National Academies Press: OpenBook

Space Studies Board Annual Report 2012 (2013)

Chapter: 5 Summaries of Major Reports

« Previous: 4 Workshops, Symposia, Meetings of Experts, and Other Special Projects
Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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5 Summaries of Major Reports

This chapter reprints the summaries of Space Studies Board (SSB) reports that were released in 2012 (or late 2011). Reports are often written in conjunction with other National Research Council boards, including the Aeronautics and Space Engineering Board (ASEB) or the Board on Physics and Astronomy (BPA), as noted.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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5.1 Assessment of a Plan for U.S. Participation in Euclid

A Report of the BPA and SSB Ad Hoc Committee on the Assessment of a Plan for U.S. Participation in Euclid

Executive Summary

NASA has proposed to make a hardware contribution to the European Space Agency’s (ESA’s) Euclid mission in exchange for U.S. membership on the Euclid Science Team and science data access.

The Euclid mission will employ a space telescope that will make potentially important contributions to probing dark energy and to the measurement of cosmological parameters. Euclid will image a large fraction of the extragalactic sky at unprecedented resolution and measure spectra for millions of galaxies.

This report responds to a request from NASA to evaluate whether a small investment in Euclid (around $20 million in hardware) is a viable part of an overall strategy to pursue the science goals of the New Worlds, New Horizons (NWNH) report’s top-ranked large-scale, space-based priority: the Wide-Field Infrared Survey Telescope (WFIRST). WFIRST has a broad, wide-field, near-infrared capability that will serve a wide variety of science programs of U.S. astronomers, including exoplanet research, near-infrared sky surveys, a guest observer program, and dark energy research. In carrying out this study the committee’s intent has been to be clear that this report does not alter NWNH’s plans for the implementation of the survey’s priorities.

The Committee on the Assessment of a Plan for U.S. Participation in Euclid concludes that the NASA proposal would represent a valuable first step toward meeting one of the science goals (furthering dark energy research) of WFIRST.

While WFIRST dark energy measurements are expected to be superior to Euclid’s, U.S. participation in Euclid will have clear scientific, technical, and programmatic benefits to the U.S. community as WFIRST and Euclid go forward.

NASA should make a hardware contribution of approximately $20 million1 to the Euclid mission to enable U.S. participation. This investment should be made in the context of a strong U.S. commitment to move forward with the full implementation of WFIRST in order to fully realize the decadal science priorities of the NWNH report.

In exchange for this small, but crucial contribution, NASA should secure through negotiation with the European Space Agency both a U.S. position on the Euclid Science Team with full data access and the inclusion of a team of U.S. scientists in the Euclid Consortium that would be selected by a peer-reviewed process with full data access as well as authorship rights consistent with Euclid policies still to be formulated.

NASA should seek independent community review of any financial commitment for hardware expenditures beyond $30 million for Euclid.

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NOTE: “Executive Summary” reprinted from Assessment of a Plan for U.S. Participation in Euclid, The National Academies Press, Washington, D.C., 2012, p. 1.

1 All costs expressed in fiscal year 2012 U.S. dollars unless otherwise specified.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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5.2 Assessment of Planetary Protection Requirements for Spacecraft Missions to Icy Solar Systems Bodies

A Report of the SSB Ad Hoc Committee on Planetary Protection Standards for Icy Bodies in the Outer Solar System

Summary

NASA’s exploration of planets and satellites over the past 50 years has led to the discovery of water ice throughout the solar system and prospects for large liquid water reservoirs beneath the frozen shells of icy bodies in the outer solar system. These putative subsurface oceans could provide an environment for prebiotic chemistry or a habitat for indigenous life. During the coming decades, NASA and other space agencies will send flybys, orbiters, subsurface probes, and, possibly, landers to these distant worlds in order to explore their geologic and chemical context and the possibility of extraterrestrial life. Because of their potential to harbor alien life, space agencies will select missions that target the most habitable outer solar system objects. This strategy poses formidable challenges for mission planners who must balance the opportunity for exploration with the risk of contamination by terrestrial microbes that could confuse the interpretation of data from experiments concerned with the origins of life beyond Earth or the processes of chemical evolution. To protect the integrity of mission science and maintain compliance with the mandate of the 1967 Outer Space Treaty to “pursue studies of outer space, including the Moon and other celestial bodies . . . so as to avoid their harmful contamination,”1 NASA adheres to planetary protection guidelines that reflect the most current experimental and observational data from the planetary science and microbiology communities.2

The 2000 National Research Council (NRC) report Preventing the Forward Contamination of Europa3 recommended that spacecraft missions to Europa must have their bioload reduced by such an amount that the probability of contaminating a Europan ocean with a single viable terrestrial organism at any time in the future should be less than 10-4 per mission.4 This criterion was adopted for consistency with prior recommendations by the Committee on Space Research (COSPAR) of the International Council for Science for “any spacecraft intended for planetary landing or atmospheric penetration.”5 COSPAR, the de facto adjudicator of planetary protection regulations, adopted the criterion for Europa, and subsequent COSPAR-sponsored workshops extended the 10-4 criterion to other icy bodies of the outer solar system.6,7

In practice, the establishment of a valid forward-contamination-risk goal as a mission requirement implies the use of some method—either a test or analysis—to verify that the mission can achieve the stated goal. The 2000 Europa report recommended that compliance with the 10-4criterion be determined by a so-called Coleman-Sagan calculation.8,9,10 This methodology estimates the probability of forward contamination by multiplying the initial bioload on the spacecraft by a series of bioload-reduction factors associated with spacecraft cleaning, exposure to the space environment, and the likelihood of encountering a habitable environment. If the risk of contamination falls below 10-4, the mission complies with COSPAR planetary protection requirements and can go forward. If the risk exceeds this threshold, mission planners must implement additional mitigation procedures to reach that goal or must reformulate the mission plans.

The charge for the Committee on Planetary Protection Standards for Icy Bodies in the Outer Solar System called for it to revisit the 2000 Europa report in light of recent advances in planetary and life sciences and examine the recommendations resulting from two recent COSPAR workshops. The committee addressed three specific tasks to assess the risk of contamination of icy bodies in the solar system.

The first task concerned the possible factors that could usefully be included in a Coleman-Sagan formulation of contamination risk. The committee does not support continued reliance on the Coleman-Sagan formulation to estimate the probability of contaminating outer solar system icy bodies. This calculation includes multiple factors of uncertain magnitude that often lack statistical independence. Planetary protection decisions should not rely on the multiplication of probability factors to estimate the likelihood of contaminating solar system bodies with terrestrial organisms unless it can be unequivocally demonstrated that the factors are completely independent and their values and statistical variation are known.

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NOTE: “Summary” reprinted from Assessment of Planetary Protection Requirements for Spacecraft Missions to Icy Solar Systems Bodies, The National Academies Press, Washington, D.C., 2012, pp. 1-4.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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The second task given to the committee concerned the range of values that can be estimated for the terms appearing in the Coleman-Sagan equation based on current knowledge, as well as an assessment of conservative values for other specific factors that might be provided to the implementers of missions targeting individual bodies or classes of objects. The committee replaces the Coleman-Sagan formulation with a series of binary (i.e., yes/no) decisions that consider one factor at a time to determine the necessary level of planetary protection. The committee proposes the use of a decision-point framework that allows mission planners to address seven hierarchically organized, independent decision points that reflect the geologic and environmental conditions on the target body in the context of the metabolic and physiological diversity of terrestrial microorganisms. These decision points include the following:

1. Liquid water—Do current data indicate that the destination lacks liquid water essential for terrestrial life?

2. Key elements—Do current data indicate that the destination lacks any of the key elements (i.e., carbon, hydrogen, nitrogen, phosphorus, sulfur, potassium, magnesium, calcium, oxygen, and iron) required for terrestrial life?

3. Physical conditions—Do current data indicate that the physical properties of the target body are incompatible with known extreme conditions for terrestrial life?

4. Chemical energy—Do current data indicate that the environment lacks an accessible source of chemical energy?

5. Contacting habitable environments—Do current data indicate that the probability of the spacecraft contacting a habitable environment within 1,000 years is less than 10-4?

6. Complex nutrients—Do current data indicate that the lack of complex and heterogeneous organic nutrients in aqueous environments will prevent the survival of irradiated and desiccated microbes?

7. Minimal planetary protection—Do current data indicate that heat treatment of the spacecraft at 60ºC for 5 hours will eliminate all physiological groups that can propagate on the target body?

Positive evaluations for any of these criteria would release a mission from further mitigation activities, although all missions to habitable and non-habitable environments should still follow routine cleaning procedures and microbial bioload monitoring. If a mission fails to receive a positive evaluation for at least one of these decision points, the entire spacecraft must be subjected to a terminal dry-heat bioload reduction process (heating at temperatures >110ºC for 30 hours) to meet planetary protection guidelines.

Irrespective of whether a mission satisfies one of the seven decision points, the committee recommends the use of molecular-based methods to inventory bioloads, including both living and dead taxa, for spacecraft that might contact a habitable environment. Given current knowledge of icy bodies, three bodies present special concerns for planetary protection: Europa, Jupiter’s third largest satellite; Enceladus, a medium-size satellite of Saturn; and Triton, Neptune’s largest satellite. Missions to other icy bodies present minimal concern for planetary protection.

The advantage of the decision framework over the Coleman-Sagan approach lies in its simplicity and in its abandoning of the multiplication of non-independent bioload reduction factors of uncertain magnitude. At the same time, the framework provides a platform for incorporating new observational data from planetary exploration missions and the latest information about microbial physiology and metabolism, particularly for psychrophilic (i.e., cold-loving microbes) and psychrotolerant microorganisms.

The committee’s third task concerned the identification of scientific investigations that could reduce the uncertainty in the above estimates and assessments, as well as technology developments that would facilitate implementation of planetary protection requirements and/or reduce the overall probability of contamination. The committee recognizes the requirement to further improve knowledge about many of the parameters embodied within the decision framework. Areas of particular concern for which the committee recommends research include the following:

• Determination of the time period of heating to temperatures between 40ºC and 80ºC required to inactivate spores from psychrophilic and psychrotolerant bacteria isolated from high-latitude soil and cryopeg samples, as well as from psychrotolerant microorganisms isolated from temperate soils, spacecraft assembly sites, and the spacecraft itself.

• Studies to better understand the environmental conditions that initiate spore formation and spore germination in psychrophilic and psychrotolerant bacteria so that these conditions/requirements can be compared with the characteristics of target icy bodies.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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• Searches to discover unknown types of psychrophilic spore-formers and to assess if any of them have tolerances different from those of known types.

• Characterization of the protected microenvironments within spacecraft and assessment of their microbial ecology.

• Determination of the extent to which biofilms might increase microbial resistance to heat treatment and other environmental extremes encountered on journeys to icy bodies.

• Determination of the concentrations of key elements or compounds containing biologically important elements on icy bodies in the outer solar system through observational technologies and constraints placed on the range of trace element availability through theoretical modeling and laboratory analog studies.

• Understanding of global chemical cycles within icy bodies and the geologic processes occurring on these bodies that promote or inhibit surface-subsurface exchange of material.

• Development of technologies that can directly detect and enumerate viable microorganisms on spacecraft surfaces.

REFERENCES

1. United Nations, Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies, U.N. Document No. 6347, Article IX, January 1967.

2. M. Meltzer, When Biospheres Collide: A History of NASA’s Planetary Protection Programs, NASA SP-2011-4234, NASA, Washington, D.C., 2011.

3. National Research Council, Preventing the Forward Contamination of Europa, National Academy Press, Washington, D.C., 2000.

4. National Research Council, Preventing the Forward Contamination of Europa, National Academy Press, Washington, D.C., 2000.

5. The recommendation to accept the 10-4 criterion was made at the 7th COSPAR meeting in May 1964 (see COSPAR, Report of the Seventh COSPAR Meeting, Florence Italy, COSPAR, Paris, 1964, p. 127, and, also, COSPAR Information Bulletin, No. 20, November, 1964, p. 25). The historical literature does not record the rationale for COSPAR’s adoption of this standard. Subsequent policy changes restricted the 10-4 standard to Mars missions (COSPAR, “COSPAR Planetary Protection Policy (20 October 2002; As Amended to 24 March 2011),” COSPAR, Paris, p. A1, available at http://cosparhq.cnes.fr/Scistr/PPPolicy%20(24Mar2011).pdf.

6. COSPAR Panel on Planetary Protection, COSPAR Workshop on Planetary Protection for Outer Planet Satellites and Small Solar System Bodies, European Space Policy Institute, Vienna, Austria, 2009.

7. COSPAR Panel on Planetary Protection, COSPAR Workshop on Planetary Protection for Titan and Ganymede, COSPAR, Paris, France, 2010.

8. C. Sagan and S. Coleman, Spacecraft sterilization standards and contamination of Mars, Astronautics and Aeronautics 3(5), 1965.

9. C. Sagan and S. Coleman, Decontamination standards for martian exploration programs, pp. 470-481 in National Research Council, Biology and the Exploration of Mars, National Academy of Sciences, Washington, D.C., 1966.

10. J. Barengoltz, A review of the approach of NASA projects to planetary protection compliance, IEEE Aerospace Conference, 2005, doi:10.1109/AERO.2005.1559319.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
×

5.3 Earth Science and Applications from Space: A Midterm Assessment of NASA’s Implementation of the Decadal Survey

A Report of the SSB Ad Hoc Committee on the Assessment of NASA’s Earth Science Program

Summary

Understanding the complex, changing planet on which we live, how it supports life, and how human activities affect its ability to do so in the future is one of the greatest intellectual challenges facing humanity. It is also one of the most important challenges for society as it seeks to achieve prosperity, health, and sustainability.1

The 2007 National Research Council report Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond (referred to in this report as the “2007 decadal survey” or “2007 survey") called for a renewal of the national commitment to a program of Earth observations in which attention to securing practical benefits for humankind plays an equal role with the quest to acquire new knowledge about the Earth system.2 The decadal survey recommended a balanced interdisciplinary program that would observe the atmosphere, oceans, terrestrial biosphere, and solid Earth and the interactions between these Earth system components to advance understanding of how the system functions for the benefit of both science and society.

NASA responded positively to the decadal survey and its recommendations and began implementing most of them immediately after the survey’s release. Although its budgets have never risen to the levels assumed in the survey, NASA’s Earth Science Division (ESD) has made major investments toward the missions recommended by the survey and has realized important technological and scientific progress as a result. Several of the survey missions have made significant advances, and operations and applications end users are better integrated into the mission teams. The new Earth Venture competitive solicitation program has initiated five airborne missions and is currently reviewing proposals submitted in response to an orbital stand-alone mission solicitation. At the same time, the Earth sciences have advanced significantly because of existing observational capabilities and the fruit of past investments, along with advances in data and information systems, computer science, and enabling technologies. Three missions already in development prior to the decadal survey—the Ocean Surface Topography Mission (OSTM), Aquarius, and the Suomi National Polar-orbiting Partnership (NPP)3—have since been successfully launched and promise significant benefits to research and applications. The potential for the science community to make use of space-based data for research and applications has never been greater.

Finding: NASA responded favorably and aggressively to the 2007 decadal survey, embracing its overall recommendations for Earth observations, missions, technology investments, and priorities for the underlying science. As a consequence, the science and applications communities have made significant progress over the past 5 years.

However, the Committee on Assessment of NASA’s Earth Science Program found that, for several reasons, the survey vision is being realized at a far slower pace than was recommended. Although NASA accepted and began implementing the survey’s recommendations, the required budget assumed by the survey was not achieved, greatly slowing implementation of the recommended program. Launch failures, delays, changes in scope, and growth in cost estimates have further hampered the program. In addition, the National Oceanic and Atmospheric Administration (NOAA) has significantly reduced the scope of the nation’s future operational environmental satellite series, omitting

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NOTE:“Summary” reprinted from Earth Science and Applications from Space: A Midterm Assessment of NASA’s Implementation of the Decadal Survey, The National Academies Press, Washington, D.C., 2012, pp. 1-14.

1From National Research Council, Earth Science and Applications from Space: Urgent Needs and Opportunities to Serve the Nation, The National Academies Press, Washington, D.C., 2005, p. 1.

2National Research Council, Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond, The National Academies Press, Washington, D.C., 2007.

3On January 24, 2012, NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project, launched on October 28, 2011, was renamed the Suomi National Polar-orbiting Partnership in honor of the late Verner E. Suomi, a renowned meteorologist from the University of Wisconsin considered by many to be “the father of satellite meteorology.” See http://www.nasa.gov/mission_pages/NPP/news/suomi.html.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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observational capabilities assumed by the decadal survey to be part of NOAA’s future capability and failing to implement the three new missions recommended for NOAA implementation by the survey (the Operational GPS Radio Occultation Mission, the Extended Ocean Vector Winds Mission, and the NOAA portion of CLARREO).

Thus, despite recent and notable successes, such as the launches of OSTM, Aquarius, and Suomi NPP, the nation’s Earth observing capability from space is beginning to wane as older missions fail and are not replaced with sufficient cadence to prevent an overall net decline. Using agency estimates for the anticipated remaining lifetime of in-orbit missions and counting new missions formally approved in their enacted budgets, the committee found that the resulting number of NASA and NOAA Earth observing instruments in space by 2020 could be as little as 25 percent of the current number (Figure S.1).4 This precipitous decline in the quantity of Earth science and applications observations from space undertaken by the United States reinforces the conclusion in the 2007 decadal survey and its predecessor, the 2005 interim report, which declared that the U.S. system of environmental satellites is at risk of collapse.5 The committee found that a rapid decline in capability is now beginning and that the needs for both investment and careful stewardship of the U.S. Earth observations enterprise are more certain and more urgent now than they were 5 years ago.

Finding: The nation’s Earth observing system is beginning a rapid decline in capability as long-running missions end and key new missions are delayed, lost, or canceled.

The projected loss of observing capability could have significant adverse consequences for science and society. The loss of observations of key Earth system components and processes will weaken the ability to understand and forecast changes arising from interactions and feedbacks within the Earth system and limit the data and information available to users and decision makers. Consequences are likely to include slowing or even reversal of the steady gains in weather forecast accuracy over many years and degradation of the ability to assess and respond to natural hazards and to measure and understand changes in Earth’s climate and life support systems. The decrease in capability by 2020 will also have far-reaching consequences for the vigor and breadth of the nation’s space-observing industrial and academic base, endangering the pipeline of Earth science and aerospace engineering students and the health of the future workforce.

CHALLENGES TO IMPLEMENTATION AND OPPORTUNITIES TO IMPROVE ALIGNMENT WITH THE DECADAL SURVEY

Although there have been a number of successes, NASA’s Earth science program has suffered multiple setbacks and other external pressures that are, in many cases, beyond the control of program management. Foremost among these is a budget profile that is not sufficient to execute the 2007 decadal survey’s recommended program. In addition, some of the survey-recommended missions have proved more challenging than anticipated, and others envisioned synergies that are not readily achieved via the suggested implementation. The ESD budget has been further strained as a result of mandates from Congress (e.g., the addition of the approximately $150 million TIRS [Thermal Infrared Sensor] to the Landsat Data Continuity Mission) and the interjection of administration priorities (e.g., the Climate Continuity missions6) without the commensurate required funding.

Finding: Funding for NASA’s Earth science program has not been restored to the $2 billion per year (in fiscal year [FY] 2006 dollars) level needed to execute the 2007 decadal survey’s recommended program. Congress’s failure to restore the Earth science budget to a $2 billion level is a principal reason for NASA’s inability to realize the mission launch cadence recommended by the survey.

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4Figure S.1 is an updated version of a similar chart produced by the 2007 decadal survey. Using agency estimates for the anticipated remaining lifetime of in-orbit missions and counting new missions only if they have been formally approved in enacted agency budgets, Figure S.1 indicates that the number of missions could decline from 23 in 2012 to only 6 in 2020, and the number of NASA and NOAA Earth-observing instruments in space could decline from a peak of about 110 in 2011 to approximately 20 in 2020. A more optimistic scenario based on the Climate-Centric Architecture put forth to leverage anticipated augmented funding to support administration priorities is also shown in Figure S.1; however, this plan, which has not been fully funded, also projects a precipitous decline in observing capabilities.

5National Research Council, Earth Science and Applications from Space: Urgent Needs and Opportunities to Serve the Nation, 2005.

6NASA, “Responding to the Challenge of Climate and Environmental Change: NASA’s Plan for a Climate-Centric Architecture for Earth Observations and Applications from Space,” June 2010. Available at http://science.nasa.gov/media/medialibrary/2010/07/01/Climate_Architecture_Final.pdf.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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FIGURE S.1 Number of operating (2000-2011) and planned (2012-2020) NASA and NOAA Earth observing missions (top) and instruments (bottom). Shown in blue are missions that are funded and have a specified launch date in NASA or NOAA budget submissions. Thus, the blue curve does not count missions (and associated instruments) that have been proposed or planned but are not yet funded or selected. Shown in pink is an “optimistic scenario” based on the Climate-Centric Architecture put forth to leverage anticipated augmented funding to support administration priorities that makes the following assumptions: GRACE-FO launches in 2016, PACE launches in 2019, ASCENDS launches in 2020, SWOT launches in 2020, EV-2 launches in 2017, SAGE-3 instrument launches in 2014, OCO-3 instrument launches in 2015, and EV-I instruments are launched every year starting in 2017 (plans are for EV-I instruments to be delivered for integration yearly; this assumes they also launch yearly). NOTE: Mission lifetimes for on-orbit missions are taken from estimates provided by NASA and NOAA; the NASA estimates are based on mission team estimates of remaining mission lifetime as provided (and reviewed by the Technical Panel) during the Senior Review process. Acronyms are defined in Appendix G. SOURCE: NASA and NOAA data.

The committee concluded that in the near term, budgets for NASA’s Earth science program will remain incommensurate with programmatic needs. However, even as NASA strives to “do more with less,” it is confronted with challenges, including limited access to affordable medium-class launch vehicles—the mainstay of Earth observation programs—and significant growth in the cost to develop instruments and spacecraft, a consequence, in part, of how NASA manages its space missions. These challenges (discussed further in Chapter 3) have hindered implementation of the envisioned balanced Earth system science program. With respect to cost growth, the committee found

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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that decadal survey missions have thus far not been managed with sufficient consideration of the scope and cost outlined in the 2007 decadal survey in either an absolute or a relative sense. Chapter 4 offers recommendations to establish and manage mission costs.

Recommendation:

• NASA’s Earth Science Division (ESD) should implement its missions via a cost-constrained approach, requiring that cost partially or fully constrain the scope of each mission such that realistic science and applications objectives can be accomplished within a reasonable and achievable future budget scenario.

Further, recognizing that survey-derived cost estimates are by necessity very approximate and that subsequent, more detailed analyses may determine that all of the desired science objectives of a particular mission cannot be achieved at the estimated cost,

NASA’s ESD should interpret the 2007 decadal survey’s estimates of mission costs as an expression of the relative level of investment that the survey’s authoring committee believed appropriate to advance the intended science and should apportion funds accordingly, even if all desired science objectives for the mission might not be achieved.

To coordinate decisions regarding mission technical capabilities, cost, and schedule in the context of overarching Earth system science and applications objectives, the committee also recommends that

NASA’s ESD should establish a cross-mission Earth system science and engineering team to advise NASA on execution of the broad suite of decadal survey missions within the interdisciplinary context advocated by the 2007 decadal survey. The advisory team would assist NASA in coordinating decisions regarding mission technical capabilities, cost, and schedule in the context of overarching Earth system science and applications objectives.7,8

The cost of executing survey-recommended missions has increased, in part because of the lack of availability of a medium-class launch vehicle. To control costs and to optimize the use of scarce fiscal resources, the 2007 decadal survey recommended mostly small- and medium-class missions that could utilize relatively low-cost small- or medium-class launch vehicles (e.g., Pegasus, Taurus, and Delta II). However, the Taurus launch vehicle has failed in its past two launches, and the Delta II is being phased out as the commercial sector focuses on heavier-lift launch vehicles, which are substantially more expensive to procure. Use of such heavy-lift launch vehicles is not generally cost-effective for Earth science missions; indeed, the excess capability and high cost of these vehicles encourage designers to grow their payloads to better match the launcher’s capabilities, which encourages growth in scope and cost. The lack of a reliable and low-cost medium-capability launch vehicle thus directly threatens programmatic robustness. The committee offers the following finding and recommendation concerning the cost and availability of medium-class launch vehicles (see the section “Access to Space” in Chapter 3):

Finding: Lack of reliable, affordable, and predictable access to space has become a key impediment to implementing NASA’s Earth science program. Furthermore, the lack of a medium-class launch vehicle threatens programmatic robustness.

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7The team, similar to the Payload Advisory Panel established by NASA to assist in implementation of its Earth Observing System (EOS), would draw its membership from the scientists and engineers involved in the definition and execution of survey missions as well as the nation’s scientific and engineering talent more broadly. (The Payload Advisory Panel was composed of the EOS Interdisciplinary Science Investigation principal investigators and was formally charged with examining and recommending EOS payloads to NASA based on the scientific requirements and priorities established by the Earth science community at large. See NASA, Earth Observing System (EOS) Reference Handbook, G. Asrar and D.J. Dokken, eds., Earth Science Support Office, Document Resource Facility, Washington, D.C., 1993.)

8The committee believes that NASA is best positioned to determine whether this advisory panel should be constituted as a Federal Advisory Committee Act-compliant advisory body.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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Recommendation: NASA should seek to ensure the availability of a highly reliable, affordable medium-class launch capability.

Another impediment to effective and efficient implementation of the 2007 decadal survey is the lack of a national strategy for establishment and management of Earth observations from space. This problem was recognized in the decadal survey report, which stated (as quoted in this midterm assessment report),

The committee is concerned that the nation’s institutions involved in civil Earth science and applications from space (including NASA, NOAA, and USGS) are not adequately prepared to meet society’s rapidly evolving Earth information needs. Those institutions have responsibilities that are in many cases mismatched with their authorities and resources: institutional mandates are inconsistent with agency charters, budgets are not well matched to emerging needs, and shared responsibilities are supported inconsistently by mechanisms for cooperation. These are issues whose solutions will require action at high levels of the federal government.9

Such a strategy is perhaps even more important in an era of severe fiscal constraint. Not only is such a strategy important for optimizing NASA’s and the nation’s resources dedicated to Earth system science, but also it is critical to meeting national needs for the results of Earth system science, including the understanding of climate change and land use. The decadal survey recommended that “the Office of Science and Technology Policy, in collaboration with the relevant agencies and in consultation with the scientific community, should develop and implement a plan for achieving and sustaining global Earth observations. This plan should recognize the complexity of differing agency roles, responsibilities, and capabilities as well as the lessons from the implementation of the Landsat, EOS, and NPOESS programs.”10,11

Despite this and other subsequent calls from the community for this national strategy, only a preliminary plan has been outlined.12 A more complete plan for achieving and sustaining global Earth observations remains to be presented or funded. However, the recently released NASA Climate-Centric Architecture plan13 includes a set of Climate Continuity missions, tacitly recognizing for the first time NASA’s role in sustained observations associated with climate (see the section “Lack of a National Strategy for Establishment and Management of Earth Observations from Space” in Chapter 3).

Finding: The 2007 decadal survey’s recommendation that the Office of Science and Technology Policy develop an interagency framework for a sustained global Earth observing system has not been implemented. The committee concluded that the lack of such an implementable and funded strategy has become a key, but not the sole, impediment to sustaining Earth science and applications from space.

Chapter 4 discusses a number of items that should be considered in the formulation of such a national strategy. In addition to cost control measures, the committee considered other ways for ESD to maximize the value of its limited resources. These include the possible augmentation of the Earth Venture-class program discussed below, and use of alternative and/or synergistic platforms or novel flight architectures (including suborbital platforms as previously mentioned), as well as seeking value-added international partnerships. Alternative platforms such as balloons and aircraft (piloted and unpiloted), hosted payloads, small satellites, the International Space Station, and flight formations (for example, the Afternoon Constellation, or “A-Train") provide NASA with a diverse portfolio

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9National Research Council, Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond, 2007, p. 61.

10National Research Council, Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond, 2007, p. 14.

11Following a major restructuring in 2010, the joint NOAA-Air Force procurement of the polar-orbiting satellite system called NPOESS was ended. The NOAA portion of the NPOESS program is now the Joint Polar Satellite System (JPSS). See, U.S. House of Representatives, “From NPOESS to JPSS: An Update on the Natioms Restructured Polar Weather Satellite System,” Hearing Charter, Committee on Science, Space and Technology, Subcommittee on Investigations and Oversight and the Subcommittee on Energy and Environment, September 23, 2011, available at http://science.house.gov/hearing/joint-hearing-investigations-and-oversight-energy-and-environment-subcommittees-polar.

12See “Achieving and Sustaining Earth Observations: A Preliminary Plan Based on a Strategic Assessment by the US Group on Earth Observations,” Office of Science and Technology Policy, September 2010, available at http://www.whitehouse.gov/sites/default/files/microsites/ostp/ostp-usgeo-report-earth-obs.pdf (accessed November 2011).

13NASA, “Responding to the Challenge of Climate and Environmental Change: NASA’s Plan for a Climate-Centric Architecture for Earth Observations and Applications from Space,” available at http://science.nasa.gov/media/medialibrary/2010/07/01/Climate_Architecture_Final.pdf.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
×

of options for exploring different and, where appropriate, less costly ways of conducting Earth observations and measurements (see the section “Alternative Platforms and Flight Formations” in Chapter 4).

Finding: Alternative platforms and flight formations offer programmatic flexibility. In some cases, they may be employed to lower the cost of meeting science objectives and/or maturing remote sensing and in situ observing technologies.

Large uncertainties are typical when attempting to factor international partner missions into long-term plans for U.S. Earth observation missions. Nevertheless, the committee found that ESD has made admirable efforts in securing such partnerships (see the section “International Partnerships” in Chapter 4).

Finding: NASA has made considerable efforts to secure international partnerships to meet its science goals and operational requirements.

STATUS OF PROGRAM ELEMENTS IN NASA’S EARTH SCIENCE PROGRAM

In its assessment of NASA’s Earth science program, the committee examined the major individual programmatic elements within NASA’s ESD and also considered the overall program’s effectiveness in realizing the objectives of the 2007 decadal survey.14 In particular, the committee reviewed the following program elements and also commented on NASA’s Climate Continuity missions. The program elements described in this summary are elaborated on in Chapter 2, where they are listed in the same order as they are here:

• Extended missions—missions whose operations have been extended beyond their nominal lifetime;

• Missions in the pre-decadal survey queue—missions that the decadal survey assumed would be launched as precursors to the decadal survey missions;

• Decadal survey missions—new missions recommended by the 2007 decadal survey;

• Climate Continuity missions;

• Earth Venture missions—a class of smaller missions recommended by the decadal survey;

• Applied Sciences Program;

• Suborbital (Earth Science) Program;

• Technology development; and

• Research and analysis.

Extended Missions

Extended missions (missions that operate and provide data beyond their originally planned and funded mission lifetimes) continue to provide a wealth of observations and measurements of benefit to society and to the Earth science community. Data from extended missions are critical to the operations of users such as NOAA’s National Weather Service; they also provide information of fundamental importance to advance Earth science research. Overall, the committee strongly supports the process of the NASA Earth Science Senior Review that evaluates these missions and makes recommendations concerning their funding and continuation.

Missions in the Pre-Decadal Survey Queue

The committee supports NASA’s efforts to fly out its pre-decadal survey mission queue, also referred to as “foundational” missions. Unfortunately, delays, changes in scope, and launch failures15 have hindered progress in implementing the pre-decadal survey mission queue.

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14A full listing of all the findings and recommendations in the 2007 decadal survey, as well as responses to each of those from NASA in 2009 and updated responses presented to the committee in April 2011, is available in Appendix E.

15Two important NASA missions—Glory and Orbiting Carbon Observatory (OCO)—were lost because of launch vehicle failures. Lack of reliable, affordable, and predictable access to space has now become a key impediment to implementing NASA’s Earth science program.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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Decadal Survey Missions

Implementation of the recommended decadal survey mission queue is proceeding at a pace that is slower than originally envisioned in the survey. Only two of the four Phase 1 missions recommended for implementation by 2013—SMAP and ICESat-2—have entered their implementation phase, while two other missions—DESDynI and CLARREO—remain in pre-Phase A formulation and will likely face significant delays as a result of budget constraints. NOAA, facing its own budget constraints, has requested that NASA assume responsibility for implementing the sea-surface vector winds mission XOVWM (see Table S.1).

Climate Continuity Missions

To balance executive branch and congressional priorities with the community guidance set forth in the decadal survey, the NASA Earth science program issued the report Responding to the Challenge of Climate and Environmental Change: NASA’s Plan for a Climate-Centric Architecture for Earth Observations and Applications from Space,16 which convolves decadal survey and administration priorities to take advantage of new funds made available by the executive branch to accelerate its priorities. Although the committee was encouraged by ESD’s incorporation of the priorities of the decadal survey into its 2010 report, the committee is concerned that in a static or shrinking budget environment there is tension between the need to continue successful Earth science measurements and the need for timely implementation of decadal survey missions. This problem is further compounded by the lack of an interagency framework for a sustained global Earth observing system.

Earth Venture Missions

NASA has moved expeditiously to implement the Earth Venture-class program, a new mission class recommended by the decadal survey.17 NASA has released two solicitations for the Earth Venture program, one targeted toward suborbital investigations and one for a stand-alone mission that involves relatively simple, small instruments, spacecraft, and launch vehicles. As of December 2011, a draft solicitation had also been released for the first Earth Venture Instruments, targeting principal investigator (PI)-led instrument development. Currently, NASA plans to release Earth Venture stand-alone solicitations every 4 years, suborbital solicitations every 4 years, and instrument of opportunity solicitations every 15-18 months. Earth Venture standalone (space-based) missions further offer an important opportunity to increase the launch frequency of Earth science missions, and thus the committee offers the following finding and recommendation.

Finding: The Earth Venture-class program is being well implemented by NASA and is a crucial component of fulfilling the 2007 decadal survey’s objectives.

Recommendation: Consistent with available budgets and a balanced Earth observation program from space based on the 2007 decadal survey recommendations, NASA should consider increasing the frequency of Earth Venture stand-alone/space-based missions.

Applied Sciences Program

The Earth science and applications from space decadal survey establishes a vision acknowledging the dual importance of basic science and applications for societal benefits. With limited resources,18 the Applied Sciences Program (ASP) within ESD has built a coherent program that is facilitating the use of remote sensing observations

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16See http://science.nasa.gov/media/medialibrary/2010/07/01/Climate_Architecture_Final.pdf.

17The decadal survey made the following recommendation, “To restore more frequent launch opportunities and to facilitate the demonstration of innovative ideas and higher-risk technologies, NASA should create a new Venture class of low-cost research and application missions (approximately $100 million to $200 million). These missions should focus on fostering revolutionary innovation and on training future leaders of space-based Earth science and applications.” See National Research Council, Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond, 2007, p. 59.

18Ray Hoff, chair of the NASA Applied Science Advisory Group, cited on p. 8 of “Meeting Minutes,” from the October 10, 2010, meeting of the NASA ASAG. Available at http://science.nasa.gov/media/medialibrary/2011/01/06/FinalASAGMeetingMinutesOctober2010-1_TAGGED.pdf.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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TABLE S.1 Current Status of Earth Science and Applications Decadal Survey Recommended Missions

Mission Mission Description
(from 2007 decadal survey)
Recommended
Launch Time Frame
Planned
Launch Date
Statusa
CLARREO
(Climate Absolute Radiance and Refractivity Observatory)
Solar and Earth radiation; spectrally resolved forcing and response of the climate system 2010-2013 Noneb Formulation (Pre-Phase A)
SMAP
(Soil Moisture Active-Passive)
Soil moisture and freeze-thaw for weather and water-cycle processes 2010-2013 November 2014 Implementation Phase (Phase B)
ICESat-II Ice sheet height changes for climate change diagnosis 2010-2013 October 2015 Implementation Phase (Phase A)
DESDynI
(Deformation, Ecosystem Structure, and Dynamics of Ice)
Surface and ice sheet deformation for understanding natural hazards and climate; vegetation structure for ecosystem health 2010-2013 Noneb Formulation (Pre-Phase A)
HyspIRI
(Hyperspectral Infrared Imager)
Land surface composition for agriculture and mineral characterization; vegetation types for ecosystem health 2013-2016 None Formulation (Pre-Phase A)
ASCENDS
(Active Sensing of CO2 Emissions over Nights, Days, and Seasons)
Day/night, all-latitude, all-season CO2column integrals for climate emissions 2013-2016 Nonec Formulation (Pre-Phase A)
SWOT
(Surface Water and Ocean Topography)
Ocean, lake, and river water levels for ocean and inland water dynamics 2013-2016 Noned Formulation (Pre-Phase A)
GEO-CAPE
(Geostationary Coastal and Air Pollution Events Mission)
Atmospheric gas columns for air quality forecasts; ocean color for coastal ecosystem health and climate emissions 2013-2016 None Formulation (Pre-Phase A)
ACE
(Aerosol/Cloud/Ecosystems Mission)
Aerosol and cloud profiles for climate and water cycle; ocean color for open ocean biogeochemistry 2013-2016 None Formulation (Pre-Phase A)
LIST
(Lidar Surface Topography)
Land surface topography for landslide hazards and water runoff 2016-2020 None Formulation (Pre-Phase A)
PATH
(Precipitation and All-weather Temperature and Humidity)
High-frequency, all-weather temperature and humidity soundings for weather forecasting and sea-surface temperaturee 2016-2020 None Formulation (Pre-Phase A)
GRACE-II
(Gravity Recovery and Climate Experiment-II)
High-temporal-resolution gravity fields for tracking large-scale water movement 2016-2020 Nonef Formulation (Pre-Phase A)
SCLP
(Snow and Cold Land Processes)
Snow accumulation for freshwater availability 2016-2020 None Formulation (Pre-Phase A)
GACM
(Global Atmospheric Composition Mission)
Ozone and related gases for intercontinental air quality and stratospheric ozone layer prediction 2016-2020 None Formulation (Pre-Phase A)
3D-WINDS (Demo)
(3D Tropospheric Winds from Space-based Lidar)
Tropospheric winds for weather forecasting and pollution transport 2016-2020 None Formulation (Pre-Phase A)
Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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aDuring Pre-Phase A, a pre-project team studies a broad range of mission concepts that contribute to program and mission directorate goals and objectives. These advanced studies, along with interactions with customers and other potential stakeholders, help the team to identify promising mission concepts and draft project-level requirements. The team also identifies potential technology needs (based on the best mission concepts) and assesses the gaps between such needs and current and planned technology readiness levels. See NASA NPR 7120.5, available at http://www.hq.nasa.gov/office/codeq/doctree/71205.htm.

During Phase A, a project team is formed to fully develop a baseline mission concept and begin or assume responsibility for the development of needed technologies. This work, along with interactions with customers and other potential stakeholders, helps with the baselining of a mission concept and the program requirements on the project. These activities are focused toward System Requirements Review (SRR) and System Definition Review (SDR/PNAR) (or Mission Definition Review (MDR/PNAR)). See NASA NPR 7120.5, available at http://www.hq.nasa.gov/office/codeq/doctree/71205.htm.

During Phase B, the project team completes its preliminary design and technology development. These activities are focused toward completing the Project Plan and Preliminary Design Review (PDR)/Non-Advocate Review (NAR). See NASA NPR 7120.5, available at http://www.hq.nasa.gov/office/codeq/doctree/71205.htm.

bIn the 2010 NASA report Responding to the Challenge of Climate and Environmental Change: NASA’s Plan for a Climate-Centric Architecture for Earth Observations and Applications from Space (available at http://nasascience.nasa.gov/earth-science/), CLARREO (the first of two mission components) and DESDynI (two spacecraft sharing a single launch vehicle) were slated for launch in 2017. The committee was informed at its first meeting on April 28, 2011, by the director of NASA’s Earth Science Division, Michael Freilich, that these plans are now on hold because the fiscal year 2012 budget request does not fund mission implementation; no new target launch dates are available for these missions.

cMission planned for launch by end of 2019 per NASA, Responding to the Challenge of Climate and Environmental Change (2010); however, a formal target launch date is not determined until after Mission Concept Review, when a budget wedge is established.

dMission planned for launch by the end of 2020 per NASA, Responding to the Challenge of Climate and Environmental Change (2010); however, a formal target launch date is not determined until after Mission Concept Review, when a budget wedge is established.

eCloud-independent, high-temporal-resolution, lower-accuracy sea-surface temperature measurements to complement, not replace, global operational high-accuracy sea-surface temperature measurements.

fThe GRACE Follow-on Mission, a climate continuity mission called for in NASA’s June 2010 climate-centric architecture report, will provide many of the observations envisioned by the 2007 decadal survey for GRACE-II.

for societal benefits, mostly through collaborations with other federal agencies. Other activities include projects to encourage experts in the applications community to participate in specific mission definition teams and workshops. The engagement of end users throughout the entire mission life cycle is necessary to ensure that user needs are well understood; ASP appears to be following this model. ASP efforts appear to be aligned with the spirit and intent of the 2007 decadal survey.

Finding: Aligned with the intent of the 2007 decadal survey, NASA’s Applied Sciences Program has begun to engage applied researchers and governmental (federal and state) operational users on some decadal survey mission science definition and applications teams and to conduct research to better understand the value of these applications.

Suborbital Program

NASA’s suborbital program was in decline for almost a decade, but following the release of the decadal survey in 2007, it has made a significant rebound with almost a doubling of financial support for its airborne program. Total flight hours have increased by a factor of 2.5, and flight hours associated with survey missions have doubled from FY2006 to FY2011. Suborbital platforms serve many purposes, including serving as technology testbeds, enabling instrument flight test and algorithm development before launch, providing data complementary to spaceborne observations, providing for calibration of instruments and algorithm validation measurements post-launch in support of data product generation, and directly contributing to local and regional scientific process studies. In addition, NASA Earth observing missions from the Airborne Science Program support “gap filler” missions, such as Operation Ice Bridge, which acquire observations between satellite missions. The committee’s review led to the following finding:

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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Finding: The suborbital program, and in particular the Airborne Science Program, is highly synergistic with upcoming Earth science satellite missions and is being well implemented. NASA has fulfilled the recommendation of the decadal survey to enhance the program.

Technology Development

Within NASA ESD is the NASA Earth Science Technology Office (ESTO), which is responsible for promoting the development of technology required to make the decadal survey missions flight ready. ESTO has funded more than 70 new, competitively selected projects that support each of the decadal survey missions to varying degrees. Furthermore, the recent ESTO solicitation for advanced information system technologies was partnered with, and partially funded by, ESD’s Applied Sciences Program to help ensure the transition into operations of technologically matured information systems through applied science demonstrations and pathfinders. Based on its review, the committee found as follows:

Finding: ESTO has organized its proposal solicitations around the 2007 decadal survey and is investing to advance technological readiness across the survey mission queue.

Research and Analysis

According to NASA, research and analysis (R&A) is “the core of the [Earth Science] research program and funds the analysis and interpretation of data from NASA’s satellites, as well as a full range of underlying scientific activity needed to establish a rigorous base for the satellite data and their use in computational models (for both assimilation and forecasting). The complexity of the Earth system, in which spatial and temporal variability exists on a range of scales, requires an organized approach for addressing complex, interdisciplinary problems, taking care to recognize the objective of integrating science across the programmatic elements towards a comprehensive understanding of the Earth system.”19 Recognizing the critical importance of R&A, the decadal survey made the following recommendation to NASA: “NASA should increase support for its research and analysis (R&A) program to a level commensurate with its ongoing and planned missions. Further, in light of the need for a healthy R&A program that is not mission-specific, as well as the need for mission-specific R&A, NASA’s space-based missions should have adequate R&A lines within each mission budget as well as mission-specific operations and data analysis. These R&A lines should be protected within the missions and not used simply as mission reserves to cover cost growth on the hardware side.”20

Through the current R&A program there have been advances in modeling, analysis, and data assimilation, yet much research is still needed to understand the processes in the Earth system and to fully assimilate Earth observations in Earth system models, thereby creating a consistent and integrated picture of Earth. Indeed, the committee emphasizes that a robust R&A program is a necessary condition to achieve the objectives outlined in the 2007 survey. Despite progress made in R&A investments, the challenges facing NASA’s entire Earth science program mean that protecting the nation’s investments in R&A is as important moving forward as in the past.

Finding: NASA has maintained a healthy investment in R&A activities and has protected the budgets of both mission-specific and non-mission-specific R&A programs against possible reallocation to cover cost growth in mission hardware.

THE NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION

The committee’s assessment of NASA’s Earth science program could not be accomplished without also reviewing the state of NOAA’s missions and Earth science program. NOAA’s current and planned polar and geostationary programs were assumed by the 2007 survey’s committee to be an integral part of the baseline capabilities as it developed its integrated strategy. Two of the survey’s recommended 17 missions (the Operational GPS Radio

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19NASA’s FY 2012 President’s Budget Request: Estimates for Science-Earth Science, p. ES-17. Available at http://www.nasa.gov/pdf/516645main_NASAFY12_Budget_Estimates-Science_Earth-508.pdf.

20National Research Council, Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond, 2007, p. 15.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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Occultation Mission and the Extended Ocean Vector Winds Mission) and part of a third (CLARREO) were directed for implementation by NOAA, but none has been implemented. This committee offers the following finding on NOAA’s implementation of recommendations to the agency from the 2007 decadal survey:

Finding: NOAA’s capability to implement the assumed baseline and the recommended program of the 2007 decadal survey has been greatly diminished by budget shortfalls; cost overruns and delays, especially those associated with the NPOESS program prior to its restructuring in 2010 to become the Joint Polar Satellite System (JPSS); and by sensor descopes and sensor eliminations on both NPOESS and GOES-R.21

These descopes impacted numerous ESD science communities. The committee notes that in an era of budget austerity, NASA’s ESD has very limited capabilities to mitigate the effect of these shortfalls.

LOOKING AHEAD: BEYOND 2020

In preparation for the next decadal survey, the committee offers in Chapter 5 a summary of “lessons learned” that are derived from its evaluation of implementation of the current decadal survey programs. In particular, regardless of how future NASA Earth science programs evolve, the committee concluded that:

1. Maintaining a long-term vision with a fixed and predictable mission queue is essential to building a consensus in a diverse Earth science community that prior to the 2007 decadal survey had not come to a consensus on research priorities spanning conventional disciplinary boundaries. The strength of the decadal survey and its value to agencies and decision makers are, in fact, the consensus priorities established by the survey’s outreach and deliberative processes. Without community “buy-in” to the survey, a return to an ad hoc decision process that is less informed and less efficient in its allocation of resources is the default to be expected.

2. Finding the balance between prioritizing science objectives and creating a mission queue that is viable will be one of the great challenges for the Earth science community over the coming decades. Too much focus on either risks the long-term sustainability and value of NASA’s Earth science program.

3. The community will need to give more thought to balancing costs with science objectives and priorities. More explicit decision rules for different budget contingencies might also prove helpful for program managers.

4. Finally, the community will have to look at different ways to construct a healthy and robust mission portfolio—for example, through partnerships and alternative platforms in addition to individual spacecraft and suborbital missions. Preparatory work to identify new technologies and readiness levels could be done ahead of any formal review and indeed could serve as an input to such a review.

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21Even before the latest round of budget-driven delays and descopes, NOAA polar and geostationary programs had experienced severe budget challenges with particular consequences for research and operations deemed outside required “core” capabilities. See National Research Council, Ensuring the Climate Record from the NPOESS and GOES-R Spacecraft: Elements of a Strategy to Recover Measurement Capabilities Lost in Program Restructuring, The National Academies Press, Washington, D.C., 2008. The Government Accountability Office (GAO) has published a number of reports detailing the origins of the cost overruns and assessing program management. See, for example, GAO, Polar-orbiting Environmental Satellites: Agencies Must Act Quickly to Address Risks That Jeopardize the Continuity of Weather and Climate Data, GAO-10-558 (Washington, D.C., May 10, 2010) and Polar-orbiting Environmental Satellites: With Costs Increasing and Data Continuity at Risk, Improvements Needed in Tri-agency Decision Making, GAO-09-564 (Washington, D.C., June 17, 2009).

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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5.4 The Effects of Solar Variability on Earth’s Climate: A Workshop Report

A Report of the SSB Ad Hoc Committee on the Effects of Solar Variability on Earth’s Climate

Overview

Solar irradiance, the flux of the Sun’s output directed toward Earth, is Earth’s main energy source.1 The Sun itself varies on several timescales—over billions of years its luminosity increases as it evolves on the main sequence toward becoming a red giant; about every 11 years its sunspot activity cycles; and within just minutes flares can erupt and release massive amounts of energy. Most of the fluctuations from tens to thousands of years are associated with changes in the solar magnetic field. The focus of the National Research Council’s September 2011 workshop on solar variability and Earth’s climate, and of this summary report, is mainly magnetically driven variability and its possible connection with Earth’s climate variations in the past 10,000 years. Even small variations in the amount or distribution of energy received at Earth can have a major influence on Earth’s climate when they persist for decades. However, no satellite measurements have indicated that solar output and variability have contributed in a significant way to the increase in global mean temperature in the past 50 years.2,3,4 Locally, however, correlations between solar activity and variations in average weather may stand out beyond the global trend; such has been argued to be the case for the El Niño-Southern Oscillation, even in the present day.

A key area of inquiry deals with establishing a unified record of the solar output and solar-modified particles that extends from the present to the prescientific past. The workshop focused attention on the need for a better understanding of the links between indices of solar activity such as cosmogenic isotopes and solar irradiance. A number of presentations focused on the timescale of the solar cycle and of the satellite record and on the problem of extending this record back in time. Highlights included a report of progress on pyroheliometer calibration, leading to greater confidence in the time history and future stability of total solar irradiance (TSI), and surprising results on changes in spectral irradiance over the last solar cycle, which elicited spirited discussion. New perspectives on connections between features of the quiet and active areas of the photosphere and variations in TSI were also presented, emphasizing the importance of developing better understanding in order to extrapolate back in time using activity indices. Workshop participants’ reviews highlighted difficulties as well as causes for optimism in current understanding of the cosmogenic isotope record and the use of observed variability in Sun-like stars in reconstructing variations in TSI occurring on lower frequencies than the sunspot cycle.

The workshop succeeded in bringing together informed, focused presentations on major drivers of the Sun-climate connection. The importance of the solar cycle as a unique quasi-periodic probe of climate responses on a timescale between the seasonal and Milankovitch cycles was recognized in several presentations. The signal need only be detectable, not dominant, for it to play this role of a useful probe. Some workshop participants also found encouraging progress in the “top-down” perspective, according to which solar variability affects surface climate by first perturbing the stratosphere, which then forces the troposphere and surface. This work is now informing and being informed by research on tropospheric responses to the Antarctic ozone hole and volcanic aerosols. In contrast to the top-down perspective is the “bottom-up” view that the interaction of solar energy with the ocean and surface leads to changes in dynamics and temperature. During the discussion of how dynamical air-sea coupling in the tropical Pacific and solar variability interact from a bottom-up perspective, several participants remarked on the wealth of open research questions in the dynamics of the climatic response to TSI and spectral variability.

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NOTE: “Overview” reprinted from The Effects of Solar Variability on Earth’s Climate: A Workshop Report, The National Academies Press, Washington, D.C., 2012, pp. 1-2.

1 G. Kopp, LASP, University of Colorado, “Overview and Advances in Solar Radiometry for Climate Studies,” presentation at the Workshop on the Effects of Solar Variability on Earth’s Climate, September 8, 2011.

2 S. Solomon, D. Qin, M. Manning, R.B. Alley, T. Berntsen, N.L. Bindoff, Z. Chen, A. Chidthaisong, J.M. Gregory, G.C. Hegerl, M. Heimann, et al., Technical Summary in Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor, and H.L. Miller, eds.), Cambridge University Press, Cambridge, U.K., and New York, N.Y., 2007.

3 National Research Council, America’s Climate Choices, The National Academies Press, Washington, D.C., 2011.

4 National Research Council, Advancing the Science of Climate Change, The National Academies Press, Washington, D.C., 2010.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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The discussion of the paleoclimate record emphasized that the link between solar variability and Earth’s climate is multifaceted and that some components are understood better than others. According to two presenters on paleoclimate, there is a need to study the idiosyncrasies of each key proxy record. Yet they also emphasized that there may be an emerging pattern of paleoclimate change coincident with periods of solar activity and inactivity, but only on long timescales of multiple decades to millennia. Several speakers discussed the effects of particle events and cosmic-ray variability. These are all areas of exciting fundamental research; however, they have not yet led to conclusive evidence for significant related climate effects. The key problem of attribution of climate variability on the timescales of the Little Ice Age and the Maunder Minimum were directly addressed in several presentations. Several workshop participants remarked that the combination of solar, paleoclimatic, and climate modeling research has the potential to dramatically improve the credibility of these attribution studies.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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5.5 NASA’s Strategic Direction and the Need for a National Consensus

A Report of the Ad Hoc Committee on NASA’s Strategic Direction of the Division on Engineering and Physical Sciences

Summary

The National Aeronautics and Space Administration (NASA) is at a transitional point in its history and is facing a set of circumstances that it has not faced in combination before. The agency’s budget, although level-funded in constant-year dollars, is under considerable stress, servicing increasingly expensive missions and a large, aging infrastructure established at the height of the Apollo program. Other than the long-range goal of sending humans to Mars, there is no strong, compelling national vision for the human spaceflight program, which is arguably the centerpiece of NASA’s spectrum of mission areas. The lack of national consensus on NASA’s most publicly visible mission, along with out-year budget uncertainty, has resulted in the lack of strategic focus necessary for national agencies operating in today’s budgetary reality. As a result, NASA’s distribution of resources may be out of sync with what it can achieve relative to what it has been asked to do.

NASA now faces major challenges in nearly all of its primary endeavors—human spaceflight, Earth and space science, and aeronautics. While the agency has undertaken new efforts to procure commercial transportation to resupply the International Space Station (ISS) and has also initiated an effort to commercially procure crew transportation as well, the agency currently lacks a means of launching astronauts on a U.S. spacecraft to Earth orbit, where the agency operates the ISS, which was built at considerable time, effort, and expense.

Although gaps in U.S. human spaceflight capability have existed in the past, several other factors, in combination, make this a unique period for NASA. These include a lack of consensus on the next steps in the development of human spaceflight, increasing financial pressures, an aging infrastructure, and the emergence of additional space-capable nations—some friendly, some potentially unfriendly. In addition, U.S. leadership in space science is being threatened by insufficient budgets to carry out the missions identified in the strategic plans (decadal surveys) of the science communities, rising cost of missions, decreasing science budgets, and the collapse of partnerships with the European Space Agency (ESA)—this at a time when others (most notably ESA and China) are mounting increasingly ambitious space programs. Finally, NASA’s aeronautics budget has been reduced to the point where it is increasingly difficult for the agency to contribute to a field that U.S. industry and the national security establishment have long dominated.

These problems are not primarily of NASA’s doing, but the agency could craft a better response to the uncertainty, for example, by developing a strategic plan that includes clear priorities and a transparent budget allocation process. A better response would improve NASA’s ability to navigate future obstacles and uncertainties. An effective agency response is vital, because at a time when the strategic importance of space is rising and the capabilities of other spacefaring nations are increasing, U.S. leadership is faltering.

For the United States to be a leader in space, as required by the 1958 National Aeronautics and Space Act, it must be a country with bold ideas, science and engineering excellence, and the ability to convince others to work with it in the pursuit of common goals. Leadership depends on the perception of others that whoever is in the lead knows the way forward, is capable of forging the trail, and is determined to succeed despite inevitable setbacks. It does not mean dominance. Those who join are partners, not followers, and partnerships must be equitable, with all voices being heard.

Leadership is more nuanced today than during the Cold War rivalry with the Soviet Union over which country would achieve the next space “first.” Countries that once depended on partnerships with the United States to execute their space programs now have other choices, including going it alone. If the United States is to continue to maintain international leadership in space, it must have a steady, bold, scientifically justifiable space program in which other countries want to participate, and, moreover, it must behave as a reliable partner.

Despite decades of U.S. leadership and technical accomplishment, many of these elements are missing today. Abrupt changes in the goals the United States is pursuing for human spaceflight, coupled with concerns about

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NOTE: “Summary” reprinted from NASA’s Strategic Direction and the Need for a National Consensus, The National Academies Press, Washington, D.C., 2012, pp. 1-7.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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U.S. unreliability in key international partnerships, can erode this country’s leadership position. The thrilling Mars Curiosity mission may be a testament to U.S. leadership in robotic space exploration today, but the sudden and dramatic proposed cut to the Mars exploration budget and withdrawal from the ExoMars program with Europe cast doubt on the future. Human spaceflight capabilities historically have served as a symbol of a country’s leadership in space. This multi-year period when the United States cannot launch humans into space, requiring reliance on Russia for access to the ISS, further undermines any claim to leadership despite the programmatic success of the development of the ISS, which is, in fact, led by the United States.

THE COMMITTEE ON NASA’S STRATEGIC DIRECTION

In late 2011, the Congress directed NASA’s Office of Inspector General to commission a “comprehensive independent assessment of NASA’s strategic direction and agency management.” Subsequently, NASA requested that the National Research Council (NRC) conduct this independent assessment. In the spring of 2012, the NRC Committee on NASA’s Strategic Direction was formed and began work on its task.

The statement of task for this study appears in Appendix A (and is summarized in the Preface). Notably, the committee was not asked to deliberate on what should be NASA’s goals, objectives, and strategy; rather, it was asked for recommendations on how these goals, objectives, and strategy might best be established and communicated.

HUMAN SPACEFLIGHT

The committee has seen little evidence that a current stated goal for NASA’s human spaceflight program—namely, to visit an asteroid by 2025—has been widely accepted as a compelling destination by NASA’s own workforce, by the nation as a whole, or by the international community. On the international front there appears to be continued enthusiasm for a mission to the Moon but not for an asteroid mission, although there is both U.S. and international interest in robotic missions to asteroids. This lack of national and international consensus on the asteroid-first mission scenario undermines NASA’s ability to establish a comprehensive, consistent strategic direction that can guide program planning and budget allocation. While the committee did not undertake a technical assessment of the feasibility of an asteroid mission, it was informed by several briefers and sources that the current planned asteroid mission has significant shortcomings.

The asteroid mission is ostensibly the first step toward an eventual human mission to Mars. A human mission to Mars has been the ultimate goal of the U.S. human spaceflight program. This goal has been studied extensively by NASA and received rhetorical support from numerous U.S. presidents, and has been echoed by some international space officials, but it has never received sufficient funding to advance beyond the rhetoric stage. Such a mission would be very expensive and hazardous, which are the primary reasons that such a goal has not been actively pursued.

There also is no national consensus on what would constitute an appropriate mix of NASA’s capability-driven and mission-driven programs. While a capabilities-driven approach may be the most reasonable approach given budget realities, such an approach still has to be informed by a clear, consistent, and constant path to the objective.

EARTH AND SPACE SCIENCE

NASA has clearly demonstrated the success of the strategic planning process for Earth and space science that is founded on the NRC’s decadal surveys (NRC, 2007; a decadal survey on life and microgravity science [NRC, 2011a] has also been produced for the Human Exploration and Operations Mission Directorate). The decadal survey process has matured into a robust method for developing a set of goals and objectives for various programs that are based on a community consensus on an achievable suite of science programs in pursuit of high-priority, compelling science questions. However, even the best strategic plan is vulnerable to severe changes in the assumptions that underlie its development, whether those changes are applied internally or externally. As an example, the recent set of surveys on astronomy and astrophysics (NRC, 2010) and planetary science (NRC, 2011b) were based on budget projections provided to the relevant decadal committees, and now these projections exceed the current budget as well as current budget projections. Rising costs associated with increasingly complex missions, declining science budgets, international partnerships that fell apart, and mission cost overruns have strained science budgets to their breaking point. As a result, key decadal priorities in astrophysics, planetary science, and Earth science will not be

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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pursued for many years, or not at all. The carefully crafted strategic planning process, with its priority setting and consensus building, which has led in the past to the United States leading the world with science missions such as the Curiosity rover on the surface of Mars and the Hubble Space Telescope, is now in jeopardy because it no longer may lead to a tangible program outcome.

AERONAUTICS

The NASA aeronautics program has made important contributions to national priorities related to the U.S. air transportation system, national defense, and those portions of the space program that include flight through Earth’s atmosphere. However, the budget for NASA’s aeronautics program shrank significantly in the 2000-2010 decade, and the full historically demonstrated potential of the aeronautics program is not being achieved given the current levels of funding. During the course of its deliberations, the committee did not hear a clear rationale for the overall decline in NASA aeronautics spending during the past 15 years.

TECHNOLOGY DEVELOPMENT

Because of the unique nature of most of its missions, NASA has had a number of very specific technological requirements in areas ranging from expendable and reusable launch vehicles to deep-space propulsion systems to radiation protection for astronauts, and much more. The recently established Space Technology Program has carried out a roadmapping and priority-setting strategic planning process for such technologies, assisted by the NRC, but the program is yet to be funded at the levels requested by the President’s budget.

BUDGETS AND BALANCE

The funding for NASA’s total budget has been remarkably level in constant-year dollars for more than a decade. However, there has been some instability at the programmatic level, and the out-year projections in the President’s budget are unreliable, which makes it difficult for program managers to plan activities that require multi-year planning. Put another way, although the budget may have been level over time, NASA experienced substantial program instability over the same period. Numerous times the agency initiated new programs with the expectation that budgets would increase to support them (a basic requirement for optimizing any development program’s budget), only to have no increases emerge. Taken in aggregate, this situation has been wasteful and inefficient. Even leaving aside the funding requirements for large procurements, it is tempting to assume that if NASA officials knew to expect a flat budget they could plan better, but in several recent cases they were told (even required) to expect funding that never ultimately emerged.

Last, flat budgets historically have not allowed NASA to pursue major initiatives in human spaceflight; see Figures 1.4 and 1.5, where the budget bumps for Apollo and the space shuttle/ISS programs are apparent.

NASA cannot execute a robust, balanced aeronautics and space program given the current budget constraints. For example, major components needed for future human exploration (including important life sciences experiments on the ISS) are not currently in the budget; high-priority science missions (including robotic planetary exploration missions that are precursors to human exploration) identified in the most recent NRC decadal survey are unfunded; and aeronautics now accounts for only about 3 percent of the total NASA budget. In addition, individual NASA centers are finding it necessary to selectively reduce their infrastructure or find alternative ways to support it (e.g., through external collaborations). External partnerships can be highly beneficial, especially in the current fiscally constrained environment, and may enable NASA to execute a robust and balanced aeronautics and space program without additional funds. However, coordination and integration of such activities for the overall benefit of NASA are both essential for success.

Because of legislative and regulatory limitations, NASA officials lack flexibility in how to manage the agency in terms of personnel and facilities, a factor contributing to the mismatch between budget and mission. With the current available-budget-driven approach, intermediate milestones and completion dates for some programs have been delayed. This in turn results in a lack of tangible near-term performance outcomes from cost-inefficient programs that by nature must accommodate increases in fixed and indirect costs. Delays also have a deleterious effect on mission performance; stretching programs out limits opportunities for NASA to develop and incorporate new technology into program architectures defined years before.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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There is a significant mismatch between the programs to which NASA is committed and the budgets that have been provided or anticipated. The approach to and pace of a number of NASA’s programs, projects, and activities will not be sustainable if the NASA budget remains flat, as currently projected. This mismatch needs to be addressed if NASA is to efficiently and effectively develop enduring strategic directions of any sort.

To reduce the mismatch between the overall size of its budget and NASA’s current portfolio of missions, facilities, and personnel, the White House, Congress, and NASA, as appropriate, could use any or all of the following four (non-mutually exclusive) options. The committee does not recommend any one option or combination of options but presents these to illustrate the scope of decisions and tradeoffs that could be made. Regardless of the approach or approaches selected, eliminating the mismatch will be difficult.

Option 1. Institute an aggressive restructuring program to reduce infrastructure and personnel costs to improve efficiency.

Option 2. Engage in and commit for the long term to more cost-sharing partnerships with other U.S. government agencies, private sector industries, and international partners. Option 3. Increase the size of the NASA budget.

Option 4. Reduce considerably the size and scope of elements of NASA’s current program portfolio to better fit the current and anticipated budget profile. This would require reducing or eliminating one or more of NASA’s current portfolio elements (human exploration, Earth and space science, aeronautics, and space technology) in favor of the remaining elements.

Each of the above sample options, with the possible exception of Option 2, would require legislative action. Every option except for Option 3 would require substantial changes within NASA in order to substantially address the mismatch between NASA’s programs and budget. Before implementation of any such options, the advantages and disadvantages, including possible unintended consequences, would deserve careful consideration. For example, if not handled carefully, Option 1 could constrain future mission options or increase future mission costs if unique facilities needed by future missions were decommissioned. Option 1 might also diminish NASA’s workforce capabilities if changes in policies prompt large numbers of key personnel to retire or seek other employment. To be effective, Option 2 might require congressional authorization for NASA to make long-term financial commitments to a particular program to assure prospective partners that neither NASA nor Congress would unilaterally cancel a joint program. Option 3, of course, is ideal from NASA’s perspective, but its selection also seems unlikely given the current outlook for the federal budget. Option 4 is perhaps the least attractive, given the value of each major element in NASA’s portfolio.

The committee has identified significant impacts of current budget constraints on the individual programs at NASA and has described the kinds of options that would have to be considered to address the mismatch between the scope of NASA’s programs and budget. It has not attempted to judge the appropriateness of the budget distribution among these programs internal to the agency. Moreover, it would have been difficult to do so because of the absence of stated priorities that would provide a framework for making that assessment. In addition, the committee notes that it was not asked to set those kinds of agency-wide priorities.

The foregoing observations (and the detailed discussions in the body of this report) lead the committee to reach the following conclusions and offer the related recommendations:

Conclusion: There is no national consensus on strategic goals and objectives for NASA. Absent such a consensus, NASA cannot reasonably be expected to develop enduring strategic priorities for the purpose of resource allocation and planning.

Recommendation: The administration should take the lead in forging a new consensus on NASA’s future that is stated in terms of a set of clearly defined strategic goals and objectives. This process should apply both within the administration and between the administration and Congress and should be reached only after meaningful technical consultations with potential international partners. The strategic goals and objectives should be ambitious, yet technically rational, and should focus on the long term.

Recommendation: Following the establishment of a new consensus on the agency’s future, NASA should establish a new strategic plan that provides a framework for decisions on how the agency will pursue its strategic

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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goals and objectives, allows for flexible and realistic implementation, clearly establishes agency-wide priorities to guide the allocation of resources within the agency budget, and presents a comprehensive picture that integrates the various fields of aeronautics and space activities.

Recommendation: NASA’s new strategic plan, future budget proposals prepared by the administration, and future NASA authorization and appropriation acts passed by Congress should include actions that will eliminate the current mismatch between NASA’s budget and its portfolio of programs, facilities, and staff, while establishing and maintaining a sustainable distribution of resources among human spaceflight, Earth and space science, and aeronautics, through some combination of the kinds of options identified above by the committee. The strategic plan should also address the rationale for resource allocation among the strategic goals in the plan.

Recommendation: NASA should work with other U.S. government agencies with responsibilities in aeronautics and space to more effectively and efficiently coordinate U.S. aeronautics and space activities.

Conclusion: The NASA field centers do not appear to be managed as an integrated resource to support the agency and its strategic goals and objectives.

Conclusion: Legislative and regulatory limitations on NASA’s freedom to manage its workforce and infrastructure constrain the flexibility that a large organization needs to grow or shrink specific scientific, engineering, and technical areas in response to evolving goals and budget realities.

Although the committee carefully analyzed NASA’s current strategic plan, as well as previous ones, it ultimately concluded that the strategic planning process is affected more by what happens outside the agency than by any process inside NASA. The lack of a national consensus on what NASA should do constrains NASA’s ability to plan and to operate.

The committee recognizes that it lacked the capability and time to conduct a detailed supporting analysis and to make specific recommendations for changes in the current NASA infrastructure. However, the committee offers a path forward for NASA to follow, in close collaboration with the President and Congress.

Recommendation: With respect to NASA centers:

• The administration and Congress should adopt regulatory and legislative reforms that would enable NASA to improve the flexibility of the management of its centers.

• NASA should transform its network of field centers into an integrated system that supports its strategic plan and communications strategy and advances its strategic goals and objectives.

Today it is common to declare that all future human spaceflight or large-scale Earth and space science projects will be international. Many U.S. leaders also assume that the United States will take the lead in such projects. However, American leadership in international space cooperation requires meeting several conditions. First, the United States has to have a program that other countries want to participate in, and this is not always the case. Second, the United States has to be willing to give substantial responsibility to its partners. In the past, the approach of the United States to international partnership has too often been perceived as being based on a program conceived, planned, and directed by NASA. Third, other nations must be able to see something to gain—in other words, a reason to partner with the United States. Finally, the United States has to demonstrate its reliability and attractiveness as an international partner.

The capabilities and aspirations of other nations in space have changed dramatically since the early days of the space race between the Soviet Union and the United States. One of the most important successes of the ISS was its international character and the role of the United States as the managing partner in a global enterprise. If the United States does seek to pursue a human mission to Mars, such a mission will undoubtedly require the efforts and financial support of many nations.

Recommendation: The United States should explore opportunities to lead a more international approach to future large space efforts both in the human space program and in the science program.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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In preparing this report, the committee held three meetings at which current and former NASA leaders, representatives of other government agencies, academics, and historians shared their views of the origin and evolution of NASA and its programs and the issues facing the agency today. The committee received input from nearly 800 members of the public through a Web-based questionnaire, and small groups of committee members visited each of the nine NASA field centers and the Jet Propulsion Laboratory. Furthermore, the committee reviewed a large number of studies conducted by the NRC and other groups over the decades that made recommendations about the conduct of NASA’s programs and the agency’s future, as well as NASA’s strategic plans back to 1986.

The committee was impressed with the quality of personnel and the level of commitment of the agency’s civil service and contractor staffs and the superb quality of the work done by the agency in general, most notably recently demonstrated by the Curiosity landing on Mars. But the committee also heard about frustration with the agency’s current path and the limitations imposed on it by the inability of the national leadership to agree on a long-term direction for the agency. Only with a national consensus on the agency’s future strategic direction, along the lines described in this report, can NASA continue to deliver the wonder, the knowledge, the national security and economic benefits, and the technology typified by its earlier history.

REFERENCES

NRC (National Research Council). 2007. Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond.

Washington, D.C.: The National Academies Press.

NRC. 2010. New Worlds, New Horizons in Astronomy and Astrophysics. Washington, D.C.: The National Academies Press.

NRC. 2011a. Recapturing a Future for Space Exploration: Life and Physical Sciences Research for a New Era. Washington, D.C.: The National Academies Press.

NRC. 2011b. Vision and Voyages for Planetary Science in the Decade 2013-2022. Washington, D.C.: The National Academies Press.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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5.6 Solar and Space Physics: A Science for a Technological Society

A Report of the SSB and ASEB Ad Hoc Committee on a Decadal Strategy for Solar and Space Physics (Heliophysics)

Summary

From the interior of the Sun, to the upper atmosphere and near-space environment of Earth, and outward to a region far beyond Pluto where the Sun’s influence wanes, advances during the past decade in space physics and solar physics—the disciplines NASA refers to as heliophysics—have yielded spectacular insights into the phenomena that affect our home in space. This report, from the National Research Council’s (NRC’s) Committee for a Decadal Strategy in Solar and Space Physics, is the second NRC decadal survey in heliophysics. Building on the research accomplishments realized over the past decade, the report presents a program of basic and applied research for the period 2013-2022 that will improve scientific understanding of the mechanisms that drive the Sun’s activity and the fundamental physical processes underlying near-Earth plasma dynamics, determine the physical interactions of Earth’s atmospheric layers in the context of the connected Sun-Earth system, and enhance greatly the capability to provide realistic and specific forecasts of Earth’s space environment that will better serve the needs of society. Although the recommended program is directed primarily to NASA (Science Mission Directorate-Heliophysics Division) and the National Science Foundation (NSF) (Directorate for Geosciences-Atmospheric and Geospace Sciences) for action, the report also recommends actions by other federal agencies, especially the National Oceanic and Atmospheric Administration (NOAA) those parts of NOAA charged with the day-to-day (operational) forecast of space weather. In addition to the recommendations included in this summary, related recommendations are presented in the main text of the report.

RECENT PROGRESS: SIGNIFICANT ADVANCES FROM THE PAST DECADE

As summarized in Chapter 3 and discussed in greater detail in Chapters 8-10, the disciplines of solar and space physics have made remarkable advances over the last decade—many of which have come from the implementation of the program recommended in the 2003 solar and space physics decadal survey.1 Listed below are some of the highlights from an exciting decade of discovery:

• New insights, gained from novel observations and advances in theory, modeling, and computation, into the variability of the mechanisms that generate the Sun’s magnetic field, and into the structure of that field;

• A new understanding of the unexpectedly deep minimum in solar activity;

• Significant progress in understanding the origin and evolution of the solar wind;

• Striking advances in understanding both explosive solar flares and the coronal mass ejections that drive space weather;

• Groundbreaking discoveries about the surprising nature of the boundary between the heliosphere—that is, the immense magnetic bubble containing our solar system—and the surrounding interstellar medium;

• New imaging methods that permit researchers to directly observe space weather-driven changes in the particles and magnetic fields surrounding Earth;

• Significantly deeper knowledge of the numerous processes involved in the acceleration and loss of particles in Earth’s radiation belts;

• Major advances in understanding the structure, dynamics, and linkages in other planetary magnetospheres, especially those of Mercury, Jupiter, and Saturn;

• New understanding of how oxygen from Earth’s own atmosphere contributes to space storms;

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NOTE: “Summary” reprinted from the prepublication version of Solar and Space Physics: A Science for a Technological Society, The National Academies Press, Washington, D.C., released on August 15, 2012, pp. 1-14.

1 National Research Council, The Sun to the Earth—and Beyond: A Decadal Research Strategy in Solar and Space Physics, The National Academies Press, Washington, D.C., 2003; and National Research Council, The Sun to the Earth—and Beyond: Panel Reports, The National Academies Press, Washington, D.C., 2003.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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• The surprising discovery that conditions in near-Earth space are linked strongly to the terrestrial weather and climate below;

• The emergence of a long-term decline in the density of Earth’s upper atmosphere, indicative of planetary change; and

• New understanding of the temporal and spatial scales involved in magnetospheric-atmospheric coupling in Earth’s aurora.

It is noteworthy that some of the most surprising discoveries of the past decade have come from comparatively small missions that were tightly cost-constrained, competitively selected, and principal investigator (PI)-led—recommendations in the present decadal survey reflect this insight.

Enabled by advances in scientific understanding as well as fruitful interagency partnerships, the capabilities of models that predict space weather impacts on Earth have also made rapid gains over the past decade. Reflecting these advances and a society increasingly vulnerable to the adverse effects of space weather, the number of users of space weather services has also grown rapidly. Indeed, a growing community has come to depend on constant and immediate access to space weather information (Chapter 7).

SCIENCE GOALS FOR THE NEXT DECADE

The significant achievements of the past decade set the stage for transformative advances in solar and space physics for the coming decade. Reports from the survey’s three interdisciplinary study panels (Chapters 8-10) enumerate the key scientific opportunities and challenges for the coming decade; collectively, they inform the survey’s four overarching science goals, each of which is considered of equal priority:

Goal 1. Determine the origins of the Sun’s activity and predict the variations in the space environment.

Goal 2. Determine the dynamics and coupling of Earth’s magnetosphere, ionosphere, and atmosphere and their response to solar and terrestrial inputs.

Goal 3. Determine the interaction of the Sun with the solar system and the interstellar medium.

Goal 4. Discover and characterize fundamental processes that occur both within the heliosphere and throughout the universe.

GUIDING PRINCIPLES AND PROGRAMMATIC CHALLENGES

To achieve these science goals, the survey committee recommends adherence to the following principles (Chapter 1):

• To make transformational scientific progress, the Sun, Earth, and heliosphere must be studied as a coupled system;

• To understand the coupled system requires that each subdiscipline be able to make measurable advances in achieving its key science goals; and

• Success across the entire field requires that the various elements of solar and space physics research programs—the enabling foundation comprising theory, modeling, data analysis, innovation, and education, as well as ground-based facilities and small-, medium-, and large-class space missions—be deployed with careful attention both to the mix of assets and to the schedule (cadence) that optimizes their utility over time.

The committee’s recommendations reflect these principles while also taking into account issues of cost, schedule, and complexity. The committee also recognizes a number of challenges that could impede achievement of the recommended program: the assumed budget may not be realized or missions could experience cost growth; the necessity to coordinate activities across multiple agencies; and the limited availability of appropriately sized and affordable space launch vehicles, particularly medium-class launch vehicles.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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RECOMMENDATIONS—RESEARCH AND APPLICATIONS

The survey committee’s recommendations are listed in Tables S.1 and S.2; a more complete discussion of the “research” recommendations—the primary focus of this survey—is found in Chapter 4 along with a discussion of the “applications” recommendations, while Chapter 7 presents the committee’s vision, premised on the availability of additional funds, of an expanded program in space weather and space climatology. The committee’s recommendations are prioritized and integrated across agencies to form an effective set of programs consistent with fiscal and other constraints. An explicit cost appraisal for each NASA research recommendation is incorporated into the budget for the overall program (Chapter 6); however, for NSF programs, only a general discussion of expected costs is provided (Chapter 5).

Research Recommendations

Baseline Priority for NASA and NSF: Complete the Current Program

The survey committee’s recommended program for NSF and NASA assumes continued support in the near term for the key existing program elements that constitute the Heliophysics Systems Observatory (HSO) and successful implementation of programs in advanced stages of development.

NASA’s existing heliophysics flight missions and NSF’s ground-based facilities form a network of observing platforms that operate simultaneously to investigate the solar system. This array can be thought of as a single observatory—the Heliophysics System Observatory (HSO) (see Figure 1.2). The evolving HSO lies at the heart of

TABLE S.1 Summary of Top-Level Decadal Survey Research Recommendations

Priority Recommendation NASA NSF Other
0.0 Complete the current program X X  
1.0 Implement the DRIVE initiative
Small satellites; mid-scale NSF projects; vigorous ATST and synoptic program support; science centers and grant programs; instrument development
X X X
2.0 Accelerate and expand the Heliophysics Explorer program Enable MIDEX line and Missions of Opportunity X    
3.0 Restructure STP as a moderate-scale, PI-led line X    
      3.1 Implement an IMAP-Like Mission X    
      3.2 Implement a DYNAMIC-Like Mission X    
      3.3 Implement a MEDICI-Like Mission X    
4.0 Implement a large LWS GDC-like mission X    

TABLE S.2 Summary of Top Level Decadal Survey Applications Recommendations

Priority Recommendation NASA NSF Other
1.0 Recharter the National Space Weather Program X X X
2.0 Work in a multi-agency partnership for solar and solar wind observations X X X
      2.1 Continuous solar wind observations from L1 (DSCOVR, IMAP) X   X
      2.2 Continue space-based coronagraph and solar magnetic field measurements X   X
      2.3 Evaluate new observations, platforms, and locations X X X
      2.4 Establish a SWx research program at NOAA to effectively transition from research to operations     X
      2.5 Develop and maintain distinct programs for space physics research and space weather specification and forecasting X X X
Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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the field of solar and space physics and provides a rich source of observations that can be used to address increasingly interdisciplinary and long-term scientific questions. Missions now under development will expand the HSO and drive scientific discovery. For NASA, these include the following:

• The Radiation Belt Storm Probes (RBSP, Living With a Star (LWS) program, 2012 launch) and related Balloon Array for RBSP Relativistic Electron Losses (BARREL; first launch 2013) will determine the mechanisms that control the energy, intensity, spatial distribution, and time variability of Earth’s radiation belts.

• The Interface Region Imaging Spectrograph (IRIS; Explorer program, 2013 launch) will deliver pioneering observations of chromospheric dynamics just above the solar surface to help determine their role in the origin of the heat and mass fluxes into the corona and wind.

• The Magnetospheric Multiscale mission (MMS; Solar-Terrestrial Probe (STP) program, 2014 launch) will address the physics of magnetic reconnection at the previously inaccessible tiny scale where reconnection is triggered.

Compelling missions that are not yet in advanced stages of development but are part of a baseline program whose continuation NASA asked the survey committee to assume include the following:2

• Solar Orbiter (European Space Agency-NASA partnership, 2017 launch) will investigate links between the solar surface, corona, and inner heliosphere from as close as 62 solar radii.

• Solar Probe Plus (SPP, LWS program, 2018 launch) will make mankind’s first visit to the solar corona to discover how the corona is heated, how the solar wind is accelerated, and how the Sun accelerates particles to high energy.

With these new investments, the powerful fleet of space missions that explore our local cosmos can be significantly strengthened. However, implementation of the baseline program will consume nearly all of the resources anticipated to be available for new starts within NASA’s Heliophysics Division through the midpoint of the overall survey period, 2013-2022.

For NSF, the previous decade witnessed the initial deployment in Alaska of the Advanced Modular Incoherent Scatter Radar (AMISR), a mobile facility used to study the upper atmosphere and to observe space weather events, and the initial development of the Advanced Technology Solar Telescope (ATST), a 4-meter-aperture optical solar telescope—by far the largest in the world—that will provide the most highly resolved measurements ever obtained of the Sun’s plasma and magnetic field. These new NSF facilities join a broad range of existing ground-based assets that provide an essential global synoptic perspective and complement space-based measurements of the solar and space physics system. With adequate science and operations support, they will enable frontier research even as they add to the long-term record necessary for analyzing space climate over solar cycles.

R1.0 Implement the DRIVE Initiative

The survey committee recommends implementation of a new, integrated, multiagency initiative (DRIVE—Diversify, Realize, Integrate, Venture, Educate) that will develop more fully and employ more effectively the many experimental and theoretical assets at NASA, NSF, and other agencies.

The DRIVE initiative encompasses specific, cost-effective, augmentations to NASA and NSF heliophysics programs. Its implementation will bring existing “enabling” programs to full fruition and will provide new opportunities to realize scientific discoveries from existing data, build more comprehensive models, make theoretical breakthroughs, and innovate. With this in mind, the committee has as its first priority for both NASA and NSF (after completion of the current program) the implementation of an integrated, multiagency initiative comprising the following components:

Diversify observing platforms with microsatellites and mid-scale ground-based assets

Realize scientific potential by sufficiently funding operations and data analysis

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2 In accordance with its statement of task, the survey committee did not reprioritize any NASA mission that was in formulation or advanced development. In addition, the study charge specified that Solar Orbiter and Solar Probe Plus would not be included in any prioritization of future mission opportunities.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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Integrate observing platforms and strengthen ties between agency disciplines

Venture forward with science centers and instrument and technology development

Educate, empower, and inspire the next generation of space researchers

The five DRIVE components are defined in Chapter 4, with specific and actionable recommendations for each element. Implementation of the NASA portion of the DRIVE initiative would require an augmentation to existing program lines equivalent to approximately $33 million in current (2013) dollars (see Chapter 6).3 The cost and implementation of the NSF portion of DRIVE are described in Chapter 5. Although the recommendations for NSF within the DRIVE initiative are not prioritized, the survey committee calls attention to two in particular:

The National Science Foundation should:

• Provide funding sufficient for essential synoptic observations and for efficient and scientifically productive operation of the Advanced Technology Solar Telescope (ATST), which provides a revolutionary new window on the solar magnetic atmosphere.

• Create a new competitively selected mid-scale project funding line in order to enable mid-scale projects and instrumentation for large projects. There are a number of compelling candidates for a mid-scale facilities line, including the Frequency Agile Solar Radiotelescope (FASR), the Coronal Solar Magnetism Observatory (COSMO), and several other projects exemplifying the kind of creative approaches necessary to fill gaps in observational capabilities and to move the survey’s integrated science plan forward.

R2.0 Accelerate and Expand the Heliophysics Explorer Program

The survey committee recommends that NASA accelerate and expand the Heliophysics Explorer program. Augmenting the current program by $70 million per year, in fiscal year 2012 dollars, will restore the option of Mid-size Explorer (MIDEX) missions and allow them to be offered alternately with Small Explorer (SMEX) missions every 2 to 3 years. As part of the augmented Explorer program, NASA should support regular selections of Missions of Opportunity.

The Explorer program’s strength lies in its ability to respond rapidly to new concepts and developments in science, as well as in the program’s synergistic relationship with larger-class strategic missions.4 The Explorer mission line has proven to be an outstanding success, delivering—cost-effectively—science results of great consequence. The committee recommends increased support of the Explorer program to enable significant scientific advances in solar and space physics. As discussed in Chapter 4, the committee believes that the proper cadence for Heliophysics Explorers is one mission every 2 to 3 years. The committee’s recommended augmentation of the Explorer program would facilitate this cadence and would also allow selection of both small- and medium-class Explorers. Historically, MIDEX missions offered an opportunity to resolve many of the highest-level science questions, but they have not been feasible with the current Explorer budget.

Regular selections of Missions of Opportunity will also allow the research community to respond quickly and to leverage limited resources with interagency, international, and commercial flight partnerships. For relatively modest investments, such opportunities can potentially address high-priority science aims identified in this survey.

R3.0 Restructure Solar-Terrestrial Probes as a Moderate-Scale, PI-Led Line

The survey committee recommends that NASA’s Solar-Terrestrial Probes program be restructured as a moderate-scale, competed, principal-investigator-led (PI-led) mission line that is cost-capped at $520 million per mission in fiscal year 2012 dollars including full life-cycle costs.

_______________

3 The survey committee assumes inflation at 2.7 percent in program costs, the same as the percentage used by NASA for new starts.

4 National Research Council, Solar and Space Physics and Its Role in Space Exploration, The National Academies Press, Washington, D.C., 2003, p. 36.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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NASA’s Planetary Science Division has demonstrated success in implementing mid-size missions as competed, cost-capped, PI-led investigations via the Discovery and New Frontiers programs. These are managed in a manner similar to Explorers and have a superior cost-performance history relative to that of larger flagship missions. The committee concluded that STP missions should be managed likewise, with the PI empowered to make scientific and mission design trade-offs necessary to remain within the cost cap (Chapter 4). With larger-class LWS missions and smaller-class Explorers and Missions of Opportunity, this new approach will lead to a more balanced and effective overall NASA HPD mission portfolio that is implemented at a higher cadence and provides the vitality needed to accomplish the breadth of the survey’s science goals. The eventual recommended minimum cadence of STP missions is one every 4 years.

Although the new STP program would involve moderate missions being chosen competitively, the survey committee recommends that their science targets be ordered as follows so as to systematically advance understanding of the full coupled solar-terrestrial system:

R3.1 The first new STP science target is to understand the outer heliosphere and its interaction with the interstellar medium, as illustrated by the reference mission5 Interstellar Mapping and Acceleration Probe (IMAP; Chapter 4). Implementing IMAP as the first of the STP investigations will ensure coordination with NASA Voyager missions. The mission implementation also requires measurements of the critical solar wind inputs to the terrestrial system.

R3.2 The second STP science target is to provide a comprehensive understanding of the variability in space weather driven by lower-atmosphere weather on Earth. This target is illustrated by the reference mission Dynamical Neutral Atmosphere-Ionosphere Coupling (DYNAMIC; Chapter 4).

R3.3 The third STP science target is to determine how the magnetosphere-ionosphere-thermosphere system is coupled and how it responds to solar and magnetospheric forcing. This target is illustrated by the reference mission Magnetosphere Energetics, Dynamics, and Ionospheric Coupling Investigation (MEDICI; Chapter 4).

The rationale for all the selections and for their ordering is detailed in Chapter 4.

Living With a Star

Certain landmark scientific problems are of such scope and complexity that they can be addressed only with major missions. In the survey committee’s plan, major heliophysics missions would be implemented within NASA’s LWS program; the survey committee recommends that they continue to be managed and executed by NASA centers. Other integral thematic elements besides the flight program are essential to the LWS science and technology program: the unique LWS research, technology, strategic capabilities, and education programs remain of great value.

R4.0 Implement a large Living With a Star mission to study the ionosphere-thermosphere-mesosphere system in an integrated fashion.

The survey committee recommends that, following the launch of RBSP and SPP, the next LWS science target focus on how Earth’s atmosphere absorbs solar wind energy. The recommended reference mission is Geospace Dynamics Constellation (GDC).

As detailed in Chapter 4, the GDC reference mission would provide crucial scientific measurements of the extreme variability of conditions in near-Earth space. Within anticipated budgets, the completion of the baseline LWS program, which includes the launch of two major missions—RBSP in 2012 and SPP in 2018—does not allow

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5 In this report, the committee uses the terms “reference mission” and “science target” interchangeably, given that the mission concepts were developed specifically to assess the cost of addressing particular high-priority science investigations. The concepts presented in this report underwent an independent cost and technical analysis by the Aerospace Corporation, and they have been given names for convenience; however, the actual recommendation from the committee is to address the science priorities enumerated in the reference mission concept.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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for the launch of a subsequent major mission in heliophysics until 2024, 6 years after SPP. This establishes what the survey committee regards as the absolute minimum needed cadence for major missions.

Applications Recommendations: Enabling Effective Space Weather and Climatology Capabilities

Multiple agencies of the federal government have vital interests related to space weather, and efforts to coordinate these agencies’ activities are seen in the National Space Weather Program (NSWP).6 Nonetheless, the survey committee concluded that additional approaches are needed to develop the capabilities outlined in the 2010 National Space Policy document and envisioned in the 2010 NSWP plan. Chapter 7 presents the committee’s vision for a renewed national commitment to a comprehensive program in space weather and climatology (SWaC). Enabling an effective SWaC capability will require action across multiple agencies and an integrated program that builds on the strengths of individual agencies.

A1.0 Recharter the National Space Weather Program

The survey committee recommends that, to coordinate the development of this plan, the National Space Weather Program should be rechartered under the auspices of the National Science and Technology Council and should include the active participation of the Office of Science and Technology Policy and the Office of Management and Budget. The plan should build on current agency efforts, leverage the new capabilities and knowledge that will arise from implementation of the programs recommended in this report, and develop additional capabilities, on the ground and in space, that are specifically tailored to space weather monitoring and prediction.

A2.0 Work in a multi-agency partnership to achieve continuity of solar and solar wind observations.

The survey committee recommends that NASA, NOAA, and the Department of Defense work in partnership to plan for continuity of solar and solar wind observations beyond the lifetimes of ACE, SOHO, STEREO, and SDO. In particular:

A2.1 Solar wind measurements from L1 should be continued, because they are essential for space weather operations and research. The DSCOVR and IMAP STP missions are recommended for the near term, but plans should be made to ensure that measurements from L1 continue uninterrupted into the future.

A2.2 Space-based coronagraph and solar magnetic field measurements should likewise be continued.

Further, the survey committee concluded that a national, multifaceted program of both observations and modeling is needed to transition research into operations more effectively by fully leveraging expertise from different agencies, universities, and industry and by avoiding duplication of effort. This effort should include determining the operationally optimal set of observations and modeling tools and how best to effect that transition. With these objectives in mind:

A2.3 The space weather community should evaluate new observations, platforms, and locations that have the potential to provide improved space weather services. In addition, the utility of employing newly emerging information dissemination system for space weather alerts should be assessed.

A2.4 NOAA should establish a space weather research program to effectively transition research to operations.

A2.5 Distinct funding lines for basic space physics research and for space weather specification and forecasting need to be developed and maintained.

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6 Committee for Space Weather, Office of the Federal Coordinator for Meteorological Services and Supporting Research, National Space Weather Program Strategic Plan, FCM-P30-2010, August 17, 2010, available at http://www.ofcm.gov/nswp-sp/fcm-p30.htm.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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Implementation of a program to advance space weather and climatology will require funding well above what the survey committee assumes will be available to support its research-related recommendations to NASA (see Table S.1). The committee emphasizes that implementation of an initiative in space weather and climatology should proceed only if it does not impinge on the development and timely execution of the recommended research program.

RECOMMENDED PROGRAM, DECISION RULES, AND AUGMENTATION PRIORITIES FOR NASA

Recommended Program

The committee’s recommended program for NASA Heliophysics Division is shown in Figure S.1. As detailed in Chapter 6, the plan restores the medium-class Explorers and, together with small-class Explorer missions and Missions of Opportunity, achieves the recommended minimum mission cadence. The plan also begins the DRIVE initiative as early in the decade as budgets allow, with full implementation achieved by mid-decade. However, funding constraints affect the restoration and recommended rebalance of heliophysics program elements such that full realization of the survey committee’s strategy is not possible until after 2017 (Figure S.1).

Decision Rules to Ensure Balanced Progress is Maintained

The recommended program for NASA cost-effectively addresses key science objectives. However, the survey committee recognizes that the already tightly constrained program could face further budgetary challenges. For example, with launch planned in 2018, the Solar Probe Plus project has not yet entered the implementation phase when expenditures are highest.7 Significant cost growth in this very important, but technically challenging, mission beyond the current cap has the potential to disrupt the overall NASA heliophysics program.

To guide the allocation of reduced resources, the committee recommends the following decision rules intended to provide flexibility and efficiency if funding is less than anticipated, or should some other disruptive event occur. These rules, discussed in greater depth in Chapter 6, maintain progress toward the top-priority, system-wide science challenges identified in this survey. The decision rules should be applied in the order shown to minimize disruption of higher-priority program elements:

Decision Rule 1. Missions in the STP and LWS lines should be reduced in scope or delayed to accomplish higher priorities (Chapter 6 gives explicit triggers for review of Solar Probe Plus).

Decision Rule 2. If further reductions are needed, the recommended increase in the cadence of Explorer missions should be scaled back, with the current cadence maintained as the minimum.

Decision Rule 3. If still further reductions are needed, the DRIVE augmentation profile should be delayed, with the current level of support for elements in the NASA research line maintained as the minimum.

Augmentations to Increase Program Value

The committee notes that the resources assumed in crafting this decadal survey’s recommended programs are barely sufficient to make adequate progress in solar and space physics; with reduced resources, progress will be inadequate. It is also evident that with increased resources, the pace at which the nation pursues its program could be accelerated with a concomitant increase in the achievement of scientific discovery and societal value. The committee recommends the following augmentation priorities to aid in implementing a program under a more favorable budgetary environment:

Augmentation Priority 1. Given additional budget authority early in the decade, the implementation of the DRIVE initiative should be accelerated.

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7 On January 31, 2012, Solar Probe Plus passed its agency-level confirmation review and entered what NASA refers to as mission definition or Phase B of its project life cycle.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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FIGURE S.1 Heliophysics budget and program plan by year and category from 2013 to 2024. The solid black line indicates the funding level from 2013 to 2022 provided to the committee by NASA as the baseline for budget planning, and the dashed black line extrapolates the budget forward to 2024. After 2017 the amount increases with a nominal 2 percent inflationary factor. Through 2016 the program content is tightly constrained by budgetary limits and fully committed for executing existing program elements. The red dashed “Enabling Budget” line includes a modest increase from the baseline budget starting in 2017, allowing implementation of the survey-recommended program at a more efficient cadence that better meets scientific and societal needs and improves optimization of the mix of small and large missions. From 2017 to 2024 the Enabling Budget grows at 1.5 percent above inflation. (Note that the 2024 Enabling Budget is equivalent to growth at a rate just 0.50 percent above inflation from 2009.) GDC, the next large mission of the LWS program after SPP, rises above the baseline curve in order to achieve a more efficient spending profile, as well as to achieve deployment in time for the next solar maximum in 2024. NOTE: LWS refers to missions in the Living With a Star line and STP refers to missions in the Solar-Terrestrial Probes line.

Augmentation Priority 2. With sufficient funds throughout the decade, the Explorer line should be further augmented to increase the cadence and funding available for missions, including Missions of Opportunity.

Augmentation Priority 3. Given further budget augmentation, the schedule of STP missions should advance to allow the third STP science target (MEDICI) to begin in this decade.

Augmentation Priority 4. The next LWS mission (GDC) should be implemented with an accelerated, more cost-effective funding profile.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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EXPECTED BENEFITS OF THE RECOMMENDED PROGRAM

Implementation of the survey committee’s recommended programs will ensure that the United States maintains its leadership in solar and space physics and, the committee believes, lead to significant—even transformative—advances in scientific understanding and observational capabilities (Table S.3). In turn, these advances will support critical national needs for information that can be used to anticipate, recognize, and mitigate space weather effects that threaten to human life and the technological systems society depends on.

TABLE S.3 Fulfilling the Science Goals of the Decadal Survey

Advances in Scientific Understanding and Observational Capabilities Goals
Advances due to Implementation of the existing program Twin Radiation Belt Storm Probes will observe Earth’s radiation belts from separate locations, finally resolving the importance of temporal and spatial variability in the generation and loss of trapped radiation that threatens spacecraft. 2, 4
  The Magnetospheric Multiscale mission will provide the first high-resolution, three-dimensional measurements of magnetic reconnection in the magnetosphere, by sampling small regions where magnetic field line topologies reform. 2, 4
  Solar Probe Plus will be the first spacecraft to enter the outer atmosphere of the Sun, repeatedly sampling solar coronal particles and fields to understand coronal heating, solar wind acceleration, and formation and transport of energetic solar particles. 1, 4
  Solar Orbiter will provide the first high-latitude images and spectral observations of the Sun’s magnetic field, flows, and seismic waves, relating changes seen in the corona to local measurements of the resulting solar wind. 1, 4
  The 4-meter Advanced Technology Solar Telescope will resolve structures as small as 20 km, measuring the dynamics of the magnetic field at the solar surface down to the fundamental density length scale and in the low corona.
  The Heliophysics Systems Observatory will gather a broad range of ground- and space-based observations and advance increasingly interdisciplinary and long-term solar and space physics science objectives. ALL
New starts on programs and missions to be implemented within the next decade The DRIVE initiative will greatly strengthen our ability to pursue innovative observational, theoretical, numerical, modeling, and technical advances. ALL
  Solar and space physicists will accomplish high-payoff, timely science goals with a revitalized Explorer program, including leveraged Missions of Opportunity. ALL
  The Interstellar Mapping and Acceleration Probe, in conjunction with the twin Voyager spacecraft, will resolve the interaction between the heliosphere, our home in space, and the interstellar medium. 2, 3, 4
  A new funding line for mid-size projects at the National Science Foundation will facilitate long-recommended ground-based projects, such as COSMO and FASR, by closing the funding gap between large and small programs. ALL
New starts on missions to be launched early in the next decade The Dynamical Neutral Atmosphere-Ionosphere Coupling mission’s two identical orbiting observatories will clarify the complex variability and structure in near-Earth plasma driven by lower atmospheric wave energy.
  The Geospace Dynamics Constellation will provide the first simultaneous, multipoint observations of how the ionosphere-thermosphere system responds to, and regulates, magnetospheric forcing over local and global scales. 2, 4
Possible new start this decade given budget augmentation and/or cost reduction in other missions The Magnetosphere Energetics, Dynamics, and Ionospheric Coupling Investigation will target complex, coupled, and interconnected multi-scale behavior of the magnetosphere-ionosphere system by providing global, high-resolution, continuous three-dimensional images and multi-point in situ measurements of the ring current, plasmasphere, aurora, and ionospheric-thermospheric dynamics. 2, 4
Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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5.7 Technical Evaluation of the NASA Model for Cancer Risk to Astronauts Due to Space Radiation

A Report of the SSB Ad Hoc Committee for Evaluation of Space Radiation Cancer Risk Model

Summary

At the request of NASA, the National Research Council’s (NRC’s) Committee for Evaluation of Space Radiation Cancer Risk Model1 reviewed a number of changes that NASA proposes to make to its model for estimating the risk of radiation-induced cancer in astronauts. The NASA model in current use was last updated in 2005, and the proposed model would incorporate recent research directed at improving the quantification and understanding of the health risks posed by the space radiation environment. NASA’s proposed model is defined by the 2011 NASA report Space Radiation Cancer Risk Projections and Uncertainties—2010 (Cucinotta et al., 2011). The committee’s evaluation is based primarily on this source, which is referred to hereafter as the 2011 NASA report, with mention of specific sections or tables cited more formally as Cucinotta et al. (2011).

The overall process for estimating cancer risks due to low linear energy transfer (LET)2 radiation exposure has been fully described in reports by a number of organizations. They include, more recently:

• The “BEIR VII Phase 2” report from the NRC’s Committee on Biological Effects of Ionizing Radiation (BEIR) (NRC, 2006);3

Studies of Radiation and Cancer from the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 2006),

The 2007 Recommendations of the International Commission on Radiological Protection (ICRP), ICRP Publication 103 (ICRP, 2007); and

The Environmental Protection Agency’s (EPA’s) report EPA Radiogenic Cancer Risk Models and Projections for the U.S. Population (EPA, 2011).

The approaches described in the reports from all of these expert groups are quite similar. NASA’s proposed space radiation cancer risk assessment model calculates, as its main output, age- and gender-specific risk of exposure-induced death (REID) for use in the estimation of mission and astronaut-specific cancer risk. The model also calculates the associated uncertainties in REID.

The general approach for estimating risk and uncertainty in the proposed model is broadly similar to that used for the current (2005) NASA model and is based on recommendations by the National Council on Radiation Protection and Measurements (NCRP, 2000, 2006). However, NASA’s proposed model has significant changes with respect to the following: the integration of new findings and methods into its components by taking into account newer epidemiological data and analyses, new radiobiological data indicating that quality factors differ for leukemia and solid cancers, an improved method for specifying quality factors in terms of radiation track structure concepts as opposed to the previous approach based on linear energy transfer, the development of a new solar particle event (SPE) model, and the updates to galactic cosmic ray (GCR) and shielding transport models. The newer epidemiological information includes updates to the cancer incidence rates from the life span study (LSS) of the Japanese atomic bomb survivors (Preston et al., 2007), transferred to the U.S. population and converted to cancer mortality rates from U.S. population statistics. In addition, the proposed model provides an alternative analysis applicable to lifetime never-smokers (NSs). Details of the uncertainty analysis in the model have also been updated and revised.

NASA’s proposed model and associated uncertainties are complex in their formulation and as such require a very clear and precise set of descriptions. The committee found the 2011 NASA report challenging to review largely because of the lack of clarity in the model descriptions and derivation of the various parameters used. The committee

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NOTE: “Summary” reprinted from Technical Evaluation of the NASA Model for Cancer Risk to Astronauts Due to Space Radiation, The National Academies Press, Washington, D.C., 2012, pp. 1-8.

1Biographical information about the members of the committee is presented in Appendix B.

2See Appendix C, “Glossary and Acronyms,” for definitions of terms and acronyms.

3The BEIR VII Phase 2 report is the most recent in a series of reports by NRC committees dealing with ionizing radiation; these are widely known as the BEIR reports.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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requested some clarifications from NASA throughout its review and was able to resolve many, but not all, of the ambiguities in the written description.

PROPOSED MODEL—OVERALL CONCLUSION

In considering NASA’s proposed model as a whole, the committee noted that the general approach to estimating cancer risks from exposure to low-LET radiation follows that utilized by ICRP, NCRP, EPA, and BEIR VII, and as such is state of the art. The specific data incorporated into NASA’s proposed model are generally appropriate, with some exceptions, noted below, relating to new data that have become available since the development of the model or additional data sets that were already available and not selected for use by NASA. There remains a need for development of additional data to enhance the current approach and to reduce uncertainty in the model; specific needs have been identified by the committee. The committee has some concerns about specific model components, particularly related to the change to an “incidence-mortality” approach for calculating mortality and to the risk-transfer approach used by NASA. The question of the effectiveness of the combination of the several modules into the proposed integrated model was most appropriately answered by the committee’s observing of a live demonstration by NASA of the application of the model for assessing risk to astronauts under some selected specific mission conditions. This demonstration showed that the model was indeed an integrated one—something that was not immediately apparent from the rather complex descriptions provided in the 2011 NASA report. The committee’s overall evaluation is that NASA’s proposed model represents a definite improvement over the current one. However, the committee urges that the necessary improvements identified in the specific recommendations provided below be incorporated before the proposed integrated model is implemented.

NASA’s proposed model is composed of a number of components or modules that separately address highly distinct aspects of radiation risk and uncertainty. The committee assessed each of the individual components of the model as well as the integrated model as a whole. The key results of its evaluations are summarized below. Possible improvements to components of the model and to the integrated model are provided, together with recommendations for addressing gaps in the model. In some cases, specific research is identified that could help NASA address gaps and/or uncertainties in its proposed model for cancer risk projections. The specific research identified is not necessarily a comprehensive list but is intended to include efforts that would have a significant impact and at the same time would be feasible to undertake within the short to medium term (less than 5 years). The recommendations provided in this Summary address those areas for which the committee perceived more substantial gaps or issues. The model components are discussed in more detail in the main body of the report (see Chapter 2), which contains advice in addition to the major recommendations and conclusions. It is the integrated model that will actually be implemented by NASA, and so it is also assessed in detail in Chapter 2 of this report, particularly with regard to the integration methodology.

PROPOSED MODEL—ASSESSMENT OF COMPONENTS

Tissue-Specific Particle Spectra

The committee considers that the radiation environment and shielding transport models used in NASA’s proposed model are a major step forward compared to previous models used. This is especially the case for the statistical solar particle event model. The current models have been developed by making extensive use of available data and rigorous mathematical analyses. The uncertainties conservatively allocated to the space physics parameters (i.e., environment and shielding transport models) are deemed to be adequate at this time, considering that the space physics uncertainty is only a minor contributor to the overall cancer risk assessment. Although further research in this area could reduce the uncertainty, the law of diminishing returns may prevail.

Given the above considerations, the committee does not recommend any specific research to improve the proposed model for tissue-specific particle spectra at this time. However, in this report the committee has identified several specific research areas that could improve the proposed environment models for tissue-specific particle spectra, including additional statistical analysis of the radial dependence of SPE intensity and solar-cycle dependence of SPE frequency and extreme events. The estimates could be further improved by adding physics-based studies of particle transport using the current picture of the heliosphere and its magnetic fields. Particle transport in the interplanetary medium is determined by its electric and magnetic fields. Theoretical and numerical studies of particle trajectories

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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would certainly result in improved transport models and smaller uncertainties in the environmental estimates, but would involve a major effort and a change in modeling approach. NASA would need to weigh the added value of such an approach to its model outputs.

Cancer Risk Projection Model for Low-LET Exposures

Epidemiology Data

A major change proposed in NASA’s model is to use the “incidence-mortality” approach used by BEIR VII (NRC, 2006) for the development of a REID. For this approach, risk coefficients from LSS cancer incidence models are converted into cancer mortality risks. A major reason for the use of the LSS cancer incidence data is that these are likely to be more accurate with respect to diagnosis than are mortality data, which suffer from misclassification of causes on death certificates. The approach results in considerable changes in the REID estimates, particularly in the pattern with age at exposure, and the committee considers this to be an improvement for site-specific cancer mortality estimation.

Recommendation: Before NASA implements its proposed major change to the “incidence-mortality” approach, the committee recommends that NASA conduct more research into the specific patterns of the underlying epidemiological biases that drive these changes. The committee also highlights a specific problem with the method of estimating the mortality probability from the ratio of cancer mortality to incidence as developed by the BEIR VII report published by the National Research Council in 2006 and proposed for use by NASA. In response, the committee recommends that NASA consider alternative methods for improved estimation of mortality probabilities for each cancer site. For example, as presented in its 2011 report EPA Radiogenic Cancer Risk Models and Projections for the U.S. Population, the Environmental Protection Agency has developed an alternative approach for breast cancer mortality estimation, and this could serve as a suitable approach to be applied by NASA.

Transfer of Cancer Risk Estimates from the Japanese to the U.S. Population

Because underlying cancer incidence rates for some cancer sites differ greatly between the Japanese and the U.S. populations, risk estimates based on an excess relative risk (ERR) model can give REID values very different from those based on an excess absolute risk (EAR) model. A number of organizations and committees (ICRP, the National Council on Radiation Protection and Measurements [NCRP], BEIR VII) have recommended that a site-specific weighted average of the ERR and EAR models be used. The proposed NASA approach follows BEIR VII (NRC, 2006) in calculating a weighted average with uncertain weights and generally follows the recommended BEIR VII weights.

Recommendation: Because there are some deviations in NASA’s proposed model from the weights recommended by BEIR VII for the excess relative risk and excess absolute risk models, the committee recommends that NASA provide additional justification for these alternative weights.

Dose and Dose Rate Effectiveness Factor

A dose and dose rate effectiveness factor (DDREF) value is applied, when appropriate, to reduce the LSS-based cancer risk coefficients for protracted exposures. A median value of 1.75 was selected by NASA for its proposed model, based on an assessment made by the National Institutes of Health (NIH) for a previous estimate and its uncertainty (NIH, 2003). For its proposed model, NASA assumed that the DDREF applies only to low-LET radiations and consequently that there is no dependence of space radiation risks on dose rate. Differences in risks between space radiation charged particles and gamma rays at low dose rate are encompassed entirely within the quality factor, QF, discussed below. A number of publications issued since the NIH report are relevant to this issue, and although these were discussed in the 2011 NASA report, they were not used by NASA in its choice of DDREF or in the associated uncertainty analysis. These studies include the Mayak workers study (Shilnikova et al., 2003), the third analysis of the United Kingdom’s National Registry for Radiation Workers (Muirhead et al., 2009), and

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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the 15-country nuclear workers study (Cardis et al., 2007), together with the review of these studies and comparison with the life span study by Jacob et al. (2009).

Conclusion: Although the proposed NASA approach for estimating a DDREF describes a number of limitations in these newer epidemiological studies and in the BEIR VII DDREF methodology, the justification given for preferring the older approach taken by the National Institutes of Health in 2003 is that it is close to the average of various recommended values of slightly less than 2. The use of this average value is somewhat problematic, given that the recommended values used to derive this average are not independent and thus applying equal weights to these is not justifiable.

Recommendation: The committee agrees with the use of an uncertainty approach for estimating DDREF, but it recommends that NASA use a central value and distribution that better accounts for the recent epidemiological and laboratory animal data.

Risk Models for Never-Smokers

The issue of the smoking status of astronauts and the potential implications for risk projections for smoking-related cancers are important, and it is appropriate that this should be investigated. Most astronauts are non-smokers, which would likely lower the risk projections for astronauts compared to estimates for the general population (a mix of never- and ever-smokers).

Recommendation: The proposed NASA approach for estimating lung cancer risks for astronauts who are never-smokers is limited and does not consider competing risks. Thus, the committee recommends that the NASA approach be developed further, given the important impact that it has on reducing estimated risk. The revised approach should use survival probabilities for competing risks that are specific to never-smokers. Further, the committee recommends that NASA make no changes at this time in the proposed model to include other smoking-related cancers. The data are not sufficiently robust for use in the modification of the REID estimate.

Uncertainties in Low-LET Cancer Risk Model and Overall Uncertainties in Cancer Risk Projections for High-LET Exposures

The 2011 NASA report addresses risk estimates and their uncertainties associated with exposure to low-LET radiation. Uncertainties are important because risk protection involves the use of safety factors, and NASA sets radiation permissible exposure limits (PELs) based on the 95 percent confidence limit that takes into account the uncertainties in risk projection models (NASA, 2005).

Uncertainty Limits and Methodology

Conclusion: Uncertainty limits on radiation-related risk reflect information about anticipated environmental radiation dose levels and accumulated knowledge about the relationship between radiation dose and cancer risk. For the approach used by NASA, more information, if available, might reduce statistical uncertainty and, assuming that the new information did not increase the central risk estimate, lower the upper 95 percent uncertainty bound criterion used by NASA to evaluate the acceptability of activity-related mortality risk.

Maximum Likelihood and Empirical Bayes Estimates

In the 2011 NASA report’s description of the proposed model, the discussion of the use of a maximum likelihood estimate (MLE) and/or empirical Bayes (EB) estimate of site-specific ERR per sievert is ambiguous with respect to the specific approach that was used in specific instances. For example, the site-specific EB estimate of ERR per sievert for kidney cancer (0.40) would be similar to the MLE (also 0.40 for this particular organ site), with a lower estimated standard error (0.19) compared to the MLE standard error of 0.32.

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
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Recommendation: On the assumption that the empirical Bayes approach has been used in NASA’s proposed model, the committee recommends that the authors ensure that the off-diagonal covariance information has been taken into account. If the EB approach has not been used, either this fact should be stated in the text of the 2011 NASA report (Cucinotta et al., 2011) or the references to the EB approach should be removed from the text.

Uncertainty in the Value of the Quality Factor

The uncertainty analysis in NASA’s proposed model reveals that the value of the quality factor (QF, as defined in NASA’s proposed model) is the largest contributor to the uncertainty of REID, introducing about a 3.4-fold uncertainty in risk. Additional analysis by NASA (Cucinotta et al., 2011) using its proposed model finds that this component could be reduced to a 2.8-fold uncertainty if two of the track structure parameters were constrained to a fixed algebraic relationship to one another (such that the Z*22 position of the maximum value of QF is held fixed). In this context, the committee notes that different values of QF are used for leukemia and solid cancers based on recent studies using animal tumor models.

Conclusion: According to NASA’s proposed model, the observation that the use of a fixed relationship between two track structure parameters reduces the uncertainty is a potentially valuable finding that may provide a method to reduce uncertainty in estimations of the risk of exposure-induced death. However, little indication is given in the 2011 NASA report as to why such a fixed position might be justified or expected. The committee suggests that further investigations into the validity and usefulness of this approach would be worthwhile.

Radiation Quality and Track Structure Risk Cross Section

The main parameter used to specify radiation quality is Z*2/β2, where Z* is the effective charge number of the particle and β its speed relative to the speed of light. Z*2/β2 replaces LET used in the conventional quality factor definition, and also by NASA in its current model. However, three additional empirical parameters (κ, Σ0/αγ, and m) are introduced to define the quality factor-risk relationships as a function of Z*2/β2. For NASA’s proposed model, values for these parameters have been selected by comparison with experimentally observed variations in relative biological effectiveness (RBE) for different types of radiation for various cellular biological effects and for selected cancer types. While this approach is broadly appropriate for the proposed model parameters, the committee was unable to determine from the 2011 NASA report or from inquiries how the particular parameter values were selected.

Recommendation: The committee recommends that NASA make a detailed comparison of the relative biological effectiveness versus Z*2/β2 dependence of the experimental data with the proposed form and parameters of the quality factor, QF, equation in order to improve the transparency of the basis for the selection of the proposed parameter values for the model and to provide guidance for future research to test, validate, modify, and/or extend the parameterization. This analysis needs to include the defined selection of different values for parameters κ and Σ0γ for ions of Z ≤ 4 compared to all ions of higher charge.

Conclusion: In the proposed model, different maximum values of quality factor, QF, are assumed for leukemia (maximum 10) and for solid tumors (maximum 40). This is a change from the current NASA risk model. The committee agrees that it is reasonable to make such a distinction on the basis of the limited animal and human data available.

Effective Dose

NASA’s proposed model defines a quantity that is analogous to “effective dose” as defined by ICRP, but it uses different gender-specific sets of normalized tissue weighting factors (wT) to match the estimated risks to the various tissues in representative space radiation environments. NASA proposes to use this as a summary quantity for mission operational purposes and, in NASA’s proposed model, it is simply termed “effective dose.” Effective dose is, strictly speaking, a quantity defined by ICRP that includes the ICRP-defined specification of numerical values for weighting

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
×

factors and sex-averaging. If considerably different tissue weighting factors and radiation quality specifications are used and “effective dose” is evaluated without sex-averaging, it is problematic for the resulting quantity still to be termed “effective dose,” and the unit sievert given to its numerical values.

The committee believes that the NASA description of the proposed model would be improved by the use of terminology and notation that distinguish NASA-defined quantities (especially the quantity termed “effective dose") from quantities defined by ICRP.

Other Issues

Non-Cancer Effects (Tissue Reactions)

In its proposed approach to estimating the safe days in deep space, NASA has used a 3 percent REID for fatal cancer as the limit. In its current model, NASA also considers dose limits for non-cancer effects—lens, skin, blood-forming organs, heart, and central nervous system. For example, “career limits for the heart are intended to limit the REID for heart disease to be below approximately 3 to 5 percent, and are expected to be largely age and sex independent” (NASA, 2005, p. 65). It was further assumed by NASA that the limits established would restrict mortality values for these non-cancer effects to less than the risk level for cancer mortality. The cancer and non-cancer risks were not combined into a single REID. More recent data have led ICRP to reconsider the threshold dose values particularly for the cardiovascular system (and cataracts) (see ICRP, 2011). It is concluded by ICRP (2011) that a threshold absorbed dose of 0.5 Gy should be considered for cardiovascular disease (and cataracts) for acute and for fractionated/protracted exposures. It is appreciated by ICRP that these values have a degree of uncertainty associated with them.

Conclusion: The revised value for the threshold dose value proposed by ICRP suggests that NASA may need to consider how it might account for cardiovascular disease in its calculations of dose limits. However, it is noted that to date there exists very little of the information on relative biological effectiveness for non-cancer effects that is needed for estimates of risks posed by exposure to space radiation.

Delayed Effects

Delayed effects pertinent to the assessment of risk principally relate to observations whereby ongoing radiation-induced genomic instability is expressed, even at long times after radiation exposure. Such effects could have important implications for radiation protection in view of current notions of the multistep mutational processes involved in carcinogenesis. An early induced change in subsequent and ongoing mutation rates in irradiated somatic cells could accelerate this process.

Conclusion: There are conflicting reports on the generality of the phenomenon of radiation-induced delayed genomic instability and some question about variation in the susceptibilities of cells from different individuals with regard to this effect. Thus, the committee concludes that it is appropriate that genomic instability not be incorporated into NASA’s proposed model, in agreement with the proposed NASA approach. However, the committee considers that further investigation of the phenomenon is certainly warranted.

Non-Targeted Effects

Non-targeted effects (NTEs) largely refer to the so-called bystander effects, by which responses can be produced in an unirradiated cell as a result of the transfer of a signal from an irradiated cell. For high atomic number and energy (HZE) radiations, doses that may be received by astronauts are very non-uniform in the sense that some cells will be traversed by the primary particle itself, whereas other cells will not be traversed; thus, an NTE is also a phenomenon that is of considerable interest.

Conclusion: Although the 2011 NASA report (Cucinotta et al., 2011) contains an extended discussion on non-targeted effects and their potential impact on risk estimates, NASA appropriately chose not to include these NTEs in its proposed model at this time. Little is known in qualitative or quantitative terms of the contribution

Suggested Citation:"5 Summaries of Major Reports." National Research Council. 2013. Space Studies Board Annual Report 2012. Washington, DC: The National Academies Press. doi: 10.17226/18315.
×

of these NTEs directly related to radiation-induced carcinogenesis, but the committee believes that studies to elucidate any such relevance should be encouraged.

Qualitative Differences

It is recognized that there are qualitative differences in the nature of the initial energy depositions and hence in initial chemical, biochemical, and biological damages from different types of ionizing radiation. Differences are particularly great between low-LET gamma rays and the wide variety of high-LET heavy ions in space radiation. This may lead to observed differences in responses of cells, tissues, and organisms such as differences in spectra of mutations and chromosome aberrations, altered gene-expression patterns, and different spectra and latencies for carcinogenesis. There is some experimental evidence for qualitative differences at each of the above levels of biological effect. As a result, it may not be entirely appropriate to apply universal values for quality factors as quantitative scaling factors, based on empirical data such as RBE that assume similar underlying biological processes.

The committee notes that this is an area in which experiments quantifying types, frequencies, and latencies of various cancers—for example, lung, colon, and breast cancer, with further study of liver cancer and leukemia—are sorely needed for radiations of varying LET, especially for high-LET particles at low particle fluences such as occur in space. Furthermore, the committee suggests that the tumor studies should be coupled with appropriate mechanistic investigations to provide an understanding of the underlying carcinogenic processes.

Probabilistic Risk Assessment

The committee notes that the risk projections discussed in NASA’s proposed space radiation cancer risk assessment model and uncertainties are not presented or intended as being based on a probabilistic risk assessment (PRA) approach. NASA’s proposed model is a health-effects model intended to provide estimates of cancer risk and uncertainties for defined space radiation exposure scenarios. More generally, however, the cancer risk to astronauts is dependent on much more than a defined scenario model of health effects, with engineered barriers, in the space radiation environment. Experience with full-scope PRAs of complex systems indicates the importance of accounting for the “what can go wrong during actual operations” scenarios, as such scenarios generally drive the overall risk. Thus, the committee suggests that comprehensive, mission-specific PRAs also be considered so as to enable accountability for the “what can go wrong” scenarios in the overall risk projections.

REFERENCES

Cardis, E., Vrijheid, M., Blettner, M., Gilbert, E., Hakama, M., Hill, C., Howe, G., Kaldor, J., Muirhead, C.R., Schubauer-Berigan, M., and Yoshimura, T., et al. 2007. The 15-Country Collaborative Study of Cancer Risk among Radiation Workers in the Nuclear Industry: Estimates of Radiation-Related Cancer Risks. Radiation Research 167(4):396-416.

Cucinotta, F.A., Kim, M.-H.Y., and Chappell, L.J. 2011. Space Radiation Cancer Risk Projections and Uncertainties—2010. NASA/TP-2011-216155. NASA Johnson Space Center, Houston, Tex. July.

EPA (Environmental Protection Agency). 2011. EPA Radiogenic Cancer Risk Models and Projections for the U.S. Population. U.S. Environmental Protection Agency, Washington, D.C.

ICRP (International Commission on Radiological Protection). 2007. The 2007 Recommendations of the International Commission on Radiological Protection. ICRP Publication 103. Ann ICRP 37 (2-4). International Commission on Radiological Protection, Ottawa, Ontario, Canada.

ICRP. 2011. Early and Late Effects of Radiation in Normal Tissues and Organs: Threshold Doses for Tissue Reactions in a Radiation Protection Context. Draft Report for Consultation. ICRP Ref 4844-6029-7736. International Commission on Radiological Protection, Ottawa, Ontario, Canada. January 20.

Jacob, P., Ruhm, W., Walsh, L., Blettner, M., Hammer, G., and Zeeb, H. 2009. Is cancer risk of radiation workers larger than expected? Occupational and Environmental Medicine 66:789-796.

Muirhead, C.R., O’Hagan, J.A., Haylock, R.G.E., Phillipson, M.A., Willcock, T., Berridge, G.L.C., and Zhang, W. 2009. Mortality and cancer incidence following occupational radiation exposure: Third analysis of the National Registry for Radiation Workers. British Journal of Cancer 100:206-212.

NASA (National Aeronautics and Space Administration). 2005. NASA Space Flight Human System Standard, Volume 1: Crew Health. NASA-STD-3001. (Approved 03-05-2007) NASA, Washington, D.C.

NCRP (National Council on Radiation Protection and Measurements). 2000. Radiation Protection Guidance for Activities in Low-Earth Orbit.

NCRP Report No. 132. NCRP, Bethesda, Md. NCRP. 2006. Information Needed to Make Radiation Protection Recommendations for Space Missions Beyond Low-Earth Orbit. NCRP Report No. 153. NCRP, Bethesda, Md.

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NIH (National Institutes of Health). 2003. Report of the NCI-CDC Working Group to Revise the 1985 NIH Radioepidemiological Tables. NIH Publication No. 03-5387. Bethesda, Md.

NRC (National Research Council). 2006. Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2. The National Academies Press, Washington, D.C.

Preston, D.L., Ron, E., Tokuoka, S., Funamoto, S., Nishi N., Soda, M., Mabuchi, K., and Kodama, K. 2007. Solid cancer incidence in atomic bomb survivors: 1958-1998. Radiation Research 168:1-64.

Shilnikova, N.S., Preston, D.L., Ron, E., Gilbert, E.S., Vassilenko, E.K., Romanov, S.A., Kuznetsova, I.S., Sokolnikov, M.E., Okatenko, P.V., Kreslov, V.V., and Koshurnikova, N.A. 2003. Cancer mortality risk among workers at the Mayak Nuclear Complex. Radiation Research 159(6):787-798.

UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation). 2006. Studies of Radiation and Cancer. Report to the General Assembly, with Scientific Annexes A and B. United Nations. New York.

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The original charter of the Space Science Board was established in June 1958, 3 months before the National Aeronautics and Space Administration (NASA) opened its doors. The Space Science Board and its successor, the Space Studies Board (SSB), have provided expert external and independent scientific and programmatic advice to NASA on a continuous basis from NASA's inception until the present. The SSB has also provided such advice to other executive branch agencies, including the National Oceanic and Atmospheric Administration (NOAA), the National Science Foundation (NSF), the U.S. Geological Survey (USGS), the Department of Defense, as well as to Congress.

Space Studies Board Annual Report 2012 covers a message from the chair of the SSB, Charles F. Kennel. This report also explains the origins of the Space Science Board, how the Space Studies Board functions today, the SSB's collaboration with other National Research Council units, assures the quality of the SSB reports, acknowledges the audience and sponsors, and expresses the necessity to enhance the outreach and improve dissemination of SSB reports.

This report will be relevant to a full range of government audiences in civilian space research - including NASA, NSF, NOAA, USGS, and the Department of Energy, as well members of the SSB, policy makers, and researchers.

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