NASA Marshall Advances 3-D Printed Rocket Engine Nozzle Technology

Through hot-fire testing at NASA’s Marshall Space Flight Center, engineers put this nozzle through its paces, accumulating more than 1,040 seconds at high combustion chamber pressures and temperatures. Now, this technology is being licensed and considered in commercial applications across the industry. (Credits: NASA/MSFC/David Olive)

HUNTSVILLE, Ala. (NASA PR) — Rocket engine nozzles operate in extreme temperatures and pressures from the combustion process and are complex and expensive to manufacture. That is why a team of engineers at NASA’s Marshall Space Flight Center in Huntsville, Alabama, developed and proved out a new additive manufacturing technique for nozzle fabrication that can greatly reduce costs and development time.

A new process called Laser Wire Direct Closeout (LWDC) was developed and advanced at NASA to build a less-expensive nozzle in significantly less time. LWDC is a different process than most 3-D printing technologies, which are powder-based and fabricated in layers. It uses a freeform-directed energy wire deposition process to fabricate material in place. This new NASA-patented technology has the potential to reduce build time from several months to several weeks.

“NASA is committed to revitalizing and transforming its already highly advanced manufacturing technologies for rocket engines,” said Preston Jones, director of the Engineering Directorate at Marshall. “What makes this development project even more unique is there were three separate, state-of-the-art, advanced manufacturing technologies used together to build a better nozzle and prove it out through hot-fire testing — an example of why Marshall continues to be a worldwide leader in manufacturing of propulsion technologies.”

Nozzles may look simple from the outside, but they are very complex. The new LWDC method employs a wire-based additive manufacturing process to precisely close out the nozzle coolant channels, which contain the high pressure coolant fluid that protects the walls from the high temperatures a nozzle must withstand.

Nozzles are actively cooled, or regeneratively cooled, meaning the propellant later used in the combustion cycle is routed through the nozzle to properly cool the walls so they do not overheat. To regeneratively cool the nozzles, a series of channels are fabricated within the nozzle, but then must be closed out, or sealed, to contain the high-pressure coolant. The new patented process using the LWDC technology closes out the coolant channels and forms a support jacket in place, reacting structural loads during engine operation.

“Our motivation behind this technology was to develop a robust process that eliminates several steps in the traditional manufacturing process,” said Paul Gradl, a senior propulsion engineer in Marshall’s Engine Components Development & Technology Branch. Gradl has focused his whole career on rocket nozzles and combustion chambers, like this one developed and patented at Marshall. “The manufacturing process is further complicated by the fact that the hot wall of the nozzle is only the thickness of a few sheets of paper and must withstand high temperatures and strains during operation.”

After Marshall co-developed and patented the LWDC process, Keystone Synergistic of Port St. Lucie, Florida, used the technology to fabricate and test a nozzle. Through hot-fire testing at Marshall, engineers put this nozzle through its paces, accumulating more than 1,040 seconds at high combustion chamber pressures and temperatures. Now, this technology is being licensed and considered in commercial applications across the industry.

The second technology tested as part of this campaign was an abrasive water jet milling process to form the coolant channels advanced by Ormond, LLC of Auburn, Washington, while a further technology developed was an arc-based deposition technology to additively manufacture the near net shape liner that would contain the water jet milled channels. All three technologies were developed through NASA’s Small Business Innovation Research program, working to bring together the agency with its industry partners to advance manufacturing. With projects such as these, Marshall is stimulating small business to maximize the return on America’s investment in space technology and exploration.

“One of the things I get excited about is advancing and proving out new technologies for our application with industry partners that a private space company can then use as part of their supply chain,” said Gradl. “That was the objective behind some of this — we formulated the concept, worked with external vendors, and now we’re partnering to infuse this new technology throughout industry to improve advanced manufacturing.”

Jennifer Stanfield
Marshall Space Flight Center, Huntsville, Ala.

  • Michael Halpern

    Pretty sure Rocket Lab beat them to it, though this printing technique is closer to Relativity Space’s process

  • Jeff2Space

    Nice. 3D printing seems to be the “hot new thing” in the CAD/CAM/CAE industry.

  • Michael Halpern

    Being able to take designs and put them into scale models, prototypes or in some cases finished product with a few mouse clicks is very useful. In areospace, where many parts are specialized and need small runs its perfect and eliminates a lot of overhead

  • Aerospike

    Beat them to what? This isn’t about 3D printing a rocket engine/nozzle in general, it is about a very specific way to solve a single issue: How to create a strong bond between two different metals/alloys when 3D printing parts.
    As far as I know,Rutherford engines are printed from one single alloy and do not contain an inner liner (or whole cooling channels) built from a different material (like copper).

    If Rocket Lab (or Relativity) had been using the very same process (or a very similar one), NASA would not have been ably to patent this due to prior art.

  • Michael Halpern

    Relativity is using a wire based feedstock, not the same process but similar, at least in the first step, the point is however this just a refinement and combination of existing techniques

  • windbourne

    not just that.
    Basically, you have subtractive and additive. with subtractive, you are taking a chunk of metal and then cutting away from it. This works great for solid pieces. BUT, once you have to cut those insides, and esp, if you have lips, or other things like that, it moves from CNC machines to handwork and it is laborious.
    For complex objects, esp. hollow, or inner work, the additive is so much easier and cheaper. Even the sintered laser approach, while complex and expensive, is still cheaper, faster, and better than the subtractive, for complexities.

  • windbourne

    IIRC, It was SpaceX that did the first 3D printed Nozzle.
    But that was using sintered laser.
    And I am pretty sure that Rocket lab used the sintered laser approach.
    This is using a thin wire similar to how a plastic 3d printer works.
    The thin wire may actually be a great deal more accurate and precise compared to sintered.

  • Michael Halpern

    Pintle injector actually

  • Tom Billings

    “IIRC, It was SpaceX that did the first 3D printed Nozzle. ”

    No, that was first done around 2010, by one of the former competitors for the a NASA prize contest on rocket VTOL. IIRC, he is now out of business. The rocket engine worked well according to him.

  • Tom Billings

    Did anyone else try the link to Laser Wire Direct Closeout (LWDC) for the patent?????

    I tried it, and I get a start on the page tab, …which then reverts to a “Not Found” page.

    Not too surprising, if this has been decided to be ITAR-controlled tech.