How 3D printing could make space settlement viable

If one were to tell you that the 3D printing technology, which as recently as the 1980s was mainly used to fabricate plastic models, could determine the future of human race, it would without a doubt sound hyperbolic. But the exponential growth witnessed by the technology, also known as Additive Manufacturing (AM), is expected to have far-reaching ramifications than what we now know of it.

Following rapid advancement over the past few decades, modern 3D printers are now being used to construct a wide range of objects from plastics, liquids, powder grains and even metals, leading to new applications in almost all aspects of life. This includes biomedicine where replacement organs and living tissues are being ‘printed’ using the technology.

Not to be left behind, space agencies and the commercial space industry have also turned to 3D printing as a way to cut costs and improve efficiency. Coupled with reusable rockets and ride share spacecrafts, this will further prove economical in launching payloads and crews to space. Beyond that, AM also has the potential to enable in-orbit assembly, allowing replacement of parts or even building an entire shuttle in space.

To this end, the European Space Agency (ESA) has recently unveiled the first 3D metal printer component ever assembled aboard the International Space Station (ISS), an accomplishment that has the potential to transform the whole space industry. The 3D metal printer was developed by an industrial team led by Airbus Defence and Space (SAS) in partnership with the ESA’s Directorate of Human and Robotic Exploration .

“This first technology demonstrator of in-space manufacturing showcased how to deal with all the specific constraints to produce metal parts in such a critical environment: how to miniaturize an industrial machine to fit into a space station rack and survive a launch to space, how to deal with the microgravity, use as efficiently as possible the raw material sent up there, mitigate the fumes and particles that may be generated by the metal fusion process, how to safely fire a high-power laser in the ISS, and finally, how to operate a manufacturing machine as autonomously as possible, with only remote control from ground operators,” said Anthony Lecossais, the lead engineer involved in the development of the 3D metal printer, explaining the significance of this milestone via an email interaction with Interesting Engineering .

By relocating this key manufacturing process to Low Earth Orbit (LEO), companies and space agencies can save costs by producing replacement parts and tools in the orbit rather than relying on resupply ships to be sent from Earth.

Predicted by science fiction

The concept of 3D printing was first described by science fiction author Murray Leinster in his 1945 short story ‘Things Pass By’. The reference comes from a short episode in the story where the main character explains the process and benefits of a special machine he has created. In the course of it, he also explains how this technology could be used to create spacecrafts:

“Ordinarily, you make a specialized machine-tool to turn out one particular part, and it will produce that part cheaper than any other method can do. But if you try to change the product, the machine is useless. You get efficiency at the cost of flexibility.

“For that reason, there aren’t any mass-production machines for big objects like ships and so on. It’s cheaper to be inefficient and flexible. But this constructor is both efficient and flexible. I feed magnetronic plastics — the stuff they make houses and ships of nowadays — into this moving arm…

“It’s ready to make a spaceship hull now.”

The term ‘3D printing’ originally referred to a specific process patented by scientists at the Massachusetts Institute of Technology in 1993 which was later licensed to several manufacturers. Today, the term is used interchangeably with additive manufacturing to refer to several related processes. Central to these processes is computer-aided design, where engineers develop three-dimensional computer models of an object. These are then translated into a series of two-dimensional ‘slices’ that the printer can begin depositing.

At present, the technology’s range, precision, and repeatability have evolved to a point that 3D printing is considered a viable tool for industrial production. In addition, the technology has expanded far beyond the use of plastics. Between the 1980s and early 2000s, scientists experimented with new processes and technologies that would give rise to 3D metal printing. This includes metal binder jetting , developed by Dr. Ely Sachs at MIT , laser-sintering technology, electron-beam melting (EBM), and Joule Printing .

A game changer for space

Compared to traditional manufacturing, 3D printing offers numerous advantages. While the former involves a ‘top-down’ approach where raw materials are stripped, shaped, and processed; 3D printing consists of a ‘ground-up’ strategy, where objects are built by adding one material layer after another (slice by slice). As Leinster predicted, these technologies have reached the point where they are being actively used to develop rocket parts and components for use in space.

The space industry is already adopting the technology to create almost everything related to rockets. For instance, NASA recently used its Reactive Additive Manufacturing for the Fourth Industrial Revolution (RAMFIRE) process to create an aluminum rocket nozzle and a rocket engine’s thrust chamber . The agency also used 3D printing to develop a prototype for a Rotating Detonation Engine (RDE), which they successfully test-fired last year .

The commercial space sector has also turned to 3D printing to streamline production. A case in point is California-based aerospace manufacturing company Relativity Space which employs 3D printing, artificial intelligence and autonomous robotics to build both the the skeleton and the engine of its rockets.

“Metal 3D printing has already revolutionized the way we develop and manufacture our satellites and launchers, with more efficient and more intricate designs, embed additional features in the part (like cooling, sensors), or reduce the number of parts and the assembly tasks. 3D printing also helps to save raw material mass compared to traditional machining, which can be of particular concerns on high-end and specific alloys for aerospace application. 3D metal printing allows for the production of complex parts with minimal setup costs, making it a cost-effective solution for low-volume production like we have in space applications,” stated Lecossais.

In-space manufacturing

Efforts to realize in-space manufacturing aboard the ISS began in 2014 when NASA launched a technology demonstrator contributed by Made In Space . The printer relies on fused filament fabrication to create objects out of plastic and proved that 3D printing could be carried out in a microgravity environment.

This was followed by setting up of the Additive Manufacturing Facility (AMF) on ISS, which gave way to the first 3D-printed tools in space, including a wrench, a rachet wrench, and more. In 2019, NASA attached the ReFabricator experiment developed by Tethers Unlimited to the ISS to create 3D-printed parts using recycled plastic materials. This demonstrated that waste materials can be reused in space to manufacture components and tools.

However, the ESA’s metal 3D printer is the first to successfully print a metal component in microgravity conditions. This technology demonstrator was launched to the ISS earlier this year and became operational by June. It produced the first 3D metal shape a month later in August. With the first metal component built, the ESA plans to create three more to be sent back to Earth for quality analysis and testing.

Space settlement, a real possibility

In the near future, space agencies and commercial space companies hope to establish operations in Low-Earth Orbit, building satellite internet constellations, space-based solar power, private space stations and even hotels. Similarly, asteroid mining prospectors and companies hope to create platforms in cislunar space to enable the mining of Near-Earth Asteroids.

Between 2012 and 2022 , the space economy has grown by over 60% and was valued at roughly $400 billion. According to some estimates, the space sector will be worth over $3 trillion by 2050 . Further growth is anticipated as launch costs become cheaper and more space agencies and companies deploy satellites and space stations to LEO. So far, proposals for private space stations include Axiom Station by Axiom Space, Voyager Space’s Starlab , the Orbital Reef by Blue Origin and Sierra Space Corporation, and Vast Space’s HAVEN-1 .

The capacity to 3D print components in space could be vital to commercial operations in LEO. As LEO becomes populated by workers, researchers, customers and engineers, there will be a growing demand for repair and replacement services. Shuttles will require maintenance and refurbishment between trips, and equipment in orbit must be serviced and repaired.

With the ability to offer print-on-demand services in orbit, space agencies and companies will not be dependent on parts and tools printed on Earth. On top of that, it could enable the on-orbit assembly of spacecraft, foundries, and factories in space.

“In-space manufacturing has the potential to revolutionize operations and logistics for space exploration by reducing the reliance on costly and lengthy launches from Earth, enabling the production of goods and materials in space that are optimized for the space environment, on-demand and in-situ producing maintenance parts without relying on logistics and storage of spare parts, and eventually supporting the robustness and autonomy of long-duration space missions on the Moon, Mars and beyond,” said Lecossais.

One of the overriding features of the new space age is the way lowered costs are increasing access to space. The long-term goal is to relocate industries, manufacturing, and research to LEO that will benefit from microgravity conditions and reduce our environmental impact on Earth. Beyond that, creating in-orbit infrastructure will facilitate missions to the Moon, Mars, and beyond and ensure people can operate in space for longer periods. Once this is achieved, settlements in space and other bodies in the Solar System will finally become a real possibility.