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2. GLOBAL GEOSPACE SCIENCE/INTERNATIONAL SOLAR TERRESTRIAL PHYSICS 
   PROJECT AT NASA/GODDARD SPACE FLIGHT CENTER
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From: Mario H. Acuna (u2mha@lepvax.gsfc.nasa.gov) 

Solar-terrestrial physics concerns the study of the generation, flow,
and evolution of mass, momentum, and energy between the Sun and the 
Earth.  The GGS Science initiative addresses the fundamental issues 
related to the quantitative understanding of the global Solar-
Terrestrial system in which we live.  GGS is part of the 
International Solar Terrestrail Physics Program (ISTP) and includes 
the POLAR spacecraft, the WIND spacecraft which will be launched 
November 1 from the Kennedy Space Center, and the Japanese GEOTAIL 
spacecraft which was launched in July of 1992.

Newly developed particle imaging detectors, quantitative multi-
spectral high resolution photon imaging, integrated theory, data 
visualization, multi-point coordinated measurements, and the 
extensive use of "intelligent" instruments are just some of the 
innovative science techniques that GGS employs.  NASA/GSFC 
instrument contributions on the WIND spacecraft include 1) the Solar
Wind Experiment (K. Ogilvie, PI), 2) the Magnetic Fields 
Investigation (R. Lepping, PI), 3) the Energetic Particle 
Acceleration, Composition, and Transport instrument (T. Von 
Rosenvinge, PI), and 4) the Transient Gamma Ray Spectrometer 
(B. Teegarden, PI).  Goddard also houses the Control and Data 
Handling Facility (CDHF) for the storage, cataloging and 
organization of data and the Science and Operations Facility 
(SPOF) to coordinate and focus instruments on various spacecraft 
for a particular event.  

Other instruments onboard include the Radio and Plasma Waves 
experiment (J. Bougeret, PI) and the University of Minnesota 
developed at the Paris Observatory, the Solar Wind Ion Composition 
Study (G. Gloeckler, PI) from the University of Maryland, and the 
Three-Dimensional Plasma Analyzer (R. Lin, PI) developed at the 
University of California/Berkeley.  The Gamma Ray Spectrometer 
(E. Mazets and T. Cline, PI's), developed by the Ioffe Institute in
Russia and NASA/GSFC, has the distinction of being the first 
Russian instrument to fly on an American satellite.

Utilizing the WIND, POLAR, GEOTAIL, and additional equatorial 
satellite data as well as ground-based observations, GGS will 
simultaneously and closely coordinate measurements of the key 
geospace regions to provide a time history of disturbances, 
theoretical studies and modeling, and a quantitative understanding 
of the physics that underlies the system.  Ultimately, with the ISTP
spacecraft additions of SOHO and Cluster spacecraft, the complete 
solar-terrestrial energy chain will be studied in detail.

Each spacecraft is strategically placed so as to derive the optimum
data from key regions.  WIND will be stationed in the solar wind 
upstream from the Earth to observe solar wind and interplanetary 
magnetic field before it reaches the Earth's magnetosphere, POLAR 
will measure the flow of plasma to and from the ionosphere on 
auroral magnetic field lines and will observe the deposition of 
particle energy into the ionosphere and upper atmosphere while 
GEOTAIL provides extensive measurements of entry, storage, 
acceleration, and transport in the geomagnetic tail.  Additional 
Equatorial missions will observe and sample the buildup of 
particles in the Van Allen radiation belts.

The WIND spacecraft, because of its position, will have the 
capability of early detection of outbursts and fluctuations in the 
solar plasma flow and will provide unique insight into the future 
prediction of magnetic storm effects on power systems, the energetic
particle effects on spacecraft, and the communication interruptions
on ground systems.

Contact:
Mario H. Acuna
Project Scientist
(301) 286-7258

Keith Ogilvie
Deputy Project Scientist for the WIND spacecraft
(301) 286-5904