Printing the Future: An Introduction to Additive Manufacturing in Space

About the Author:


Rachel Clemens has focused her career on advancing life science research and product development through experiments in space. In her current role as a Commercial Innovation Manager at the ISS US National Lab, she brings life science research to low earth orbit. She leads partnership development with life science companies – she finds that every sector, from start-ups to big pharma, can benefit from research in space. She is eager to entertain even the craziest of ideas and passionate about finding new solutions to Earth-bound problems.

After earning a Ph.D. in Molecular Biology from Oregon Health and Science University, Rachel became a Scientist at NASA Ames Research Center leading research on how microgravity affects host-immune systems and microbial pathogenesis. In addition to her current role at the National Lab, Rachel volunteers as a Scientific Project Manager at the Rare Genomics Institute, which connects rare disease patients around the world and provides tools and support to the greater rare disease community. She is based in San Francisco, CA where she blazes trails on foot, conquers hills by bike, and bravely hosts dinner parties in her micro-studio.

Rachel will be speaking at 3DHEALS2020 (and answering questions) on microgravity/ISS for 3D printing directly.

Additive manufacturing (AM) in space may not be top of mind for most people in the field of 3D printing, but it is hardly a new idea. The year 2014 marked the first time an object was 3D printed in space. NASA astronaut Barry Wilmore printed the object onboard the International Space Station (ISS) using the Zero Gravity Printer, which was engineered by Made In Space and served as a predecessor to the company’s Additive Manufacturing Facility (AMF) currently on the ISS. Since then, other firms have joined in to prove new platforms and develop additive printing applications for commercial use. Companies such as Made In Space are working to additively manufacture satellites and spacecraft in orbit, while companies such as TechShot and Organ.Aut have developed technology for bio-compatible 3D printing.

You may be asking yourself: Why 3D print anything in space? One reason for the aerospace industry is that it may be more economical to launch 3D printing feedstocks than it is to launch satellite components and spare parts from Earth. A more general reason, however, is that certain 3D printing processes can benefit from the microgravity environment of space.

A Multipurpose Precision Maintenance Tool that was 3D printed on the ISS using the AMF. The tool was the winning design of the 2014 Future Engineers Space Tool design competition, in which students submitted designs of tools for ISS crew members that could be 3D printed with the AMF. (CREDIT: Made In Space )

The ISS is in free fall as it orbits the Earth once every 90 minutes, creating an environment of sustained microgravity. On Earth, we live with gravity as a constant, and this force accounts for a major influence on observed phenomena in physical systems. In sustained microgravity, however, gravity-dependent phenomena such as sedimentation and convection are substantially diminished. Additionally, without gravity, other physical forces like viscosity and surface tension dominate. Because of these factors, microgravity presents a unique opportunity for research and product development in numerous fields, including AM.

There are several questions being addressed by researchers and engineers conducting 3D printing experiments on the ISS, and I will list some examples here. First, because surface tension becomes a dominant phenomenon in microgravity, there is an opportunity to print using lower-viscosity “bioinks” for AM with or without scaffolds. This is of particular interest to those working in biological systems, where scaffolds are critical to creating tissue structure for the growth of cells and cellular structures like blood vessels within the tissue. It is also one reason why the arrival of the Biofabrication Facility by TechShot to the ISS is so exciting. Now researchers can experiment with lower-viscosity bioinks in microgravity and explore creating tissue constructs that are more like the tissues inside the human body. These tissue constructs could then be used for testing pharmaceuticals or one day even for transplant in patients on Earth.

Additionally, because sedimentation becomes negligible in the absence of significant gravitational force, companies are also interested in leveraging microgravity to create structures in which discrete layering of different materials is important to product function. Although layering of material is feasible on the ground, in some scenarios, the process can be executed more rapidly in space. For other situations in which layering of material on the ground is challenging, microgravity may offer a solution. LambdaVision is an example of a company that has used microgravity to improve product development by leveraging microgravity to optimize the manufacture of layered retinal implants. Although this team is not using a 3D printer to produce the implants, it is another example of how researchers are using microgravity to achieve greater control over the process of AM.

LambdaVision’s tiny protein-based retinal implant. The implant is the small purple dot, which is about the size of a paper hole punch. (CREDIT: Peter Morenus/UConn Photo)

Microgravity can also make it easier to work with three-dimensional structures that are likely to collapse in a 1g environment. Somewhat related to the possibilities for discrete layering of material AM on the ISS presents the opportunity to produce novel structures that would be challenging to create on the ground, due to factors like the need to use a low-viscosity feedstock or the delicacy of the structure itself. To this end, the ISS U.S. National Laboratory has partnered with the Methuselah Foundation to offer a spaceflight opportunity for the winning team from the NASA Vascular Tissue Challenge, a collaboration between NASA and the Methuselah Foundation to stimulate research that would improve vascularization technology. Although the program is agnostic to the tool, multiple companies using 3D bioprinting technologies are participating in the challenge.

Another outcome resulting from a lack of sedimentation is a slower polymerization rate. Molecular crystallographers have been leveraging this aspect of microgravity for decades to produce higher-quality protein crystals that diffract at a better resolution. More recently, teams from several companies—including Fiber Optic Manufacturing in Space, Made In Space, and Physical Optics Corporation—have been investigating how microgravity could yield higher-quality ZBLAN optical fibers. In microgravity, ZBLAN can be produced with fewer defects due to the reduced impact of sedimentation as the glass solidifies. While these fibers are not produced via AM, they demonstrate the improved mechanical and material properties that can be produced by some materials manufactured in space. The successes achieved in this area are especially exciting, as they suggest a commercially viable product manufactured in space may be just around the corner.

On the left, a ZBLAN fiber pulled in microgravity. On the right is a fiber pulled on the ground. (CREDIT: NASA)

No doubt, AM in space also has some technical challenges. For example, many 3D printing technologies depend on gravity for deposition. Despite this fact, with creative engineering solutions, AM in space has made much progress since the first 3D printing facility arrived on the ISS. There is, however, plenty of room to grow. Much of the near-term work will likely be to conduct proof-of-concept studies, while others may set their sights on in-orbit manufacturing. And, as outlined above, there is a truly unique opportunity to innovate new products in health care with AM in space.

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