JPL Planetary Gravity Efforts and Techniques

The Magellan spacecraft has provided the highest resolution global gravity data set from spacecraft measurements. The X-band Doppler tracking is sensitive to harmonic degree of 120 or greater. We have developed a 75th degree and order global spherical harmonic model using a spatial constraint instead of the usual method. Results are presented for JPL Venus and Mars gravity field determination efforts and efforts are reviewed for developing higher degree models on supercomputers.