Computational Engineering Algorithm Autonomously Designs a 20-Metric-Ton Rocket Engine

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LEAP 71, a pioneer in computational engineering, and HBD, a manufacturer of large-format 3D metal printers, have developed and manufactured one of the world’s most complex aerospace propulsion systems—not using traditional CAD, but with the help of an autonomous algorithm.

The engine, designated XRA-2E5, was developed using Noyron, the large-scale “computational engineering” model for the LEAP 71. Simply put, it is a design AI that calculates complex 3D geometries not through manual modeling, but purely algorithmically based on physical requirements and manufacturing rules. The software uses these principles to generate functional designs completely autonomously and without human intervention. 

“Aerospikes are often considered the Holy Grail of space propulsion,” explains Josefine Lissner, CEO of LEAP 71 and chief architect at Noyron. “They promise significant performance advantages over conventional engines, but their complex geometry has made design, manufacturing, and operation extremely difficult in the past. By combining computational engineering with advanced additive manufacturing, we can finally make them fly.”

The new engine shares its development DNA with two earlier Aerospike engines produced by Noyron, which have already undergone hot-fire tests on the LEAP 71 over the past 15 months. According to reports, the current 200-kN design is the largest 3D-printed aerospike ever produced and is specifically suited for the upper stages of large reusable launch vehicles.  

The Design Challenge: “Inside-Out” Architecture

Aerospike engines use a ring-shaped (toroidal) combustion chamber and a central spike. To cope with the enormous thermal loads generated by the combustion gases, the XRA-2E5 employs a complex regenerative cooling strategy that has been integrated directly into the structure thanks to software design and 3D printing. Unlike conventional engines with bell-shaped nozzles, aerospikes maintain high efficiency from sea level all the way into a vacuum. This makes them particularly attractive for next-generation fully reusable launch systems, in which both the booster and upper stage return to Earth. This requires propulsion systems that operate efficiently in all layers of the atmosphere and can be throttled down significantly (deep throttling).

Manufacturing at the Limits of What Is Possible

HBD 3D-printed the monolithic engine in one piece in a record time of 289 hours. “Just a year ago, it would have been impossible to manufacture such an engine on this scale,” emphasizes Kevin Chen, director of marketing at HBD. “The physically constrained geometry of the aerospike, with its flat overhangs and highly complex internal structures, pushes even advanced metal 3D printing processes to their limits. The fact that the engine was successfully produced on the very first print attempt demonstrates the stability and precision of our large-format additive manufacturing platform.”

The close collaboration between the two companies ensured that Noyron’s algorithmic design strategy was optimally tailored to the capabilities of the HBD system. The result is a fully integrated monolithic engine, 3D-printed from Inconel 718 alloy.The XRA-2E5 marks a major milestone in the validation of manufacturing as part of LEAP 71’s multi-year propulsion development project with Aspire Space for the fully reusable Oryx spacecraft and now provides the hardware needed to move into the qualification phase with hot-fire tests.

About HBD
HBD (Shanghai Hanbang United 3D Tech Co., Ltd.) is a leading Chinese manufacturer of industrial metal 3D printers (LPBF technology) headquartered in Shanghai. Founded in 2007, the company has already installed over 1,000 systems worldwide. Its product portfolio ranges from small platforms to large-format multi-laser systems for industries such as aerospace, automotive, medical, and robotics.
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About LEAP 71
Founded in 2023 by aerospace engineer Josefine Lissner and serial entrepreneur Lin Kayser, LEAP 71 (Dubai, UAE) is a pioneer in the field of computational engineering. At the heart of the company is Noyron—an algorithmic software model that designs physical components, such as space propulsion systems, completely autonomously and without human intervention. This software generates finished designs in a matter of minutes that are optimally tailored to modern manufacturing processes such as industrial 3D printing.

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