3
Implementation Strategy and Recommendations
The decadal survey report1 recommended a carefully reasoned program for addressing high-priority science issues within the constraints of what was understood to be an attainable timeline and budget plan (Figure 3.1 (a)). Priority missions in both the STP and LWS lines were included, balancing underlying basic science with space weather applications to serve national needs. With respect to space weather, the decadal survey report focused on research support for the National Oceanic and Atmospheric Administration and the Department of Defense, and this committee believes that providing such research support remains an important role for NASA that is highly complementary to the NASA exploration vision. The recommended sequence of missions was supported by a strong base of Explorer missions, MO&DA, suborbital activities, and SR&T, which provide the core strength of the SEC research base.
The integrated research strategy presented in the decadal survey for the period 2003 to 2013 is based on several key principles. First, addressing the scientific challenges that were identified in the survey report requires an integrated set of ground- and space-based experimental programs along with complementary theory and modeling initiatives. Second, because of the complexity of the overall solar-heliospheric system, the greatest gains will be achieved by a coordinated approach that addresses the various components of the system, where possible, in combination. Third, a mix of basic, targeted basic,2 and applied research is important so that the advances in knowledge and the application of that knowledge to societal problems can progress together. Finally, containing cost is an important consideration because the recommended program must be affordable within the anticipated budgets of the various federal agencies.
Finding 4. The committee concurs with the principles that were employed for setting priorities in the decadal survey report and believes that those principles remain appropriate and relevant today.
FIGURE 3.1 (a) SEC sample budget as presented in the decadal survey report. SOURCE: Adapted from National Research Council, The Sun to the Earth—and Beyond: A Decadal Research Strategy in Solar and Space Physics, p. 8, The National Academies Press, Washington, D.C., 2003. (b) Sample budget that accommodates the new vision for exploration. The overlap between MMS and SDO was recommended in the decadal survey report. The fiscal plans are presented in constant FY2002 dollars. The additional cost associated with the application of full-cost accounting to these programs is not included. SOURCE: Committee discussions with NASA representatives.
With those principles in mind, the decadal survey report recommended a specific sequence of high-priority programs as a strategy for solar and space physics in the next decade. To accomplish this task, the survey report presented an assessment of candidate projects in terms of their potential scientific impact (both in their own subdisciplines and for the field as a whole) and potential societal benefit (i.e., with respect to space weather). The survey report also took into consideration the optimum affordable sequence of programs, what programs would benefit from being operational simultaneously, the technical maturity of missions in a planning phase, and what programs should have the highest priority in the event of budgetary limitations or other unforeseen circumstances that might limit the scope of the overall effort.
Finding 5. The committee concludes that, for an SEC program that properly fulfills its dual role of scientific exploration and of enabling future exploration of the solar system, the prioritized sequence recommended in the decadal survey report remains important, timely, and appropriate.
Although the recommendations and schedule presented in the decadal survey were formulated in 2002 before the adoption by NASA of the new exploration vision, the essential reasoning behind the conclusions of the survey report remain valid: to explore and characterize the solar system and to understand and predict the solar-planetary environment within which future exploration missions will take place requires a scientific approach that treats the environment as a complex, coupled system. There is not yet a sufficient understanding of how the system works to be able to rely only on empirical models based on simple monitoring of solar or other inputs. To properly support the exploration vision, the SEC program must continue to develop the understanding of basic physical processes that control the variations in hazardous penetrating radiation in space.
Recommendation 1. To achieve the goals of the exploration vision there must be a robust SEC program, including both the LWS and the STP mission lines, that studies the heliospheric system as a whole and that incorporates a balance of applied and basic science.
MO&DA, Explorer and suborbital flights, and SR&T activities are the lifeblood of SEC research because they provide core research, flexibility, innovative technologies, and invaluable training for the next generation of workers for our nation’s space enterprise.3 The Explorer program provides innovative, fast-response missions to fill critical gaps. The Suborbital program (sounding rockets, balloon payloads) provides low-cost access to space, yielding compelling science, a platform for testing instrumentation, and a vital opportunity to educate the next generation of scientists and engineers at the nation’s universities. MO&DA resources ensure that missions continue to produce valuable data, sometimes even decades after launch. In addition, continued operation of existing missions are cost-effective ways to provide measurements of space weather in a severely constrained budgetary environment. The research and analysis program provides smaller grants for basic research, data analysis, and the development of new techniques so as to foster innovative approaches, new ideas, and combined analysis of multiple data sources not envisioned in original mission proposals. This range of activities is vitally important to the basic structure and diversity of SEC activities.
Recommendation 2. The programs that underpin the LWS and STP mission lines—MO&DA, Explorers, the Suborbital program, and SR&T—should continue at a pace and a level that will ensure that they can fill their vital roles in SEC research.
The scientific rationale that supported the decadal survey report’s recommendations and mission sequencing remains valid, but the committee recognizes that adjustment of the implementation schedule may become necessary to respond to evolving resource constraints. The preceding chapters have outlined the relevance, scientific validation, and prioritization of the SEC missions, research, and research support activities. The implementation of the near-term SEC mission should remain in the order recommended by the decadal survey report: i.e., MMS (with a 2010 launch), Geospace Network, GEC, and MHM/Sentinels with as much overlap as feasible within available resources.
A sample SEC resource allocation through FY2009 as presented in the decadal survey report is shown in Figure 3.1(a). To demonstrate the recommended mix of missions and how these missions can be accomplished within realistic SEC cost constraints, Figure 3.1(b) presents a composite schedule and fiscal projection in keeping with this committee’s recommendations. The revised plan represents a significant decrease in annual funding and a delay of mission start dates relative to the plan recommended in the decadal survey report. The recommended plan includes a balance of missions addressing the interrelated research areas of solar physics, heliospheric processes, and solar-planetary interactions. This mix of missions supports the exploration vision with a balance of applied and basic science. This mix also will provide the key data resources needed to support human and robotic exploration, including the underlying physical understanding needed to make these data resources relevant.
MMS remains the highest-priority new moderate mission recommended by the committee. The need for overlap of MMS and the Geospace Network probes with the SDO mission indicates a 2006 start date for Geospace Network and the maintenance of a 2010 launch for MMS. The balanced approach that underlies the program plan indicates starts of the Solar Orbiter, GEC, and MHM/Sentinels investigations in 2009 and shortly thereafter. The decadal survey report recommended Solar Probe as the highest-priority large mission, with a new start in 2006 in the survey report's preferred program. The survey report also presented a more constrained profile in which Solar Probe would slip to a start in 2011. This committee recommends that even in a more constrained resource environment Solar Probe should start by 2008 because of its importance for enabling exploration.
The committee has considered whether a reordering of the mission sequence would provide better support for the exploration vision. The information currently available on the proposed missions does not warrant a change in the near-term missions in the plan developed in the decadal survey report. The timing of MHM/Sentinels and other later missions should be reconsidered after further planning of these missions occurs so that they can be properly prioritized in light of the exploration goals.
Recommendation 3. The near-term priority and sequence of solar, heliospheric, and geospace missions should be maintained as recommended in the decadal survey report both for scientific reasons and for the purposes of the exploration vision.
In the new, “stretched” schedule that accommodates the expanded scope of exploration, the scientific goals for solar and space physics are compromised, particularly in the loss of synergy among missions that will no longer overlap unless missions are extended beyond their nominal lifetime. For example, the Geospace Network is devoted to studying the response of the near-space environment and the radiation belts. The near-space environment is dramatically influenced by the solar extreme ultraviolet (EUV) spectral flux. A significant science objective of the missions is to uncover the relative influence of EUV radiation and magnetospheric and solar particles in controlling the storm time evolution of the atmosphere. Detailed measurements of the solar EUV spectrum on SDO and overlap between SDO and the Geospace Network ionosphere-thermosphere storm probes would allow this question to be fully resolved. Such an accomplishment will now require an extended mission for SDO. Similarly a critical overlap between MMS and the Geospace Network radiation belt storm probes was envisaged to relate storm time energization of the inner-zone electrons to reconfiguration of magnetic and electric fields in the magnetosphere and therefore more directly to solar activity. Such a study will now require an extended mission for MMS.
In addition to the losses of scientific synergy that will arise from delaying the pace at which missions are executed there will be other important consequences. A number of missions that were recommended in the decadal survey report will be deferred beyond the 10-year planning horizon. This could be the case for the Jupiter Polar Mission, Stereo Magnetospheric Imager, Magnetospheric Constellation, Solar Wind Sentinels, and Mars Aeronomy Probe. These issues will demand careful attention as NASA develops its overall plan for science in the exploration vision. The committee concurs with the views expressed in the decadal survey report that there should be opportunities to leverage contributions from both inter-agency and international partners in a way that will permit a more robust program in a constrained resource environment.
The Jupiter Polar Mission, which was given a high priority in the decadal survey report, is an important exploration science mission in its own right. The Mars Aeronomy Probe, which was
recommended in the solar system exploration survey4 but deferred in the solar and space physics decadal survey report, now takes on heightened significance because of its role as both an enabling mission and a scientific exploration mission. Both missions deserve serious consideration in the overall context of solar system exploration priorities.
