NASA planetary missions are the most visible aspect of the agency’s solar system exploration program. While missions get the lion’s share of the public’s attention, they are supported by an infrastructure and research program that are vital for mission success. These research activities also generate much of the planetary program’s science value on their own, independent of individual missions.
Funding for scientific planning and technological development as precursors to missions, for data analysis and theoretical interpretations during and after each mission’s operational phase, and for data archiving and sample curation are provided through NASA’s Supporting Research and Analysis (SRA) programs. The central roles of supporting research and related activities at NASA and their relevance to the quality of the space exploration program have recently been described and analyzed by the NRC Committee on the Role and Scope of Mission-Enabling Activities in NASA’s Space and Earth Science Mission. The committee strongly supports the recommendations of that committee’s report.1
Given the importance of the diverse activities sponsored by SRA funding, the report cited above raises a concern regarding the ability of a small staff in the NASA Science Mission Directorate to handle its responsibilities, suggesting that it is not adequately sized. The committee echoes this concern and, in particular, highlights and endorses a key finding of the report, which states: “The mission-enabling activities in NASA’s Science Mission Directorate (SMD)—including support for scientific research and research infrastructure, advanced technology development, and scientific and technical workforce development—are fundamentally important to NASA and to the nation” (p. 47).
Planetary spacecraft return data, but these data have value only when they are interpreted. Interpretation of data requires sophisticated analysis, theoretical investigations, and computer simulations. These activities are supported at NASA through grants to investigators made by research and analysis programs. Data are archived and distributed to scientists worldwide by the Planetary Data System. And scientific results are conveyed to the most important stakeholders in planetary exploration—the taxpayers who funded it and the students who will help assure its future—via education and public outreach programs. The health of all these SRA programs is vital to planetary exploration.
|Chapter 4 The Primitive Bodies||Chapter 5 The Inner Planets||Chapter 6 Mars||Chapter 7 The Giant Planets||Chapter 8 Satellites|
|Ground-based telescopes||Ensure access to large telescopes for planetary science observations.
Maintain the capabilities of Goldstone and Arecibo radar systems.
|Support building and maintaining Earth-based telescopes.||—||Ensure access to large telescopes.||—|
|Laboratory research/research support||Continue funding of programs to analyze samples of primitive bodies in hand and develop next-generation instruments for returned samples.||A strong research and analysis program is critical.
Investigate modeling a cross-disciplinary program on the existing Mars Climate Modeling Center.
|Vigorous research and analysis programs are needed to enhance the development and payoff of missions and to refine the sample collection requirements and laboratory analysis techniques needed for Mars Sample Return.||Maintain robust programs of data analysis, laboratory work, and computational development.||—|
|Data archiving||Support the ongoing effort to evolve the Planetary Data System.||Continue to evolve the Planetary Data System and Deep Space Network.||—||Support the ongoing effort to evolve the Planetary Data System.||—|
|Education and public outreach||—||Strengthen efforts to archive the results of past education and public outreach efforts.||—||—||—|
Research and Analysis Programs
The research related to planetary missions begins well before a mission is formulated and funded, and continues long after it is over. Research provides the foundation for interpreting data collected by spacecraft, as well as the guidance and context for identifying new scientifically compelling missions.
Research and analysis programs allow the maximum possible science return to be harvested from missions. Along with analysis of spacecraft data, the portfolios of research and analysis programs include laboratory experiments, theoretical studies, fieldwork using Earth analogs, planetary geologic mapping, and analysis of data from Earth-based telescopes. Important examples of supporting laboratory work include characterization of extraterrestrial materials and collection of spectroscopic data sets (for more representative coverage of solar system objects), experimental investigation of the states and behaviors of materials and planetary and space environments, and analog experiments (e.g., fluid dynamics experiments). Scientific and technical advances derived from these programs are used to identify important goals for future exploration, determine the most suitable targets for space missions, and develop and refine the instrumental and analytical techniques needed to support new missions. Through the direct involvement of students and young investigators, the programs help train future generations of space scientists and engineers. The recommended missions in Chapter 9 were derived from the key science questions in Chapter 3, and those questions were informed primarily by the results of the research and analysis programs.
The science return from a mission increases when investigators outside the mission teams synthesize data from multiple missions, test new theoretical insights, and link observations from different sources in interdisciplinary
investigations. New interdisciplinary fields, such as planetary climatology and exoplanet studies, are emerging as a consequence.
The Level of Research and Analysis Support
All of these fields of research are important to NASA’s long-term planetary science goals, and all require funding. This funding not only leads to the gathering and dissemination of new scientific knowledge but also lays the groundwork for the future of the field. In particular, the use of NASA SRA funds to support graduate students and provide early career fellowships for new Ph.D.s is crucial for developing and maintaining the workforce that will explore the solar system in the coming decades. Historically this burden of funding has fallen almost entirely on NASA, as it will for the foreseeable future. As noted in the NRC’s Enabling Foundation report cited above, “In the case of planetary science, NASA is by far the principal sponsor of research, and thus programs supported by other agencies are not a major factor.”2
Current NASA research and analysis funding in most programs supporting planetary research is distributed as multiple small grants. An unfortunate and very inefficient aspect of this policy is that researchers must devote an increasingly large fraction of their time to writing proposals instead of doing science. Over the 7 fiscal years 2003-2009, on average 37 percent of the grant proposals submitted to an average of 18 or 19 programs in NASA’s Planetary Science Division were supported. The success ratio is lower than desirable, but the negative impact of the low success rate on the science community is magnified by the small-grant policy; many researchers seeking support for themselves and/or their students must submit half a dozen proposals each year to make ends meet. The problem of raising funds is especially challenging for soft money researchers who must find support for their own salaries as well as for direct research expenses. Numerous previous reports have noted that this effort is highly inefficient and stressful to the research community. This burden on the community is then compounded by the substantial and growing further effort required to review all of these proposals. The committee strongly encourages NASA to find ways (e.g., by merging related research programs and lengthening award periods) to increase average grant sizes and reduce the number of proposals that must be written, submitted, and reviewed by the community.
Another clear message from study of the SRA programs is that the number of good ideas for research surpasses the funding available to enable that research. More funding for research and analysis would result in more high-quality science being done. However, recommendations for increased research funding must be tempered by the realization that NASA’s resources are finite, and that such increases will inevitably cut into funds that are needed to develop new technologies and fly new missions. An appropriate balance must thus be sought. After consideration of this balance, and consistent with the mission recommendations and costs presented in Chapter 9, the committee recommends that NASA increase the research and analysis budget for planetary science by 5 percent above the total finally approved FY2011 expenditures in the first year of the coming decade, and increase the budget by 1.5 percent above the inflation level for each successive year of the decade. This modest increase will allow the scientific benefits of NASA’s planetary missions to be reaped more fully, while still permitting the vigorous program of planetary missions and related technology development described in Chapters 9 and 11, respectively, to be carried out. In addition, NASA should periodically evaluate the strategic alignment and funding level of all its SRA programs to ensure that they remain healthy and productive.
Mission Flight Teams
The science return from planetary missions, especially complex ones like flagship missions, is maximized by effective communication and data sharing among all the scientists involved in the mission. Science teams for large missions should be put together so that data sharing is built into the mission structure from the outset, and free access to data among all instrument teams on a mission should be strongly encouraged. Such policies should be defined in the Announcement of Opportunity so that teams are aware of them and can plan for them from the start. When science instruments are competed, there should be mechanisms, such as competition after instrument selection, for interdisciplinary or participating scientists. Such a mechanism will allow the most qualified scientists
to be part of the mission even if they are not members of a selected instrument team. Particular attention should be paid to the addition and full participation of younger scientists in long-duration missions.
Theory and Modeling
Theory and modeling play an important and growing role in planetary science. Simulations have strong visual appeal, can clarify complex processes, and can test hypotheses. Numerical modeling is an essential tool for extracting information from spacecraft observations by explaining new phenomena. Such modeling must be based on physical principles, validated with spacecraft data, and, in many cases, must be supported by additional laboratory measurements. General circulation models (GCMs) for the atmospheres of Mars, Venus, Titan, and the giant planets are one of the best examples of the interplay between data and theory. These circulation models are fundamental tools in the study of planetary atmospheric processes. They are also useful as mission planning tools, for example in predicting the winds that will be encountered by planetary entry probes and landers.
Significant advances in many planetary fields have occurred during the past decade largely due to the availability of increasing computing power and more sophisticated software, but also because of improved understanding of physics and chemistry. Examples include the following:
• Improved modeling of planetary accumulation processes and how they relate to the isotopic constraints on cosmochronology,
• Efforts to relate observable aspects of bodies (e.g., tectonics, volcanism, and magnetic fields) to internal state and evolution,
• Models for tidal heating and plumes on Enceladus,
• Impact dynamics and the physical processes in small bodies,
• Magnetohydrodynamic models that provide insight into the dynamical responses within the magnetospheres that envelop Jupiter and Saturn,
• Modeling of orbital histories (e.g., the accumulation of bodies, the delivery of meteoroids, the solar system’s structure, and a lunar impact origin),
• Identification of chaos (e.g., mean-motion and secular resonances and their overlap) in the solar system, and
• The inclusion of moist convection and cloud microphysics in atmospheric modeling.
Although many of the processes of interest have Earth analogs and well-developed codes for Earth science problems, planetary applications often require going far beyond terrestrial experience, and validation of codes in unusual situations is often needed.
Theoretical development and numerical modeling are crucial for planning future planetary missions, as well as for maximizing the science return from past and ongoing missions.3,4 For example, the stability of the jovian jet streams is a major topic of theoretical research, and it has recently been applied to predict the bulk rotation rate of Saturn.5 The theory and modeling of two-dimensional turbulence have advanced understanding of spatial scales of jets and vortices.6 The investigation of hydrogen’s equation of state has a major theoretical component involving molecular dynamics modeling.7 Detailed modeling of planetary rings requires both analytical and numerical calculations.8 As scientists plan for new missions to these bodies—such as the various missions evaluated for this decadal survey—they incorporate this work into their plans and requirements.
Research on primitive bodies also depends heavily on theory and modeling in part because the objects are so diverse and their numbers so vast. Fundamental theoretical investigations and numerical modeling are essential to the understanding of primitive bodies and the processes through which they evolve. For example, both were needed to begin to understand how the structure of the Kuiper belt has evolved through time. Both were also needed to address important processes that cannot be studied directly in the laboratory such as the collisions between asteroid-size bodies.
As mission data sets become larger and more diverse, and as understanding of integrated planetary systems increases and models become more complex, the computing power required for data analysis and simulation is growing. Research tasks that require large computational resources include dynamical studies of planet formation, atmospheric GCMs, planetary interior convection and dynamo models, thermodynamic first-principle calculations to determine equations of state, simulations of solar wind-magnetosphere interactions, hydrocode simulations of impacts, and image processing.
Additional funds to maintain and upgrade large, centralized supercomputing facilities at NASA centers will be required in the coming decade. It is equally important to broaden the access to and to streamline data pipelines from these facilities to accommodate the exponentially increasing need for data and information. The right balance must be struck between providing funds for the purchase of powerful computing hardware and funding the technical staff support needed to utilize these facilities with optimum efficiency.
Complementing the large NASA computational facilities, revolutionary improvements have been made in recent years in the computing capabilities of servers that are commercially available and accessible to individual researchers. These advances have enabled substantial cost-effective progress in computations that in the past were possible only on large supercomputers. Support should be made available to permit acquisition of such computing facilities by individual principal investigators when appropriate.
Data Distribution and Archiving
Data from space missions remain scientifically valuable long after the demise of the spacecraft that provided them, but only if they are archived appropriately in a form readily accessible to the community of users and if the archives are continually maintained for completeness and accuracy. Data curation is particularly critical for planetary missions, which are infrequent, costly, and often capture temporally unique planetary snapshots. NASA has for many years recognized its responsibility to archive data from planetary missions and make them widely available to the research community. The first analysis of newly acquired spacecraft data is often part of the spacecraft mission budget, but full analysis requires many years of thoughtful work. Some of the most important advances are often the result of analyses carried out using data archives supported by the SRA program years or even decades after a mission has ended.
The Planetary Data System (PDS) provides critical data archiving and distribution to the planetary science community. Over the last 20 years, the PDS has established a systematic protocol for archiving and distributing mission data that has become the international standard. It is crucial that the capabilities of the Planetary Data System be maintained by NASA, both to provide a permanent archive of planetary data and to provide a means of distributing those data to the world at large. It is also essential that newly acquired data continue to be archived and made accessible to the science community within no more than 6 months following receipt and validation. For data from ground-based or international partner instruments, contractual agreements should be used to ensure the timely delivery of such data to the PDS (sometimes within funding agreements from specific supporting research and analysis programs). The PDS should also consider developing requirements for data archiving by small groups that have implemented creative data processing that enhances the value of existing planetary data sets.
High-level data products must be archived along with the low-level products typically produced by instrument teams. For future missions, Announcements of Opportunity (AOs) should mandate that instrument teams propose and be funded to generate derived products before missions have completed Phase E. In the interim, separate support should be provided for development of high-level data products in cases where such support cannot be provided by mission funding.
Use of the appropriate standards is essential to enable synergistic application of planetary data sets. Over the past two decades the development of the Navigation and Ancillary Information Facility (NAIF) at JPL, together with the evolving standards associated with SPICE kernels—i.e., specific data files containing ancillary information relating to the orientation, location, operating mode, and other operating characteristics relevant to how data from a particular spacecraft instrument was collected—have greatly streamlined and standardized planning,
acquiring, and archiving information about observations. The NAIF facility and SPICE kernels should continue to be used, and NASA planetary missions should adopt SPICE as a standard during mission planning, operations, and archiving. Development of standards for geodetic and cartographic coordinate systems should be encouraged, and these systems should be documented and archived within a NAIF/SPICE framework.
With expected large increases in data volume during the next 10 years, PDS capabilities will have to expand. The existing PDS is very much a product of its original decade of creation. The planned PDS upgrade will better leverage modern databases and web services, creating an online resource that will serve the more complex needs of modern science user communities. New types of data, such as pertinent laboratory measurements and telescopic data, could be added where appropriate. Periodic reviews, as already performed, will ensure that the science communities’ needs are met. A balanced SRA program will allow for further development of related public domain software, such as OLAF (for data ingestion) and ISIS (image manipulation and mosaicking), and a coordinated set of standards (geodetic, cartographic maps, and other systems). And as planetary exploration continues to become a more international enterprise, it will be increasingly important for NASA to ensure interoperability of the PDS with other international repositories of planetary data.
Communicating with the Public: Education and Outreach
The tremendous interest in planets and planetary exploration points to a deeply rooted resonance between the work done by planetary scientists and the broader public. In its grandest sense, planetary exploration challenges us all to be curious about the world in which we live. Such curiosity can lead to a greater appreciation of the role that science in general and planetary science in particular can play in fostering a vigorous and economically healthy nation.
Defining the Need
Jon Miller, in his paper “Civic Scientific Literacy Across the Life Cycle,” states that only 30 percent of the U.S. population is scientifically literate.9 This scientific illiteracy extends even to the most basic facts about our universe. For example, the National Science Board estimates that more than a third of Americans do not understand that Earth orbits the Sun.10 The United States is losing its scientific and technological competitiveness, a situation that can be reversed only if science literacy and proficiency become a national priority.11
The role that science can play in economic development was articulated in the 2007 and 2010 reports Rising Above the Gathering Storm: Energizing and Employing America for a Brighter Economic Future12 and Rising Above the Gathering Storm, Revised: Rapidly Approaching Category 5.13 These reports argue that the science and technology research that powers the U.S. economy is not adequately funded and does not attract as many practitioners as it does in other countries. The specific recommendations from the 2007 Gathering Storm report can be succinctly summarized as follows:
• Increase America’s talent pool by vastly improving K-12 science and mathematics education;
• Sustain and strengthen the nation’s commitment to long-term basic research;
• Make the United States the most attractive setting in which to study and perform research; and
• Ensure that the United States remains a leading place in the world to innovate.
Exploration of the planets can play a key role in addressing these challenges, because it is among the most exciting and accessible of the scientific activities funded by NASA, and indeed by any government agency. NASA’s planetary program has a special opportunity, and therefore a special responsibility, to reach out to the public. Planetary exploration research has connections today with many other areas of science, technology, engineering, and mathematics: geology, chemistry, biology, aerospace engineering, high-performance computing, electrical engineering and advanced optics, and computer science. By attracting young people to science and technology careers and providing the kind of education and training that can help solve major societal challenges involving science and technology, planetary exploration offers a solid return on investment for the United States. Public
interest in the exploration of the solar system translates to opportunities to educate and influence future scientists, engineers, teachers, policy makers, and the public at large, through classroom instruction or informal education.
In addition, the America COMPETES Act also highlighted three areas of endeavor as having high importance to the nation; planetary exploration can contribute directly to these areas:
1. To strengthen research investment and to foster innovation and frontier research. Planetary exploration research is transformative at the most fundamental level, exploring areas as far-reaching as the origin of life, the origins of the solar system, the evolution of planetary environments, and the search for Earth-like planets in other solar systems. Planetary exploration can drive innovation in technology such as advanced sensors and data processing.
2. To strengthen educational opportunities in science, technology, engineering, and mathematics (and critical foreign languages). Planetary science has broad public appeal and vibrant ties to other branches of science and technology, enabling the field to contribute to science education in uniquely powerful ways. Planetary exploration is also increasingly an international endeavor.
3. To develop a workforce for the 21st century. Planetary exploration can play a central role in raising U.S. science literacy at all levels from kindergarten through university, and within the general public as well.14 Many of the breakthroughs being made in our understanding of the solar system involve close connections with other fields of science such as geology, geochemistry, and biology, developments that also find increasing application in our everyday lives.
Education and Outreach Opportunities
Technological advances over the past decade have dramatically changed the nature of public outreach. Nearly instant public availability of raw images from planetary missions, and global access to planetary data, feed growing online communities of committed space enthusiasts. Interested members of the public can be informed of discoveries and mission events as they happen through social media. At the same time, the decline of traditional science journalism, with its ability to synthesize results into a coherent whole and present them to a mass audience, and the ever-accelerating news cycle, may erode scientific understanding by the public. It is crucial, then, for scientists themselves to make their work and findings comprehensible, appealing, and available to the public.
The federal government provides significant support for many informal education and outreach activities. In the past, NASA devoted roughly 1 percent of the cost of major missions to education and public outreach and created imaginative websites and activities concerning its missions to engage students, teachers, and the public.
Although the funding for education and public outreach by NASA increased from 1996 to 2004, it has off in the past half decade. Recent National Research Council studies have indicated that for a better return on the federal investment in education and public outreach, a more rigorous program of assessment is needed of outcomes and efficacy across the entire spectrum of space science education and public outreach activities.15 This is particularly important in the many less formal outreach activities.16
Much effort is required to transform raw scientific data into materials that inform and appeal to the general public. NASA planetary science funding is used for education and public outreach activities based on the discoveries of planetary missions. Efforts to integrate effective outreach should be directly embedded within each planetary mission. The committee strongly endorses NASA’s informal guideline that a minimum of 1 percent of the cost of each mission be set aside from the project budget for education and public outreach activities. Modest additional funding must also be set aside to convey to the public the important scientific results from the longer-term supporting research and analysis programs, and individual scientists should be strongly encouraged to participate in communicating the results of their research broadly.
The committee also encourages organizing and maintaining NASA’s educational efforts, matched to national educational standards, through science education and public outreach forums, formal content review, and newly evolving product databases. Local efforts, in addition to national efforts, can help ensure the compatibility of scientifically rigorous educational materials with state-by-state curriculum needs. NASA’s efforts leverage the agency’s expertise and engaging content and have a record of producing innovative curricula for schools and programs for other venues.17
Planetary missions rely heavily on technology. Nowhere is this more true than in the technology for new scientific instrumentation, which can revolutionize the science returned by a mission. Chapter 11 contains an in-depth discussion of technology development for planetary missions, including new scientific instruments. In particular, that chapter advocates a dedicated technology funding line that, among other things, will fill the need to develop new flight instruments to a higher level of technological readiness than has been the norm in the past. NASA’s Planetary Instrument Definition and Development Program (PIDDP) has been very successful in initiating many new instrument concepts and maturing them to low technology readiness levels (TRLs). The technology program called for in Chapter 11 will provide the funding to bring the most promising low-TRL instrument concepts to the point that they can be reliably selected for flight, reducing mission cost and schedule risk.
Each planetary environment is unique, and each instrument flown on a planetary mission must be customized to some degree for the mission and planetary target. Every future mission will be enabled or enhanced by improvements in instrument miniaturization and advanced electronic component design. Both remote and in situ instruments will benefit from improved technologies and components. Significant development is needed, in particular, for in situ instruments for sample selection and handling, age dating, organic detection and characterization, isotopic identification, and instruments that function in extreme environments of temperature, pressure, and high radiation. Semi-autonomous sample handing and manipulation pose significant challenges in any environment, and operation in extreme environments makes it all the more challenging.
The mission studies performed for this decadal survey (Appendix G) resulted in more than 50 specific instruments cited in strawman payloads. These instruments range widely in their design requirements due to the unique conditions of each target body. Examples of the most commonly mentioned measurements and instrumentation and selected areas where development or improvements should be supported are summarized in Table 10.2, which is not intended to be comprehensive, but only representative. All of these instrument types are candidates for future development under the technology program described in Chapter 11. It is, of course, important for instrument development funding to be tied to specific future missions and goals.
For further discussion and recommendations regarding instrument development and its role in NASA’s broader planetary technology development program, see Chapter 11.
NASA Telescope Facilities
Most bodies in the solar system were discovered using telescopes. Utilization of the enormous discovery potential of telescopes is an essential part of the committee’s integrated strategy for solar system exploration. Major scientific findings have been made in recent years using Earth-based telescopes. As just one important example, the discovery of extrasolar planets has had a major impact on researchers’ perceptions of the solar system.
Many spacecraft missions, including ones recommended in this report, are designed to follow up on discoveries made using telescopes. Recent telescopic observations of Uranus, for example, have demonstrated that the ice giant’s atmosphere undergoes changes that were not apparent during the Voyager 2 flyby in the 1980s. The Kuiper belt was revealed in the 1990s as a vast, unexplored, and previously only postulated “third domain” of the solar system beyond the realms of the terrestrial and giant planets. Even the still-preliminary understanding of the dynamics of the objects beyond Neptune has led to wide acceptance of the outward migration of Neptune early in the solar system’s history. And telescopic observations were largely responsible for the reported detection of methane in the atmosphere of Mars.
Telescopes also help identify targets to which spacecraft missions can be flown. A key example of a “found” population is that of the near-Earth objects (NEOs), which are now understood to pose a potential impact threat to Earth, but also to be exploitable for both sample return and as springboards for future human exploration missions. NEOs are particularly attractive targets for spacecraft missions because many require lower energy trajectories than do most planetary bodies.
TABLE 10.2 Commonly Cited Improvements and/or Technology Developments Required in Measurements and Instrumentation Mentioned in the Mission Studies Performed in Support of This Decadal Survey
|Commonly Cited Instrumentation||Increased Resolution or Sensitivity||Reduction of Mass||Radiation Resistance||Ability to Operate in Extreme Environments|
|Tunable Laser Spectrometer Spectroscope||X||X||X||X|
|Radar/Synthetic Aperture Radar/Interferometrie Synthetic Aperture Radar||X||X||X|
|Surface sampling and handling tools||X||X|
|Subsurface sampling devices||X||X|
|Cryogenic handling equipment||X||X|
NOTE: The mission study reports are listed in Appendix G and are available (unedited) on the CD supplied with this report.
Earth-based telescopes also provide ongoing support for spacecraft missions, both before and after the mission. Particularly effective examples were the global observing campaign that supported the Deep Impact mission to comet Tempel 1 and the impact of LCROSS on the Moon. And, in a much broader sense, Earth-based observations provide the context for nearly all mission results. For example, Earth-based studies alone have allowed taxonomic systems for asteroids and comets to be developed.
Although most government-supported telescope facilities in the United States are funded by the National Science Foundation (see below), NASA continues to play a major role in supporting the use of Earth-based optical and radar telescopes for planetary studies. Subsequent sections discuss ground-based, airborne, and orbital telescopes that support planetary science using NASA funding.
NASA Infrared Telescope Facility
NASA provides operational support for the 3-meter Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii, for observational programs with an emphasis on support for planetary and astrophysics space missions. The planetary science community has special needs for access to ground-based telescope facilities that differ from the requirements for stellar and extragalactic astronomy. Among these needs are the ability to observe bright targets, and flexible scheduling for unpredictable or time-dependent phenomena, such as studies of comets, planetary impacts, Earth-approaching asteroids, and unexpected cloud activity on planets. In addition, many solar system
targets are frequently observable only at small angular separation from the Sun, requiring capabilities for daylight and near-horizon observations. At present and in the foreseeable future, the IRTF is the only observatory that is designed and operated primarily to meet the broad needs of planetary investigations. The IRTF meets the needs of planetary astronomy through continuing telescope and instrument upgrades (supported also by the NSF), expanded capabilities for remote observing, and flexible scheduling.
W.M. Keck Observatory
The Keck Observatory, consisting of twin 10-meter telescopes on Mauna Kea, is supported in part by NASA in partnership with the University of California and the California Institute of Technology. A fraction of Keck telescope time is allocated specifically for NASA programs, with much of that time devoted to the search for and study of extrasolar planetary systems. Only a small fraction of the NASA time (e.g., just 5 of the 28 successful NASA Keck proposals in the first half of 2010) is typically available for use by the broad community of planetary scientists. NASA Keck time is critical for planetary objects that require high spatial resolution (e.g., Uranus, Neptune, Titan, and Io) and/or deep sensitivity (e.g., Pluto and Kuiper belt objects). At present, Keck is the only facility that can provide diffraction-limited adaptive optics imaging on Uranus and Neptune.
Goldstone, Arecibo, and the Very Long Baseline Array Two existing facilities, the Goldstone Solar System Radar (part of NASA’s Deep Space Network) and the Arecibo Observatory, are critically important for radar studies of near-Earth objects. The Arecibo Observatory, with its 305-m antenna and 900-kW transmitter (at 13-cm wavelength), is the most powerful research radar in the world. The Goldstone facility, with its greater steerability, provides twice the sky coverage and much longer tracking times than does the Arecibo antenna. In addition to giving the highest achievable spatial resolution, radar observations offer the unique capability to refine NEO orbital characteristics (and hence the probability of NEO impact on Earth) to high precision; a single radar detection improves the instantaneous positional uncertainty by orders of magnitude in comparison with an orbit determined only by optical methods. The Goldstone and Arecibo radars have also made important observations of Mercury, Venus, the Moon, Mars, the satellites of Jupiter, and the satellites and rings of Saturn.
The Very Long Baseline Array (VLBA) is a network of radio telescopes spread from Hawaii to the Virgin Islands and operated by the National Radio Astronomy Observatory. The VLBA is able to determine spacecraft positions to high accuracy, which allows refinement of planetary ephemerides. It also has assisted in tracking probe release and descent (Cassini’s Huygens probe is an example).
Ground-based facilities that receive NASA support, including the Infrared Telescope Facility, the Keck Observatory, Goldstone, Arecibo, and the Very Long Baseline Array, all make important and in some cases unique contributions to planetary science. NASA should continue to provide support for the planetary observations that take place at these facilities.
Balloon- and rocket-borne telescopes offer a cost-effective means of studying distant planets and satellites at ultraviolet and infrared wavelengths inaccessible from the ground. Because of their modest costs and development times, they also provide training opportunities for would-be developers of future spacecraft instruments.18 NASA’s Science Mission Directorate regularly flies balloon missions into the stratosphere that carry payloads funded via research and analysis programs. However, there are few funding opportunities to take advantage of this resource for planetary science, because typical planetary SRA awards are too small to support these missions. A funding line to promote further use of suborbital observing platforms for planetary observations would complement and reduce the load on the already oversubscribed planetary astronomy program.
Stratospheric Observatory for Infrared Astronomy (SOFIA)
The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a NASA facility consisting of a 2.7-meter telescope mounted in a modified Boeing 747-SP aircraft that began science flights in mid-2010. Operations costs and observing time are shared by the United States (80 percent) and Germany (20 percent). Flying at altitudes up to 13.5 km, SOFIA observes from above more than 99 percent of the water vapor in the atmosphere, opening windows in the infrared spectrum that are unavailable to ground-based telescopes. SOFIA also provides opportunities for rapid response to time-dependent astronomical phenomena (e.g., comets and planetary impacts) and geography-dependent phenomena (e.g., stellar occultations). Solar system studies are one of the four primary science themes (together with star and planet formation, the interstellar medium, and galaxies and the galactic center) to which SOFIA’s observing time is dedicated.19
Hubble Space Telescope
Hubble observations are crucial for research on the giant planets (especially Uranus and Neptune) and their satellites, and for planning future missions to these systems. Hubble’s ultraviolet capability has been critical for studies of auroral activity on the gas giants, discovery of the atmospheres of Ganymede and Europa, and investigations of the plumes and atmosphere of Io. During the past decade, Hubble was also used to discover two additional moons (Nix and Hydra) around Pluto, and two additional moons (Cupid and Mab) and two new rings around Uranus. Hubble, although recently serviced, has a finite lifetime and will eventually be de-orbited, and no replacement space telescope with equivalent ultraviolet capability is currently planned.
James Webb Space Telescope
The James Webb Space Telescope (JWST) will be a 6.5-meter infrared-optimized telescope placed at the Sun-Earth L2 point. It is currently scheduled for launch no earlier than 2018. JWST will provide unprecedented sensitivity and stability for near- and mid-infrared imaging and spectroscopy, especially at wavelengths blocked by Earth’s atmosphere. JWST will contribute to planetary science in numerous ways, including diffraction-limited imaging (in the near infrared) of both large and small bodies difficult to match with existing ground-based facilities, spectroscopy of the deep atmospheres of Uranus and Neptune, planetary auroral studies with high spatial resolution, and observations of transient phenomena (storms and impact-generated events) in the atmospheres of the giant planets. JWST will overlap with several planetary missions, offering unique complementary and supplementary observations, and can extend studies of Titan beyond the 2017 end of the Cassini mission. The ability to track moving targets—a necessity for planetary observations—is currently being implemented. JWST’s Science Working Group is planning many types of solar system observations, including imaging and spectra of Kuiper belt objects and comets, as well as Uranus and Neptune and their satellites and ring systems. Work is currently being done to assess the feasibility of observations of the brighter planets such as Mars, Jupiter, and Saturn.
The discovery, characterization, and hazard mitigation of NEOs called for in the 2005 NASA Authorization Act are treated in a recent NRC study.20 This section focuses on instrumentation and infrastructure needed for scientific surveys of NEOs. Discussion of hazard mitigation is beyond the scope of this decadal survey.
Earth-based telescopic observations probe the shapes, sizes, mineral compositions, orbital and rotational attributes, and physical properties of NEOs. These data are used in defining the science goals and operational constraints for spacecraft missions to specific asteroids, and are critical for extrapolating what is learned from the limited number of asteroid missions that will be possible to broader populations of small bodies. The Arecibo Observatory and the Goldstone facility are critical to refining NEO orbital and physical characteristics. New optical facilities, such as the Large Synoptic Survey Telescope (LSST) and Panoramic Survey Telescope and Rapid-Response System (Pan-STARRS), can dramatically increase scientific understanding of NEOs by expanding the
catalog of known objects and their orbits, thus providing better population statistics and improved predictions for close passages by Earth.
Perhaps the greatest advance in characterizing NEOs will come from spacecraft missions that analyze them from orbit and/or return samples to Earth where sophisticated laboratory techniques can be brought to bear. The committee commissioned a technology study on the accessibility of NEOs by spacecraft using solar-electric propulsion (Chapter 4). With sufficient technology development such missions might be conducted within the Discovery program, and there are intriguing possibilities for human missions to NEOs supported by NASA’s Exploration Systems Mission Directorate (ESMD). Instruments (mapping cameras and spectrometers) for orbital characterization are already developed, but sampling instruments, especially for accessing the subsurface, require development.
The Deep Space Network
The Deep Space Network (DSN) is a critical element of NASA’s solar system exploration program. It is the only asset available for communications with missions to the outer solar system, and it is heavily subscribed by inner solar system missions as well. As instruments advance and larger data streams are expected over the coming decade, this capability must keep pace with the needs of the mission portfolio. In addition, future capabilities afforded by optical communication, transponder advances, advanced software, and other means may provide future increases in returned data volumes and will be important to meeting mission demands.
The DSN is composed of three stations located in Goldstone, California, Madrid, Spain, and Canberra, Australia, along with operations control and other services in the United States. Each station has one 70-meter antenna, one 34-meter high-efficiency antenna, and at least one 34-meter beam wave guide antenna. There is an additional beam wave guide antenna at Madrid and two more at Goldstone. These antennas support more than three dozen missions with downlink and uplink capabilities in S-band, X-band, and Ka-bands (limited). Collectively, these stations can provide nearly continuous full-sky coverage.
The 70-meter dishes are in high demand, particularly during critical events, because of their downlink capability, sensitivity, and ability to satisfy other mission requirements. As such, they are heavily oversubscribed, and current deep-space missions are limited mostly by downlink rather than onboard storage capacity. For example, the Cassini mission routinely must choose which data to play back, because the capacity of its solid-state recorder exceeds what can be played back to Earth within allocated passes (Table 10.3). The DSN must also contend with aging infrastructure, particularly the 70-meter antennas that were constructed in the 1960s. Nonetheless, the DSN continues to perform extraordinarily well, returning data with a very low drop-out rate and achieving command and telemetry availabilities of better than 95 percent to most operating missions.
The DSN’s current budget supports expansion of Ka-band downlink capability, and addition of two 34-meter beam wave guide antennas at Canberra and one at Madrid by 2018. The longer-term configuration goal through the end of the decade includes plans for one more 34-meter beam wave guide antenna at each station by 2023 to nearly mimic the capability of a 70-meter antenna, while keeping the 70-meter antennas operational for as long as possible. In addition, there are plans for higher-power spacecraft transmitters, development of a Universal Space Transponder, and increases in on-board data compression and selection coding techniques.
Future demands on the DSN will be substantial. There is an ever-growing need for downlink capacity. Sophisticated next-generation instruments can generate terabits of data, or more, in short time periods. With advances in, for example, LIDAR, synthetic aperture radar, and hyperspectral imaging, missions will require Ka-band, and higher, transmission rates to handle these data, even with improvements in on-board data processing.
Solar system exploration also requires either 70-meter antennas or equivalent arrays to achieve the sensitivity needed for distant outer solar system missions, such as to the inner Kuiper belt. In addition, critical event monitoring and other operations of missions to closer bodies also require the high sensitivity and downlink margin of larger apertures.
The DSN must be able to receive data from more than one mission at one station simultaneously. If new arrays can only mimic the ability of one 70-meter station and nothing more, missions will still be downlink-constrained and will have to compete against one another for limited downlink resources.
TABLE 10.3 Typical Data Volumes for Some Current and Future Planetary Missions Using Different Deep Space Network Antennas and Communication Bands
|Typical Data Volume (gigabit/8-hour pass)|
|Antenna||Band||Maximum Data Rate (kbps)a||MROb||JEOc||Cassinid||Uranuse||New Horizonsf at Pluto|
NOTE: Bold text denotes downlink-limited cases, and italic text denotes theoretical capability.
a Actual downlink rate depends on spacecraft transmitter power, high-gain antenna size/gain, distance, DSN elevation, weather.
b MRO has 35 W Ka-band and 100-W X-band transmitters, 3-m high-gain antenna, 160-Gbit storage.
c JEO assumes 25-W X- and Ka-band transmitters, 3-m high-gain antenna, 17-Gbit storage.
d Cassini has 20-W X-band transmitter, 3-m high-gain antenna, 4-Gbit storage.
e Uranus Orbiter and Probe assumes 40-W Ka-band transmitters, 2.5-m high gain antenna, 32-Gbit storage.
f New Horizons has 12-W X-band transmitter, 2.1-m high-gain antenna, 132-Gbit storage.
g Non-optimal test case.
h Best case.
Although Ka-band downlink has a clear capacity advantage, there is a need to maintain multiple-band downlink capability. For example, three-band telemetry during outer planet atmospheric occultations allows sounding of different pressure depths within the atmosphere. In addition, S-band capacity is required for communications from Venus during probe, balloon, lander, and orbit insertion operations because communications in other bands cannot penetrate the atmosphere. X-band capability is required for communication through the atmosphere of Titan, and also for emergency spacecraft communications. Finally, the DSN is crucial for precision spacecraft ranging and navigation, and this capability must be maintained.
The committee recommends that all three Deep Space Network complexes should maintain high power uplink capability in the X-band and the Ka-band, and downlink capability in the S-, Ka-, and X-bands. NASA should expand DSN capacities to meet the navigation and communication requirements of missions recommended by this decadal survey, with adequate margins.
Sample Curation and Laboratory Facilities
Planetary samples are arguably some of the most precious materials on Earth. Just as data returned from planetary spacecraft must be carefully archived and distributed to investigators, so must samples brought at great cost to Earth from space be curated and kept uncontaminated and safe for continued study. Samples are a “gift that keeps on giving,” yielding discoveries long after they have been collected and returned. Even today, scientists are using new, state-of-the-art laboratory instruments to discover more about lunar samples collected during the Apollo program four decades ago. NASA rightly takes responsibility for the curation and distribution of planetary materials.
Collections of extraterrestrial materials are composed of:
• Samples that are delivered naturally to Earth in the form of meteorites and interplanetary dust particles, and
• Samples collected by spacecraft missions and returned to Earth for study.
Recent sample return missions include Genesis, which collected samples of the solar wind, and Stardust, which collected cometary material as it flew through the coma of Comet Wild 2. These missions continue a legacy of sample return that includes the robotic Luna and the human Apollo missions to the Moon. Currently, two sample return missions are under Phase-A study for NASA’s New Frontiers program: OSIRIS-REx as a sample return mission to
Near-Earth Asteroid 1999 RQ36, and MoonRise as a sample return mission to the South Pole-Aitken Basin region of the Moon.21 The missions recommended in Chapter 9 also include return of samples from a comet nucleus and Mars. In the decade 2013-2022, then, requirements for sample curation will rapidly grow to become of highest priority.
Samples to be returned to Earth from many planetary bodies (e.g., the Moon, asteroids, and comets) are given a planetary protection designation of “Unrestricted Earth Return” because they are not regarded as posing any biohazard to Earth. However, future sample return missions from Mars and other targets that might potentially harbor life (e.g., Europa and Enceladus) are classified as “Restricted Earth Return” and are subject to quarantine restrictions, requiring special receiving and curation facilities that can preserve the pristine nature of the returned materials and prevent potential contamination of Earth. Such a Mars Returned-Sample Handling (MRSH) facility has been discussed in detail for Mars Sample Return,22,23,24 and would also need to be considered for return from other targets that are classified as Restricted Earth Return.
Consistent with past recommendations in the reports cited above, an MRSH facility for Restricted Earth Return samples would provide the following:
• Biohazard assessment (following established protocols for life detection);
• Sterilization of samples for potential early release; and
• Release from containment of samples deemed to be safe, and transfer to appropriate curation facilities.
Current biohazard facilities focus predominantly on sample containment, and so existing biocontainment facilities would not be optimal for receiving extraterrestrial materials and characterizing the hazards associated with them. Nonetheless, it is a good policy, when appropriate, to use existing capabilities to reduce cost and risk, while maintaining the required safety requirements. A coordinated approach to all potentially hazardous returned samples is needed that leverages the considerable expertise within NASA and the scientific community in working with extraterrestrial samples. As plans move forward for Restricted Earth Return missions, including Mars sample return, NASA should establish a single advisory group to provide input on all aspects of collection, containment, characterization and hazard assessment, and allocation of such samples. This advisory group must have an international component.
The major site for curation and distribution of extraterrestrial samples within the United States is the Astromaterials Acquisition and Curation Office (AACO) of the Astromaterials Research and Exploration Science division at NASA’s Johnson Space Center. The AACO oversees the preparation and allocation of samples for research and education, initial characterization of new samples, and secure preservation for the benefit of future generations. Decisions about sample allocation are performed under the guidance of the Curation and Analysis Planning Team for Extraterrestrial Materials (CAPTEM) and the Meteorite Working Group (MWG), both supported through the Lunar and Planetary Institute. Currently, the Johnson Space Center’s AACO has separate laboratories that support curation and distribution of Apollo lunar samples, Antarctic meteorites, Stardust cometary materials, Genesis solar wind samples, cosmic dust collected in upper atmosphere flights, and space-exposed hardware. Plans are in place for a new asteroid laboratory if OSIRIS-REx is selected as the next New Frontiers mission, and for expansion of the lunar laboratory if MoonRise is selected.25
Sample curation facilities are critical components of any sample return mission and must be designed specifically for the types of returned materials and handling requirements. Early planning and adequate funding are needed early in the mission cycle so that an adequate facility is available once samples are returned and deemed ready for curation and distribution. Particular challenges for the future include cryogenic handling of materials from comets, asteroids, the icy satellites, and the frigid depths of unlit craters on the Moon and Mercury, as well as biocontainment of samples from Mars and other targets of biological interest. Every sample return mission flown by NASA should explicitly include in the estimate of its cost to the agency the full costs required for appropriate initial sample curation. The cost estimates for sample return missions recommended in Chapter 9 of this report include these curation costs.
The most important instruments for any sample return mission are the ones in the laboratories on Earth. To derive the full science return from sample return missions, it is critical to maintain technical and instrumental capabilities for initial sample characterization, as well as foster expansion to encompass appropriate new
instrumentation as it becomes available and as different sample types are acquired. It is equally crucial for NASA to maintain technical and instrumental capability in the sample science community. The development of new laboratory instrumentation is just as important for sample return missions as is development of new spacecraft instruments for other planetary missions. Well before planetary missions return samples, NASA should establish a well-coordinated and integrated program for development of the next generation of laboratory instruments to be used in sample characterization and analysis.
The National Science Foundation’s principal support for planetary science is provided by the Division of Astronomical Sciences in the Directorate for Mathematical and Physical Sciences. The Astronomy and Astrophysics Research Grants (AAG) program, for example, provides individual investigator and collaborative research grants for observational, theoretical, laboratory, and archival data studies in all areas of astronomy and astrophysics, including planetary astronomy. Planetary astronomy themes include planetary interiors, surfaces, and atmospheres, planetary satellites, comets and asteroids, trans-Neptune objects, the interplanetary medium, and the origin and evolution of the solar system. Typical awards range from $95,000 to $125,000 per year for a nominal 3-year period. The focus of the program is scientific merit with a broad impact and the potential for transformative research. Planetary scientists can also be supported directly through various career programs. NSF also provides peer-reviewed access to telescopes at public facilities. In short, NSF supports nearly all areas of planetary science except space missions, which it supports indirectly through laboratory research and archived data.
Further contributions to planetary science are realized through investigator grants in the Directorate for Geosciences, and by NSF support of major observatory facilities that are open to planetary scientists, Antarctic meteorite collection and curation, and the study of Antarctic geomorphic analogs to ancient Mars.
NSF grants and support for field activities are an important source of support for planetary science in the United States and should continue.
Ground-Based Astronomical Facilities
Importantly, the NSF is the largest federal funding agency for ground-based astronomy in the United States, supporting five national observatories:
• The National Optical Astronomy Observatory,
• The Gemini Observatory,
• The National Astronomy and Ionosphere Center,
• The National Radio Astronomy Observatory, and
• The National Solar Observatory.
These facilities are collectively known as the National Observatories.
National Optical Astronomy Observatory
The National Optical Astronomy Observatory (NOAO) operates two 4-meter and other smaller telescopes at the Kitt Peak National Observatory in Arizona and the Cerro Tololo Inter-American Observatory in Chile. NOAO plays a valuable role within the optical-infrared astronomical system. It provides merit-based access to the telescopes directly under NOAO management, it administers the Telescope System Instrumentation Program (see the section “Public-Private Partnerships” below) and other merit-based funds for access to a broader range of apertures and instruments operated by other institutions, and it serves as a community advocate and facilitator for LSST (see below) and an eventual U.S. role in extremely large telescopes.
The Gemini Observatory operates two 8-meter optical telescopes, one in the Southern and one in the Northern Hemisphere in an international partnership. These telescopes and their associated instrumentation, including adaptive optics and spectroscopy in the near- and mid-infrared, are very important for planetary studies. Gemini’s diffraction-limited mid-infrared imaging capability is particularly so. The Gemini international partnership agreement is currently under renegotiation, and the United Kingdom, which holds a 25 percent stake, has announced its intent to withdraw from the consortium in 2012. This eventuality would provide a good opportunity for increasing the U.S. share of Gemini, and also presents an opportunity for restructuring the complex governance and management structure.26 The Gemini partnership might consider the advantages of stronger scientific coordination with NASA mission planning needs.
The National Astronomy and Ionosphere Center
The National Astronomy and Ionosphere Center operates the Arecibo Observatory in Puerto Rico. As noted in the preceding discussion of observatories that receive some NASA support, Arecibo is a unique and important radar facility that plays a particularly important role in NEO studies.
The National Radio Astronomy Observatory
The National Radio Astronomy Observatory (NRAO) operates the Very Large Array (VLA), the Very Long Baseline Array, and the Green Bank Telescope (GBT), and also supports the Atacama Large Millimeter Array (ALMA). In the microwave and submillimeter wavelength regions, the two ground-based facilities ALMA and the Expanded VLA are of great importance to future planetary exploration. When the VLA expansion is completed later in this decade it will produce high-fidelity, wide-band imaging of the planets across the microwave spectrum. The VLA, with its full suite of X- and Ka-band receivers, also provides a back-up downlink location to the DSN—Cassini, for example, has recently been successfully tracked with the VLA at the Ka-band. ALMA, expected to come online this next decade, will provide unprecedented imaging in the relatively unexplored wavelength region of 0.3 mm to 3.6 mm (84 GHz to 950 GHz). ALMA will also yield an angular resolution of 0.1” and brightness accuracies to 0.1 percent of the peak image brightness.
The National Solar Observatory
The National Solar Observatory (NSO) operates telescopes on Kitt Peak and Sacramento Peak, New Mexico, and six worldwide Global Oscillations Network Group (GONG) stations. Understanding the Sun is critical to understanding its relationship to planetary atmospheres and surfaces. The 2010 astronomy and astrophysics decadal survey report provides a comprehensive discussion of current and planned solar facilities.27 The committee notes that national ground-based solar facilities will be transformed when the Advanced Technology Solar Telescope becomes operational in 2017. Solar ground-based observations from optical to radio wavelengths are increasingly complemented by extensive probing at optical and ultraviolet wavelengths from spacecraft like SOHO, TRACE, STEREO, and Solar Dynamics Observatory. Advances in solar physics over the next decade will likely expand in areas that directly involve solar effects on Earth and other planets. The committee endorses and echoes the 2010 astronomy and astrophysics decadal survey report’s recommendation that “NSF should work with the solar, heliospheric, stellar, planetary, and geospace communities to determine the best route to an effective and balanced ground-based solar astronomy program that maintains multidisciplinary ties.”28
Many important advances in planetary research have come from access to private facilities such as the Keck, Magellan, and MMT observatories via NSF’s Telescope System Instrumentation Program (TSIP). This program
provides funding to develop new instruments that enhance the scientific capability of telescopes operated by private (non-federally funded) observatories, in exchange for public access to those facilities. For example, in 2007 Uranus ring-plane crossing observational work was supported at Keck via NOAO/TSIP time. The highly successful NSF TSIP program should continue with full support. The development of instrumentation that addresses the needs of the planetary community, such as low mass and power, high spatial resolution and sensitivity, and mid-infrared capability, are particularly encouraged.
The committee supports the National Observatories’ ongoing efforts to provide public access to its system of observational facilities, and encourages the National Observatories to recognize the synergy between ground-based observations and in situ planetary measurements, perhaps through coordinated observing campaigns on mission targets.
The ground-based observational facilities supported wholly or in part by NSF are essential to planetary astronomical observations, both in support of active space missions and in studies independent of (or as follow-up to) such missions. Their continued support is critical to the advancement of planetary science.
Large Synoptic Survey Telescope
One of the future NSF-funded facilities most important to planetary science is the Large Synoptic Survey Telescope (LSST), a 6.5-meter wide-field survey telescope that will image the entire sky visible from its observing site in Chile in six wavebands some 1,000 times in a period of 10 years.29 LSST will discover many small bodies in the solar system, some of which will require follow-up observations for the study of their physical properties. Some of these bodies are likely to be attractive candidates for future spacecraft missions. The potential for finding new populations of small bodies that are currently unknown but that will further illuminate the dynamical history of the solar system is especially exciting. LSST will play a potentially critical role in completing the so-called George E. Brown Survey of all near-Earth asteroids down to a diameter of 140 meters (mandated by the Congress), especially in the absence of a space-based infrared survey telescope optimized for this purpose. The nominal schedule for LSST calls for a 2-year commissioning phase starting in mid-2016 and the beginning of the 10-year operational phase in mid-2018. The committee encourages the timely completion of LSST and stresses the importance of its contributions to planetary science, as well as astrophysics, once telescope operations begin.
Extremely Large Telescopes
With apertures of 30 meters and larger, extremely large telescopes (ELTs) will play a significant future role in planetary science. Among the advantages of such telescopes is improved spatial resolution at mid-infrared and longer wavelengths where planetary observations are impaired by the diffraction limit; even 8- to 10-meter telescopes have difficulty with the small angular sizes of Uranus and Neptune. Observations using a 30-meter telescope could, for example, resolve thermal emission from Neptune with about the same resolution as the 3-meter IRTF can for Saturn at the same wavelength, and give compositional information on a large number of trans-Neptune objects. International efforts for ELT development are proceeding rapidly, with at least three such telescopes in the planning stages: the Giant Magellan Telescope (GMT), the Thirty-Meter Telescope (TMT), and the European Extremely Large Telescope. The committee does not provide specific guidance to NSF on this issue. It endorses the recommendations and support for these facilities made by the 2010 astronomy and astrophysics decadal survey and encourages NSF to continue to invest in the development of ELTs, and to seek partnerships to ensure that at least one such facility comes to fruition with provisions for some public access. The committee believes that it is essential that the design of ELTs accommodate the requirements of planetary science to acquire and observe targets that are moving, extended, and/or bright, and that the needs of planetary mission planning be
considered in awarding and scheduling public time for ELTs. The earliest possible date NSF can seek approval from the National Science Board to provide partial support to either the GMT or the TMT project is 2014.
Small telescopes are also very useful for some solar system problems; amateurs with their personal telescopes are playing an increasing role in laying groundwork for professionals. The 2009 and 2010 Jupiter impacts were discovered by amateurs who alerted the professional community, and within hours of each event, observatory telescopes around the world were being mobilized for follow-up observations. Likewise, monitoring of Uranus and Neptune for anomalous cloud activity is solidly within the capabilities of amateurs. Amateurs play an increasing role in the study of asteroids, both through photometric monitoring and occultations, as well as observing fast-moving near-Earth objects for orbit determinations. NSF support for modest investments in small observing facilities, such as equipment or filter sets for modest telescopes operated on university campuses or by amateur astronomers, would enhance the current synergy with professionals.
Laboratory Studies and Facilities for Planetary Science
To maximize the science return from NSF-funded ground-based observations and NASA space missions alike, materials and processes must be studied in the laboratory. Needed support for planetary science activities includes the development of large spectroscopic databases for gases and solids over a wide range of wavelengths, including derivation of optical constants for solid materials, laboratory simulations of the physics and chemistry of aerosols, and measurements of thermophysical properties of planetary materials. Planetary science intersects with many areas of astrophysics that receive NSF funding for laboratory investigations. Although laboratory research costs a fraction of the cost of missions, in most areas it receives insufficient support, with the result that existing infrastructure is often not state of the art and required upgrades cannot be made. NSF can make a huge impact on planetary science by supporting this vital area of research. The committee recommends expansion of NSF funding for the support of planetary science in existing laboratories, and the establishment of new laboratories as needs develop. Areas of high priority for support include the following:
• Development and maintenance of spectral reference libraries for atmospheric and surface composition studies, extending from x-ray to millimeter wavelengths. Studies should specifically include ices and organics and their modification through bombardment by charged particles typical of planetary magnetospheres, as well as the interfaces among atmospheric, surface, and subsurface phases.
• Laboratory measurements of thermophysical properties of materials over the range of conditions relevant to planetary objects, including phase diagrams in high-pressure and low-temperature regimes, equations of state relevant to the interiors of the giant planets, rheological properties, photochemistry, and energy-dependent radiation chemistry.
• Investment in laboratory infrastructure and support for laboratory spectroscopy (experimental and theoretical), perhaps through a network of general-user laboratory facilities.
• Investigations of the physics and chemistry of aerosols in planetary atmospheres through laboratory simulations.
The ties between planetary science and laboratory astrophysics will continue to strengthen and draw closer with the expanding exploration of exoplanets and the development of techniques to study their physical-chemical properties.
1. National Research Council. 2010. An Enabling Foundation for NASA’s Space and Earth Science Missions. The National Academies Press, Washington, D.C.
2. National Research Council. 2010. An Enabling Foundation for NASA’s Space and Earth Science Missions. The National Academies Press, Washington, D.C., p. 22.
3. W.B. McKinnon. 2009. Exploration Strategy for the Outer Planets 2013-2022: Goals and Priorities. White paper submitted to the Planetary Science Decadal Survey, National Research Council, Washington, D.C.
4. M.S. Tiscareno. 2009. Rings Research in the Next Decade. White paper submitted to the Planetary Science Decadal Survey, National Research Council, Washington, D.C.
5. P.L. Read, T.E. Dowling, and G. Schubert. 2009. Saturn’s rotation period from its atmospheric planetary-wave configuration. Nature 460:608-610.
6. A.R. Vasavada and A.P. Showman. 2005. Jovian atmospheric dynamics: An update after Galileo and Cassini. Reports on Progress in Physics 68:1935-1996.
7. M.A. Morales, E. Schwegler, D. Ceperley, C. Pierleoni, S. Hamel, and K. Caspersen. 2009. Phase separation in hydrogen-helium mixtures at Mbar pressures. Proceedings of the National Academy of Sciences 106:1324.
8. See, for example, J. Schmidt, K. Ohtsuki, N. Rappaport, H. Salo, and F. Spahn, Dynamics of Saturn’s dense rings, pp. 413-458 in Saturn from Cassini-Huygens (M.K. Dougherty, L.W. Esposito, and S.M. Krimigis, eds.), Springer, Heidelberg, Germany, 2009.
9. J.D. Miller. 2007. Civic Scientific Literacy across the Life Cycle, paper presented at the annual meeting of the American Association for the Advancement of Science, San Francisco, California, February 17.
10. National Science Board. 2006. Science and Engineering Indicators 2006. National Science Foundation, Arlington, Va. Available at http://www.nsf.gov/statistics/seind06/pdf/volume1.pdf.
11. National Academy of Sciences, National Academy of Engineering, Institute of Medicine. 2007. Rising Above the Gathering Storm Energizing and Employing America for a Brighter Economic Future. The National Academies Press, Washington, D.C.
12. National Academy of Sciences, National Academy of Engineering, Institute of Medicine. 2007. Rising Above the Gathering Storm: Energizing and Employing America for a Brighter Economic Future. The National Academies Press, Washington, D.C.
13. National Academy of Sciences, National Academy of Engineering, Institute of Medicine. 2010. Rising Above the Gathering Storm, Revised: Rapidly Approaching Category 5. The National Academies Press, Washington, D.C.
14. Education in STEM as important areas of competency is emphasized in, for example, the America COMPETES Act (H.R. 2272), initiatives within the U.S. Department of Education and National Science Foundation, and in Rising Above the Gathering Storm: Energizing and Employing America for a Brighter Economic Future, a report of the National Academy of Sciences, National Academy of Engineering, and Institute of Medicine (The National Academies Press, Washington, D.C., 2007).
15. National Research Council. 2008. NASA’s Elementary and Secondary Education Program: Review and Critique. The National Academies Press, Washington, D.C.
16. As highlighted in National Research Council, Learning Science in Informal Environments: People, Places, and Pursuits (P. Bell, B. Lewenstein, A.W. Shouse, and M.A. Feder, eds.), The National Academies Press, Washington, D.C., 2009.
17. The most recent assessment of NASA’s Education programs by the Office of Management and Budget was rated “moderately effective”; available at http://www.whitehouse.gov/omb/expectmore/agency/026.html.
18. For more details concerning NASA’s suborbital program see, for example, National Research Council, Revitalizing NASA’s Suborbital Program: Advancing Science, Driving Innovation, and Developing a Workforce, The National Academies Press, Washington, D.C., 2010.
19. NASA. 2009. The Science Vision for the Stratospheric Observatory for Infrared Astronomy. NASA Ames Research Center, Moffett Field, Calif.
20. National Research Council. 2010. Defending Planet Earth: Near-Earth-Object Surveys and Hazard Mitigation Strategies. The National Academies Press, Washington, D.C.
21. On May 25, 2011, following the completion of this report, NASA selected the OSIRIS-REx asteroid sample-return spacecraft as the third New Frontiers mission. Launch is scheduled for 2016.
22. D.W. Beaty, C.C. Allen, D.S. Bass, K.L. Buxbaum, J.K. Campbell, D.J. Lindstrom, S.L. Miller, and D.A. Papanastassiou. 2009. Planning considerations for a Mars sample receiving facility: Summary and interpretation of three design studies. Astrobiology 9:745-758.
23. National Research Council. 2002. The Quarantine and Certification of Martian Samples. National Academy Press, Washington, D.C.
24. National Research Council. 2007. An Astrobiology Strategy for the Exploration of Mars. The National Academies Press, Washington, D.C.
25. On May 25, 2011, following the completion of this report, NASA selected the OSIRIS-REx asteroid sample-return spacecraft as the third New Frontiers mission. Launch is scheduled for 2016.
26. For additional details concerning Gemini and recommendations for its future, see, for example, National Research Council, New Worlds, New Horizons in Astronomy and Astrophysics, The National Academies Press, Washington, D.C., 2010, pp. 177-179.
27. National Research Council. 2010. New Worlds, New Horizons in Astronomy and Astrophysics. The National Academies Press, Washington, D.C.
28. National Research Council. 2010. New Worlds, New Horizons in Astronomy and Astrophysics. The National Academies Press, Washington, D.C., p. 34.
29. For additional information about and recommendations concerning the LSST, see, for example, National Research Council, New Worlds, New Horizons in Astronomy and Astrophysics, The National Academies Press, Washington, D.C., 2010, pp. 224-225.