Dubai, UAE — December 11, 2025 — In under three weeks from specification to first flame, LEAP 71 has successfully hot-fired two radically different 20 kN methalox rocket engines — a conventional bell nozzle and a full-scale aerospike — designed entirely without human intervention by the Noyron Large Computational Engineering Model.
Each engine generates 2 tons of thrust (4,500 lbf) burning cryogenic methane and liquid oxygen (methalox), making them suitable for orbital-launcher applications. The test campaign provides the latest validation of Noyron, which generates complex machinery directly from specification to production-ready design. It encodes first-principles physics, engineering logic, manufacturing constraints, and practical considerations into a coherent system that outputs directly to the fabrication process.
“Noyron is our ongoing attempt to comprehensively encode the process of engineering into a computational model that can operate independently of humans — radically compressing iteration times and making objects possible that were previously unfeasible. These physical tests — literally hot-firing the engines — generate crucial data that can only be obtained in the real world,” said Lin Kayser, Co-Founder of LEAP 71.
Space propulsion is one of LEAP 71’s key focus areas, with the company firing a Noyron-generated engine on average every four weeks over the past 18 months. Each of these engines was distinctly different, testing the boundaries of Noyron’s physics representation.
“Methane is a complex propellant to model,” said Josefine Lissner, CEO of LEAP 71 and Principal Architect of Noyron. “Contrary to the kerosene fuel we tested in the past, it undergoes significant density changes under different temperatures and pressures. So Noyron’s predictions need to be spot on in order to produce working hardware. Also, the increased size of the engines comes with its own operational challenges.”
LEAP 71 tested both a conventional engine with a traditional bell nozzle and an aerospike configuration. While radically different in shape and internal geometry, both engines were generated by the same Noyron model, relying on the same physics and logic.
The aerospike — with its toroidal combustion chamber and central spike — promises higher efficiency, wider operational usability, and better deep-throttle performance than conventional engines; yet no aerospike has ever successfully flown to space. LEAP 71 previously tested a 5 kN kerolox aerospike in December 2024.
Over a week of testing, LEAP 71 put both 20 kN engines through their paces, gathering crucial data that is now being fed back into Noyron. The aerospike could only be operated for a single burn because of issues encountered during startup transients; however, it reached full chamber pressure at 50 bar and validated the fundamentals of the design.
The conventional bell-nozzle thruster reached steady state at nominal chamber pressure and thrust, validating the underlying physics models and operating above 93% combustion efficiency — a strong result for a first test. The hot-fire provided important feedback about real-life pressures and temperatures, all of which fell within the expected ranges.
To improve startup and shutdown transients, especially for the aerospike, LEAP 71 will integrate an advanced ignition system, which was also successfully tested during the campaign.
The engines were entirely 3D-printed from a high-temperature copper alloy (CuCrZr) by German additive manufacturing company Aconity3D.
Josefine Lissner said: “In the last 12 months we tested kerolox engines from 1.5 to 7.5 kN, using different materials and configurations. Noyron now delivers first-time-right rocket thrusters for kerosene and cryogenic liquid oxygen. We are confident that we are close to achieving the same for cryogenic methane. This test was an important step for us, validating that we can radically reduce the time for our customers to get to the launch pad with Noyron-generated engines.”
The newly tested 20 kN methalox engines represent roughly 10% of the thrust class LEAP 71 aims to hot-fire in 2026. Manufacturing validation of the 200 kN — and even larger 2,000 kN — methalox engine designs is already underway, making use of the largest metal 3D-printing systems in the world.
About LEAP 71
LEAP 71 was founded on the vision that radically accelerating real-world engineering is essential to shaping the future of humankind. Strategically based in Dubai, UAE, the company works with customers around the globe to design advanced machinery in fields such as aerospace, electric mobility, robotics, and thermal systems.
A pioneer in the emerging field of Computational Engineering, LEAP 71 designs physical objects autonomously — without human intervention. At its core is Noyron, a Large Computational Engineering Model that encodes logic, physics, production methodologies, and real-world feedback into a coherent, deterministic system. It has been called “the first AI that builds machines.”
Noyron generates functional designs in seconds or minutes, optimized for modern manufacturing technologies such as industrial 3D printing.
A key focus for the company is enabling access to space. LEAP 71 is developing a spectrum of reference designs for space propulsion systems that serve as the DNA for customer-specific engines. Frequent physical testing and validation are used to continuously enrich Noyron’s models.
LEAP 71 was founded in 2023 by aerospace engineer Josefine Lissner and serial entrepreneur Lin Kayser.
Visit the LEAP 71 website for more information.
