The progress bar of 3D printing for commercial rockets in China: How far is it from "capable of printing" to "capable of mass production"?

The competition in 3D-printed engines may seem like a technological choice for rocket companies, but in essence, it's a contest of the supply chain.

From July 12th to August 4th, Indian space startup Skyroot Aerospace plans to conduct the first flight mission of Vikram-1.

This is India's first orbital rocket developed by a private enterprise. It has a full carbon composite rocket body and a 3D-printed engine, with a low-orbit payload capacity of about 350 kilograms.

Skyroot has previously disclosed that the design of its 3D-printed engine can achieve a 50% weight reduction and an 80% reduction in the manufacturing cycle. Behind these figures lies the ongoing change in global rocket engine manufacturing. 3D printing has evolved from an innovative label to an engineering option for more and more rocket companies.

So, what stage has the 3D-printed engine development of Chinese companies reached, and what are the real bottlenecks in mass production?

I. Three Global Routes

The Rutherford engine of Rocket Lab is one of the most mature mass production routes at present.

This is an electric pump cycle liquid oxygen kerosene engine used on the Electron small launch vehicle. The main components such as the combustion chamber, injector, pump, and main valve are all manufactured using 3D printing. Rocket Lab's early statement was that the main components of a single engine can be printed within 24 hours.

By May 2026, the 1000th Rutherford engine will roll off the production line. It has completed a large number of orbital launches with the Electron, and both its production volume and flight times have entered the industrialized range.

The characteristic of this route is that the engine thrust is not large, but the model is stable, the structure is simple, and the manufacturing rhythm is fast. Here, 3D printing solves the problems of mass manufacturing, rapid delivery, and consistency control.

Relativity Space takes a different route.

Terran 1 is its first rocket. Approximately 85% of its components by mass are manufactured using 3D printing. In March 2023, Terran 1 passed Max-Q during its first flight and reached space, but the second stage failed to ignite, and it ultimately did not enter orbit. After that, Relativity abandoned Terran 1 and turned to the larger reusable rocket Terran R.

The lesson this experience left for the industry is that a high 3D printing ratio does not mean a mature rocket system. The printing ratio itself is not the goal. The key lies in whether it reduces complexity, improves manufacturing consistency, and can withstand flight verification.

SpaceX's route is closer to "structural integration".

The Raptor 3 does not pursue publicizing the printing ratio. Instead, through additive manufacturing and design for additive manufacturing, it integrates cooling, secondary flow paths, and some external pipelines into the engine structure, reducing bolt connections, external pipelines, and heat insulation structures.

This usage is closer to the advanced form of 3D printing in engines. It changes the part boundaries at the design stage, reduces connection relationships, and shortens the iteration cycle.

These three companies actually correspond to three logics. Rocket Lab proves that small-thrust engines can be mass-produced; Relativity proves the boundaries of the full-printing route; SpaceX turns 3D printing into part of the engine structural integration.

II. Progress of Chinese Companies

The application of 3D printing in Chinese commercial rocket companies has entered the core components of engines.

The Thunder RS engine of Deep Blue Aerospace is a 130-ton reusable liquid oxygen kerosene engine. Public information shows that the weight of its 3D-printed components accounts for more than 85%. Key parts such as the turbine pump housing, impeller, inducer, turbine housing, and turbine stator blades are all manufactured using 3D printing.

The oxygen main valve housing is integrally formed using high-temperature alloy 3D printing, and the kerosene main valve housing is integrally formed using titanium alloy 3D printing. The inner wall of the thrust chamber is 3D-printed using copper alloy, with high aspect ratio cooling channels.

In September 2025, the Thunder RS completed its first full-engine ignition test. For a reusable engine in the hundred-ton class, 3D printing has entered the core positions such as the turbine pump, valves, and thrust chamber, which truly affect performance and lifespan.

The Tianque 12B engine of LandSpace uses liquid oxygen methane propellant, and its thrust reaches the hundred-ton class. Public reports show that the proportion of 3D-printed parts in the Tianque 12B exceeds 70%, the number of cancelled parts is about 30%, the pipelines are significantly reduced, and the internal structure is also reconfigured.

In April 2025, LandSpace completed the offline production of the 100th Tianque series liquid oxygen methane engine. The significance of this milestone is that commercial rocket engines are starting to move from single-unit development to mass manufacturing.

The application scope of Galactic Energy is relatively more concentrated. In the engines related to Hyperbola-2, components such as tees and injectors are manufactured using 3D printing. Although the overall printing ratio is not as high as that of Deep Blue Aerospace and LandSpace, the application position has shifted from peripheral parts to key engine components.

It should be noted that Deep Blue Aerospace's 85% is the weight ratio, while LandSpace's over 70% is the part ratio.

III. The Real Bottlenecks Are Upstream

The first bottleneck is copper alloy powder.

The gas temperature inside the thrust chamber can reach over 3000°C, but this is not the actual operating temperature of the copper alloy wall. The melting point of copper is only about 1085°C. If the material body reaches 3000°C, the thrust chamber will directly fail.

The core reason for using copper alloy for the inner wall of the thrust chamber is high thermal conductivity. The engine uses regenerative cooling to send the propellant into the cooling channels in the thrust chamber wall to continuously remove heat and control the metal wall temperature within the material's tolerance range.

Therefore, the real test is the strength, thermal conductivity, thermal fatigue resistance, and batch consistency of the copper alloy powder under high heat flux, thermal cycling, pressure load, and long-term operation.

Copper alloy systems such as the GRCop series, CuCrZr, CuNb, and CuNiSi are all developed around this issue. Domestic related materials have made breakthroughs and passed hot test verifications. However, from "single-piece usability" to "stable batch supply", there are still hurdles to overcome, including powder sphericity, oxygen content, particle size distribution, printing process window, and heat treatment consistency.

The second bottleneck is large-scale metal 3D printing equipment.

The thrust chamber, turbine pump housing, and large and complex flow channel structures of hundred-ton class engines have high requirements for forming size, number of lasers, powder spreading stability, thermal field control, and process monitoring.

Domestic equipment manufacturers have launched large-scale, multi-laser metal 3D printers, which have also entered the manufacturing of aerospace engine components. However, compared with overseas equipment manufacturers such as EOS, Nikon SLM Solutions, and Renishaw, the gap lies not only in hardware specifications but also in long-term process databases, fault models, quality traceability, and batch production stability.

Manufacturing a rocket engine doesn't end with printing the parts. Each batch of powder, each set of parameters, and each heat treatment must be linked with non-destructive testing, flow calibration, mechanical property testing, and hot test data. The equipment stability will ultimately be reflected in the engine's lifespan and consistency.

The third bottleneck is hot test verification.

3D printing enables faster design changes, but the verification cycle of rocket engines will not be shortened as a result.

The thrust chamber has to withstand the scouring of high-temperature gas and high-pressure flow in the cooling channels. The turbine pump has to face problems such as high-speed rotation, low-temperature media, vibration, and sealing. The valves have to operate multiple times under extreme temperature and pressure. The cost of a single hot test is high, the test resources are limited, and it's not easy to determine the cause after a failure.

For reusable engines, the difficulty is even higher. It not only needs to be ignited and operate stably but also needs to be started multiple times, have deep thrust adjustment, work for a long time cumulatively, and maintain structural reliability after repeated thermal cycles.

The competition in 3D-printed engines may seem like a technological choice for rocket companies, but in the end, it depends on the supply chain.

Rocket Lab took many years to produce 1000 Rutherford engines, which is supported by equipment, powder, process databases, and flight data. Relativity's Terran 1 shows that a high printing ratio alone cannot replace systems engineering. SpaceX's Raptor 3 demonstrates another path, where they integrate 3D printing into engine design and redefine part boundaries.

Chinese companies' design capabilities and engineering progress are not slow. Companies such as Deep Blue Aerospace, LandSpace, and Galactic Energy have already applied 3D printing to the core components of engines. Next, it depends on whether the copper alloy powder can be stably supplied, whether the large-scale equipment can operate stably in the long term, and whether the hot test data can support batch delivery and reuse verification.

This article is from the WeChat official account "Star Movement Unlimited", author: UniLym, published by 36Kr with authorization.