SPARTA: IN-DEPTH CHARACTERIZATION OF THE GEOMECHANICAL PROPERTIES OF PLANETARY REGOLITH

Comprehensive characterization of the subsurface properties of in situ planetary regolith is critical to the operational success of all future planetary landed science missions involving surface or near-surface contact. Understanding the geomechanical properties of planetary regolith and determining the presence and the chemical potentials of water and ice are central to NASA’s exploration strategy for future manned long-term exploration of the Moon. SPARTA (Soil Properties Assessment, Resistance, Thermal, Analysis) is a highly versatile, miniature toolkit that can robotically deploy a cone penetrometer/vane shear geomechanical tool that incorporates a dielectric probe and thermal conductivity measurements at depth (< 1m) into planetary surfaces.

NASA’s planetary exploration enterprise depends on a thorough understanding of the near-surface environmental and geomechanical properties of planetary regolith. Understanding the regolith properties can shed light on several important scientific questions, such as how the surface evolved over time, how water is delivered and distributed within the inner solar system, and how the regolith temperature changes within the diurnal cycle. Understanding regolith properties is also crucial for the success of planetary missions. In addition, the validation of future rover concepts and operations will rely on a comprehensive examination of the strength and deformation behavior of in situ planetary regolith. Designers of landing systems, such as pads, airbags, and braking rockets require an understanding of how their hardware will interact with the regolith, and Understanding the geomechanical properties of in situ planetary regolith is critical for such determinations. SPARTA is a toolkit designed to analyze planetary regolith's in situ geomechanical properties and ice content, including the density and thermal properties at specified increments with depth. The miniaturized SPARTA toolkit encompasses four terrestrial regolith components, a Thermal Conductivity Probe (TCP), a Vane Shear Tester (VST), a Cone Penetration Tester (CPT), and a Dielectric Spectroscopy Probe (DSP) designed for a variety of planetary surfaces; for bodies as diverse as Trojan asteroids, Mars, Titan, Moon, and Ocean World bodies (Planetary Science Decadal Study, 2022).