<h2>AAS 95-310</h2><h2>Preliminary Results from the Joint GSFC/DMA Gravity Model Project</h2><h4>R. S. Nerem, NASA Goddard Space Flight Center, Greenbelt, MD</h4><h2> Abstract </h2>The NASA/Goddard Space Flight Center (GSFC) and the Defense Mapping Agency (DMA) have embarked on a joint effort to develop an improved degree and order 360 spherical harmonic expansion of the Earth's gravitational potential which incorporates the best available surface gravity data, satellite altimetry, and satellite tracking data.  The new model will be of immediate use in defining a geoid undulation model that will be the basis for an enhanced WGS-84 geoid, however it will also be unclassified and thus useful for a variety of scientific and engineering applications.  A description of the model development and preliminary results will be presented.<br><br>