HR: 0800h
AN: SA51B-1133    [Abstracts]
TI: Dippers, Constellations, and Mappers -- Satellite Orbits and Multiple Satellite Configurations to Significantly Advance our Knowledge of the Earth`s Ionosphere and Thermosphere
AU: * Pfaff, R F
EM: rob.pfaff@gsfc.nasa.gov
AF: NASA/GSFC, Code 612.3, Greenbelt, MD 20771 United States
AU: Grebowsky, J M
EM: joe.grebowsky@ssedmail.gsfc.nasa.gov
AF: NASA/GSFC, Code 612.3, Greenbelt, MD 20771 United States
AB: Direct measurements using in situ probes have been at the forefront of aeronomy research since the earliest satellite and rocket-borne measurements of the upper atmosphere. The most effective in situ measurement packages are those that gather simultaneous measurements of comprehensive gas properties (density, composition, temperature, and velocity of both the neutral and ionized species), electrodynamic parameters (DC and AC electric fields and magnetic fields), and energetic charged particle populations including both electrons and ions from suprathermal to higher energies. Although satellite measurements are essential for revealing the numerous physical plasma and neutral gas processes at work in the upper atmosphere and how they are related to the magnetosphere above and the troposphere below, there remain many critical regions of the earth's upper atmosphere that have not yet been sampled, or have been sampled very poorly. Chief among these is the lower ionosphere/thermosphere (below 200 km), where our direct knowledge of the energy transfer and dissipation, winds, electrodynamics, and chemistry are practically non-existent. The lower ionosphere remains very much a 'frontier' within geospace for which our knowledge base is poor and for which critical measurement inputs for models of the ionosphere/thermosphere system are not available. Multiple satellite missions in the ionosphere/thermosphere region are expected to revolutionize our knowledge of aeronomy in the earth's ionosphere/thermosphere system. Examples of new missions concepts, including some that are already far advanced in the NASA formulation stage, include: (1) constellations of identical satellites (e.g., GEC) that will be flown in a variety of configurations to provide information on the neutral and plasma scales and how they interact, couple, and dissipate energy; (2) missions with simultaneous orbits along different longitudes (e.g., I-TSP, Ionospheric Mappers) that promise to provide critical information at different local times which are essential to understand the large scale/global extent of key physical processes; and (3) multiple satellites in elliptical orbits within the same orbit plane but with diametrically opposed major axes (e.g., Tropical Coupler) which will provide the simultaneous measurements at different altitudes needed for understanding the chemistry, gravity wave, and electrodynamic structuring within the I-T system with respect to altitude. This talk will present a variety of new mission concepts involving in situ probes and discuss the most critical areas in aeronomy for which such measurements promise to significantly advance our knowledge and understanding. We discuss the trade space and challenges of optimizing orbit and platform selection given the restrictions imposed by both finite resources as well as the physical laws of motion which govern satellite orbits.
DE: 0355 Thermosphere: composition and chemistry
DE: 2427 Ionosphere/atmosphere interactions (0335)
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2435 Ionospheric disturbances
DE: 2467 Plasma temperature and density
SC: SPA-Aeronomy [SA]
MN: Fall Meeting 2005