A Pre-Landing Assessment of Regolith Properties at the InSight Landing Site

• Published in: Space science reviews Vol. 214; no. 6; pp. 1 - 47
• Main Authors: Morgan, Paul, Grott, Matthias, Knapmeyer-Endrun, Brigitte, Golombek, Matt, Delage, Pierre, Lognonné, Philippe, Piqueux, Sylvain, Daubar, Ingrid, Murdoch, Naomi, Charalambous, Constantinos, Pike, William T., Müller, Nils, Hagermann, Axel, Siegler, Matt, Lichtenheldt, Roy, Teanby, Nick, Kedar, Sharon
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.09.2018; Springer Nature B.V; Springer Verlag
• Subjects: Aerospace Technology and Astronautics; Albedo; Astrophysics and Astroparticles; Atmospheric pressure; Broadband; Diffusivity; Earth Sciences; Elastic properties; Emissivity; Engineering Sciences; Geophysics; Internal friction; Investigations; Lunar exploration; Mars; Mars landing; Mars missions; Mars surface; Mechanical properties; Modulus of elasticity; Physical properties; Physics; Physics and Astronomy; Planetology; Poisson's ratio; Pressure changes; Regolith; Sciences of the Universe; Seismic wave velocities; Seismic waves; Seismometers; Size distribution; Space Exploration and Astronautics; Space missions; Space Sciences (including Extraterrestrial Physics; Spacecraft; Specific heat; The InSight Mission to Mars II; Thermal conductivity; Thermal inertia; Thermophysical properties; Wave attenuation; Wave velocity; InSight landing site; Mars; Regolith; Physical properties; Regolith Physical properties
• ISSN: 0038-6308; 1572-9672
• DOI: 10.1007/s11214-018-0537-y

This article discusses relevant physical properties of the regolith at the Mars InSight landing site as understood prior to landing of the spacecraft. InSight will land in the northern lowland plains of Mars, close to the equator, where the regolith is estimated to be ≥ 3 – 5 m thick. These investigations of physical properties have relied on data collected from Mars orbital measurements, previously collected lander and rover data, results of studies of data and samples from Apollo lunar missions, laboratory measurements on regolith simulants, and theoretical studies. The investigations include changes in properties with depth and temperature. Mechanical properties investigated include density, grain-size distribution, cohesion, and angle of internal friction. Thermophysical properties include thermal inertia, surface emissivity and albedo, thermal conductivity and diffusivity, and specific heat. Regolith elastic properties not only include parameters that control seismic wave velocities in the immediate vicinity of the Insight lander but also coupling of the lander and other potential noise sources to the InSight broadband seismometer. The related properties include Poisson’s ratio, P- and S-wave velocities, Young’s modulus, and seismic attenuation. Finally, mass diffusivity was investigated to estimate gas movements in the regolith driven by atmospheric pressure changes. Physical properties presented here are all to some degree speculative. However, they form a basis for interpretation of the early data to be returned from the InSight mission.