A series of hot-fire bench experiments of the RD-191MR liquid rocket engine, a critical component of the modernized Angara-A5M heavy-class launch vehicle, were conducted by Russian specialists in 2025. The concept’s viability for further implementation was confirmed by the engine’s stable performance at approximately 200 tons of thrust, which was achieved through the use of extensive additive (3D printing) technologies on Russian industrial printers with domestically developed materials.
It is important to note that the initial successful tests of the 3D-component variant were reported in the summer of 2025, yet information regarding this success was not widely shared until late February 2026. At that time, the story was largely disregarded by Russian media, and the initial release on the company’s website was removed. This move subsequently sparked additional interest when the information resurfaced in early 2026.
What Is the RD-191MR and Where Did It Come From?
NPO Energomash, one of Russia’s premier rocket engine manufacturers, has developed the RD-191MR, a new modification of the RD-191 engine family. An oxidizer-rich staged combustion cycle is employed by the baseline RD-191, a single-chamber liquid rocket engine that operates on kerosene (RP-1) and liquid oxygen (LOX). This configuration guarantees high efficiency and adjustable thrust, making it suitable for contemporary space missions.
Engineers devised the RD-191M version, which is a modification with an approximate 10% increase in thrust, based on the original RD-191. This version is specifically designed for upgraded Angara launch vehicles. This upgraded RD-191M architecture serves as the foundation for the RD-191MR, which integrates a variety of additive manufacturing technologies into its manufacturing process.
Therefore, the RD-191MR is not a completely new engine design; rather, it is a development of a well-established platform that incorporates innovative manufacturing techniques while maintaining its fundamental operational characteristics.
Additive Manufacturing in Rocket Engineering: How the RD-191MR Was Built
The RD-191MR differentiates itself by its comprehensive use of additive manufacturing technologies. Advanced metal 3D printing techniques, including selective laser melting and direct laser deposition, were used to fabricate critical engine components.
Complex structural elements were printed layer by layer from metal particle alloys, rather than machining large metal billets and assembling numerous separately manufactured components. This method considerably simplified specific structural assemblies, reduced the number of welds, and improved the precision of the production of geometrically complex parts.
Carefully selected materials and equipment were used to individually manufacture engine components. In order to guarantee the necessary performance characteristics, composite materials, titanium elements, and special heat-resistant nickel alloys that were specifically designed for high-temperature and high-pressure environments were implemented.
The project was collaborative in nature. The engine components were developed and produced with the assistance of teams from NPO Energomash, the VIAM Institute of the Kurchatov Center, the enterprise Kompozit, and specialists from the Saint Petersburg State Marine Technical University, where the industrial 3D printers used in the project were manufactured.
In 2025, successful hot-fire tests were conducted to confirm that a rocket engine manufactured using additive technologies can satisfy the rigorous operational requirements of heavy launch vehicles.
Production Advantages and Economic Efficiency
The RD-191MR project demonstrated substantial economic advantages in addition to the technological breakthrough. Specialists conducted an economic evaluation of the implementation of additive technologies in rocket engine manufacturing by utilizing specially developed alloy particles following the completion of testing.
The adoption of the new technology enables a 25% reduction in labor intensity in the fabrication of prototype engines, as indicated by data published on February 27, 2026. This decrease is the result of reduced manual assembly of intricate units, fewer machining operations, and simplified production chains.
Even more significantly, the complete implementation of additive manufacturing has the potential to reduce engine production costs by nearly 40% when contrasted with conventional manufacturing methods. These savings are significantly influenced by the consolidation of multiple components into single printed structures and the reduction in material waste.
Additionally, it is feasible to decrease production time by approximately 2.5 times. Such acceleration is strategically significant in the aerospace industry, where development cycles are lengthy and manufacturing timelines often exceed months. Faster production necessitates more frequent testing, iteration, and eventual serial deployment.
Why This Matters for the Angara Launch Vehicle
Russia’s modular rocket system, the Angara family of launch vehicles, is capable of deploying a diverse array of payloads into a variety of orbits. The Angara-A5 configuration, which is quite heavy, is capable of delivering an estimated 24 to 27 tons to low Earth orbit.
It is anticipated that the Angara-A5M variant, which has been modernized and comes with higher-thrust engines like the RD-191MR, will improve competitiveness in both domestic and international launch markets by increasing payload capacity.
The technological foundation of the Angara-A5M program is fortified by the successful hot-fire testing of the RD-191MR. Additionally, the substitution of conventionally manufactured components with 3D-printed elements may reduce structural mass, enhance reliability by reducing the number of weld joints, and simplify serial production.
As the heavy-lift launch segment experiences an increase in global competition, the ability to maintain a competitive edge may be contingent upon improvements in manufacturing efficiency and cost structure.
A More Comprehensive Technological and International Context
The RD-191MR’s additive manufacturing approach is indicative of a more extensive transformation in the global aerospace industry. On a global scale, 3D printing has been increasingly incorporated into the production of intricate rocket engine components, combustion chambers, injectors, and turbopump elements by companies and agencies.
The application of additive manufacturing at the magnitude of a 200-ton-thrust liquid rocket engine represents an important industrial milestone for Russia. It illustrates the advanced state of domestic 3D printing hardware, materials science capabilities, and high-temperature alloy development.
It is crucial to note that the RD-191 family has already established a robust operational history as part of the Angara program. Hence, the RD-191MR’s innovation is primarily centered on production methodology, rather than a fundamental redesign of engine architecture.
The technology could potentially be applied to other engine families, upper-stage propulsion systems, and potentially next-generation heavy-lift rockets if additive methodologies are proven to be reliable over long-term operational cycles, in addition to RD-191 variants.
Looking Ahead
The RD-191MR’s successful fire tests are indicative of more than just the validation of a particular engine. They represent a strategic shift toward the integration of sophisticated industrial technologies into the space sector of Russia.
Additive manufacturing provides a means to achieve increased design flexibility, reduced material waste, lower costs, and speedier production. In an industry characterized by extreme engineering tolerances and financial intensity, these advantages have the potential to significantly alter operational economics and development timelines.
3D printing may become a standard method for producing critical rocket components in Russia within the coming years if large-scale implementation proceeds as anticipated. This would not only expedite the modernization of the Angara program but also enable domestic aerospace manufacturing to more effectively adapt to changing technological and geopolitical requirements.
Consequently, the RD-191MR may be regarded as an important milestone in the development of a new manufacturing paradigm in Russian rocketry, in addition to serving as an enhanced engine for the Angara-A5M.