SpaceX Reaches Merlin Milestone

100: Image Credit SpaceX

SpaceX has announced via website update a milestone in the production of its Merlin 1D engine.

“Less than two years after SpaceX began producing the Merlin 1D engines that power the Falcon 9 rocket, the 100^th Merlin 1D engine is complete. SpaceX is currently the largest private producer of rocket engines in the world.”

“Engines are currently manufactured at a rate of four per week, projected to rise to five per week by the end of 2014. The production process begins with major engine components – injector, turbopump, gas generator, thrust chamber, valves and actuators – integrated with tubing, sensors, and other small components to form the major sub-assemblies of the engine. These sub-assemblies are put together to become the engine’s lower and upper assembly. Once the lower and upper assemblies are stacked and mated, the engine undergoes a series of quality checks prior to testing.”

“To date, eighty Merlin 1Ds have launched, exceeding the propulsion heritage of the RS-68/68A engine (41 flown) on the Delta and the RD-180 engine (55 flown) on Atlas variants.”

There are a couple of interesting points here.

While early days saw critics take a number of shots at SpaceX for attempting to produce an EELV class booster powered by 9 main engines, a stark contrast to the approach taken by Arianespace, United Launch Alliance and others, it is a strategy which has paid off rather well for several reasons.

In early years, the selection of a small main engine grouped in a cluster allowed the company to directly apply experience gained with the Falcon 1 to the much larger Falcon 9.  Critically, SpaceX has applied an iterative design and production process which has seen progressive improvements to the engine family, going from the original ablatively cooled Merlin 1A, to the Merlin 1B which never flew, on to its first regeneratively cooled Merlin 1C which powered the last three Falcon 1 flights and the original Falcon 9, and now the Merlin 1D which just saw its 100th engine completed.

Part of the advance has been not just been an improvement in the engine’s performance, but in the production process as well.  Around the world, the aerospace industry is now in its seventh decade of producing liquid rocket engines dating back to the German V2. Arguably, SpaceX is the first entitiy in all that time to teach itself how do so inexpensively while still maintaining quality, a process which cannot even begin if you do not own the means of production, a lesson ULA and Orbtial Sciences are now learning the hard way.

If that were all, it would still be impressive, but that is not all.  In aggressively pursuing a fully reusable launch system, SpaceX is getting very close to recovering a Falcon 9 first stage. One of the overlooked benefits of reaching that next milestone is the insight it will give engineers into how it engines are faring in the actual launch environment. Post flight analysis, thus far available only with the hyper complicated Space Shuttle Main Engines is nearly certain to provide further guidance in improving the Merlin 1-D’s already spectacular reliability record.

That in turn, stands to benefit both the Falcon Heavy, which will rely on 27 first stage engines performing nicely, and as well as what could be the most significant development announced to date, the all new Raptor, methane fueled Raptor engine, which is intended to apply Merlin class operations to a Saturn V, F-1 class engine.