Aerojet Rocketdyne: Successful Hot-Fire Test of 3D Printed RL10 Engine Thrust Chamber Assembly

We talk a lot about California-based aerospace and defense leader Aerojet Rocketdyne, a subsidiary of Aerojet Rocketdyne Holdings, Inc., starting when it 3D printed an entire liquid oxygen/kerosen engine in just three parts back in 2014. Aerojet hasn’t slowed down, successfully completing hot-fire tests of 3D printed rocket engine injectors for the AR1, and signing a contract with NASA to mature the 3D printed MPS-130 CubeSat propulsion system. The company’s expertise in 3D printing technology and rocket engines is so well-known, Aerojet was even tapped by the US Air Force to define standards for 3D printed rocket engine components. It recently achieved another aerospace 3D printing milestone, with the successful hot-fire test of a full-scale, additively manufactured thrust chamber assembly for its RL10 rocket engine.

Aerojet’s RL10 has been the premier upper-stage rocket engine for over 50 years in the US. Known as the launch industry’s workhorse, it was first tested in 1959, and has helped to send spacecraft to every planet in our solar system, including Voyager 1 and New Horizons, the fastest spacecraft to leave Earth orbit. Three engines have been derived from the original RL10: the RL10A-4-2, the RL10B-2, and the RL10C-1. The company has been working to incorporate 3D printing technology into the RL10, and other propulsion systems, for ten years, in order to keep production costs down while also enjoying the performance and design capabilities of 3D printing technology.

Eileen Drake, Aerojet Rocketdyne CEO and President, said, “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. Incorporating additive manufacturing into the RL10 is the next logical step as we look to make the engine even more affordable for our customers.”

The RL10 thrust chamber assembly was built from a copper alloy, using SLM technology. The Defense Production Act Title III program management office, headquartered at Wright-Patterson Air Force Base near Dayton, Ohio, enabled the recent hot-fire test of the assembly. The thrust chamber of the current RL10C-1 model design uses a complex array of brazed-together hydroformed, drawn stainless tubes; the 3D printed RL10 copper thrust chamber would replace this model.

The design, which is made of just two primary copper parts, reduces the overall production lead time, as it can be additively manufactured in less than a month. In comparison with traditionally manufactured RL10 thrust chambers, the 3D printed RL10 copper thrust chamber, with lower complexity and cost, has a significantly reduced part count of over 90%. 3D printing also allows manufacturers to design and build more advanced features that are desirable to the aerospace industry, such as improved heat transfer, which in turn makes for a lighter, more compact engine.

“We believe this is the largest copper-alloy thrust chamber ever built with 3-D printing and successfully tested. Producing aerospace-quality components with additive manufacturing is challenging. Producing them with a high-thermal-conductivity copper alloy using SLM technology is even more difficult. 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,” said Additive Manufacturing Program Manager Jeff Haynes.

Aerojet Rocketdyne recently completed successful hot-fire testing of a full-scale, additively manufactured thrust chamber assembly for the RL10 rocket engine at its West Palm Beach, Florida facility

RL10 Program Director Christine Cooley said, “”This full-scale RL10 thrust chamber test series further proves that additive manufacturing technology will enable us to continue to deliver high performance and reliability while substantially reducing component production costs. 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. With the next generation of RL10 engines, we aim to maintain the reliability and performance that our customers have come to expect, while at the same time making the engine more affordable to meet the demands of today’s marketplace.”

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