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Solar and Space Physics: A Science for a Technological Society
REPORT OF THE PANEL ON ATMOSPHERE-IONOSPHERE-MAGNETOSPHERE INTERACTIONS
183
missions; Explorers, suborbital, and other platforms; ground-based facilities; theory and modeling; and
enabling capabilities. Priorities within each are indicated below.
8.5.1 Spaceflight Missions
As stated previously, the nature of AIM science is that it requires a synergistic complement of spacebased and ground-based observational approaches with complementary theory and modeling activities.
However, there are no NASA missions in development or approved for development that address these
priorities, and therefore there is a void in the current capacity to understand the solar-terrestrial system
and to contribute to the space weather needs of 21st-century society. It is the AIMI panel’s view that the
Heliophysics Systems Observatory should be continued with a mission that determines how solar energy
drives ionosphere-thermosphere variability, and that lays the foundation for a space weather prediction
capability. There are two complementary notional missions that are put forth as the panel’s highest-priority
imperatives to satisfy this need: GDC and DYNAMIC. Out of the many different means of measuring the AIM
system, they are representative of the types of missions that will provide the needed global view unattainable in any other way (i.e., Explorer-class missions, which are less costly). GDC (a large-class mission) and
DYNAMIC (a moderate-class mission) are described immediately below. Some level of detail is provided
to enable the reader to understand the scope of mission required to achieve its science goals and to relate
this to the broad cost categories described in Chapter 1 of this report. Thus, although some details are
provided, these missions are not prescriptive; the AIM community will ultimately decide on the optimal
implementation to achieve the science goal. Two additional notional missions, ESCAPE (Energetics, Sources
and Couplings of Atmosphere-Plasma Escape) and MAC (Magnetospheric-Atmosphere Coupling), are also
described below; each addresses very high priority science topics (i.e., regulation of the IT-magnetosphere
interaction and fundamental plasma processes).
8.5.1.1 GDC (Geospace Dynamics Constellation) Mission (Intermediate Class)
Overview
Assuming resources enable a new start early in the decadal survey interval, the AIMI panel sees the
Geospace Dynamics Constellation (GDC) as the optimal way to significantly advance both solar-terrestrial
and AIM science. GDC would be a fundamental contributor to the Heliophysics Systems Observatory while
also enabling measurements that are highly relevant for research aimed at understanding and developing
a predictive capability for space weather. The primary focus of GDC is to gather the necessary data to
reveal how the IT operates as a system and how it regulates its response to external forcing. With current
and foreseeable technologies, this requires a robust, systematic observation approach using in situ probes
to gather data at all local times and latitudes simultaneously. Furthermore, these satellites must gather data
at sufficiently low altitudes where both the neutral and ionized gases are sufficiently dense and inherently
coupled.
The observational problem is that such global dynamics cannot be captured by a single satellite regardless of the number of its instrument probes. When averaged over a sufficiently long period of time, data from
a single satellite provides a useful climatology as a function of latitude and longitude. However, such data
are static and do not show the physical coupling inherent in the continuously adjusted density contours
and velocity patterns (dynamics) that, by their very nature, respond at all local times to the interconnected
processes that define the AIM system. On the other hand, a constellation of identical, multiple satellites
in low Earth orbit, such as proposed here as the Geospace Dynamics Constellation, would provide the
necessary global, simultaneous observations covering all latitudes and local times while orbiting Earth in
Solar and Space Physics: A Science for a Technological Society
REPORT OF THE PANEL ON ATMOSPHERE-IONOSPHERE-MAGNETOSPHERE INTERACTIONS
183
missions; Explorers, suborbital, and other platforms; ground-based facilities; theory and modeling; and
enabling capabilities. Priorities within each are indicated below.
8.5.1 Spaceflight Missions
As stated previously, the nature of AIM science is that it requires a synergistic complement of spacebased and ground-based observational approaches with complementary theory and modeling activities.
However, there are no NASA missions in development or approved for development that address these
priorities, and therefore there is a void in the current capacity to understand the solar-terrestrial system
and to contribute to the space weather needs of 21st-century society. It is the AIMI panel’s view that the
Heliophysics Systems Observatory should be continued with a mission that determines how solar energy
drives ionosphere-thermosphere variability, and that lays the foundation for a space weather prediction
capability. There are two complementary notional missions that are put forth as the panel’s highest-priority
imperatives to satisfy this need: GDC and DYNAMIC. Out of the many different means of measuring the AIM
system, they are representative of the types of missions that will provide the needed global view unattainable in any other way (i.e., Explorer-class missions, which are less costly). GDC (a large-class mission) and
DYNAMIC (a moderate-class mission) are described immediately below. Some level of detail is provided
to enable the reader to understand the scope of mission required to achieve its science goals and to relate
this to the broad cost categories described in Chapter 1 of this report. Thus, although some details are
provided, these missions are not prescriptive; the AIM community will ultimately decide on the optimal
implementation to achieve the science goal. Two additional notional missions, ESCAPE (Energetics, Sources
and Couplings of Atmosphere-Plasma Escape) and MAC (Magnetospheric-Atmosphere Coupling), are also
described below; each addresses very high priority science topics (i.e., regulation of the IT-magnetosphere
interaction and fundamental plasma processes).
8.5.1.1 GDC (Geospace Dynamics Constellation) Mission (Intermediate Class)
Overview
Assuming resources enable a new start early in the decadal survey interval, the AIMI panel sees the
Geospace Dynamics Constellation (GDC) as the optimal way to significantly advance both solar-terrestrial
and AIM science. GDC would be a fundamental contributor to the Heliophysics Systems Observatory while
also enabling measurements that are highly relevant for research aimed at understanding and developing
a predictive capability for space weather. The primary focus of GDC is to gather the necessary data to
reveal how the IT operates as a system and how it regulates its response to external forcing. With current
and foreseeable technologies, this requires a robust, systematic observation approach using in situ probes
to gather data at all local times and latitudes simultaneously. Furthermore, these satellites must gather data
at sufficiently low altitudes where both the neutral and ionized gases are sufficiently dense and inherently
coupled.
The observational problem is that such global dynamics cannot be captured by a single satellite regardless of the number of its instrument probes. When averaged over a sufficiently long period of time, data from
a single satellite provides a useful climatology as a function of latitude and longitude. However, such data
are static and do not show the physical coupling inherent in the continuously adjusted density contours
and velocity patterns (dynamics) that, by their very nature, respond at all local times to the interconnected
processes that define the AIM system. On the other hand, a constellation of identical, multiple satellites
in low Earth orbit, such as proposed here as the Geospace Dynamics Constellation, would provide the
necessary global, simultaneous observations covering all latitudes and local times while orbiting Earth in