Satellite Geodynamics

Satellite geodynamics concerns the use of space technology in the study of the dynamic processes and movements of the solid Earth. The study involves measurements of the Earth's gravity and magnetic fields, the distortions and relative motions of its tectonic plates and the orientation of, and rate of rotation about, its axis. These studies address fundamental questions of geophysics such as the causes of Earth movements and earthquakes, the nature of convection in the mantle, and the origin of the magnetic field. The use of space technology has helped advance our concepts and models in solid-Earth geophysics. Shortly after the dawn of the space age, tracking data were used to precisely define the pear-shaped Earth. Since that time, other data have given several up-to-date representations of the secularly changing magnetic field and global models of the gravity field. Using this technology, it is now possible to determine the contemporary rate of relative plate motion at the level of about 1 cm a year. There are exciting prospects for future missions in satellite geodynamics. The Geopotential Research Mission is designed to improve gravity and magnetic field models and new, highly portable geodetic systems based on the Global Positioning System and spaceborne laser systems should permit rapid determination of positions with 1-cm precision.