Behind the scenes of the first metal part 3D printed aboard the ISS

In August 2024, a historic breakthrough was made aboard the International Space Station (ISS) when the first-ever metal part was successfully 3D printed in space. This achievement marks a significant leap for the field of space manufacturing, opening new doors for future missions that could rely on in-orbit production and repairs. Led by the European Space Agency (ESA), this pioneering mission demonstrated that printing metallic parts in microgravity is not only possible but also crucial for future space exploration.

The Journey to the ISS: the metal 3D printer’s arrival

The metal 3D printer, developed by Airbus and its consortium partners under ESA’s funding, arrived on the ISS in January 2024. The printer’s main goal was to demonstrate the feasibility of producing metallic components in the unique conditions of space. After its installation on the Columbus module of the ISS in May, preparations for the actual 3D printing began, led by ESA astronaut Andreas Mogensen, who ensured the printer was hermetically sealed and ready for its first operation.

This achievement was not a solo endeavor. It required a close-knit collaboration among several organizations. Airbus Defence and Space spearheaded the development of the 3D printer, with significant input from French metal AM hardware company AddUp, as well as Cranfield University, and Highftech Engineering. Each partner played a key role in bringing this ambitious project to fruition. Their joint effort, under the ESA’s guidance, ensured that the cutting-edge technology made it to space, paving the way for future advancements in manufacturing.

Importance and challenges of metal 3D printing in space

The capability to produce metal parts in space represents a major milestone for future space missions. Traditionally, all components for space exploration must be produced on Earth and transported to orbit. This process can be costly and logistically complex. However, with the advent of metal 3D printing aboard the ISS, astronauts could potentially manufacture tools, components, or even replacement parts directly in orbit. This ability could save time, reduce costs, and enhance the self-sufficiency of space missions, especially long-duration ones.

Manufacturing in space is far more complex than on Earth due to microgravity. Traditional manufacturing methods depend on gravity to position materials and guide processes. The absence of gravity means processes like molten metal deposition behave unpredictably. As such, engineers had to develop new strategies and technologies to adapt the 3D printing process to work in these challenging conditions. The ISS environment provided a unique testing ground to understand these challenges and develop viable solutions.

The capability to manufacture parts in space has broad implications. The most immediate advantage is the ability to create spare parts and tools on demand. This could prove invaluable during long-duration missions, such as those to Mars or the Moon, where resupply missions from Earth would be impractical. Additionally, in-space manufacturing could enable the construction of larger structures that would be difficult or impossible to launch from Earth. This could include everything from satellites to space habitats.

Preparation and setup in the ISS Columbus Module

Once the printer arrived at the ISS, the next step was installation. The Columbus module became its home, and astronaut Andreas Mogensen played a critical role in setting up the machine. A vital part of the setup involved sealing the printer’s door to create a controlled environment necessary for safe and successful operations. Given the safety concerns associated with operating a high-powered laser in space, these initial steps were critical for ensuring both astronaut safety and the integrity of the equipment.

Safety was a top priority throughout the project. The printer was hermetically sealed to prevent any harmful gases or particles from escaping into the ISS atmosphere. This process also involved carefully controlling the internal environment within the printer to minimize any risks during operation. The printer’s interior atmosphere was modified to reduce the oxygen level, which helped mitigate the risks of combustion due to the high temperatures required for metal printing.

The printing process: stainless steel DED

The actual 3D printing process began with the deposition of stainless steel. Unlike traditional desktop 3D printers that use plastic filament, this printer used stainless steel wire, melted by a powerful laser. The high-powered laser reached temperatures of over 1,200°C to melt the metal wire, which was then deposited layer by layer onto a moving plate. Over time, the part would take shape, with each layer carefully built on top of the previous one.

Before diving into full-scale production, the team conducted a series of commissioning tests to ensure that all the printer’s subsystems were functioning correctly. These tests were essential to verify that components like the wire feed system, the laser, and the moving plates were properly synchronized. The tests also ensured that the printer could deposit metal with the precise control needed for a successful 3D print in microgravity.

The first step in the printing process was to create a simple 2D shape: the letter “S.” This was a crucial milestone, as it demonstrated that the printer could deposit material in the correct shape. Lead Engineer Anthony Lecossais described this as the first successful test of the system’s ability to handle 2D prints. The next challenge was moving from 2D to 3D, which involved depositing multiple layers on top of each other to create a fully three-dimensional object.

Achieving the first complete 3D printed metal part

The transition to 3D printing was not without its challenges. The team at Airbus and CNES worked closely to monitor the process in real-time, making necessary adjustments along the way. Printing in microgravity presented unique challenges, such as ensuring that each layer was correctly aligned. This meticulous process required constant feedback between the ISS and ground control, with print operations often broken into short sequences, followed by assessments and adjustments.

One of the most critical aspects of the 3D printing process was ensuring that each layer of metal was deposited at the correct height. This process required extreme precision, as even slight deviations could affect the final product’s structural integrity. The team monitored the height of each layer and made calibration adjustments between layers to ensure that the final part would meet the necessary specifications.

By mid-July 2024, the team had successfully printed 55 layers, marking the halfway point of the first sample. This achievement signaled the start of what was called the “cruise phase,” where the team was able to accelerate the printing process thanks to a series of optimizations both on the ground and on the ISS. These optimizations allowed the printer to operate more efficiently, increasing the printing time from 3.5 to 4.5 hours per day.

Astronautical efficiency

One key area of improvement was the noise generated by the printer. After analyzing the noise requirements, the team was able to extend the printer’s operational hours, which in turn accelerated the printing process. By early August 2024, the first 3D-printed metal sample was ready for retrieval, marking the culmination of months of hard work and careful planning.

Once the printing process was complete, astronauts Sunita Williams and Jeanette Epps were tasked with retrieving the first sample from the metal 3D printer. The printer’s sealed box had to be carefully handled to maintain the correct atmosphere inside and ensure onboard safety. This involved reintroducing oxygen to the box to make it safe for the astronauts to access the printed part.

During the printing phase, the printer’s interior was filled with nitrogen to prevent oxidation of the metal and reduce the risk of fire caused by the high-powered laser. Nitrogen played a vital role in ensuring both the quality of the print and the safety of the ISS crew. Once the printing was complete, the team restored the atmosphere inside the printer to normal levels before allowing the astronauts to retrieve the part.

What’s next for space additive manufacturing?

The next phase of the project involves analyzing the printed metal part on Earth. The ESA plans to compare the mechanical properties of the part produced in space with a similar part produced in a laboratory under Earth’s gravity. This comparison will provide valuable data on the effects of microgravity on the 3D printing process. The results will help refine future printing techniques and improve the reliability of in-space manufacturing.

The success of this metal 3D printing experiment marks a significant step forward for in-space manufacturing. With the ability to produce metal parts on demand, future space missions will have greater flexibility and self-sufficiency. This capability could prove crucial for deep space missions, where resupply from Earth is not an option. Looking ahead, this technology could be used to manufacture everything from spare parts to large structures in space, supporting the long-term exploration and colonization of other planets.

The successful printing of the first metal part in space represents a major leap forward in space technology. By demonstrating that 3D printing can work in microgravity, the ESA, Airbus, and their partners have opened up a world of possibilities for future space missions. As engineers and researchers continue to refine this technology, the dream of manufacturing everything from tools to entire habitats in space is becoming more of a reality.