Additive manufacturing for space exploration

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Eliana Fu, of Trumpf and formerly SpaceX, shares how additive manufacturing can aid humanity’s cosmological journey

We are in the midst of a new and exciting global space race. In the 1950s and 60s we saw the first space race between the USA and the USSR, with goals to be the first human in space and then, the first human on the moon.

As a species we have not set foot on the moon since the year of my birth, but rather we have shifted our emphasis to learn how the human body can exist in microgravity for extended periods.

The new space race, featuring private and small companies, is to achieve space flight using smaller, more nimble launch vehicles. Laser additive manufacturing (AM), or 3D printing, is an ideal technology for these companies as a manufacturing process to quickly design, build and iterate structures and vehicles for space flight. Moreover, many of these new and smaller companies have limited resources and space for capex and tooling costs, so AM is ideal, with a smaller manufacturing footprint.

In traditional manufacturing, rocket ships for space exploration have used well-known and established manufacturing processes. For the barrel sections of rockets, these would be produced using friction stir welding of aluminium sheet metal after bump-forming and shearing; for iso-grids, pockets would be machined out of thick plate; and for domes, welding and hot-spin-forming would be used. All of these processes have associated lead times for raw material, processing, cleaning and inspection. Any reduction in lead time for any or all of these processes not only results in decreased overall lead time, but allows extra time for any proof testing, hot fire testing and vehicle integration.

Agile Space is one of many new space vehicle propulsion system providers using laser AM. (Image: Agile Space)

Components for space exploration that can be produced using AM include propulsion devices and structural components. For propulsion, specifically rocket engines, the advantage of using AM is obvious: reduction in the overall number of parts (reducing the risk of manufacturing flaws as only tens of parts need to be dealt with compared to hundreds of parts), design simplification, the ability to print cooling channels with unique overhanging angles, and improved thrust. With better materials that are designed specifically for AM, better heat capacity and strength can be obtained, resulting in improved engine efficiency.

This can translate into achieving higher orbit or being able to transport larger payloads. For structural components including the tanks and barrel sections of rocket vehicles, the ability to use AM eliminates the cost of requiring tooling for sheet metal forming and fixturing for friction stir welding, which can run into the $2m-cost range.

Hot fire testing of a rocket engine built using laser AM, at Relativity Space. (Image: Relativity Space)

3D printed parts are now on Mars – the Perseverance rover has 11 components produced by laser AM. Astronauts have already successfully printed polymer and ceramic parts on the International Space Station, where the feedstock is less volatile than metal powder – fines can be pyrophoric. However, the goal of 3D printing on another planet is now in reach. On Earth we have been able to print low-cost housing with ceramics, so this will very likely translate to the next logical step: printing with regolith on other planetary bodies such as the moon or Mars. It will be obviously easier to print extra-terrestrially using native feedstock, rather than dealing with the storage and handling of material feedstock during launch, flight and landing.

The overall reduction in lead time from traditional manufacturing processes results in a greater number of flight windows for the final vehicle. The increased availability of flight windows, higher orbits and larger payloads opens up more opportunities for customers to go into space, whether it be space tourism or satellite customers.

Future missions to planets must include 3D printing. (Image: Nasa)

It is an exciting time to be involved in space exploration, and laser AM is the perfect tool to achieve these lofty goals. Keep watching the skies!

Eliana Fu was educated at Imperial College, University of London with a Masters and PhD in Materials Science. She performed post-doctoral research at Loughborough University (UK) and Clemson University (USA). After working extensively in the traditional manufacturing world, with TWI, then TIMET and SpaceX, she turned her attention to AM at SpaceX, then with Relativity Space as a senior engineer of additive technologies. She then joined Trumpf as industry manager aerospace & medical. She is the Women in 3D Printing ambassador for Las Vegas and is involved with other volunteer STEM activities for middle-school children. Eliana has written a book based on her experiences at SpaceX.

This article was provided by the Laser Institute of America.