Chromatic 3D materials, an advanced 3D printing materials company, recently announced it had successfully static-fired tested its 3D-printed rocket propellant. The tests, which took place at the integrated solutions for systems (IS4S) test range in Opekia, Alabama, demonstrated that the company's propellant can withstand over 1800 psi of combustion pressures without structural failure. The company describes the development as a “critical milestone in advancing resilient, next-generation propulsion manufacturing for rockets and defense applications.”
Rocket propellants, the high-energy material rocket engines combust and eject to produce thrust, are generally classified by their physical state as liquid, solid, hybrid, and gas — each with its own benefits and drawbacks. Solid propellants offer the benefits of simplicity and readiness, at the expense of efficiency and control, the hallmarks of their liquid counterparts.
These propellants allow rockets to be stored fully fueled and ready to go, unlike liquids or gases that require loading. Furthermore, solid propellants don't require mixing, so there are no complex moving parts such as valves, plumbing, or pumps. They also make it possible to store fueled rockets for decades and have them still fire reliably. These characteristics make solid propellants the only choice for missiles and ICBMs.
Traditionally, solid rockets are made by mixing the propulsion material — fuel and oxidizer — with a binder into a thick slurry, pouring it directly into the prefabricated rocket's casing, and then baking it for days to weeks to cure it into a hard, rubbery rock. A large metal rod, called a mandrel, is typically positioned at the center of the mold before casting and then removed after solidification, leaving a hollow channel for the combustion chamber.
This method, which has been the standard for over 60+ years, has several drawbacks. First, while the process has been developed to be quite precise, it doesn't eliminate the possibility of a tiny air bubble or crack near the casing that could lead to an explosion when the rocket is ignited or in flight.
There's also the matter of the mandrel. Casting around a rod and then yanking it out later is crude by today's manufacturing standards. It could lead to cracks, and more importantly, the mandrel significantly limits the shapes that can be cast — a critical limitation, as shape often determines speed and thrust. Lastly, baking and curing are energy-intensive and can take days or weeks.
Chromatics’ 3D printing materials and processes completely solve these problems and offer several additional benefits. The company's solution is a full-stack system that encompasses both advanced materials and the printing technology required to 3D print rocket propellants.
First, the technology. Chromatics had earlier developed a proprietary, chemical-reaction-based Reactive Extrusion Additive Manufacturing (RX-AM) platform that 3D prints durable elastomeric materials. Instead of melting plastic like in fused deposition modeling, the platform pumps a chemical mixture that reacts and hardens almost instantly as it is laid down.
As a material science company at its core, the second — arguably the main — part of Chromatics' big breakthrough is the material. The company did not exactly reinvent rocket fuel. Instead, it used the existing binders in standard rocket fuel and tweaked the chemistry so it stays liquid in the printer but hardens as it exits. Basically, the company took existing materials and adapted them for its RX-AM process.
In doing this, Chromatic has “opened a world of possibilities.” In a solid rocket, the shape of the hollow core in the middle of the fuel determines how it burns and how much thrust it creates. 3D printing enables “impossible” internal shapes that can't be made with a mold, potentially leading to rockets that fly farther or more efficiently.
3D printing the fuel also eliminates the long cure times and the need for complex tooling characteristic of solid fuels, making rocket production faster and more agile — an always-welcome description for the defense supply chain.
Although several 3D printing techniques have proven capable of matching their formative manufacturing counterparts in finished product strength, there were concerns about whether the 3D-printed fuel could withstand the immense pressure of launch. In the recent test, fuel proved that it can indeed handle the heat of a real launch — literally. According to Chromatic, “the propellant achieves energetic loading levels comparable to top-performing conventional propellants while delivering the structural integrity required to withstand high-pressure combustion environment.”
Beyond matching the capabilities of conventional propulsion systems, Chromatic’s technology unlocks new performance possibilities. Integrating propellant directly into structural components allows the company to reduce unnecessary mass, create more efficient internal geometries, and precisely tailor thrust behavior in ways that are difficult or impossible with traditional manufacturing methods.
Another possibility is 3D printing different types of fuel in the same rocket, to vary speed and thrust at different stages of flight. The result of these possibilities could be lighter propulsion systems with higher performance, longer range, and greater operational flexibility for future missions.
“These results demonstrate that additive manufacturing is not only viable for defense propulsion — it can drive meaningful performance gains across at least 90% of the U.S. rocket arsenal,” said Dr. Cora Leibig, Founder and CEO at Chromatic 3D Materials. “We’re showing that it’s possible to maintain compatibility with existing systems while opening the door to rockets that fly farther, hit harder, and can be produced faster.”
As defense supply chains come under growing pressure, Chromatic’s manufacturing approach could offer a more flexible and resilient alternative. By allowing rocket propellant to be produced on demand and closer to the point of need, RX-AM reduces reliance on large, centralized production infrastructure and long logistics chains. 3D printing technology continues to offer performance advantages beyond conventional systems. Last year, Korean engineers managed to 3D-print a titanium fuel tank for space travel.
