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Aerojet Rocketdyne applies 21st century manufacturing technology to 20th century workhorse engine

Aerojet Rocketdyne has completed a series of hot fire tests of a thrust chamber manufactured by 3-D printing.

Aerojet Rocketdyne has completed a series of hot fire tests of a thrust chamber manufactured by 3-D printing. Photo credit: Aerojet Rocketdyne

Additive manufacturing (AM), also known as 3-D printing, holds the promise of greatly reducing manufacturing times and costs across a broad range of industries, not the least of which is aerospace propulsion. In a bid to reduce costs on one of the longest-serving family of rocket engines, Aerojet Rocketdyne recently performed a test fire of a 3-D printed, full-scale thrust chamber assembly for their RL10 powerplant.

Space is expensive

Spaceflight is not an inexpensive endeavor, and one of the single largest cost centers is the propulsion system. Indeed, when looking to reduce the expense of getting a payload to orbit, United Launch Alliance (ULA) is proposing recovering the engine assembly of their upcoming Vulcan rocket. The engines themselves account for more than half of the cost of the booster, according to ULA.

Other companies, like SpaceX, aim to reduce launch costs by vertical manufacturing – meaning they make as many parts of the rocket themselves – and by recovering as much of the vehicle as possible after each mission. To this end, the NewSpace company recently relaunched one of their Falcon 9 rockets that was previously flown nearly a year ago on CRS-8.

However, recovery and vertical manufacturing aren’t the only avenues to significant cost reductions. What if the expense of making the hardware could be reduced to a fraction of nominal costs, while also minimizing the number of parts required and slashing the time to manufacture?

We can build it fast… better… cheaper

Aerojet Rocketdyne’s RL10 family of engines has been a key component of more than 475 flights and has been the upper stage engine of choice on NASA’s missions to every planet in the Solar System. The RL10 is a reliable and highly efficient engine and has been tapped to power the upper stages of both the Space Launch System (SLS) and flights of Boeing’s CST-100 Starliner on the Atlas V.

However, the RL10 is expensive and requires several months to manufacture. Aerojet Rocketdyne aims to address both of those shortcomings by employing additive manufacturing.

Using 3-D printing, Aerojet Rocketdyne plans to reduce the time to manufacture the chamber from several months down to less than 30 days. Not only does additive manufacturing promise to cut production time but also will greatly reduce the number of parts needed to manufacture the engine. The thrust chamber alone could see a greater than 90 percent reduction in the number of parts necessary for a full assembly.

Aerojet Rocketdyne recently conducted the first successful test of a full-scale 3-D printed thrust chamber for their RL10 engine.

Aerojet Rocketdyne recently conducted the first successful test of a full-scale 3-D printed thrust chamber for their RL10 engine. Photo Credit: Aerojet Rocketdyne

“Aerojet Rocketdyne has made several major upgrades to the RL10 to enhance the engine’s performance and affordability since it first entered service in the early 1960s,” stated Aerojet Rocketdyne CEO and President Eileen Drake, in a release issued by the company. “Incorporating additive manufacturing into the RL10 is the next logical step as we look to make the engine even more affordable for our customers.”

Let’s light this candle

Recently, the company performed a hot-fire test of a full-scale thrust chamber of their RL10C-1 engine, which was completely manufactured by an additive process called selective laser melting (SLM). This involves using precisely-aimed lasers to melt a powdered copper alloy, which effectively “prints” the part according to a detailed, digitized blueprint.

“We believe this is the largest copper-alloy thrust chamber ever built with 3-D printing and successfully tested,” noted Additive Manufacturing Program Manager Jeff Haynes, in the release.

Using the printed copper alloy, instead of the more complex assemblage of braised stainless steel tubes, allows for the introduction of desirable attributes into the design. Being able to use a less complicated thrust chamber may translate into an engine that is both lighter and more compact – two traits that work well in the aerospace industry.

What next?

The successful test of the 3-D printed thrust chamber is merely the next step in what the company sees as the future of engine manufacturing. In fact, Aerojet Rocketdyne looks to incorporate additive manufacturing across its entire line of engines, including the SLS’ RS-25.

“Now that we have validated our approach with full-scale testing of a 3-D printed injector and copper thrust chamber, we are positioned to qualify a new generation of RL10 engines at a much lower cost; largely attributed to the additive manufacturing capabilities we have developed and demonstrated,” stated Christine Cooley, RL10 Program Director at Aerojet Rocketdyne.

How might this impact the larger spaceflight industry?

“Infusing this technology into full-scale rocket engines is truly transformative as it opens up new design possibilities for our engineers and paves the way for a new generation of low-cost rocket engines,” concluded Haynes.

A video showcasing Aerojet Rocketdyne’s work in additive manufacturing. Video Credit: Aerojet Rocketdyne



Curt Godwin has been a fan of space exploration for as long as he can remember, keeping his eyes to the skies from an early age. Initially majoring in Nuclear Engineering, Curt later decided that computers would be a more interesting - and safer - career field. He's worked in education technology for more than 20 years, and has been published in industry and peer journals, and is a respected authority on wireless network engineering. Throughout this period of his life, he maintained his love for all things space and has written about his experiences at a variety of NASA events, both on his personal blog and as a freelance media representative.

Reader Comments


The RL-10 was a fine engine in its time. However now it is so old as to considered for antique status. Some attempts were made to update the engine. The RL-60 / MD-60 most notably. The craftsmen ship construction methods certainly is a start for cost savings.

However, if Aerojet / Rocketdyne are going to maintain relevancy in the now fast pass lunch service industry they better do more than an update of exceedingly old technology.

Whole new concepts and continuous improvement of its products need to be engrained in the culture or A/R will be the Pan Am of the new Rocket age.

Make that launch service rather than lunch service.

My opinion- according to the 3D image of it with drives RL 10 is nozzle short and anough apart.

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