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Solar and Space Physics: A Science for a Technological Society
SUMMARY
7
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.
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 Heliophysics Division 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 mission 6 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.
6 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.
Solar and Space Physics: A Science for a Technological Society
SUMMARY
7
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.
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 Heliophysics Division 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 mission 6 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.
6 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.