and Ionospheric Coupling Investigation (MEDICI). The survey committee notes that MEDICI could not begin before 2024 absent a NASA Heliophysics Division budget augmentation or a reduction in the cost of other missions.

Each of the survey committee’s recommended STP moderate-scale space missions was subjected to a cost and technical evaluation (CATE) process (Box 1.4), and projected cost assessments were found to be consistent with the proposed life-cycle cost of $520 million for a mission in this renewed STP line. However, these costs are possible only so long as the STP missions are executed as competitively selected, cost-capped, and PI-led missions, as recommended.

Major Space Missions

Certain very-high-priority science investigations are of such scope and complexity that they can be undertaken only with major-mission-based research. In the current decade, two such missions are already underway—the Magnetospheric Multiscale mission, which is scheduled for launch in 2014, and the Solar Probe Plus (SPP) mission, which is scheduled for launch in 2018. In its deliberations, the survey committee


In September 2010, shortly after the present decadal survey commenced, the survey committee distributed widely to the solar and space physics community a request for information (RFI) for “a concept paper (e.g., about a mission or extended mission, observation, theory, or modeling activity) that promises to advance an existing or new scientific objective, contribute to fundamental understanding of the Sun-Earth system, and/or facilitate the connection between science and societal needs (e.g., improvements in space weather prediction).”1

Each submission was assigned to one or more of the survey’s three study panels for review, and each submission was assigned to a specific reader who prepared a short presentation that was discussed by the panel. Concepts of particular interest were discussed in more detail at a subsequent session, and, at the end of a lengthy review process, panels developed a short list of concepts for consideration by the survey committee. In making their selections, panels mapped concepts against their prioritization of science targets and also considered factors such as technical readiness, scientific impact on a particular discipline or disciplines, and, in some cases, operational utility. It is important to note that the concepts that were eventually forwarded to the survey committee were in some cases an amalgam of more than one submission; they also drew on the expertise of panel members.

At a meeting of the decadal survey committee, 12 mission concepts were selected for further study by the Aerospace Corporation, which under contract to the National Research Council provided a preliminary cost and technical evaluation (CATE) of the concepts. At a subsequent meeting, the survey committee reviewed the results of the pre-CATE and selected six concepts for a more thorough analysis, including an evaluation of the options for descopes and other trade-offs that would affect estimated cost. Details of this process are explained in Appendix E.

The CATE process provided an independent analytical approach to realistically assessing the cost and risk related to recommended initiatives that are typically expected at an early stage of formulation. Each of the Solar-Terrestrial Probes and Living With a Star missions recommended in this report were chosen from among the six candidate missions that underwent the detailed CATE process.


1 Further information about the RFI along with a compilation of submissions, which numbered nearly 300, is available on the decadal survey website at



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