Simulation gravity modeling to spacecraft‐tracking data: Analysis and application

Abstract

It is proposed that line‐of‐sight gravity measurements derived from spacecraft‐tracking data can be used for quantitative subsurface density modeling by suitable orbit simulation procedures. Such an approach avoids complex dynamic reductions and is analogous to the modeling of conventional surface gravity data. This procedure utilizes the vector calculations of a given gravity model in a simplified trajectory integration program that simulates the line‐of‐sight gravity. Solutions from an orbit simulation inversion and a dynamic inversion on Doppler observables compare well (within 1% in mass and size), and the error sources in the simulation approximation are shown to be quite small. An application of this technique is made to lunar crater gravity anomalies by simulating the complete Bouguer correction to several large young lunar craters. It is shown that the craters all have negative Bouguer anomalies.

Lunar Multiring Basins and the Cratering Process

“…For instance, it is possible that as one goes to larger crater sizes, the importance of acoustic fluidization becomes increasingly important in terms of the amount of uplift that occurs on the Moho. The fact that smaller craters (∼100 km diameter) are largely uncompensated (Phillips et al 1978) indicates that little floor uplift has occurred for these craters, consistent with this hypothesis.…”

Gravity anomalies on Venus

“…Simulations were performed, where two different topographic features were evaluated. The simulations were made using the spacecraft orbital elements of the real orbit, so all geometries of the real data situation were duplicated [Phillips et al, 1978]. The simulated observations were then reduced in the same manner as the real data (i.e., a least squares batch filter).…”

Stress analysis of Tellus Regio, Venus, based on gravity and topography: Comparison with Venera 15/16 radar images

“…Despite the fact that we have had data from the Pioneer Venus Orbiter for more than 10 years and Venera 15/16 radar images for more than 5 years, we still lack a basic understanding of the style of tectonics on Venus. The evidence for terrestrial-type plate tectonics on Venus has been generally questioned [Phillips et al, 1981;Phillips and Malin, 1983;Kaula, 1984Kaula, , 1990Grimm and Solomon, 1989], although the issue is far from resolved [Head et al, 1981;Crumpler et al, 1987]. However, preliminary analysis of Magellan images indicates that large-scale surface deformation on Venus is not compatible with terrestrial-type seafloor spreading.…”