Comparison of Phobos Geophysical Properties for different Shape Models using Voxel Mascons

• DOI: 10.5194/epsc2024-507
• Publication Date: 2024-07-03T11:09:04Z
• Authors: Benjamin Haser; Thomas Andert

AbstractSeveral space missions like Mars Global Surveyor, Express and Phobos 2 have already visited the Martian moon performed measurements regarding its geophysical properties. Those shown that it has a low average density (1861±11)kgm-3 [1], indicating high proportion of porosity. Comparison with other objects is challenging task, as not entirely clear whether C-type or D-type asteroid. highly irregular shape, resembling heavily cratered The limited information about inner mass distribution makes an interesting object for future research. By determining gravity field through precise orbit determination around body, possible to draw assumptions on body’s distribution. Information interior properties can then be used make conclusions formation evolution. However, investigate structure, some challenges must overcome. First, conversion discrete elements shape mandatory due contribution gravitational field. Secondly, suitable simulation environment necessary, which compute efficiently precision.This study compares two models Phobos, Ernst et. al [1] Willner [2] using voxel-based mass-concentration method [3], discretize each model different cube resolution reconstruction algorithms. We influence model, edge length choice algorithm following quantities, assuming homogeneous distribution:Gravity Coefficients Cnm, Snm Near-Surface Acceleration Principle Moments Inertia Ixx, Iyy, Izz Libration Amplitude Θ are able Gravity up arbitrary order, but focus our analysis C20 C22, since current only available values order two.Preliminary results volume in following. Figure 1 shows discretization Ernst’s voxels 400m pointcloud reconstruction. It observed various characteristics, such larger craters especially Stickney crater, well represented. Figure 1: Voxel model.Figure illustrates reconstructed voxel lengths green lines denote upper lower boundaries volume, while red blue dots correspond algorithm. representations demonstrate consistency measurement data, accounting uncertainties numerical errors. Results parameters will discussed this study.Figure 2: Volume approximation model.References[1] ERNST, Carolyn M., et al. High-resolution Deimos from stereophotoclinometry. Earth, Planets Space, 2023, 75. Jg., Nr. 1, S. 103[2] WILLNER, Konrad; SHI, Xian; OBERST, Juergen. Phobos' topography models. Planetary Space Science, 2014, 102. 51-59.[3] HASER, B., Voxel-based Density Models accurate Field Computation, EGU24