Review of Goals and Plans for NASA's Space and Earth Sciences (2006)

As charged by NASA and Congress, the Panel on Review of NASA Science Strategy Roadmaps reviewed six science roadmaps. It found that the proposed roadmaps have significant scientific merit and that, with a few notable exceptions, their near-term recommendations are generally consistent with the decadal-scale studies produced by the National Research Council (NRC). The panel believes that the roadmaps are reasonable inputs to NASA’s strategic planning/efforts process and together provide rationales for future planning that are generally well supported by the existing NRC decadal surveys.^1-4

The main sources of gaps and potential missed opportunities in some of the six roadmaps are a shortage of scientific justification for their stated goals and an overly narrow interpretation of the presidential exploration vision by the NASA roadmap teams. If science in pursuit of the exploration vision is to be aligned with the priorities set forth by the scientific community in NRC decadal survey reports, it will be essential for NASA to embrace the broadly based science program that has been recommended by the 2004 report of the President’s Commission on Implementation of United States Space Policy⁵ and the principles articulated in the 2005 Space Studies Board report Science in NASA’s Vision for Space Exploration.⁶ Also, much more should be done to coordinate planning across the various roadmaps and with other federal agencies. The short timescale for writing the roadmaps and the lack of community input may have contributed to these shortcomings.

The panel was able to draw some broad conclusions from its review, which are provided as general principles for integration and prioritization of the strategic planning to fulfill the exploration vision. These principles are stated briefly in this Executive Summary and in more detail in Chapter 7. The most important result of the roadmapping activity may now be its contribution to a balanced and clearly defined decision process. The panel’s key recommendations are that the overall science program be guided by scientific merit and be driven by discoveries.

The Robotic and Human Exploration of Mars strategic roadmap⁷ provides a reasonable approach to future Mars science exploration during the next three decades. The roadmap’s strengths are its early recognition of broad scientific goals, consideration of preparations for human exploration, and strategies for developing the next generation of Mars scientists. Its major weakness is that the scientific goals are poorly linked to the specific missions, which focus on putting humans on Mars. The roadmap does not present scientific justification for its goal of placing humans on Mars, and the issues of forward and back contamination are not addressed adequately.

The panel recommends careful consideration of the broad science goals and priorities for Mars studies set forth in the NRC decadal survey New Frontiers in the Solar System⁸when the robotic and human exploration of Mars is being planned.

To maintain flexibility and ensure responsiveness to new discoveries, the panel recommends that clear budget lines of small- (Scout-class) and medium-scale missions be developed for the long-term robotic exploration of Mars.

The panel finds that overall the proposed missions and timescales in The Solar System Exploration Strategic Roadmap⁹ have significant scientific merit, and the near-term recommendations are consistent with those of the NRC decadal survey New Frontiers in the Solar System. The Solar System Exploration Strategic Roadmap appropriately recognizes the importance of timely technology development to support cost-capped missions, and it emphasizes the contributions to NASA’s education and outreach program and the need to continue this vital effort.

The panel agrees with the breakdown of goals listed in the roadmap and notes that they are consistent with, and support, the goals outlined in the NRC solar system decadal survey. However, the roadmap uses the concept of planetary habitability as its basic premise for scientific exploration, but it does not clearly articulate how the planned investigations will address planetary habitability and how each proposed mission will build on previous mission results.

The panel recommends that a proper science approach be developed and that clearer relationships between the concept of habitability and missions proposed to demonstrate habitability be articulated and maintained in any future NASA solar system exploration program.

The two roadmaps Universe Exploration and The Search for Earth-like Planets^10,11 make a strong case for exploring the fundamental physics associated with the beginning of the universe and the nature of space-time and for searching for Earth-like planets. They do not, however, present the most robust case possible for the suite of missions that address the important broad range of astrophysical questions at the forefront of astrophysical research. Not all of these missions fall conveniently in the scope of the Beyond Einstein and the Search for Earth-like Planets programs. The division of topics between these two roadmaps also tends to deemphasize the capability of some of the proposed missions, which are critical to the search for Earth-like planets, to do broader astrophysical research. Finally, the partitioning into two roadmaps has deemphasized the value of shared technology, facilities, and infrastructure.

A significant issue conspicuously absent in the Universe Exploration roadmap is the future of the Hubble Space Telescope (HST). In a 2004 report the NRC laid out a continuing science role for HST in astronomy and astrophysics.¹² The fate of HST is intimately connected to the development of other NASA missions in the roadmap.

Much of NASA’s former Structure and Evolution of the Universe and Origins programs has been redefined as the Pathways to Life theme, which appears to be an overly narrow interpretation of the vision for space exploration. However, a broader interpretation of NASA’s science mission in the exploration vision was described by the president’s commission’s report A Journey to Inspire, Innovate, and Discover¹³ and also expressed in the NRC report Science in NASA’s Vision for Space Exploration.¹⁴ Those reports stated that astronomy can and should be more than the search for life.

The Search for Earth-like Planets roadmap outlines an ambitious plan of large, expensive, and technologically challenging missions; however, the roadmap contains very little discussion of mission costs and technological challenges and milestones that must be met for each mission to be successful. The realism of the proposed mission timeline and the ability of the proposed missions to fit into the budget line are serious concerns.

The panel recommends that broad-based community input be sought to guide decisions about priorities and scientific directions if any significant revision to the Search for Earth-like Planets strategic roadmap mission sequence becomes necessary.

Unlike the other roadmaps, Exploring Our Planet for the Benefit of Society, the strategic roadmap for Earth science and applications from space¹⁵ had no NRC decadal survey to guide it. Past NRC studies have articulated the importance of broad community discussion and input as an essential part of NASA’s long-term strategic planninginput that will be available after completion of the NRC decadal survey on Earth science and applications that is now in progress.

The panel recommends that the forthcoming NRC Earth science and applications decadal survey be used as a starting point for mid- to long-term planning (i.e., for beyond 2010). Before the completion of the decadal survey, NASA planning and advanced technology programs should remain flexible to avoid commitments to missions that might not receive broad community support. In the near term NASA should focus foremost on the specific recommendations made in the NRC decadal survey interim report.¹⁶ In particular, attention should be given to the near-term gaps in the current program of long-term observations.

Interagency cooperation is critical for ensuring long-term operational measurements, and ongoing mission planning will be needed with the National Oceanic and Atmospheric Administration (NOAA), which plays a strong role in atmospheric and oceanic observations. International cooperation also will be important in implementing and enhancing the NASA program.

Recognizing the strong message from the NRC Earth sciences decadal survey interim report that “NASA must retain Earth science as a central priority, to support critical improvements in understanding the planet and developing useful applications,”¹⁷the panel recommends that NASA strongly support the Earth science program independent of its involvement in the vision for space exploration.

The Sun-Solar System Connection roadmap¹⁸ is a well thought out document that succeeds in placing many science objectives into the context of the vision for space exploration. The roadmap correctly notes that the science program has reached a level of maturity that allows it to focus on “systems science” that addresses the strong interactions between all of the different components of the Sun-solar system environments, even while essential work continues on the individual constituents. Adjustments have been made to accommodate resources and to support the vision for the space exploration schedule; however, the resulting overall priorities are roughly consistent with the relevant NRC decadal survey¹⁹ and its recent follow-on NRC study.²⁰ The latter study reexamined the NRC decadal survey recommendations in the context of the objectives of the vision for space exploration.

At the highest level the panel generally supports the science and implementation program developed in the roadmap. However the rationale undervalues the role of fundamental discovery science, instead focusing too single-mindedly on how scientific findings will flow down to other applications and operations interests. This may result in a program that is too narrow to match the broad scientific exploration goals of the vision for space exploration.

The panel, in addition to reviewing each of the six roadmaps individually, considered the principles that should be used for prioritization and integration, leading to an overall space and Earth science exploration program spanning more than two decades. These principles are an expansion and amplification of the principles noted in the NRC report Science in NASA’s Vision for Space Exploration.²¹

A guiding principle should be scientific merit, as measured by the advancing intellectual understanding of the cosmos and our place in it. The goals and objectives set in relevant NRC decadal surveys and similar reports should be the primary criteria for setting priorities and program content. These surveys have always striven to identify the most important, revolutionary science that should be undertaken and, as such, have set a high bar of excellence. The NRC decadal surveys have benefited from the broad inputs by the scientific community and are recognized for their credibility and stability. This process has been one of the foundations that has enabled NASA to develop an outstanding scientific program with a long and successful record to its credit. Science that is enabled by exploration should be held to the same standard of scientific merit and advancing intellectual understanding as the science goals embodied and recommended in past NRC decadal surveys.

The integrated science program constructed by NASA based on these roadmaps should have characteristics such that all major scientific disciplines can make progress toward their goals as established in NRC decadal surveys or other similar reports. The program should be discovery driven and not rigid, allowing exciting new discoveries to be rapidly accommodated in a program plan, and should include the broad scientific community’s involvement in the decision process. Flexibility is enhanced by having a mix of small, highly responsive missions as well as flagship missions that may take the better part of a decade to complete.

A robust, sustainable aerospace community is required. Investment in the nation’s intellectual and physical infrastructure that provide the basis for the capability for space exploration—and stewardship of that infrastructure—are daunting but essential tasks if we are to continue to be a space-faring nation.

Explicit strategies should be defined for developing the next generation of space scientists and space engineers, and the generation after that. These strategies, which include public outreach and education, need to have a scope commensurate with the scope of the vision for space exploration.

Research and analysis programs, theory programs, and rocket- and balloon-based research programs provide the training and experience base at our universities and research institutes. These programs should be evaluated, judged, and prioritized using the same high standard the panel recommends as applicable to initiatives described in NRC decadal surveys.

Continuing, vigorous development of technology is necessary for the success of the exploration program. Advanced technology needs should be assessed, prioritized, and properly funded so that technologies with long lead times can be developed in time to reduce mission technical risk as well as schedule and cost risk. Multiple-use technologies that are applicable to several branches of the space sciences, for example, those spanning several of the scientific disciplines addressed by the roadmaps, should receive special consideration.

Capabilities to handle the communications and data transmission, storage, and archive needs of the space exploration initiative require assessment and appropriate investment for timely implementation. The NASA roadmap integration and strategic planning process should consider these needs as a vital part of developing the space exploration initiative infrastructure.

The panel’s review of NASA strategic roadmaps suggests that NASA research can have societal benefits in addition to increasing fundamental knowledge in science. There is much to be gained by enhancing the connections with other agencies of the executive branch that have responsibilities for or interests in space research and space technology. These agencies include NOAA, the Department of Defense, the Department of Energy, and the National Science Foundation. The impact of space research now transcends the space science community and in many cases involves nonscientists, affecting diverse areas such as agriculture, fisheries, and a host of other enterprises and activities at the commercial, industrial, and state level. An important goal is reinvigorating the transition from space research to operations—typically from NASA to NOAA—and enhancing the ultimate use of the data by a host of enterprises.

NASA has had a decades-long history of international cooperation in human and robotic space activities. Cooperative missions with other nations have provided direct scientific benefits to both the United States and the other cooperating nations. Although the panel recognizes that international cooperation can have its negative aspects as well, the subject should receive serious explicit attention.

The extraordinary scope of the exploration vision and the multigenerational span of this effort provide an opportunity to seek out partners from other nations to join us in this grand adventure. The panel recognizes that current implementation of International Traffic in Arms Regulations (ITAR) continues to be a serious impediment to international cooperation; however, the overwhelming imperative of the exploration vision should provide the basis for a renewed effort to ameliorate the effects of ITAR so that ITAR goals can be obtained without unduly affecting NASA’s international cooperation efforts with foreign partners.

The panel was struck by the relative paucity of crosscutting opportunities identified in the six individual roadmaps. To be sure, some opportunities were noted, but it is the judgment of the panel that the scope and span of the opportunities noted in the roadmaps do not do justice to the scope and span of the vision for space exploration

The panel notes two additional crosscutting issues. Although it did not review a lunar roadmap, the panel was concerned about the interrelation between lunar and martian exploration and scientific goals. Although it recognizes that human lunar exploration goals should be secondary to human Mars exploration goals, the panel emphasizes that lunar science is of great intrinsic scientific interest and should not be neglected under the lunar exploration program.

The panel also notes that several similar or related missions appear in separate roadmaps. The panel warns that in such cases, desirable but not required missions can seem more important because of multiple appearances in roadmaps. As noted in the prioritization criteria above, the panel reiterates that every proposed mission should be evaluated on the basis of its scientific merit and ability to meet the goals of the NRC decadal survey in its particular discipline.

1. National Research Council (NRC). 2003. New Frontiers in the Solar System: An Integrated Exploration Strategy. The National Academies Press, Washington, D.C.

2. NRC. 2005. The Sun to the Earthand Beyond: A Decadal Research Strategy in Solar and Space Physics. The National Academies Press, Washington, D.C.

3. NRC. 2001. Astronomy and Astrophysics in the New Millennium. National Academy Press, Washington, D.C.

4. NRC. 2005. Earth Science and Applications from Space: Urgent Needs and Opportunities to Serve the Nation [interim report]. The National Academies Press, Washington, D.C.

5. President’s Commission on Implementation of United States Space Exploration Policy. 2004. A Journey to Inspire, Innovate, and Discover. Available at <govinfo.library.unt.edu/moontomars/>.

6. NRC. 2005. Science in NASA’s Vision for Space Exploration. The National Academies Press, Washington, D.C.

7. National Aeronautics and Space Administration (NASA), Advanced Planning and Integration Office. 2005. Robotic and Human Exploration of Mars. NASA, Washington, D.C. Available at <www.hq.nasa.gov/office/apio/pdf/mars/mars_roadmap.pdf>.

8. NRC. 2003. New Frontiers in the Solar System.

9. NASA, Advanced Planning and Integration Office. 2005. SRM 3—The Solar System Exploration Strategic Roadmap. NASA, Washington, D.C. Available at <www.hq.nasa.gov/office/apio/pdf/solar/solar_roadmap.pdf>.

10. NASA, Advanced Planning and Integration Office. 2005. Universe Exploration: From the Big Bang to Life. NASA, Washington, D.C. Available at <www.hq.nasa.gov/office/apio/pdf/universe/universe_roadmap.pdf>.

11. NASA, Advanced Planning and Integration Office. 2005. The Search for Earth-like Planets. NASA, Washington, D.C. Available at <www.hq.nasa.gov/office/apio/pdf/earthlike/earthlike_roadmap.pdf>.

12. NRC. 2005. Assessment of Options for Extending the Life of the Hubble Space Telescope. The National Academies Press, Washington, D.C.

13. President’s Commission on Implementation of United States Space Exploration Policy. 2004. A Journey to Inspire, Innovate, and Discover.

14. NRC. 2005. Science in NASA’s Vision for Space Exploration.

15. NASA, Advanced Planning and Integration Office. 2005. Exploring Our Planet for the Benefit of Society: NASA Earth Science and Applications from Space Strategic Roadmap. NASA, Washington, D.C. Available at <www.hq.nasa.gov/office/apio/pdf/earth/earth_roadmap.pdf>.

16. NRC. 2005. Earth Science and Applications from Space [interim report].

17. NRC. 2005. Earth Science and Applications from Space [interim report], p. 14.

18. NASA, Advanced Planning and Integration Office. 2005. Sun-Solar System Connection. NASA, Washington, D.C. Available at <www.hq.nasa.gov/office/apio/pdf/sun/sun_roadmap.pdf>.

19. NRC. 2002. The Sun to the Earth—and Beyond: A Decadal Research Strategy in Solar and Space Physics.

20. NRC. 2004. Solar and Space Physics and Its Role in Space Exploration. The National Academies Press, Washington, D.C.

21. NRC. 2005. Science in NASA’s Vision for Space Exploration.