NASA’s mission directorates that have primary interest and/or applications for space-based additive manufacturing are the Space Technology Mission Directorate (STMD), the Human Exploration and Operations Mission Directorate (HEOMD), and the Science Mission Directorate (SMD). STMD has primary responsibility for NASA space technology insertion, including small satellites, and is the point of contact for the NASA element of this study. STMD is necessarily the primary and initial NASA stakeholder in development and application of space-based additive manufacturing. The directorate has begun efforts to identify and prioritize an initial roadmap for advanced manufacturing in general, which specifically includes elements of a future space-based additive manufacturing strategic plan and implementation strategy. The committee believes that this is a good first step.
SMD is responsible for developing its own mission-specific technology. However, SMD often also looks to the technology development efforts of STMD and HEOMD to provide technology products and guidance for potential inclusion in their principal investigator-led investigations. SMD is primarily interested in robotic space exploration and operates a large fleet of satellites to conduct Earth science, astronomy and astrophysics, heliophysics, and planetary science research missions (Figure 4.1). Many of these missions will undoubtedly benefit from ground-based additive manufacturing, and in fact the first additively manufactured parts to be flown in an SMD space mission are aboard the Juno spacecraft that will enter Jupiter orbit in 2016. Planetary science research could possibly utilize space-based additive manufacturing for future missions involving lunar, asteroid, or martian surface operations. However, SMD will most probably not be an early user or directly involved in space-based additive manufacturing activities, other than as a possible recipient of products developed that can satisfy their science and mission requirements.
The International Space Station (ISS), managed by HEOMD, is the prime candidate for advanced concept technology demonstrations of space-based additive manufacturing technologies, processes, and products, as well as an initial test bed and staging platform for utilization and optimization of products developed with space-based additive manufacturing. In addition to ISS space hardware repair, replacement, and repurposing and manufacturing of essential experiment-unique hardware, space-based additive manufacturing products could also be developed for applications such as in situ resource utilization, life support, synthetic-biology-based biomanufacturing, disposable medical products and devices, food production, and astronaut-specific interface items. In the near-term (less than 5 years), the possibility exists to produce small satellite systems such as CubeSats on the ISS, using a combination of standardized functional components, transported from the ground to the ISS, coupled with space-based additively manufactured structures, interfaces, and payload elements.
FIGURE 4.1 NASA’s Science Mission Directorate operates a large fleet of scientific missions conducting various types of research and participates in several international missions as well. SOURCE: Courtesy of NASA.
NASA has considerable efforts and activities involving CubeSats and nanosats and has had several successful CubeSat missions over the past 10 years. The first domestic NASA CubeSat launched on a U.S. vehicle was GeneSat, a 3U CubeSat carrying a biological payload, developed by NASA Ames Research Center in collaboration with Stanford University, Santa Clara University, and Cal-Poly San Luis Obispo. GeneSat was launched as a secondary payload aboard the Department of Defense (DOD) TacSat-2 mission on December 16, 2006. There have been several other successful ad hoc CubeSat missions up through the present, and several centers, including Ames, the Jet Propulsion Laboratory (JPL), Goddard Space Flight Center (GSFC), and Johnson Space Center, have initiated or flown CubeSat/nanosat missions and technology demonstrations. Most recently, NASA Ames Research Center, in collaboration with San Jose State University students, successfully launched the first CubeSat from the ISS, TechEdSat. Other centers, particularly JPL and GSFC, have begun to place particular interest on use and application of smaller satellites and nanosatellites, for both early stage technology demonstration, as well as to implement science missions, possibly including future interplanetary and deep-space nanosatellites.
In 2011, STMD created the Small Spacecraft Technology Program (SSTP), whose objectives are the following: (1) identify and support the development of new subsystem technologies to enhance or expand the capabilities of small spacecraft; (2) support flight demonstrations of new technologies, capabilities, and applications for small spacecraft; and (3) use small spacecraft as platforms for testing and demonstrating technologies and capabilities that might have more general applications in larger-scale spacecraft and systems. As stated by the program, “All efforts focus on small spacecraft capabilities that are relevant to NASA’s missions in science, exploration, space opera-
tions and aeronautics including those with crosscutting applications for NASA and other users.” Because SSTP is incubating and demonstrating newer, higher-risk technologies, mission directorates and program managers who necessarily have to be somewhat risk adverse, often adopt a wait and see attitude, which hampers communication and collaboration and compromises adoption and utilization of SSTP (and other advanced technology programs) developed technologies. Additionally, because the focus of SSTP is on development of the satellite subsystems and integrated technologies from the platform standpoint, emphasis and focus on specific enabling technology areas necessary for additive manufacturing do not get specific and focused visibility.
As the use and application of CubeSats/nanosats matures and expands from university aerospace education and technology demonstration efforts to peer-reviewed science and technology and specific mission applications, their utility, awareness, and acceptance as viable platforms is becoming increasingly evident in both NASA, DOD, and other government agencies, as well as commercial and entrepreneurial space markets. As that happens, concerns for quality control, mission development efficiencies, and cost reductions become increasingly relevant. A major benefit of using space-based additive manufacturing to build CubeSats or nanosats, compared to building space hardware on the ground, is the relaxation of launch load and environmental stress requirements, as well as the possibility for rapid assembly, integration, and deployment. Additive manufacturing is unlikely to reduce the mass of these already lightweight satellites, but the structure design may not have to consider launch loads and vibration.
Finding: For additive manufacturing in space, considering a 20-year time horizon, NASA has a unique opportunity to encourage innovative thinking about how to capitalize on the lack of gravity or the lack of atmosphere to achieve
- More rapid formation of objects similar to those made on Earth and
- Objects better than those which can currently be produced on Earth.
There is already activity on the part of NASA field centers and their contractors in the field of engineering development of additive manufacturing. At the agency and mission directorate level, additive manufacturing efforts are managed from STMD. The Advanced Manufacturing Strategic Technology Development Project, which involves multiple centers and discipline areas, represents NASA on the National Advanced Manufacturing Initiative Committee. STMD involvement and interests cross all technology readiness levels (TRLs), from low-TRL activities, including the Materials Genome Initiative, the NASA Institute for Advanced Concepts (NIAC), research fellows, and Small Business Independent Research projects, to higher-TRL technology development and demonstration projects. Examples include the NIAC Printed Electronics Project at JPL, the SSTP Printable Spacecraft Project by COSMIAC at the University of New Mexico in collaboration with University of Texas, El Paso (UTEP), and the Made In Space Technology Demonstration project discussed earlier in this report. For the additive manufacturing of metals, technology development and demonstration efforts are being conducted primarily at Marshall Space Flight Center (MSFC), Langley Research Center, and Glenn Research Center. The NASA Additive Manufacturing Working Group consists of participants from the engineering and technology services and products from all centers. Despite the existence of this working group, the committee learned that additive manufacturing researchers at different centers were not fully aware of work going on at other centers and determined that better agency coordination and communication is needed.
In addition to the agency-level activities described above, there exist additive manufacturing technology projects, expertise, and capabilities at all NASA centers, sometimes as part of engineering and technology organizations, but also in science and technology research and development groups. For instance, NASA Ames recently created the “Space Shop,” which is an advanced additive manufacturing facility modeled after the “fab lab” concept (discussed in Chapter 2), which was created at the Massachusetts Institute of Technology Center for Bits and Atoms and co-located with the traditional machine and manufacturing shop. The Space Shop facility is made available as a mentored resource to all who have properly trained on the use and operation of the equipment. Other centers have initiated or have plans for similar, in-house, fab lab-type facilities.
Beyond the engineering and technology activities, and owing to the do it yourself and “Maker Community”
visibility, some NASA scientists, principal investigators, researchers, and contractors are also starting to experiment with using additive manufacturing for advanced concept and prototype development of unique and mission-specific hardware and components and as part of their scientific instruments and future space payloads. There have been many early-stage projects, such as development of additive manufacturing technology for synthetic biology-based hybrids, nanotechnology-based additive manufacturing projects, CubeSat-based technology projects, and other science- and instrument-based hardware design and development efforts. These efforts cross virtually all NASA science and technology disciplines and applications.
As often happens in emerging technology disciplines, and particularly in this nascent field of space-based additive manufacturing for space technology applications, the committee has observed an apparent lack of fully coordinated efforts outside of STMD. This could result in disconnects between technology possibilities and applications and additive manufacturing and end-user applications. Some of this is possibly due to the emergent nature of additive manufacturing technologies. In other cases, there is simply no overarching mechanism to facilitate communication and collaboration on additive manufacturing technologies and applications, including space-based additive manufacturing. Such a capability would enable and enhance the development, use, and application of both space- and ground-based additive manufacturing technologies agency wide.
Finding: NASA would benefit from coordination of its many and diverse additive manufacturing activities. NASA’s full use and application of additive manufacturing technologies, both in space and on the ground, could be made more efficient and effective if there was a stronger associative link between additive manufacturing technology and facility developers and users who may benefit in areas of efficiency, complexity, and cost reductions.
Previous chapters of this report discuss the many different additive manufacturing techniques, methodologies, and capabilities now being undertaken worldwide. There are four fundamental factors that will likely have the strongest influence on the future use of additive manufacturing in NASA space applications. These factors can be summarized as follows:
- The degree to which additive manufacturing will provide technical and programmatic benefits. These include reduced mass structures, volumetric efficiencies, increased flexibility in the design-for-space systems, as well as cost and schedule efficiencies;
- The degree to which additive manufacturing production of satellites and other space hardware can be automated and best practices can be shared among NASA centers and contractors;
- The availability of sufficient space-based resources and infrastructure to ensure the effective use of additive manufacturing systems aboard the ISS (e.g., the rate of production of artifacts, the cost effectiveness of the production system, etc.) and in other human exploration missions; and
- The degree to which space-based additive manufacturing technologies and products can be validated as to their utility, efficacy, and applicability and are demonstrated to address and solve specific mission and programmatic needs and requirements.
In order to define and scope a proper space-based additive manufacturing roadmap for NASA to produce useable in-space products, it is not sufficient to describe and consider only additive manufacturing technologies of which, as it has been shown in this report, there are many platforms, processes, and technologies. The environmental conditions and operational constraints in which the space-based additively manufactured product is to be produced will also have to be considered. Accordingly, the roadmap should probably include at least the following three scoping elements:
- The manufacture and production of space-qualified hardware platforms, subsystems, components, and functions necessary to implement the target system;
- The assembly, integration, test and performance verification, and certification test of all elements of the space-based additive manufacturing product; and
- The required infrastructure products necessary for the designated space-based additive manufacturing technique, such as those required for automated or semi-automated sample and feedstock acquisition, preparation, manipulation, and handling of additive manufacturing materials.
Although the demonstration of space-based additive manufacturing onboard the ISS has not yet been accomplished at the time of this report, development of additive manufacturing technology can greatly benefit from human presence.
Each of these factors is important to NASA’s use of additive manufacturing. They also help determine the most effective areas of application for additive manufacturing in space activities, up to and including whether or not it is feasible to manufacture a complete spacecraft in space, and if not, what elements can and should be produced.
The committee was impressed with the number of ideas and potential uses for this emerging technology. Although it recognized that some of the ongoing research is proprietary, the committee concluded that there are many people and groups that could benefit from sharing ideas and making contacts while identifying the unique challenges associated with space-based additive manufacturing.
Recommendation: NASA should consider additional investments in the education and training of both materials scientists with specific expertise in additive manufacturing and spacecraft designers and engineers with deep knowledge of the use and development of additively manufactured systems.
Recommendation: NASA should sponsor a space-based additive manufacturing workshop to bring together current experts in the field to share ideas and identify possible research projects in the short term (1-5 years) and medium term (5-10 years).
Recommendation: NASA should quickly identify additive manufacturing experiments for all areas of International Space Station (ISS) utilization planning, and identify any additive manufacturing experiments that it can develop and test aboard the ISS during its remaining 10 years of service and determine if they are worthy of flight. NASA currently has methods for providing research grant funding for basic research on additive manufacturing. The agency should closely evaluate them to determine which would allow the most rapid transition of funded research for additive manufacturing to the ISS.
Finding: Because of its broad-reaching activities involving additive manufacturing, NASA could consider establishing or co-sponsoring an ongoing technology interchange forum devoted to additive manufacturing engineering technologies, focusing on serving all NASA centers, universities, small companies, and other organizations. Such a forum could function as a focusing element to orient the agency’s efforts and activities in space-based additive manufacturing, providing an integrative, phased capability to identify, facilitate, integrate, and maximize attention and resources to this difficult, long-term objective.
An example of one such forum for a specific technology area is the Small Satellite Conference, the premier conference in this field, which is sponsored by the American Institute of Aeronautics and Astronautics, now in its 28th year of existence. Held annually at the Utah State University, this gathering brings together the small satellite community, including developers, managers, technologists, exhibitors, users, and students from government, industry, and academia, including international participants.1
The forum could enable partnerships among NASA, government, university, and industry participants coming together to further develop additive manufacturing, particularly space-based capabilities. The technologies could be developed for applications that enable industry and university participation along with NASA and other government
agencies. With proper support and backing, such a forum could facilitate the leveraging of resources, mechanisms, and necessary infrastructure for efficient coordination and implementation of defined and approved objectives. Such an entity could serve as a resource for communication, collaboration, and interchanges necessary to enable development, integration, validation, and application of required components and subsystems for spaceflight and human and robotic exploration and related terrestrial scenarios.
The Space Technology Roadmaps (Figure 4.2) highlight 14 critical technology areas, including those necessary to facilitate robotic human exploration beyond low Earth orbit. The roadmaps target timelines where technology development is needed to enable space exploration, and one of those specifically discusses advanced and additive manufacturing. At the next level, the roadmaps identify specific technology subareas deemed necessary to accomplish the target mission objectives. By definition, NASA, via STMD, and with review and critique from open review and the National Research Council, has approved the format, implementation strategy, teaming approaches, and content and projections put forth in these roadmaps. Figure 4.3 shows an example of a representative roadmap, in this case, for launch propulsion systems.
Beyond the original 14 roadmaps, NASA has begun to identify other technology areas where emphasis is warranted to support and facilitate NASA and national objectives for human and robotic exploration. Although it is not at the same level as the 14 technology roadmaps, NASA would be well served to apply this same approach and strategy in creating an agency-inclusive, overarching, space-based additive manufacturing roadmap. Such a roadmap would help guide the agency and carefully manage its scarce technology development funds.
FIGURE 4.2 The 14 current NASA Space Technology Roadmaps. SOURCE: Courtesy of NASA.
FIGURE 4.3 NASA Launch Propulsion Systems Roadmap. SOURCE: Courtesy of NASA.
Recommendation: NASA should convene an agency-wide space-based additive manufacturing working group to define and validate an agency-level roadmap, with short- and longer-term goals for evaluating the possible advantages of additive manufacturing in space, and with implications for terrestrial additive manufacturing as well. The roadmap should take into consideration efficiencies in cost and risk management. NASA should build on the considerable experience gained from its Space Technology Roadmaps. The space-based additive manufacturing roadmap objectives should include, but not be limited to the following:
- Developing goals for using the technology to assist the agency in meeting its key missions, covering all appropriate mission directorates, especially long-duration human spaceflight and planetary operations, by defining, understanding, evaluating, and prioritizing the direct and supporting technologies for autonomously or minimally attended space-based additive manufacturing and robotic precursor and free-flyer missions;
- Identifying flight opportunities, such as on the International Space Station during its next decade of operations;
- Targeting the full technology-development life-cycle and insertion strategies through 2050, aligned with target agency missions, for all appropriate mission directorates and related collaborations; and
- Ensuring that support for incremental advances to address the technical challenges is supplemented with support for activities related to reaching the full potential of additive manufacturing.
The incremental advances are likely to be smaller efforts—desktop thought exercises, modeling projects and physical experiments—that invent space-specific additive manufacturing processes rather than adapt current manufacturing methods to the space environment. An example is research related to creating ribbons, trusses, and gossamer arrangements in space. Ribbon structures, for example, require the ability to pultrude thermoplastic ribbons made from carbon fiber. This technique, a combination of material extrusion and sheet lamination techniques, is likely not being explored in any major way in existing federal programs.
Recommendation: NASA should seek opportunities for cooperation and joint development with other organizations interested in space-based additive manufacturing including the Air Force, the European Space Agency, the Japanese Space Agency, other foreign partners, and commercial firms.
Figure 4.4 depicts NASA’s strategy and capability partitioning for migration from terrestrial additive manufacturing capabilities to utilization of the ISS for both development and demonstration of space-based additive manufacturing, and finally to planetary surface platforms.
MSFC has already taken the lead in developing additive manufacturing in space and has a long history in seeking to develop in-space manufacturing capabilities, sponsoring the first in-space additive manufacturing research in the late 1990s. MSFC has already developed a “Technology Development Vision” that can serve as a basis for an in-space additive manufacturing roadmap (Figure 4.5). However, because agency expertise and talent is spread among the centers, contractors, and universities and research institutions, NASA requires an integrated roadmap developed at the headquarters level and modeled on its previous efforts.
Looking into the out-years at a 20- to 40-year event horizon and the pace of progress that can occur over that period, it is difficult to envision what ground and space-based additive manufacturing capabilities might be achieved by 2040 or 2050. However, given NASA’s mission objectives and long-term plans, it should be possible to craft a near-, mid-, and long-term technology development strategy envisioning a convergence of technologies and processes to enable a full-scale, space-based additive manufacturing capability.
Although NASA currently leads in the development of space-based additive manufacturing technology, other organizations also have current or potential interest in developing the technology as well. In the course of developing its roadmap, and certainly following its development, NASA should seek opportunities for cooperation. This
FIGURE 4.4 NASA’s general description of available and target platforms for in-space additive manufacturing. SOURCE: Dr. Michael Gazarik, NASA, “Space Technology Mission Directorate Briefing,” presentation to the committee, November 12, 2013.
cooperation could take many forms, including NASA making resources available on the ISS in return for access to the results of the research conducted there.
Even as the technology materials, products, systems, and processes are being developed for future in-space advanced manufacturing efforts, and despite the considerable programmatic, technical, operational, and logistical obstacles and hurdles necessary to accomplish these objectives, the committee believes that, in addition to space-based additive manufacturing, the results and products will have considerable benefits for ground-based space systems, platforms, hardware, and product development. These developments will advance the state of the art in automated and autonomous space manufacturing and lead to increased manufacturing and product efficiencies, much as full-scale and semi-attended, robotic-automated manufacturing factories and facilities have benefitted traditional product and manufacturing industries, such as automotive and aerospace and the manufacture of cell phones, personal information devices, and semiconductors.
The committee believes that it is in NASA’s interest to continue to define and develop technologies to produce useable in-flight space systems and hardware using both space- and ground-based manufacturing approaches and to define where those activities should occur. In some cases, the options and trade-offs will be based on operational, cost, and logistical concerns. In other cases, it will become increasingly essential to have space-based additive manufacturing capabilities to support NASA’s orbital, lunar, Mars, and deep space endeavors beyond low Earth orbit. An iterative, phased approach that evolves from semi- to fully autonomous ground and space production capabilities, to a semi-autonomous (minimally-attended) in-space manufacturing and production factory using a free flyer or platform based on the Moon, Mars, or an asteroid, is probably the best path for NASA if the agency continues developing this technology.
FIGURE 4.5 NASA Space Technology Mission Directorate’s In-space Manufacturing Technology Development Vision, which can serve as a useful starting point for development of an agency-wide roadmap. SOURCE: NASA Marshall Space Flight Center.