Solar and Space Physics and Its Role in Space Exploration (2004) / Chapter Skim
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Appendix B: Sun-Earth Connection Missions and Exploration
Appendix B: Sun-Earth Connection Missions and Exploration
Pages 35-51
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From page 35... ...
B Sun-Earth Connection Missions and Exploration The following one-page summaries describe key elements of the NASA Sun-Earth Connection program, including planned and recommended future Living With a Star and Solar Terrestrial Probe mission lines, the Explorer program, and critical supporting activities. The summaries utilize program information from NASA and the committee's assessment of the relevance of the projects and activities to the NASA exploration vision.
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From page 36... ...
Science Objectives Explorer missions are currently providing: Data on the triggering of coronal mass ejections (TRACE) and the source of solar energetic particles (RHESSI)
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Ground observatories time auroral breakup onset. Three inner probes at ~10 Re monitor current disruption onset, while two outer probes, at 20 and 30 Re, respectively, remotely monitor plasma acceleration due to lobe flux dissipation.
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This approach will shed light on the way that the Sun's magnetic field modulates solar luminosity and generates the milliondegree corona and supersonic solar wind, and also how the magnetic field contributes to the explosive release of solar flares and coronal mass ejections into the solar system. Solar-B will provide the first space-based observations of the Sun's vector magnetic fields, gathering continuous high-spatial- and high-temporal-resolution measurements over active-region scale fields of view.
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The resulting stereoscopic vision will help to construct a global picture of the Sun and its influences on the space environment. Science Objectives STEREO will attempt to: Understand the causes and mechanisms triggering coronal mass ejections, Characterize the propagation of coronal mass ejections through the heliosphere, Discover the mechanisms and sites of energetic particle acceleration in the low corona and the interplanetary medium, and Develop a three-dimensional, time-dependent model of the magnetic topology, temperature, density, and velocity structure of the ambient solar wind.
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Science Objectives SDO will study: The mechanisms driving the quasi-periodic, 11-year cycle of solar activity; The synthesis, concentration, and dispersion across the solar surface of the active region magnetic flux; The relation between magnetic reconnection on small scales and the reorganization of largescale field topology as well as magnetic reconnection's significance in heating the corona and accelerating the solar wind; The origins of the observed variations in the Sun's EUV spectral irradiance and their relation to magnetic activity cycles; The magnetic field configurations that lead to coronal mass ejections, filament eruptions, and flares that produce energetic particles and radiation; The degree to which the structure and dynamics of the solar wind near Earth can be determined from the magnetic field configuration and atmospheric structure near the solar surface; and The possibility of making accurate and reliable forecasts of space weather and climate. Relevance to Exploration Because solar activity is the primary driver of a range of potentially hazardous space weather effects, SDO's observations of the magnetic causes and dynamic repercussions of events such as coronal mass ejections and flares will, in conjunction with realistic models, greatly improve the accuracy of space weather forecasts.
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From page 41... ...
Reconnection is fundamental to our understanding of astrophysical and solar system plasma phenomena such as coronal mass ejections, solar flares, magnetospheric substorms, and the acceleration of relativistic particles throughout the cosmos. It is only in Earth's magnetosphere, however, that reconnection is readily accessible for sustained study through the in situ measurement of plasma properties and the electric and magnetic fields that govern its behavior.
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Science Objectives The Geospace Network will seek to understand and characterize: Radiation belt dynamics and underlying physical mechanisms including the acceleration, global distribution, and variability of radiation belt electrons and ions that produce the harsh space environment for spacecraft and humans; Mid-latitude ionospheric variability and the irregularities that affect communications and navigation systems as well as space assets; and The energetic and dynamical coupling between the mid-latitude ionosphere/thermosphere, the plasmasphere, and the ring current. Relevance to Exploration The Geospace Network addresses two fundamental processes of space physics -- particle acceleration and ionosphere-thermosphere-magnetosphere coupling -- each of which plays important roles in space weather.
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The basic physics of magnetosphere-ionosphere-thermosphere coupling is common to other planetary systems, specifically terrestrial planets such as Mars, and is best studied in the more readily accessible terrestrial environment. GEC will significantly improve our understanding of space weather processes in the lower ionosphere that are particularly relevant to NASA's research support to the DOD.
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The Solar Probe mission includes both in situ and remote sensing instruments on the spacecraft to fully characterize and understand the source regions and mechanisms governing the generation and flow of the solar wind, which links the Sun's magnetic field to the Earth and beyond. Science Objectives Solar Probe will seek to determine: The origin of the solar wind; Why the hot corona exists around the Sun; How the solar wind is accelerated; The mechanisms that store, accelerate, and transport energetic particles; The role of the plasma turbulence near the Sun; The quantitative relation between remote observations and the underlying fundamental physics of the corona; and The coronal magnetic field strength.
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These solar sentinels will study the formation and evolution of eruptions and flares from the Sun to Earth's magnetosphere, and they will try to explore and characterize the connection between solar events and geospace disturbances. Science Objectives The Multisatellite Heliospheric Mission is intended to determine: How the global character of the inner heliosphere changes with time, How geo-effective structures (coronal mass ejections, shocks, corotating interaction regions)
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The Solar Orbiter will co-rotate with solar active regions and be able to view the dynamic processes of flares and coronal mass ejections with very high precision. Science Objectives The Solar Orbiter will investigate: The in situ properties and dynamics of plasma, fields, and particles in the near-Sun heliosphere; The fine detail of the Sun's magnetized atmosphere using a camera capable of detecting solar features as small as 35 kilometers across; The links between activity on the Sun's surface and the resulting evolution of the corona and inner heliosphere using solar co-rotation passes; and The Sun's polar regions and equatorial corona from high latitudes.
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The atmospheric structure and dynamics and, in particular, the density profile are affected by variations in inputs from the Sun such as flares and coronal mass ejections, by inputs from the lower atmosphere like gravity waves, and by underlying crustal magnetic fields. The measurements to be returned by the Mars Aeronomy Probe and the subsequent modeling and data analysis will lead directly to predictive models for these important upper atmospheric effects.
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From a polar orbit, a Jupiter Polar Mission can study the plasma dynamics and moonionosphere electromagnetic coupling, processes that transfer angular momentum from the spinning central object to the surrounding plasma and have implications for the early phases of the formation of solar and planetary systems. Science Objectives The Jupiter Polar Mission can identify: The relative contributions of planetary rotation and the solar wind to the energy budget of the jovian magnetosphere, How the plasma circulates in the magnetosphere, The role of Io's volcanism in providing mass that drives the circulation process, The charged particles responsible for the jovian aurora and how those particles become energized, and The electrodynamic processes that couple the jovian moons to the planet's high-latitude ionosphere.
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The prime mission funding is guaranteed under the mission budget, and the extended mission funding is competitively awarded through periodic review of all ongoing missions. During the prime mission, an average of approximately 25 to 33 percent of the MO&DA budget is spent on missions operations, and the remainder is spent on science data analysis.
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Relevance to Exploration The Research and Analysis programs contribute significantly to the knowledge base needed to pursue the exploration initiative. Theoretical and modeling studies provide a conceptual foundation for interpreting measurements and observations in the Sun-heliosphere-planetary system, including those related to martian aeronomy, the jovian system, empirical data in Earth's near-space environment, and other regions relevant to the exploration initiative.
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Science Objectives The Suborbital program provides investigations into: Mesosphere/ionosphere interactions, Auroral physics, Equatorial ionosphere investigation of the electrojet and spread-F phenomena, Polar cusp studies, High-resolution solar coronal imaging, and Magnetic reconnection. Relevance to Exploration Suborbital missions stand to produce great technological and human capital benefits for the exploration initiative because of the programs' efficient approach to technology development and the hands-on training of the future workforce that these student-friendly missions enable.
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