»Recycling is the key«
Interview: Thomas Masuch; Photos: NASA — 2019/05/30
In its history, NASA has successfully realized some of humankind’s most technologically demanding projects. With its missions to the Moon and Mars and numerous other activities in space, the agency operates at the forefront of technological developments and opportunities. For over 30 years, NASA scientists and engineers have also been working with 3D printing. We had the opportunity to talk to John Vickers – Principal Technologist for Nanotechnology, Advanced Manufacturing, and Lightweight Materials within NASA’s Space Technology Mission Directorate – about the role additive manufacturing plays at NASA in both its current and future missions.
Numerous missions and projects are prepared and implemented at the 10 NASA Centers. Can you give us an overview of how additive manufacturing has developed within the agency and where the technology is used today?
VICKERS: We have been involved in 3D printing since its inception in the late ’80s and we have some of the first Beta machines for stereo lithography. We continue to follow that industry because we see the great benefits for what we do at NASA. We have continued to be right on the cutting edge of the machines, trying to acquire the latest different machines as they come out. We work in partnership with the global community. If you want to do something big and new you must have diverse partners. Our team of global industry and academia is the ecosystem of partners that allows us to accelerate this technology for NASA applications.
It sounds like AM already plays a very important role …
VICKERS: Additive manufacturing is certainly one of the most important elements of advanced manufacturing processes. We have hundreds of additive manufacturing activities going on within the agency, at all 10 NASA centers. They span many technology readiness levels (TRL) – a NASA measurement system used to assess the maturity level of a particular technology – all the way from basic research to testing a system in a relevant environment, or TRL 6.
»We have lots of concepts for in-space additive metal manufacturing.«
There are nine TRL levels at NASA. What are the next steps at level six?
VICKERS: For NASA technology development that we intend to share immediately with industry, development generally stops at TRL 6. The production parts would generally come from our NASA industry suppliers. We work continuously and closely with them, but we are generally not doing that work internally.
Can you give us some examples of applications in which you use additive manufacturing?
VICKERS: We cover the entire technology spectrum. NASA missions are complex and 3D printed parts might be critical to the performance of a mission. It’s important to understand all the requirements of parts that we are working within R&D or for a particular vehicle. That can be a propulsion system, launch vehicle, satellite or a rover on Mars. We are using additive parts for all of those. But, we are still early in the adoption of additively manufacturing specific critical parts.
How are things going in the current space projects that employ 3D printing?
VICKERS: We have three 3D printers on board the International Space Station. We just installed the Refabricator – that’s the name of the newest 3D printer in space. Once operational, it will recycle materials as well as 3D print. All these machines are polymer based. We also do a lot of work in the propulsion arena. I would say NASA is a leader for rocket engine propulsion components. And those require even more rigorous qualification and certification processes. Here, we spend a lot of time understanding these processes and making sure the parts are safe.
great proving ground
With polymer parts already being produced in space, is there also a plan to produce metal parts?
VICKERS: There are plans to produce metal parts. We awarded contracts to three companies for a first-generation, in-space, multi-material fabrication laboratory, or FabLab, for space missions. That’s likely the next equipment beyond the Refabricator that will be installed on the space station. The minimum requirement for FabLab is to produce metal parts. Another requirement is to produce multi- material parts combining electronics, composites and polymers.
How is the experience gained on the International Space Station helping to further improve the usage of AM?
VICKERS: The International Space Station is a great proving ground for us to operate in, giving us access to test these technologies in microgravity. Beyond that, we are looking at in orbit assembly, servicing and manufacturing capabilities. NASA plans to build the Gateway, which is essentially a small space station in orbit around the moon. One of the first pieces of equipment on Gateway will likely be a 3D printer.
You mentioned the Refabricator that is already on board the ISS. What have the experiences with it been like so far?
VICKERS: When you have a long-term sustainable presence in space, recycling is key. This is the first step. There is a lot of plastic material, all kinds of packaging for food and other products, that would all be waste and we would have to bring it back to Earth. The farther you go in space, the harder it is to return waste back to Earth.
NASA has a extensive experience with 3D printing. For example, you’ve been using EBF3 (Electron-beam freeform fabrication) for a long time, including in testing during parabolic flights. Is this a technological approach that NASA is concentrating on?
VICKERS: That’s a label that refers to a certain system and a process. You can also buy this commercially, but there are half a dozen similar processes. I don’t think that the three companies involved in the FabLab project are using electron beam as a power source. There are unique processes that they are proposing for the FabLab. We have lots of concepts for in-space additive metal manufacturing. Electron Beams is just one of them.
Here on Earth, one of the biggest challenges in AM is post-processing. Does the same apply in space as well, or do you focus on parts that can be used right out of the printer?
VICKERS: You are exactly right. Post-processing, especially heat treating, is a research area for all of us in the community. There are still a lot of unknowns. We are not even sure if we need that heat treatment at all. We would like to have fewer operational constraints when we get into space, and heat treatment would be very difficult to accomplish.
And let’s not forget steps like milling or drilling …
VICKERS: We are looking at all of that. There are machines that can perform the additive process and some post processes, machining surface finishing all in one machine. There are also projects about printing habitats.
Is there already a timeline for building the first 3D printed habitats in space or is that too far away now?
VICKERS: Just a couple of weeks ago, we announced the winners of our 3D-printed habitat competition. The idea is to develop a 3D printed structure for a habitat on the Moon or Mars. It’s a hardware approach of using materials that are applied from Earth along with on-site resources. So, we use what can be easily found on the Moon or Mars as a building constituent as you would use concrete for an Earth-based construction. These structures can be used for a habitat, but for different infrastructure as well.
And how far off is that?
VICKERS: If you see the results of that competition you can see how fast we can make that happen. We are not that far away. I think we have the engineering understanding and the technical capability to do that as fast as the program will allow us. We are certainly capable to do it within the next 10 years.
Mr. Vickers, thank you very much for these interesting insights.
John Vickers serves as the principal technologist within the area of advanced materials and manufacturing in the Space Technology Mission Directorate at NASA Headquarters. He also serves as the associate director of the Materials and Processes Laboratory at NASA’s Marshall Space Flight Center and as the manager of the NASA National Center for Advanced Manufacturing with operations in Huntsville, Alabama and New Orleans, Louisiana. He has over 35 years of experience in materials and manufacturing. As principal technologist, he leads the nationwide NASA team to develop advanced manufacturing technology strategies to accomplish the goals of NASA’s space exploration-focused missions.