Feasibility of Imaging Asteroid Interior Using Gravity Gradiometry

Monday, 15 December 2014
Bradley Wilson and Yaoguo Li, Colorado School of Mines, Center for Gravity, Electrical, and Magnetic Studies, Department of Geophysics, Golden, CO, United States
We present a numerical study to evaluate the feasibility of imaging the interior structure of asteroids using gravity gradiometry. With the rapid advancement in gravity instrumentation in geosciences, it is realistic to envision space-borne systems that can measure the gravity field or its spatial gradients produced by asteroids in the near future. Such systems have related applications in planetary studies and in space resource exploration. It is therefore important to understand the information content in such data and the feasibility of imaging and characterizing asteroids using this emerging technology. Toward this goal, we focus on gravity gradiometry and carry out numerical simulations to understand the variation of gravity gradient tensors produced by asteroids, evaluate the signal strength due to the interior variation of density, and to assess the feasibility of imaging the internal structure through the reconstruction of density variation from measured gravity gradiometry data. We forward model the gravity gradiometry response from near-Earth asteroid 433 Eros by assuming a uniform density and observation points on spherical orbits at different distances. We also introduce synthetic density structure to assess the corresponding anomaly strengths. As a second example, we apply the simulation to 25143 Itokawa, which is known to have a strong internal density differential, and investigate the potential of directly imaging the transition between the two segments with strong density contrast.