Applying Near-surface Geophysicical Technology to Determine Engineering Properties of the Upper 30m of the Lunar Surface

Introduction: Several experiments performed by the astronauts on the Moon (e.g., the Apollo Lunar Surface Experiments Package, ASLEP), and proposed experiments as ground-prep for the return of humans to the Moon (RPLP-2/LPRP-2) involve the use of seismic (acoustic) energy for exploration. These seismic signals can be used for a wide array of purposes, from imaging the Lunar interior to detecting evidence of strange quark matter. However, one important—but often overlooked—use of seismic signals is in determining engineering properties (e.g., Poisson's Ratio) of the shallowest layers of the Lunar subsurface. Understanding the physical properties within the upper 100m of the Lunar surface will be critical as Lunar exploration advances and the deployment of large structures becomes necessary. A priori knowledge of the load-bearing capacities of the surface layers will be critical. Methods: There have been tremendous advances in near-surface geophysical technology, since the Apollo missions, which have greatly improved our ability to quickly and easily resolve subsurface variations in physical properties that relate to Young's Modulus, Bulk-or Shear-Modulus, and Poisson's Raito [1]. These active-source seismic techniques include the analysis of seismic surface waves and P-& S-wave refraction tomography. A large volume of literature exists demonstrating the usefulness of these techniques in determining engineering parameters