NMIS offers solution to ‘one of the long-standing challenges in rocket engine production’

A significant problem in rocket manufacturing could have a potential solution, according to engineers at the National Manufacturing Institute Scotland (NMIS), after they successfully demonstrated a fresh approach to the task.

Describing it as “one of the long-standing challenges in rocket engine production”, the team at the Paisley facility explored a new way to manufacture large copper structures with intricate cooling channels. The approach used high-pressure cold spray, which deposits copper in a solid state to avoid melting and reduce the risk of thermal distortion or material degradation.

Rocket combustion chambers and nozzles are among the most critical components in spacecraft systems, operating in extreme environments where temperatures exceed the melting point of the structural materials. These conditions place significant demands on manufacturing methods to produce challenging geometries while retaining stringent material performance and cost efficiency.

Traditional production routes are typically slow and labour-intensive, an NMIS announcement said today (26 May), often requiring multiple fabrication stages and extensive machining.

“Although additive manufacturing approaches such as powder bed fusion offer increased design freedom, they are constrained by build size, limiting their suitability for large components. Electroplating is also commonly used to manufacture copper rocket nozzles, but long production lead times remain a significant challenge at the scales required. As a result, production can take several months, with high costs and limited flexibility to adapt or scale designs,” the announcement said.

Copper presents an additional challenge, the engineers said. Its thermal and mechanical properties, combined with its highly reflective nature, make it difficult to process using conventional additive manufacturing techniques. This has restricted the production of advanced geometries, they said, particularly the complex internal cooling features that are critical to rocket nozzle performance.

To overcome those limitations, the NMIS engineers developed a hybrid manufacturing approach centred on high-pressure cold spray technology. Using the approach, the main structure of a nozzle was built up layer by layer through rapid material deposition. “The process supports large-scale production while maintaining fine geometric detail, enabling complex internal features to be integrated efficiently within the structure,” the announcement said.

The institute said its rocket nozzle highlights the potential of high-pressure cold spray to transform how large copper parts are manufactured. With deposition rates of up to 10kg per hour, the process could cut production lead times from months to days, while significantly reducing material waste compared with conventional machining.

“This project marks an important milestone in demonstrating how advanced manufacturing can be applied to complex rocket engine components,” said Calum Hicks, senior technologist at the NMIS Digital Factory.

“Developing the copper rocket nozzle allowed us to explore new approaches to producing high‑performing thermal management structures, reducing development times and improving production efficiency. This work strengthens the UK’s capabilities in the space sector and beyond.”

While developed for space, the implications of the approach “extend far beyond its immediate use”, the announcement said. It could offer a scalable manufacturing option for sectors including aerospace, energy and shipbuilding, where robust and corrosion-resistant materials are critical. The technology could also be applied to repair and remanufacture existing components, extending asset life and supporting more sustainable manufacturing practices.

“The real value of this work is in showing how advanced manufacturing can move beyond experimentation into practical application,” said Ryan Devine, senior research and development engineer at NMIS. “By combining engineering expertise with innovative processes such as high-pressure cold spray, we’re enabling manufacturers to rethink how complex components are designed, produced and maintained. Taking these steps allows us to support faster development cycles and more resilient manufacturing systems.”