Introduction
On December 11, 2017, President Donald Trump signed Space Policy Directive-1 (SPD-1).1 The new directive replaced original text in the National Space Policy of the United States of America2 and instructed the Administrator of the National Aeronautics and Space Administration (NASA) to
Lead an innovative and sustainable program of exploration with commercial and international partners to enable human expansion across the solar system and to bring back to Earth new knowledge and opportunities. Beginning with missions beyond low-Earth orbit, the United States will lead the return of humans to the Moon for long-term exploration and utilization, followed by human missions to Mars and other destinations.
While retaining the existing long-term human spaceflight aspirations, the new policy refocuses on the interim steps required to achieve success—on building an exploration system defined not only by the spacecraft and supporting ground- and space-based architectures but also by a workforce and network of partnerships that draw on the complementary strengths of government, private industry, and foreign nations. SPD-1 acknowledges that such an exploration system is necessary to sustain exploration activities long into the future.
Before humans reach the lunar surface again, however, the exploration—for scientific gain, for resource prospecting, and for the sake of exploring—will be carried out by robotic missions. The U.S. robotic missions currently operating do so under the purview of NASA’s Science Mission Directorate (SMD). Thus, in response to and in support of the vision expressed in SPD-1, NASA’s fiscal year 2019 (FY2019) budget proposal for the Planetary Science Division (PSD) included a line item to support lunar exploration and discovery.3 Following submission of the budget request, James L. Green, then director of PSD, requested that the Committee on Astrobiology and Planetary Science (CAPS) author a short report addressing the science aspects of this new lunar initiative. The committee’s statement of task for this report follows.
Statement of Task
At the CAPS March 2018 meeting, the committee will prepare a concise report reviewing the planetary science aspects of the Administration’s lunar science and exploration initiative. The short report will address the following topics:
- Review the Planetary Science Division portion of NASA’s plans for the lunar science and exploration initiative; and
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1 Federal Register v. 82 no. 239, pp. 59501-59502.
2 The original text of Presidential Policy Directive 4: National Space Policy of the United States of America read, “Set far-reaching exploration milestones. By 2025, begin crewed missions beyond the moon, including sending humans to an asteroid. By the mid-2030s, send humans to orbit Mars and return them safely to Earth.” See https://www.hsdl.org/?abstract&did=22716.
3 Listed at $218 million in J.L. Green, NASA Science Mission Directorate, 2018, “Status Report: Planetary Science Division,” presentation to the committee on March 27.
- Determine if NASA’s plans are consistent with Vision and Voyages for Planetary Science in the Decade 2013-20224 and other National Academies reports.
In response to the above charge, this report first reviews decadal and other community-guided lunar science priorities as context for NASA’s current lunar plans and then presents and evaluates the actions being taken by NASA PSD to support lunar science. At the request of NASA PSD, plans for commercial partnerships, lunar infrastructure development, and related aspects of NASA’s lunar science and exploration initiative are the subject of a separate short report titled Report Series: Committee on Astrobiology and Planetary Science—Review of the Commercial Aspects of NASA SMD’s Lunar Science and Exploration Initiative.
Community-Guided Lunar Science Priorities: 2007-Present
In reviewing NASA’s plans for the current lunar science and exploration initiative, it is useful to understand the recent evolution of community consensus lunar science priorities. NASA’s lunar science program has a strong history of being guided by these community consensus goals and priorities. The 2007 National Research Council (NRC) report The Scientific Context for the Exploration of the Moon5 (hereafter Scientific Context) provided prioritized lunar science concepts, goals, and recommendations that have informed subsequent consensus studies and lunar community activities and documents through the present. The Scientific Context committee identified and, based on scientific merit, prioritized eight science concepts to guide future lunar science and exploration. These are reproduced below in their original priority order.6
- The bombardment history of the inner solar system is uniquely revealed on the Moon.
- The structure and composition of the lunar interior provide fundamental information on the evolution of a differentiated planetary body.
- Key planetary processes are manifested in the diversity of lunar crustal rocks.
- The lunar poles are special environments that may bear witness to the volatile flux over the latter part of solar system history.
- Lunar volcanism provides a window into the thermal and compositional evolution of the Moon.
- The Moon is an accessible laboratory for studying the impact process on planetary scales.
- The Moon is a natural laboratory for regolith processes and weathering on anhydrous airless bodies.
- Processes involved with the atmosphere and dust environment of the Moon are accessible for scientific study while the environment remains in a pristine state.
Taking into account the findings of the Scientific Context report, the NRC planetary science decadal survey Vision and Voyages for Planetary Science in the Decade 2013-2022 (hereafter Vision and Voyages) recommended that PSD consider two medium-class, New Frontiers lunar missions for selection between 2013 and 2022.
- Lunar South Pole-Aitken Basin Sample Return. This mission was adopted from the 2003 planetary science decadal survey New Frontiers in the Solar System: An Integrated
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4 National Research Council (NRC), 2011, Vision and Voyages for Planetary Science in the Decade 2013-2022, The National Academies Press, Washington, D.C.; referred to as Vision and Voyages.
5 NRC, 2007, The Scientific Context for Exploration of the Moon, The National Academies Press, Washington, D.C.
6 NRC, 2007, Scientific Context, p. 3.
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Exploration Strategy.7Vision and Voyages continued to support the mission as “among the highest priority activities for solar system science”8 because of the mission’s importance in constraining the bombardment history of the inner Solar System, directly measuring the composition and age of the Moon’s lower crust and mantle, characterizing a large lunar impact basin, understanding lunar thermal evolution and differentiation, and identifying differences in mantle source regions on the lunar far side, which has yet to be accessed by human missions.9
- Lunar Geophysical Network. Also identified as a mission concept in the 2003 decadal survey in planetary science, the geophysical network would comprise a global, long-lived network of identical landers carrying suites of geophysical instruments selected to help understand the structure and evolution of the lunar interior. The Lunar Geophysical Network would also investigate early differentiation processes, early planetary dynamics, the initial composition of the Earth-Moon system, the Moon’s thermal evolution, and the distribution and origin of current lunar seismicity.
Vision and Voyages highlighted that, because of the Moon’s proximity, those areas not prioritized in large- and medium-class mission concepts, such as the study of lunar surface processes and the nature and distribution of volatiles, could be competitively selected for small, Discovery-class missions.10 The survey report noted that contemporary planned and launched lunar missions—the orbital Gravity Recovery and Interior Laboratory (GRAIL) and Lunar Reconnaissance Orbiter (LRO) missions, the Lunar Crater Observation and Sensing Satellite (LCROSS) impactor, and the Lunar Atmosphere and Dust Environment Explorer (LADEE)—offered significant science return at Discovery-class size or smaller. Furthermore, lunar landers could be accommodated in the Discovery mission class.
In anticipation of a renewed focus on scientific and other exploration of the Moon, the Planetary Science Division recently asked the lunar community to revise the existing consensus priorities, taking into account discoveries made since publication of the 2007 Scientific Context and 2011 Vision and Voyages reports. In August 2017, the Lunar Exploration Analysis Group (LEAG) convened the Advancing Science of the Moon Specific Action Team (ASM-SAT).11 The ASM-SAT was charged with evaluating progress made in the past decade toward accomplishing the goals of the Scientific Context report and identifying how to proceed toward accomplishing these goals.
The ASM-SAT found that progress has been made in addressing many of the main concepts in the Scientific Context report. Based on a decade of advances in lunar science, the ASM-SAT identified or, more precisely, reemphasized three additional science concepts that augment the list presented in the Scientific Context report. These represent revitalized avenues of inquiry based largely on advanced analyses of existing lunar samples and results from the recent lunar missions highlighted above. In no priority order, these additional concepts are
- The origin of the Moon.
- The lunar volatile cycle.
- Lunar tectonism and seismicity.
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7 NRC, 2003, New Frontiers in the Solar System: An Integrated Exploration Strategy, The National Academies Press, Washington, D.C.
8Vision and Voyages, p. 127.
9 The China National Space Administration accomplished the first successful lunar far side landing with the Chang’e 4 mission on January 3, 2019.
10Vision and Voyages, p. 134.
11 Lunar Exploration Analysis Group, 2018, Advancing Science of the Moon: Report of the Lunar Exploration Analysis Group Special Action Team, https://www.lpi.usra.edu/leag/reports/ASM-SAT-Report-final.pdf.
Many of these key lunar discoveries—made since publication of both Scientific Context and Vision and Voyages—were subsequently summarized in the 2018 decadal survey midterm report, Visions into Voyages for Planetary Sciences in the Decade 2013-2022: A Midterm Review (hereafter referred to as the “decadal midterm”).12 The summary is included below as a quote (parenthetical references and figure callouts have been removed from the original text for brevity).
The Lunar Reconnaissance Orbiter (LRO) was launched in 2009 and continues to collect important data. Evidence for widespread OH or water on the surface has been inferred from spectral data … obtained from the Indian spacecraft Chandrayaan-1. The different forms of water now identified from the lunar interior, across the lunar surface, and sequestered at the poles have become areas of intense active research and are now known to represent different fundamental processes active on the Moon and other silicate bodies of the inner solar system. The distribution of polar hydrogen deposits has led to the recognition of true polar wander arising from changes in the internal mass distribution of the Moon, most likely associated with lunar mare volcanism. LRO and its instruments continue to operate in good health and should continue to do so into the foreseeable future.
NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) orbited the Moon to gather detailed information about the structure and composition of the thin lunar atmosphere, and confirmed that there is a dust cloud surrounding the Moon over time, which is sustained by the continual bombardment of interplanetary dust particles.
Gravity Recovery and Interior Laboratory (GRAIL; a pair of spacecraft that provided very accurate gravity and topography) provided many new results for lunar structure, including confirmation of the existence of a small core, global mapping of the crustal thickness (less than thought) and crustal density (lower than thought). Ancient igneous intrusions were identified, indicating an early phase of expansion of the Moon by a few kilometers. Mass anomalies on a new and increasingly precise level of spatial resolution were identified, and the circum-Procellarum fracture network was identified in the gravity gradient map. The mass anomalies are important for lunar geology, and for models of interior dynamics and volcanic processes. Topography and gravity suggest frozen-in bulges from both early faster rotation and tidal heating, together with possible true polar wander (a large reorientation of the Moon’s polar axis).
The 2018 decadal midterm additionally notes that lunar science addresses numerous crosscutting investigation themes identified in Vision and Voyages, particularly the accretion, accretion timing, water supply, chemistry, and differentiation of their inner planets, the role of early bombardment, and current volatile composition and distribution.13 The ASM-SAT, however, found that, despite significant progress in lunar science, knowledge gaps still exist for all eight concepts. Seven of the eight concepts have not been investigated by dedicated missions, even though missions to address Concepts 1 and 2 are specified in Vision and Voyages.
Finding. Progress has been made in lunar science through NASA-led missions of approximately Discovery-class size. No New Frontiers-class lunar missions specified in Vision and Voyages have been selected, although these are able to address high-priority lunar science concepts.
Groundbreaking lunar science has also been accomplished through a growing number of international lunar collaborations and missions—notably China’s Chang’e 1, 2, and 3 (2010-2013); Japan’s Kaguya (2007-2009); and India’s Chandrayaan-1 (2008-2009). These orbiters and landers have made important lunar science discoveries and have signaled a growing prioritization of lunar exploration by other nations. For example, Chandrayaan-1, carrying the NASA Moon Mineralogy Mapper
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12 National Academies of Sciences, Engineering, and Medicine (NASEM), 2018, Visions into Voyages for Planetary Sciences in the Decade 2013-2022: A Midterm Review, The National Academies Press, Washington, D.C. (referred to as the “decadal midterm”), p. 28.
13 Decadal midterm, pp. 28.
spectrometer (M3), identified and mapped lunar surface water (OH or H2O) within sunlit terrains.14 The Japanese Space Agency (JAXA) Kaguya Lunar Radar Sounder discovered intact lava tubes near the Marius Hills and elsewhere,15 and provided a global lunar survey with surface compositional (mineralogical, elemental abundance) information, topography, and gravity. In the near-term, Chang’e 4 and 5 and Chandrayaan-2 are recently-landed or planned future missions to the Moon involving orbiters, landers with rovers, and sample return. NASA’s international collaborations with such missions have the opportunity to continue to advance lunar science. Such collaborations are in agreement with Vision and Voyages, which “strongly supports international efforts and encourages the expansion of international cooperation on planetary missions.”16
Finding. International collaborations on lunar missions have been greatly beneficial to lunar science, and future opportunities for continued international cooperation exist.
Finding. Vision and Voyages strongly supports international efforts and encourages expansion of international cooperation on planetary missions.17
Conclusion. CAPS concludes that recent scientific discoveries regarding the Moon are both exciting and compelling. These recent advances, coupled with continuing international interest in lunar science, warrant the increased attention they are now receiving, which will ensure that the resultant scientific findings continue to be leveraged and built upon in the future.
The New Lunar Discovery and Exploration Initiative
The FY2019 Planetary Science Division budget request allocates approximately $200 million for the new Lunar Discovery and Exploration Program, with that budget projection remaining flat in the out years.18 The new program is not intended to replace funding for prioritized, community consensus lunar missions (i.e., Discovery- and New Frontiers-class missions). Rather, the program is intended to support partnerships with industry as well as new, innovative approaches to accomplishing lunar science research and human exploration goals. These elements are incorporated into the evolving NASA Exploration Campaign (see Figure 1).
Research and technology developments in support of the new lunar initiative are being implemented (Early Science and Technology Initiative; see Figure 1) as both new programs and refocusing of existing programs toward lunar science. The Solar System Exploration Research Virtual Institute (SSERVI) has released its third Cooperative Agreement Notice (CAN) draft. Although SSERVI is not a new program, the newest solicitation has a potential focus on lunar nodes (teams) and in situ resource utilization (ISRU). The primary role of SSERVI is to provide a virtual collaboration platform for research teams investigating fundamental research on the Moon, near-Earth asteroids, the martian moons, and the near space around these targets.19 Through its digital collaboration tools, SSERVI offers
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14 C.M. Pieters, J.N. Goswami, R.N. Clark, M. Annadurai, J. Boardman, B. Buratti, J.-P. Combe, et al., 2009, Character and spatial distribution of OH/H2O on the surface of the Moon seen by M3 on Chandrayaan-1, Science 326(5952):568-572.
15 T. Kaku, J. Haruyama, W. Miyake, A. Kumamoto, K. Ishiyama, T. Nishibori, K. Yamamoto, et al., 2017, Detection of intact lava tubes at Marius Hills on the Moon by SELENE (Kaguya) Lunar Radar Sounder, Geophysical Research Letters 44(20):10155-10161.
16Vision and Voyages, p. 67.
17Vision and Voyages, p. 67.
18 J.L. Green, NASA Science Mission Directorate, 2018, “Status Report: Planetary Science Division,” presentation to the Committee on Astrobiology and Planetary Science, March 27.
19 See the Solar System Exploration Research Virtual Institute website at https://sservi.nasa.gov/.
researchers studying different target bodies a means of accessing the resources and knowledge of other teams, and of promoting the incorporation of cross-disciplinary ideas and methods into research.
Additional elements will be added to programs supporting the analysis of existing lunar samples. Under the enhanced lunar sample analysis campaign, there will be development of an archiving system for lunar (and other) sample data, the digitization of lunar curation data, and the Apollo Next Generation Sample Analysis Program (ANGSA),20 which will be funded under Research Opportunities in Earth and Space Science 2018 (ROSES-18) and has solicited proposals for studying selected, specially curated samples including vacuum-sealed drive tube samples from Apollo missions 15 and 17.
The near-term lunar exploration campaign also includes a concentrated effort to increase deployment of lunar CubeSats and small satellites through both SMD and HEOMD (see Figure 1). Within SMD, the Lunar Polar Hydrogen Mapper (LunaH-Map) is a lunar CubeSat that has been selected under the Small Innovative Missions for Planetary Exploration (SIMPLEx) call to fly as a secondary payload on the first Exploration Mission (EM-1) of the Space Launch System (SLS).21 LunaH-Map will observe lunar hydrogen abundances at less than 10 km spatial scales and examine the relationship between hydrogen and permanently shadowed regions, such as craters, at the Moon’s poles, with an emphasis on the south polar region. Additional lunar CubeSats have also been selected through HEOMD to fly on EM-1 as technical demonstrations. In keeping with the demonstrated efficacy of international collaboration, and in support of Vision and Voyages’ positive tone toward such endeavors, NASA will also be providing an instrument and participating scientists for the Korea Aerospace Research Institute’s Korea Pathfinder
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20 NASA, 2018, “Amendment 12: New Opportunity in C.24 Apollo Next Generation Sample Analysis,” May 14, https://science.nasa.gov/researchers/sara/grant-solicitations/roses-2018/amendment-12-new-opportunity-c24-apollo-next-generation-sample-analysis.
21 See the LunaH-Map website at http://lunahmap.asu.edu/.
Lunar Orbiter (KPLO), scheduled for launch in 2020. A similar cooperative agreement, or other collaboration, with the Indian Space Research Organisation (ISRO) on its upcoming Chandrayaan-2 mission is also planned. Additionally, the Third Stand Alone Missions of Opportunity Notice (SALMON-3) through its SIMPLEx Program Element is soliciting proposals for small lunar missions, among others.
Further near-term lunar science and technology initiatives begun by SMD include the Development and Advancement of Lunar Instrumentation (DALI) call, also funded out of ROSES-18. The call will support development of all lunar instrument types including lander/rover-based instruments and orbital instruments, although the emphasis will be placed on instruments intended for small, stationary landers.22 Instruments are encouraged to support NASA’s broader lunar exploration goals including science, technology, human exploration, and ISRU. Enabling science instrument technologies for the future may include cryogenic sample return or sealed sample return (solar wind studies). Example instruments include, but are not limited to, small (<10 kg) seismometers and mass spectrometers or tunable laser spectrometers for isotopic measurements of volatiles. Larger (>10 kg) instruments that address key science objectives, such as in situ geochronology (e.g., Rb-Sr and K-Ar),23-25 could either be incorporated into larger, medium-class landers or potentially further miniaturized to fit into smaller payloads. The DALI funding will support technologies that could reach flight readiness (technology readiness level, or TRL, of at least 6) as early as 2021.
The augmented lunar science research program described by SMD to CAPS26 directly addresses several high-priority lunar science questions as outlined in Vision and Voyages, the decadal midterm, and the Scientific Context report. New SSERVI nodes with lunar emphases can address an even broader array of lunar science and exploration questions. The near-term exploration campaign, for example, through LunaH-Map, is focused on exploring the lunar polar volatile cycle (i.e., Scientific Context science concept 4 and ASM-SAT concept 2). Future lunar instrumentation, developed under DALI and future programs, can address a broad variety of lunar science questions, but the potential for in situ geochemical and geophysical science is especially great. Future CubeSats and small satellites (<180 kg)27 also hold promise for lunar surface and interior studies.
The augmented program described to CAPS comprises both existing and new capabilities. In some cases, existing programs are enhanced or given an increased lunar focus (e.g., ANGSA, SSERVI), whereas in others (e.g., DALI), new capabilities are being developed. Certain programs that already have lunar elements (e.g., SIMPLEx) will continue. In addition, the existing orbital platform, LRO, continues to serve as a valuable asset for geological exploration (for example, by monitoring the present-day impact flux on the Moon’s surface). Itself initially an Exploration Systems Mission Directorate (precursor to HEOMD) mission, LRO is also a potentially valuable asset in support of future science and robotic and human exploration (for example, by providing context and change detection for future landed missions).
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22 These are envisaged as part of NASA’s new Commercial Lunar Payload Services program, which is addressed in detail in Report Series: Committee on Astrobiology and Planetary Science—Review of the Commercial Aspects of NASA SMD’s Lunar Science and Exploration Initiative.
23 B. Cohen, 2016, “The Potassium-Argon Laser Experiment (KArLE): In situ geochronology for planetary robotic missions,” pp. 1-10 in 2016 IEEE Aerospace Conference, doi:10.1109/AERO.2016.7500945.
24 K.A. Farley, J.A. Hurowitz, P.D. Asmow, N.S. Jacobson, and J.A. Cartwright, 2013, A double-spike method for K-Ar measurement: A technique for high precision in situ dating on Mars and other planetary surfaces, Geochimica et Cosmochimica Acta 110:1-12.
25 F.S. Anderson, J. Levine, and T.J. Whitaker, 2015, Dating the martian meteorite Zagami by the 87Rb-87Sr isochron method with a prototype in situ resonance ionization mass spectrometer, Rapid Communications in Mass Spectrometry 29:191-204.
26 J.L. Green, NASA Science Mission Directorate, 2018, “Status Report: Planetary Science Division,” presentation to the Committee on Astrobiology and Planetary Science, March 27.
27 NASA, 2015, “What are SmallSats and CubeSats?,” February 26, https://www.nasa.gov/content/what-are-smallsats-and-cubesats.
Finding. Continued support for the ongoing LRO would maximize success of the Science Mission Directorate (SMD) Lunar Discovery and Exploration Program.
Conclusion. CAPS concludes that NASA’s Planetary Science Division (PSD) has responded rapidly and effectively to Space Policy Directive-1 (SPD-1). PSD has taken early measures to ensure participation of the lunar science community and that decadal lunar science priorities are or will be addressed in its Lunar Discovery and Exploration Program. The initial, near-term steps taken toward implementing the lunar program—including introducing new programs and realigning or enhancing existing programs with new lunar focus—emphasize high-priority science and are useful directions for SMD’s lunar discovery and exploration initiative.
Further Considerations
Lunar science community events organized by the Lunar Exploration Assessment Group (LEAG) and NASA SMD have promoted involvement in the new lunar initiative. The first such event was the Lunar Science for Landed Missions Workshop,28 held in January 2018. The workshop participants examined the existing science priorities from Vision and Voyages, Scientific Context, the ASM-SAT, and other reports and identified 14 landing sites29 that would address high-priority lunar science and, in many cases, exploration questions. This trend continued with the “Survive and Operate Through the Lunar Night” workshop that took place in November 2018.30
As noted, efforts are under way to develop new lunar instrumentation. Instruments are being solicited through the DALI competition, which is open to other SMD divisions, including Heliophysics and Astrophysics, as well as to HEOMD for the development of ISRU instrumentation. Several aspects of lunar science and exploration have goals that crosscut SMD divisions and science communities. For example, new generation retroreflectors—multimirror instruments that allow the Earth-Moon distance to be precisely measured—could be placed on the lunar surface. Augmentation of the preexisting Apollo lunar retroreflector network would not only benefit the planetary science community by better constraining lunar tidal responses but would also potentially benefit the astrophysics community, which can use retroreflectors as a test of fundamental physics.31 The potential for crosscutting interdisciplinary science and exploration concepts that can be addressed at the Moon warrant continued attention.
The synthesis of human exploration and science goals that is portrayed in the roadmap of the new lunar initiative (see Figure 1) raises an additional point—the interplay between science and human exploration. Adopting a positive view of the synergistic relationship between science and human exploration, Vision and Voyages also discussed the potential of robotic missions, particularly those in operation (e.g., LRO) or planned for the near-term exploration of the Moon, and human exploration to be mutually beneficial. The survey report urged “the human exploration program to examine this decadal survey and identify—in close coordination and negotiation with the SMD—objectives whereby human-tended science can advance fundamental knowledge.”32 This was done, however, under a cautionary note.
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28 NASA Ames Research Center, 2018, “Lunar Science for Landed Missions Workshop,” June, https://lunar-landing.arc.nasa.gov/.
29 E.R. Jawin, S.N. Valencia, R.N. Watkins, J.M. Crowell, C.R. Neal, and G. Schmidt, Lunar Science for Landed Missions Workshop Findings Report, accessed March 26, 2018, https://lunar-landing.arc.nasa.gov/downloads/LunarLandedScience_Summary_final_071818.pdf.
30 Lunar and Planetary Institute, “Survive and Operate Through the Lunar Night Workshop: Final Announcement,” https://www.hou.usra.edu/meetings/survivethenight2018/.
31 D.E. Smith, M.T. Zuber, E. Mazarico, A. Genova, G.A. Neuman, X. Sun, M.H. Torrence, and D.-d. Mao, 2018, Trilogy, a planetary geodesy mission concept for measuring the expansion of the solar system, Planetary and Space Science 153:127-133.
32Vision and Voyages, p. 26.
Vision and Voyages endorsed33 the following statement made by the Review of the U.S. Human Spaceflight Plans Committee: “It is essential that budgetary firewalls be built between [the human exploration program and the robotic scientific exploration program]. . . . Without such a mechanism, turmoil is assured and program balance endangered.”34 It is notable that, despite apparent plans for future interfacing between these two mission directorates, the associated goals and program elements were not clearly defined to CAPS, presumably because they are still in formulation.
The Lunar Discovery and Exploration Program offers many opportunities to address high-priority lunar science questions. The lunar New Frontiers missions outlined in Vision and Voyages, however, particularly South Pole-Aitken Basin and Lunar Geophysical Network, require integrated suites of instruments or long-lived, globally distributed science payloads appropriate to a New Frontiers-class mission. With that in mind, the decadal midterm stated that new opportunities may present themselves that were not considered in a previous decadal survey.35 These can take the form of new programmatic objectives (e.g., SPD-1), new technological capabilities (CubeSats and other small satellites, new instrument capabilities), or scientific developments and discoveries (as summarized above). The challenge is to find methods of taking advantage of new opportunities while not abandoning the carefully laid out plans and strategies from Vision and Voyages. The decadal midterm review committee concluded36 that there is a middle ground in which NASA and the science community could give thoughtful consideration to potential deviations from the decadal plans laid out in Vision and Voyages. The decadal midterm highlighted that it is important to consider new opportunities while ensuring that they are consistent with the general philosophy and approach of Vision and Voyages. Furthermore, these new opportunities warrant input from the science community, including on the scientific value of possible deviations as well as the priorities relative to the previously established directions, which is valuable to incorporate into the decision process.
Finding. The number of self-organized lunar community publications and activities that have occurred since SPD-1 indicate that the lunar science community is actively engaged in planning how to leverage the new lunar initiative to advance lunar science goals.
Conclusion. Although Vision and Voyages is generally positive toward the synthesis of human exploration and science goals, the cautionary note is appropriate at this early stage in the new Lunar Discovery and Exploration Program because the expected relationship between these two elements appears to be as yet undefined.
Conclusion. CAPS concludes that the renewed interest in the exploration of the Moon, embodied by the Lunar Discovery and Exploration Program, is a welcome development that has the potential to greatly benefit lunar science and could evolve into a program with large science return. The program as currently formulated, while aligned with decadal priorities, does not, however, replace the lunar science priorities and missions recommended in Vision and Voyages, the latter of which remain competitive in the New Frontiers class. It remains the responsibility of the next planetary science decadal survey to evaluate these missions as well as the planetary science aspects of the Lunar Discovery and Exploration Program in the context of the planetary program.
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33Vision and Voyages, p. 26.
34 NASA, 2009, Seeking a Human Spaceflight Program Worthy of a Great Nation, Washington, D.C., https://www.nasa.gov/pdf/396093main_HSF_Cmte_FinalReport.pdf, p. 114. Commonly referred to as the “Augustine Committee,” after the committee chair, Norman R. Augustine.
35 Decadal midterm.
36 Decadal midterm.
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