This report examines the current state and science potential of CubeSats—defined by the committee as a spacecraft sized in units, or U’s, typically up to 12U (a unit is defined as a volume of about 10 cm × 10 cm × 10 cm) that is launched fully enclosed in a container. Although the concept of launching a “canisterized” secondary payload has existed since the space shuttle program, two university groups formally introduced the concept of CubeSats in 1999 as an educational platform, seeking to give students hands-on experience building, launching, and operating spacecraft. Over the 15 years since their introduction, CubeSats have been shown to share many characteristics of disruptive innovations, such as rapid improvement of capabilities and finding niche uses in research, commercial, and homeland and national security communities. Accordingly, the National Aeronautics and Space Administration (NASA) and the National Science Foundation (NSF) asked the National Academies of Sciences, Engineering, and Medicine to establish an ad hoc committee to explore the current state of CubeSats and examine the potential of the use of CubeSats to obtain high-priority science data. The full statement of task for the Committee on Achieving Science Goals with CubeSats is reprinted in Appendix A.
The rapid speed of CubeSat development has been enabled, in part, by fast “fly-learn-refly” cycles—in which two flight models are developed and the second model is modified and launched if issues arise during the first flight—comparatively low development costs, miniaturized electronics, and timely availability of affordable launch opportunities. A pioneering CubeSat-based research program launched in 2008 within NSF’s Division of Atmospheric and Geospace Sciences was responsible for the first systematic support of CubeSat-based science investigations and led to a growing engagement with universities. Furthermore, a growing commercial sector for the use of CubeSats for Earth observations and remote sensing has also helped to spur rapid technology development. Commercial demand has given rise to a fast-growing component-supplier industry. These commercial users and suppliers are now major drivers of technology development for CubeSats, and many technologies or subsystems can be purchased “off the shelf” by groups that seek to use CubeSats to address science objectives.
Since 2010, the use of CubeSats for science has grown especially rapidly due to NSF’s program and because of an increase of interest within various NASA programs. More than 80 percent of all science-focused CubeSats have been launched from 2012 to 2016. Similarly, more than 80 percent of peer-reviewed papers describing new science based on CubeSat data have been published in the past 5 years. The committee’s review of a subset of these papers is discussed in Chapter 4 and Appendix B.
The committee concluded that CubeSats have already produced high-value science. CubeSats are useful as instruments of targeted investigations to augment the capabilities of large missions and ground-based facilities,
and they enable new kinds of measurements and have the potential to mitigate gaps in measurements where continuity is critical.
The committee developed a list of sample science goals for CubeSats (Chapters 4 and 7). Many of these goals address targeted science, often in coordination with other spacecraft, or use “sacrificial,” or high-risk, orbits that lead to the demise of the satellite after critical data have been collected. Other goals relate to the use of CubeSats as constellations or swarms deploying tens to hundreds of CubeSats that function as one distributed array of measurements.
The committee also concluded that although all space science disciplines can benefit from innovative CubeSat missions, CubeSats cannot address all science objectives and are not a low-cost substitute for all platforms. Activities such as those needing large apertures, high-power instruments, or very-high-precision pointing most likely will always require larger platforms because of the fundamental and practical constraints of small spacecraft. Also, large spacecraft excel at large-scale investigations when, for example, several instruments need to be collocated. CubeSats excel at simple, focused, or short-duration missions and missions that need to be comparatively low cost or that require multipoint measurements.
The set of science goals where the use of CubeSats would be enabling is evolving too quickly for the committee to create a comprehensive list, and the committee was not tasked with prioritizing CubeSat missions. However, the following examples, from those listed in Chapter 4, provide a sampling of high-priority science goals that could potentially be pursued using CubeSats:
- Solar and space physics, Earth science and applications from space—Exploration of Earth’s atmospheric boundary region. CubeSats are uniquely suited because of their expendability to explore the scientific processes that shape the upper atmospheric boundary using short-lifetime, low-altitude orbits.
- Earth science and applications from space—Multipoint, high temporal resolution of Earth processes. Satellite constellations in low Earth orbit could provide both global and diurnal observations of Earth processes that vary throughout the day, such as severe storms, and are currently under-sampled by Sun-synchronous observatories.
- Planetary science—In situ investigation of the physical and chemical properties of planetary surfaces or atmospheres. Deployable (daughter-ship) CubeSats could expand the scope of the motherships with complementary science or site exploration.
- Astronomy and astrophysics, solar and space physics—Low-frequency radio science. Interferometers made of CubeSats could explore the local space environment and also galactic and extragalactic sources with spatial resolution in ways not accessible from Earth.
- Biological and physical sciences in space—Investigate the survival and adaptation of organisms to space. CubeSats offer a platform to understand the effects of the environment encountered in deep space, such as microgravity and high levels of radiation.
To unlock the science potential of CubeSats or missions relying on CubeSat technology, federal investments continue to be crucial, especially in areas that will not see commercial investment. Both NSF and NASA have active CubeSat programs. NSF’s program has the dual goals of supporting small satellite missions to advance space weather-related research and of providing opportunities to train the next generation of experimental space scientists and aerospace engineers. As of 2015, NSF had launched 8 science-based CubeSat missions (consisting of 13 CubeSat spacecraft) and has 7 missions (11 CubeSat spacecraft) in development. The committee believes that the program has been successful with regard to both goals and that NSF’s current program continues to be valuable. The program is particularly well aligned with the goals and recommendations of the 2013 decadal survey for solar and space physics, Solar and Space Physics: A Science for a Technological Society (National Research Council, The National Academies Press, Washington, D.C.); however, other disciplines at NSF, such as Earth science and astronomy and astrophysics, could also benefit from the scientific and educational opportunities that CubeSats provide.
Recommendation: The National Science Foundation (NSF) should continue to support the existing CubeSat program, provide secure funding on a multiyear basis, and continue to focus on high-priority science and the training of the next generation of scientists and engineers. In particular, NSF should consider ways to
increase CubeSat opportunities for a broad range of science disciplines going beyond solar and space physics, with financial support from those participating disciplines.
Although most CubeSat science results published today have come from NSF-sponsored investigations, that is expected to change. NASA’s programs, which are distributed throughout the agency, thus far have placed greater emphasis on maturing new technologies. However, NASA provided a large increase in opportunities to propose science-based CubeSat missions in 2013. As of 2015, NASA had launched a total of 18 CubeSat missions (34 spacecraft) with science and technology objectives. Each of the four NASA Science Mission Directorate science divisions, at least two other directorates, and at least five NASA centers are developing CubeSat missions. Additionally, some of the science divisions and centers may have more than one funding opportunity for CubeSats.
The committee observed that CubeSat activities within NASA programs have remained largely independent—perhaps, not surprisingly, as a result of rapid growth in the use of CubeSats—and a lack of coordination has impacted NASA’s ability to communicate a clear strategic plan and vision on the role of CubeSats for scientific exploration internally within NASA and to the community. The explosion of interest in the deployment of CubeSats has led to some management challenges that have the potential to stifle the impact that CubeSats can have for science. Newcomers seeking NASA support for CubeSat missions have difficulty navigating the rapidly evolving and varied programs, technologies, and funding opportunities at the agency. Interested partners in academia, government, and industry may have difficulty finding and creating collaborations. In addition, because of the disaggregated nature of CubeSat programs at NASA, programs have begun to duplicate efforts in some areas—for example, communication and propulsion technology development—and are not systematically sharing lessons learned. Technology development by industry is evolving equally rapidly and is underleveraged in many government programs, including at NASA.
CubeSats have proven their usefulness in the pursuit of science, most notably demonstrated by the increase in the publication of scientific papers. Thus, it is now time for NASA to respond by increasing coordination of their CubeSat programs for science and science-enabling technology, with the goal of further increasing the overall scientific return and advancing sophisticated uses of CubeSats, such as large constellations. An additional level of management is needed that can continue to encourage innovation—in all of the science disciplines and at different costs—but also can reduce duplication in common technology areas by targeting resources to the most promising developments.
Recommendation: NASA should develop centralized management of the agency’s CubeSat programs for science and science-enabling technology that is in coordination with all directorates involved in CubeSat missions and programs, to allow for more efficient and tailored development processes to create easier interfaces for CubeSat science investigators; provide more consistency to the integration, test, and launch efforts; and provide a clearinghouse for CubeSat technology, vendor information, and lessons learned. The management structure should use a lower-cost and streamlined oversight approach that is also agile for diverse science observation requirements and evolutionary technology advances.
The goal of this increased management focus is to leverage NASA’s investments to maximize scientific output. However, it is equally important to encourage innovation by maintaining a variety of programs.
Recommendation: NASA should develop and maintain a variety of CubeSat programs with cost and risk postures appropriate for each science goal and relevant science division and justified by the anticipated science return. A variety of programs are important to allow CubeSats to be used for rapid responses to newly recognized needs and to realize the potential from recently developed technology.
For example, a solar and space physics-focused CubeSat with a short development cycle and lower cost might be able to take rapid advantage of a technological breakthrough. On the other hand, a CubeSat flying as part of a planetary science mission might be developed on the same timescale as the larger spacecraft of the mission and require higher reliability, which is typically associated with higher cost.
One critical benefit of NASA’s engagement in CubeSats is the role of CubeSats in training students, early career project scientists, engineering teams, and project managers. Care must be taken to not inadvertently stifle such training opportunities as CubeSats evolve toward more capable science missions and as the proposed new management structure is implemented.
Recommendation: NASA should use CubeSat-enabled science missions as hands-on training opportunities to develop principal investigator leadership, scientific, engineering, and project management skills among both students and early career professionals. NASA should accept the risk that is associated with this approach.
There is one type of mission class that is of high priority for multiple disciplines and that deserves focused investment and development—the creation of swarms and constellations of CubeSats. Many high-priority science investigations of the future will require data from constellations or swarms of 10 to 100 spacecraft that, for the first time, would have the spatial and temporal coverage to map out and characterize the physical processes that shape the near Earth space environment. Historically, the cost associated with large constellations has been prohibitive, but the time is ripe to develop this capacity.
Recommendation: Constellations of 10 to 100 science spacecraft have the potential to enable critical measurements for space science and related space weather, weather and climate, as well as some astrophysics and planetary science topics. Therefore, NASA should develop the capability to implement large-scale constellation missions taking advantage of CubeSats or CubeSat-derived technology and a philosophy of evolutionary development.
The capacity to do science with CubeSats strongly depends on the technological capabilities available to the investigators. These capabilities, which have the most impact on the ability of CubeSats to enable high-priority science and are currently limiting the use of CubeSats in some science applications, are the subject of the next recommendation.
Recommendation: NASA and other relevant agencies should invest in technology development programs in four areas that the committee believes will have the largest impact on science missions: high-bandwidth communications, precision attitude control, propulsion, and the development of miniaturized instrument technology. To maximize their impact, such investments should be competitively awarded across the community and take into account coordination across different agencies and directorates, including NASA’s Science Mission Directorate and Space Technology Mission Directorate, and between different NASA and Department of Defense centers.
An additional area of technology development that is important to several disciplines is thermal control, a much broader topic than those recommended above. Aspects of thermal control vary from maintaining low temperatures for imaging spectrometers to creating a stable payload environment for biology experiments with live specimens.
Recommendation: As part of a CubeSat management structure, NASA should analyze private capabilities on an ongoing basis and ensure that its own activities are well coordinated with private developments and determine if there are areas to leverage or that would benefit from strategic partnerships with the private sector.
The committee also examined the challenges regarding policy—in particular, the regulatory framework—that could constrain the expansion of CubeSats for science applications. The following three challenges stand out: (1) the reality and perception of science CubeSats as an orbital debris hazard, (2) the complexities and constraints of radio spectrum availability, and (3) the availability of affordable launch opportunities. Chapter 6 of this report quantifies and discusses these issues and recommends that they be addressed more comprehensively.
Recommendation: NASA, with the National Science Foundation, and in coordination with other relevant federal agencies, should consider conducting a review and developing a plan to address CubeSat-related policies to maximize the potential of CubeSats as a science tool. Topics may include, but are not limited to, the following: guidelines and regulations regarding CubeSat maneuverability, tracking, and end-of-mission deorbit; the education of the growing CubeSat community about orbital debris and spectrum-licensing regulatory requirements; and the continued availability of low-cost CubeSat launch capabilities. It is important to consider that current and new guidelines promote innovation, rather than inadvertently stifling it, and ensure that new guidelines are science-based, equitable, and affordable for emerging players within the United States and internationally.
In Chapter 2, the committee discusses the theory of disruptive innovation with respect to CubeSats and revisits historic instances of disruptive innovations that originated in the federal research and development space. CubeSats share many of the characteristics of disruptive innovations. History has shown that the likelihood of success and economic impact of potentially disruptive innovations is difficult to predict in the early days of the disruption. Currently, it seems that CubeSats will become an effective tool for a specific and eventually well-defined performance envelope, similar to balloons or sounding rockets. However, it is possible that CubeSats will have a much bigger impact and lead to new types of missions and scientific data and, perhaps, even lead to a more macroscopic realignment of the space industry. The principles of disruptive innovations informed the above recommendations and also led the committee to suggest the following best practices to guide the ongoing development of CubeSats:
- Avoid premature focus. Although the committee recommends a NASA-wide management structure to create opportunities for new investigators and provide a clearinghouse for information and lessons learned, premature top-down direction that eliminates the experimental, risk-taking programs would slow progress and limit potential breakthroughs.
- Maintain low-cost approaches as the cornerstone of CubeSat development. It is critical to resist the creep toward larger and more expensive CubeSat missions. Low-cost options for CubeSats are important because more constrained platforms and standardization, coupled with higher risk tolerance, tend to create more technology innovation in the long run.
- Manage appropriately. As missions grow more capable and expensive, management and mission assurance processes will have to evolve. Yet, it is critical to manage appropriately, without burdening low-cost missions with such enhanced processes, by actively involving CubeSat experts in policy changes and discussions as well as in proposal reviews.