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Despite being around for several decades already, 3D printing is still considered an up-and-coming technology. It does offer a revolutionary approach to manufacturing but is still hindered by several technical or physical limitations. For this reason, 3D printing will need to be adopted by more innovative agencies before it can become mainstream.
One of these innovative agencies is NASA. On the cusp of the next era of space exploration, NASA has been looking into the unique capabilities of 3D printing to deliver supplies and equipment to space-bound teams. How has NASA been using 3D printing and what does this mean for the industry?
Reduces costs and increased reliability
What’s the point of using 3D printing for space exploration anyway? The answer is easy when we consider how much equipment, tools, and spare parts NASA sends out for every trip. To support the International Space Station, NASA takes a “better be safe” approach and sends more tools and supplies than necessary. As you imagine, this is logistically more complicated and increases the cost of every space expedition. Every piece of payload that goes into these rockets cost thousands of dollars to deploy.
There is another downside to this approach. Since teams try and take as many parts and tools as possible, a lot of these often end up not getting used. This creates a lot of clutter and generates waste which eventually has to be disposed of.
What if the ISS needs to replace a part that is not available in the station? It could take several months to more than a year for anything the be sent to orbit. This reduces the reliability of any space expedition and may even compromise the safety of the people in the station.
For this reason, the development of 3D printing technology for space exploration is looked at as a way to reduce the cost of deployment while enhancing the safety and reliability of space stations and trips. Space teams can print their own parts and tools when needed and will not have to wait for several months to do critical repairs.
3D printing in the ISS
Early efforts to developing 3D printing technology started at NASA’s Marshall Space Flight Center in Huntsville, Alaska. Partnering with California-based startup Made in Space, NASA kickstarted the In-Space Manufacturing program. The aim of the program was to develop on-demand manufacturing technologies to support teams that will be deployed – ultimately- on the Moon and Mars.
The premise behind “Made in Space” is that it hopes to overcome one of the major limitations of space exploration – namely, that everything used in space came from the Earth. What if space-bound teams had the technology to create their own tools and parts? The founders of Made in Space believed that this could open up new frontiers in space exploration.
When designing a 3D printer for space, several unique factors had to be considered. Primary of this is the lack of gravity. The team went to work on a gravity-independent 3D printer that used fundamental FDM technology. It took three years and several research flights on airplanes that simulated zero-gravity conditions before the team created a prototype 3D machine that could be sent to the ISS for actual testing.
The Additive Manufacturing Facility (AMF) 3D printer prototyped by Made in Space was an FDM printer with a 6 x 6 x 6-inch build area. It was designed to use common 3D printing materials including ABS, ULTEM 9085, and HDPE.
In 2014, the first 3D printed tool in space was manufactured – a ratchet wrench. It was also the first 3D printed object based on a design that was transmitted from the Earth. Nineteen other objects were 3D printed on the same trip, but these were all based on models that have been pre-programmed into the printer.
In 2019, Made in Space flew a polymer recycler into the ISS. This was designed to address the issues of added waste, which is a natural consequence of 3D printing. Seattle-based Tethers Unlimited has also designed and sent the ReFabricator unit to the ISS, which was designed specifically to recycle the ULTEM 9085 material.
Since then, Made in Space has been hard at work at making improved versions of the 3D printing technology they have developed. The ultimate goal? Make a 3D printer that can use lunar or Martian dust as feedstock.
Metal 3D printing in space
Material is a major limitation of deploying FDM-based 3D printers in space. FDM printers are perfectly fine for plastic tools and parts, but how about parts that have to be made with metal? Is there also a way to 3D print components parts for electronic circuitry?
However rare they may be, the technology for metal 3D printing already exists. The method with the most potential is selective laser melting (SLM), a process where metal powder is deposited onto a build plate at very thin layers. When the metal powder is in place, a laser quickly heats the metal just to the point of melting, thus fusing them together.
This technology is expensive, but the price is not what is hindering NASA from adopting it. The method requires a large amount of power for the laser, which may not be practical for a space station. Moreover, the metal powder can be a serious fire and respiratory hazard in a zero-gravity environment.
Efforts to adopt metal 3D printing technology for use in space are already underway by various groups. Made in Space has developed equipment based on additive manufacturing using metal wires melted via electrical arcs. Both Fabrisonic and Ultra Tech Machinery are exploring the use of ultrasonic additive manufacturing.
Techshot is working on a full-featured facility for metal 3D printing that will include the additive manufacturing process and a furnace and endmill for post-processing. Coined the Multimaterial Fabrication Laboratory or “FabLab,” this is likely one of the biggest projects taking on the metal 3D printing dilemma and is anticipated to take over an entire rack of the ISS should it become a reality.
3D printed food in space
NASA isn’t just exploring the use of 3D printing for parts and tools in space stations. How does a 3D printed pizza sound like? Probably pretty good if you’ve been stuck in space for months.
In 2013, NASA awarded a Small Business Innovations Research (SBIR) grant to Texas-based company Systems and Materials Research Corporation (SMRC). The contract was to create a system for using 3D printing technology to create food from basic components like starch, fat, and protein.
The goal of the project was to provide food that had precise amounts of nutrients and the proper texture for edible structures. The “raw material” for the process were macronutrients and flavors stored in packets as gels or liquids.
While the Phase 1 SBIR project culminated in what seemed like a feasible concept, it was not immediately followed up by a Phase 2 contract. Still, the senior engineers at SMRC learned enough from the experience to think about more “terrestrial” applications of 3D printing of food.
In 2016, the people who worked on the project founded a company called BeeHex, which secured a seed funding of $1 million after some media exposure. From the conceptual demo that created a customized pizza using traditional ingredients, BeeHex has now applied for a patent for their Chef 3D device.
In the future, the company is hoping to leverage health data collected from users to come with food that will cater to a person’s individual needs. BeeHex has explored this idea with the US army through a concept that aims to create customized breakfast bars based on the user’s daily recommended nutritional values.
Now that the technology for 3D printed food has advanced significantly, we expect it to eventually find its way back in the sights of NASA. Perhaps the idea of a 3D printed pizza in space is not so impossible anymore.
Large-scale 3D printing
In many cases, the objects you can 3D print are limited in size. After all, a 3D printer only has a limited build area. However, NASA is considering using 3D printing technology not just for the tools and parts needed by the crew onboard these rockets. With the Artemis program, NASA is exploring how 3D printing can be used to create rocket engine parts.
The project is called Rapid Analysis and Manufacturing Propulsion Technology (RAMPT). The project uses a selective laser melting method where metal powder is fused together using lasers. To give the finished prints structural integrity, the metal powder is deposited into a pool of molten metal, eliminating the innate porosity of fully powder-based metal 3D printing. This is essentially a modification of the technology being used in most metal 3D printing applications.
This technology, called blown powder directed energy deposition, is suitable for this project as it is capable of producing very large pieces with highly complex designs. So far, the RAMPT team has been able to 3D print a nozzle for a jet engine that measures 40 inches in diameter and has a length of 38 inches. It wasn’t just a simple nozzle as it also had integrated cooling channels. 3D printing the nozzle took 30 days – a huge reduction from the one year it usually takes using traditional manufacturing methods.
Dimensional accuracy is one thing, but can these 3D printed parts withstand the extreme conditions for space travel? To answer this question, 3D printed rocket parts go through rigorous hot fire tests that subject them to the 6000-degree combustion temperatures and pressures expected during a rocket launch.
Towards a 3D printed habitat
Ultimately, what is the goal of space exploration? There probably isn’t a single answer to that question. For the most part, space expeditions have focused on gathering information on other bodies in space, therefore expanding the boundaries of human knowledge. However, is there truly a way for space exploration to give way to the possibility of establishing a human habitat outside the Earth?
Bringing construction materials to build a habitat on Mars or the Moon would be simply impractical and expensive. The solution? 3D printing. In 2015, NASA launched the 3D-Printed Habitat Challenge that invited people, teams, and agencies to use 3D printing technology to design and build a habitat fit for Mars.
Out of 11 participating groups, three were chosen because of the concepts they presented via virtual modeling. These models were then transformed to reality in 2019 during a grueling 30-hour 3D printing session. Two teams came out on top of this competition – New York-based agency AI Space Factory and a team from Penn State.
AI Space Factory constructed their egg-shaped habitat using a material composed of basaltic fibers and bioplastics. The idea was for the material to fully strengthen in just 5 minutes but for it to be recycled or composted once the building’s life cycle is completed.
For their part, the team from Penn State used a sand-based cement to build their igloo-like habitat. The material dries faster than standard concrete and develops full strength in only 120 minutes. The inclusion of a cone-shaped roof on the habitat was a feat for the team, proving that the material can support overhanging features to some degree.
Both structures were constructed using massive industrial robots that worked non-stop for a total of 30 hours over three days of competition. Just to be clear, the structures created during the competition were only one-third scale models of a real human-sized habitat. The habitats were both subjected to a series of strength and integrity tests, with the AI Space Factory habitat eventually coming out on top after withstanding over 50,000 pounds of compressive force.
While the conditions simulated during the competition are far from what one would normally expect in space, the demonstration represented the beginnings of what NASA wants to achieve eventually. The idea is to develop a fully automatic 3D printer, delivered via a rover, which can 3D print habitats using whatever material is available on the Moon or on Mars.
Research on this had already been started by researchers at the Washington State University back in 2012. Using simulated moondust composed of silicon, calcium, iron, aluminum, and magnesium oxides, the researchers tried to use 3D printing technology to create bone scaffolds.
The results of the study were still far from what NASA envisioned as a way to repair broken parts or build structures using moon dust, but it still proved that moon dust can be used to create strong free-standing objects. The limitation back then was the incompatibility of powdered raw material with standard 3D printing methods.
3D printing technology has certainly evolved in huge bounds since 2012. Even with the limited results of the 2012 study, the research team concluded that the idea of creating 3D printed parts using the material you can just scoop off the ground was not far-fetched. As the 2019 habitat competition demonstrated, creating structurally sound habitats using 3D printing technology was also possible.
We’re probably still a long way away from building houses on the Moon that people could live on. There’s still the problem of scale and the fact that creating houses from real lunar dust is still a concept that is yet to be tested.
However, there’s probably potential for this technology to be explored in more Earth-bound applications. Can 3D printing be used for sustainable housing? There’s probably enough social and environmental value for this concept to be worth delving into.
3D printing and space exploration are two frontiers of human knowledge that seem to perfectly complement each other. 3D printing offers capabilities uniquely suited to address the challenges of space travel. With NASA on the case, the various ways in which 3D printing has been developed has also benefited the 3D printing industry.
At this point, we fully expect 3D printing to be a mainstay in all space exploration projects. Just how significantly the technology will impact this particular frontier remains to be seen – we remain very optimistic.
Warning; 3D printers should never be left unattended. They can pose a firesafety hazard.