Rocket company Launcher has teamed up with 3D printer VELO3D and simulation software provider Ansys to overhaul the design and manufacture of its liquid oxygen (LOX) turbopump, a critical component of the company’s E-2 rocket engine.
The E-2 project is ambitious: Launcher aims to manufacture the highest performance liquid rocket engine in the growing commercial space industry—a rocket with the most thrust, most efficient propellant consumption, and cheapest cost per pound of thrust on the market. The E-2 will power the Launcher Light rocket, which is currently in mid-development and is expected to test-fly in 2024. The company intends to bring the engine to market in 2026, with a focus on launching small satellites.
For small vehicles such as the Launcher Light, the turbopump played a critical role in helping them reach and achieve the right level of thrust since it is directly responsible for injecting fuel into the engine. Launcher licensed an LOX turbopump design that had been used on the Ukrainian RD-8 rocket—a vehicle that had successfully completed 72 orbital flights as part of the second stage of the Zenit family of launchers.
Having found a component with a reliable performance record, the rocketmaker then worked with VELO3D and Ansys to redesign, manufacture and test the turbopump, installing an upgraded impeller and housings. As a result, the new component now features greater part complexity, lower production cost and faster lead times—and the production process is now able to rapidly iterate future parts.
To optimize propellant flow and pressure to the engine’s thrust chamber, Launcher had to produce and test it in-house. Launcher engineers used the Ansys CFX platform, a computational fluid dynamics (CFD) software for turbomachinery applications, to ensure that the rocket’s projected thrust level matched its actual performance. Simulated test runs helped the engineers to optimize the component’s parameters.
“Before we got into manufacturing, we worked with Ansys to simulate the performance of our flow path in our LOX pump,” said Andre Ivanovic, mechanical engineer at Launcher. “We wanted to do this to ensure that the predicted performance was in line with the desired parameters for our entire rocket engine system.”
Next, components of the redesigned pump—particularly the pump inlet and outlet housing—were 3D printed on VELO3D’s Sapphire metal additive manufacturing platform. The inlet housing was produced with aluminum alloy F357 and the outlet housing was printed using Inconel 718.
This required an incredible amount of precision because the LOX pump contains overhanging internal geometries that make it difficult to print using conventional powder bed printers. Many 3D metal printers struggle to meet the printing requirements due to limitations imposed by internal supports. The Sapphire system, however, was able to print the part without needing those internal supports.
With Sapphire, the 3D printing process resulted in a part that is significantly less complex, requires less time and wastes less materials than it would have using conventional manufacturing processes. The manufacturing process itself was also far less costly and labor intensive compared to conventional production processes.
Launcher’s engineering team used a similar approach to redevelop the pump’s impeller—the component on which the blades are installed and which transfers the energy from the pump to the liquid. The impeller had incredibly precise requirements: it needs to spin at 30,000 rpm, in the cryogenic conditions of space while flowing highly combustible liquid oxygen!
The design was a challenge as well. Hooded impellers tend to have a low overhang, which makes it difficult to print or access the part’s support structures. As a result, the impeller is often angled on the build plate as it is printed, which can lead to inconsistent mass distribution and imbalance. Instead, the team used the VELO3D printer to 3D print the impeller flat, giving it a uniform mass distribution and preventing it from causing engine issues during rotation.
“By printing the part flat, we got a nice symmetric mass distribution of the part relative to that central rotational axis,” said Ivanovic. “Balancing is needed, because if a rotational component in turbomachinery is not balanced, then, on every rotation, there will be a large vibration that’s impulsed into your system and into your bearings.”
Once the part was manufactured, Launcher put it through a battery of engine tests at NASA’s Stennis Space Center. These tests included two-minute test-fires at a nominal rpm, a 30-second input and output pressure check, and a 30-second 33,000 rpm test. The results: Launcher’s upgraded pump completed all three tests successfully—with the first parts it produced.
Launcher isn’t limiting its use of 3D printing to its turbopump. In fact, that component will be installed inside a combustion chamber that was also entirely 3D printed in a single piece. Launcher has relied on additive manufacturing throughout its rocket design process—a strategy meant to keep costs down and optimize the rocket for potential mass production once it’s ready to hit the market.
Launcher’s efforts to optimize its products via additive manufacturing are just the latest example of how 3D printing has become a source of innovation in the space sector—a market that has been at the forefront of disruption since being opened up to private companies. Around 50 private space companies are using 3D printing in their operations. Almost two-thirds of the firms develop spacecraft and technologies to travel to the International Space Station and low earth orbit, though companies such as ULA and SpaceX have ambitious plans to take their technologies beyond those realms—to the moon and Mars. Many of these companies—72 percent—are in the United States.
“3D printing is actually an entirely new tech stack for aerospace that we really haven’t changed the paradigm of in the last 60 years—building products one at a time by hand with hundreds of thousands to millions of individual piece parts in a factory, full of fixed tooling and a very complicated supply chain,” said Tim Ellis, CEO of Relativity Space—another company that is pushing the 3D printing envelope in the commercial space sector.
The advantages are clear: 3D printing offers design freedom to create components that weigh less and cost less—two factors that are essential in an industry where every ounce of a payload can cost more money to lift into space. This is why the technology finds itself in everything from launch vehicle parts to rocket engines and more. And it will no doubt continue to have a revolutionary impact on the rapidly growing commercial space sector—and on human aspirations to explore new worlds.
Read more about how 3D printing is changing space travel at 3D-Printed Rocket Engines & The Future of Spaceflight.