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Solar and Space Physics: A Science for a Technological Society
240
SOLAR AND SPACE PHYSICS: A SCIENCE FOR A TECHNOLOGICAL SOCIETY
X-ray detectors will be launched on stratospheric balloons to measure electron precipitation in conjunction with RBSP. These measurements will quantify the precipitation loss rate, will probe the global spatial
structure of energetic precipitation for the first time, and, when combined with RBSP measurements, will
allow for quantitative tests of wave-particle interaction theories.
The critical importance of these two missions for achieving some of the panel’s high-priority science
objectives for the coming decade leads to the following SWMI imperative:
SWMI Imperative: Complete the strategic missions that are currently in development (MMS, RBSP/
BARREL) as cost-effectively as possible.
Solar Probe Plus and Solar Orbiter
These missions, while aimed directly at solar and heliospheric science objectives, are also likely to shed
light on fundamental physical processes that are high on the list of science objectives for SWMI, namely,
particle acceleration, reconnection, turbulence, and wave-particle interactions. Insights gained about how
these processes work near the Sun can potentially help advance understanding of how they operate in
near-Earth space, thereby helping address SWMI critical science goals 4 through 6.
9.5.2.2 Heliophysics Systems Observatory
The globally coupled nature of the solar wind-magnetosphere-ionosphere system demands simultaneous measurements of related phenomena in widely spaced locations. Thus, crucial information comes
from combining observations from existing operating satellites, both from NASA (ACE, TWINS, SAMPEX,
THEMIS, Cluster, planetary missions, and so on) and from other agencies and other nations (e.g., GOES,
LANL, DMSP, POES). The demonstrated value of these existing assets far surpasses their original intended
use, and it is extremely important that they continue to be supported for the contributions they can make
to the evolving science objectives.
In the area of comparative magnetospheres, Juno will enter its prime mission phase when it arrives at
Jupiter in 2016, while Cassini at Saturn is approved for a final mission extension to 2017, and Messenger
will complete its prime mission early in the decade. Past and current missions continue to provide deep
insights into general solar wind magnetosphere interactions. For example, Ganymede’s Alfvén wings
have led to modern theories of Earth’s own polar cap potential saturation mechanism; Saturn’s explosive
energy releases have much in common with substorm injections at Earth; and Jupiter’s interchange motions
enabling convection under Io’s mass loading have led to similar theories pertaining to inward penetration
of fast reconnection flows. As is the case for Earth-orbiting satellites, extended missions for planetary missions that continue to return valuable science data are strongly encouraged.
SWMI Imperative: A high priority of the panel is to ensure strong continued support for existing satellite assets that can still contribute significantly to high-priority science objectives. For example, careful
optimization of existing assets to address RBSP and MMS objectives will result in a significant gain in the
science return from these missions.
9.5.2.3 Explorers and Alternate Platforms
Since the inception of the space age, the Explorer program has been a mainstay of science return,
including significant contributions to the progress outlined in Section 9.3. The Explorer missions, with science objectives and implementations identified competitively, provide scientific agility and the ability to
Solar and Space Physics: A Science for a Technological Society
240
SOLAR AND SPACE PHYSICS: A SCIENCE FOR A TECHNOLOGICAL SOCIETY
X-ray detectors will be launched on stratospheric balloons to measure electron precipitation in conjunction with RBSP. These measurements will quantify the precipitation loss rate, will probe the global spatial
structure of energetic precipitation for the first time, and, when combined with RBSP measurements, will
allow for quantitative tests of wave-particle interaction theories.
The critical importance of these two missions for achieving some of the panel’s high-priority science
objectives for the coming decade leads to the following SWMI imperative:
SWMI Imperative: Complete the strategic missions that are currently in development (MMS, RBSP/
BARREL) as cost-effectively as possible.
Solar Probe Plus and Solar Orbiter
These missions, while aimed directly at solar and heliospheric science objectives, are also likely to shed
light on fundamental physical processes that are high on the list of science objectives for SWMI, namely,
particle acceleration, reconnection, turbulence, and wave-particle interactions. Insights gained about how
these processes work near the Sun can potentially help advance understanding of how they operate in
near-Earth space, thereby helping address SWMI critical science goals 4 through 6.
9.5.2.2 Heliophysics Systems Observatory
The globally coupled nature of the solar wind-magnetosphere-ionosphere system demands simultaneous measurements of related phenomena in widely spaced locations. Thus, crucial information comes
from combining observations from existing operating satellites, both from NASA (ACE, TWINS, SAMPEX,
THEMIS, Cluster, planetary missions, and so on) and from other agencies and other nations (e.g., GOES,
LANL, DMSP, POES). The demonstrated value of these existing assets far surpasses their original intended
use, and it is extremely important that they continue to be supported for the contributions they can make
to the evolving science objectives.
In the area of comparative magnetospheres, Juno will enter its prime mission phase when it arrives at
Jupiter in 2016, while Cassini at Saturn is approved for a final mission extension to 2017, and Messenger
will complete its prime mission early in the decade. Past and current missions continue to provide deep
insights into general solar wind magnetosphere interactions. For example, Ganymede’s Alfvén wings
have led to modern theories of Earth’s own polar cap potential saturation mechanism; Saturn’s explosive
energy releases have much in common with substorm injections at Earth; and Jupiter’s interchange motions
enabling convection under Io’s mass loading have led to similar theories pertaining to inward penetration
of fast reconnection flows. As is the case for Earth-orbiting satellites, extended missions for planetary missions that continue to return valuable science data are strongly encouraged.
SWMI Imperative: A high priority of the panel is to ensure strong continued support for existing satellite assets that can still contribute significantly to high-priority science objectives. For example, careful
optimization of existing assets to address RBSP and MMS objectives will result in a significant gain in the
science return from these missions.
9.5.2.3 Explorers and Alternate Platforms
Since the inception of the space age, the Explorer program has been a mainstay of science return,
including significant contributions to the progress outlined in Section 9.3. The Explorer missions, with science objectives and implementations identified competitively, provide scientific agility and the ability to