During the course of the workshop, Michael H. Moloney, director of the Space Studies Board, provided several brief tutorials on the decadal studies and the processes used by the different Earth and space science communities to define and draft their survey reports. These tutorials have been combined to create this section of the workshop summary. While no two decadal surveys are identical in scope and structure, each of the four most recent surveys sponsored by NASA’s Science Mission Directorate (SMD) have many similarities.
SSB Director Michael Moloney summarized the key features of the decadal survey process at the conclusion of the keynote session. Over the past 50 years there have been six astronomy surveys, two each for planetary science and for solar and space physics, and one each for Earth science and applications from space and for life and physical sciences research in space.1 The NASA Authorization Acts of 2005 and 2008 provided a formal legislative mandate for decadal surveys in each NASA science area. The 2005 act also mandated National Research Council (NRC) reviews of NASA’s performance in each discipline at 5-year intervals (Public Law 109-155). The 2008 act called for “independent estimates of the life cycle costs and technical readiness of missions assessed in the decadal surveys whenever possible” (Public Law 110-422) and for identifying conditions or events that might trigger a reexamination of the survey’s priorities.
Moloney explained that the purpose of the surveys are to assess the current state of knowledge in a specific discipline; identify and prioritize the most important scientific questions for the next decade; and prioritize the ground- and space-based missions and activities that can address these questions. Although the organizational structures and details of the study methodology vary by discipline, all of the surveys were led by a main steering committee that drew input from a set of panels, some of which were discipline-oriented and others of which were organized on cross-cutting themes. All of the surveys utilized broad community input via multiple town meetings, solicitation of scientific or mission-oriented white papers, and other outreach efforts. Moloney noted that the recent surveys each involved participation by hundreds of scientists. An important new feature of the three most recent surveys (astronomy and astrophysics, planetary science, and solar and space physics) has been the inclusion of independent cost and technical evaluations of proposed initiatives and recommendations that are made within specified budget scenarios.
1 As explained in the Preface, the decadal survey on life and physical sciences is not discussed during this workshop.
To provide additional information about the decadal survey process, SSB Director Michael Moloney provided an additional presentation prior to the workshop’s Panel on Decadal Survey Program Formulation and Opportunities for Improvement. He prefaced his presentation by commenting that it is almost certainly true to say that no one person can claim to fully understand every detail of how each of the last four decadal surveys was organized and implemented. Indeed, there is no such thing as a typical decadal survey.
Each and every survey conducted since the very first (in astronomy) in 1964 has employed a different organizational structure and study methodology. Moreover, the differences between surveys cannot be attributed to any one single factor (e.g., community idiosyncrasies). Nevertheless, the most recent surveys do display a number of broad similarities that can be discussed most easily under the headings of survey organization and study process.
The organizational structures employed by the four most recent decadal surveys sponsored by NASA SMD are illustrated in Figures 2.1 through 2.4. Although the details differ, each survey encompassed a leadership group and a number of supporting panels. The leadership group—known variously as the “steering group,” “steering committee,” or, as will be used hereafter, the “survey committee”—typically consisted of 15-20 senior members of the relevant discipline community whose collective expertise spanned the entire range of scientific, programmatic, technical, and policy issues relevant to the survey’s activities. The survey committee is responsible for the overall conduct of the decadal study, aggregating and adjudicating the various panel recommendations, and, in particular, for the drafting of its top-level conclusions and recommendations.
The survey panels typically consisted of 10-15 members with specific expertise in some key subset of a decadal survey’s domain of responsibility. The membership of the panels typically included a greater proportion of more junior members of the relevant scientific and technical communities than the respective survey committee. To maintain lines of communication between the panels and the survey committee, the chair or vice chair of the panel is also a member of the survey committee. It can be argued that the panels form the survey’s principal interface with the membership of the scientific and technical communities they seek to represent. On the other hand, the survey committee forms the principal interface between the survey and its sponsoring agencies and organizations.
The number of panels and their thematic orientation is perhaps the most obvious dissimilarity between the four recent decadal surveys. The number of panels varied from three for solar and space physics to 15 (or more, depending on how they are counted) for the astronomy and astrophysics survey. The number of panels represents a complex convolution of the complicated scientific and technical issues being addressed, the personal preferences of the chair (or co-chairs) of the survey committee, and the resources available to support the decadal study.
The thematic orientation of the panels is primarily a function of the dominant means by which each community conducts its scientific investigations. Thus, since planetary science, for example, is intimately concerned with spacecraft observations on or in close proximity to particular solar system bodies, a panel structure organized, to first approximation, around like objects—e.g., inner planets or outer planets—is most appropriate. For reasons of continuity, the most recent planetary science decadal survey explicitly chose, with one exception,2 the same thematic structure that was used by the 2003 planetary science decadal study.
2 Unlike the 2003 planetary science decadal survey, the most recent survey did not included a panel on astrobiology.
FIGURE 2.1 Organization of the 2010 astronomy and astrophysics decadal survey. NOTE: *, Consisted of an Executive Committee and three subcommittees: the Subcommittee on Science, the Subcommittee on Status of the Profession, and the Subcommittee on Programs. †, These groups were not appointed and consisted of volunteer consultants.
FIGURE 2.2 Organization of the 2007 Earth science and applications from space decadal survey.
FIGURE 2.3 Organization of the 2011 planetary science decadal survey.
FIGURE 2.4 Organization of the 2013 solar and space physics decadal survey. NOTE: *, These groups were composed of a mixture of survey committee and panel members augmented by non-appointed, volunteer consultants.
The research agenda in solar and space physics is intimately concerned by the physical processes occurring at the interfaces between domains where the particle and/or electromagnetic field environments are significantly different. Thus, a panel structure organized around the interfaces between the principal particle/field regimes is appropriate. This primary organizational scheme was supplemented by semi-formal, cross-panel national capabilities working groups addressing topics such as theory and modeling and instrument development, among others.
The 2010 astronomy and astrophysics decadal survey adopted a complex substructure consisting of five science frontiers panels and four program prioritization panels. The former were charged to define key science priorities in key components of the cosmos, such as extrasolar planetary systems, stars, galaxies, and so on. Once their tasks were completed, the science frontiers panels disbanded and their priorities were passed on to the program prioritization panels. The program prioritization panels, organized around different observing wavelengths, techniques, and regimes, were charged to come up with the most appropriate means for implementing the science priorities outlined by the science frontiers panels. The activities of these two sets of panels were supplemented by six informal (i.e., not appointed by the NRC) study groups addressing different aspects of the status of the astronomical community.
The thematic orientation of the seven panels for the Earth science and applications from space decadal survey, differing significantly from those of the other three surveys, were organized around combinations of both scientific and operational themes—for example, human health and security; Earth science applications and societal benefits; and solid Earth hazards, natural resources, and dynamics.
Schematic timelines illustrating the high-level features of the study process employed by the four most recent decadal surveys sponsored by NASA SMD are illustrated in Figures 2.5 through 2.8. Activities common to most, if not all, of the most recent surveys include the following:
• Alternating meetings of the survey committees and their supporting panels. The public start of the decadal study process typically occurs with the first meeting of the survey committee. Thereafter, meetings of the panels and survey committee alternate. Survey committees typically hold five or six full meetings plus numerous additional conference calls. Panels typically meet three times each (plus additional conference calls, as necessary) and complete their work prior to the third or fourth meeting of the survey committee.
• Community input via the solicitation of white papers. All four recent decadal surveys included a mechanism by which members of the relevant scientific communities could submit white papers discussing important scientific, technical, or programmatic issues. The solicitation typically occurs soon after the first meeting of the survey committee. The submission deadline is timed so that the white papers are available for consideration by the supporting panels soon after their first meetings.
• Formulation of science priorities by the panels. Most, if not all, survey committees delegate the drafting of key science questions to their supporting panels. The most explicit example of this occurred in the 2010 astronomy and astrophysics decadal survey, where the science frontiers panels existed specifically to undertake this task.
• Mission formulation and design phase. This is perhaps the most complex activity undertaken by any decadal survey and, also, the most idiosyncratic. All four recent decadal studies had a mission formulation phase, but no two surveys employed the same process. These differences were driven mainly by the status of mission-planning activities in each of the relevant disciplines at the time the survey was initiated, by the resources directly or indirectly available to support each decadal study, and by the survey’s statement of task. The astronomy and astrophysics survey committee, for example, issued a request for information (RFI) to the scientific community for potential mission concepts. Many, if not all, of the responses to this RFI derived from concepts formulated in a pre-decadal round of community-based mission studies funded by NASA’s Astrophysics Division.
Although NASA’s Planetary Science Division had sponsored several large mission studies (e.g., the Europa Jupiter System Mission, the Titan Saturn System Mission and the Enceladus flagship) prior to (and independent of) its respective survey, pre-decadal studies of mid-size (New Frontiers class) were few and far between. However, sufficient resources were directly and indirectly available to the planetary science survey to enable it to commission more than 20 additional mission studies at leading design centers.
The solar and space physics community was even less well endowed with mission design activities prior to or in the context of its decadal survey. The resources available to this survey activity were only sufficient to allow the study of a dozen mission concepts by a design team at the Aerospace Corporation.
Mission formulation and design activities were not a major facet of the activities conducted in support of the decadal survey in Earth science and applications from space. Mission designers at several NASA centers did assist the survey committee to determine the likely costs of key components—e.g., instruments, spacecraft buses, launch vehicles and ground systems—of mission concepts devised by the supporting panels. However, these activities nowhere near matched the scope of the studies conducted prior to or within the context of the three other recent decadal surveys.
• Cost and technical evaluation (CATE) of mission concepts by the Aerospace Corporation. A key facet of three of the four most recent decadal studies was the inclusion of an independent assessment of the likely cost and technical risk associated with priority mission concepts outlined in the survey reports. All of the surveys, except the one concerned with Earth science and applications from space, engaged the services of the Aerospace Corporation to conduct independent assessments using the proprietary CATE methodology. The CATE analyses were typically briefed to the relevant survey committee at its meeting immediately following the final set of panel meetings.
• Assessment of Aerospace Corporation input and the formulation of final priorities for ground- and space-based priorities. The results of the CATE analyses of the priority missions identified by the three decadal studies that made use of this methodology enabled the survey committees to make last-minute adjustments to some mission concepts. In other words, selective descoping or rescoping of some mission concepts occurred following the initial briefing of the CATE results. The revised mission concepts were then “re-CATEd” to validate that the re/descoping had the desired result.
FIGURE 2.7 Mission study and cost and technical evaluation (CATE) timeline of the 2011 planetary science decadal survey. NOTE: *, The second meeting was a teleconference; other teleconferences are not shown; APL, Applied Physics Laboratory; GSFC, Goddard Space Flight Center; JPL, Jet Propulsion Laboratory.