When living on the Moon, there will be no such thing as rubbish. An ESA project has investigated a new method of 3D printing that could enable the reuse of scrap metal salvaged from old spacecraft or landers for the in-situ production of new high-performance parts.

To establish a viable lunar economy, future settlers will need to make use of all the resources at their disposal, including scrap metal. At the same time they will need to overcome environmental challenges – most notably the high probability that manufacturing processes will be contaminated by lunar dust.

Austrian additive manufacturing company Incus, specialising in Lithography-based Metal Manufacturing (LMM), worked with Lithoz GmbH and OHB on an ESA project to establish the feasibility of printing using recycled metal, while showing that a degree of contamination by lunar dust is a manageable problem.

LMM involves printing layers of metal powder in a binder that can be selectively hardened where required by exposure to light. The part is then shaken free of the leftover feedstock and ‘sintered’ or baked hard.

"This project has proven that LMM technology is able to use recycled powder for the feedstock material and provide sustainable zero-waste workflow," comments Incus CEO Gerald Mitteramskogler. "We expect that further developments in metal recycling technologies will open the way to metal materials with more settled sintering processes for the lunar environment."

The project used a combination of new and recycled titanium, plus up to 10% of simulated lunar dust by volume. Higher levels of dust contamination were shown to increase ‘viscosity’ (or runniness) of the feedstock but optimal powder to binder ratios could overcome this phenomenon to achieve the desired part quality, with strength comparable to conventional Metal Injection Molding parts.

Martina Meisnar, ESA’s technical officer for the project, adds: “Considering the challenge of bringing humans back to the Moon and building a base, the topic of in-situ resource utilisation (ISRU) is gaining significant momentum. Projects like this, recently completed by Incus and project partners, demonstrate that manufacturing methods like LMM are very good candidates to support such an endeavour.”

“This successful collaboration showed that lithography-based AM techniques are among the most promising candidates to let 3D printing in space become a reality in the future,” notes Martin Schwentenwein, Head of Material Development at Lithoz.

Francesco Caltavituro, system engineer for the project at OHB: “Our work done so far, and our follow-up research and development, aims to continue to open the way towards a sustainable Moon settlement released from dependency on Earth.”

The 18-month research project was supported through ESA’s Technology Development Element.