engines got their names? Luckily, Mueller was kind enough to share the story on Quora:

When we first started SpaceX we just called our booster engine the 60 K engine, but after we started running it Elon told me to come up with a name for it that wasn’t numbers and letters (like RD-180, RS-68, etc.). One of the people working on the turbopump from Barber Nichols was a Falconer and she suggested we name it after a Falcon. I thought that sounded good so I asked her what are some Falcon names. She named off a bunch and I can’t recall them all but I do remember that the Kestrel is the small one, the Merlin is a medium size Falcon and the Peregrine and Gyrfalcon are large Falcons. I thought great, we’ll name the small second stage engine Kestrel and the medium sized engine the Merlin. I knew we would develop bigger engines in the future so I planned to reserve Peregrine for later. Elon liked the naming so it stayed. Years later we started work on a staged combustion engine which was a different type than Merlin, so I was thinking along the lines of Eagle or something. I eventually came up with Raptor, which is a general definition of birds of prey including Eagles, Hawks, Falcons and Owls. No, it’s not named after a dinosaur! That was accepted as the name of the engines for BFR.

This answer typed on my phone at Orlando Airport on the way back from the Falcon Heavy test launch where 28 Merlin’s engines did their job spectacularly!

Bonus! Watch Tom Mueller explain how the Merlin engine works:

Tip: You can learn more about the powerful Raptor engine in the Starship Compendium.

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