Exploring planetary regolith: deriving geotechnically meaningful properties from penetrometry
Abstract
Understanding the properties of planetary regolith is important for unravelling the origin and evolution of bodies in our solar system. On Earth, properties of regolith are identified in the laboratory through a variety of methods such as coring samples, shear tests, and triaxial tests. In space missions, these laboratory methods cannot be used, and one must rely on in-situ measurements for identifying soil mechanical properties. Penetrometers are perfect for this due to their small size, light weight and simple use. Penetrometers have been used on Earth to identify soil shear strength properties such as cohesion and angle of internal friction. However, results are highly dependent on the experimentally obtained data and the types of soil that are tested. In this paper, we use a model developed by Kang et al., that links penetrometry data to geotechnically relevant quantities such as the angle of internal friction, test this model using our own laboratory experiments, and compare this to known values as well as triaxial test results. We identified that for silica glass beads the effects of grain size and tip shape are very pronounced, with similar values of internal friction found in other sources and our triaxial tests. We observed that penetrometry can indicate similar angles of internal friction comparable to laboratory values for more irregular and angular sample materials such as the Phobos simulant used to prepare for JAXA's MMX mission. Our results suggest that a penetrometer could be used as a ‘poor man's triaxial test’ in planetary exploration.
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BibTeX
@article{smythmoore2026exploring,
title = {{Exploring planetary regolith: deriving geotechnically meaningful properties from penetrometry}},
author = {Alexander Smyth-Moore and Erika Kaufmann and Qi Jia and Naomi Murdoch and Hideaki Miyamoto and Mikael Granvik and Axel Hagermann},
journal = {Monthly Notices of the Royal Astronomical Society},
year = {2026},
month = oct,
doi = {10.1093/mnras/staf982},
url = {https://hal.science/hal-05723770v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Exploring planetary regolith: deriving geotechnically meaningful properties from penetrometry
AU - Alexander Smyth-Moore
AU - Erika Kaufmann
AU - Qi Jia
AU - Naomi Murdoch
AU - Hideaki Miyamoto
AU - Mikael Granvik
AU - Axel Hagermann
PY - 2026
DA - 2026/10/01
JO - Monthly Notices of the Royal Astronomical Society
DO - 10.1093/mnras/staf982
UR - https://hal.science/hal-05723770v1
AB - Understanding the properties of planetary regolith is important for unravelling the origin and evolution of bodies in our solar system. On Earth, properties of regolith are identified in the laboratory through a variety of methods such as coring samples, shear tests, and triaxial tests. In space missions, these laboratory methods cannot be used, and one must rely on in-situ measurements for identifying soil mechanical properties. Penetrometers are perfect for this due to their small size, light weight and simple use. Penetrometers have been used on Earth to identify soil shear strength properties such as cohesion and angle of internal friction. However, results are highly dependent on the experimentally obtained data and the types of soil that are tested. In this paper, we use a model developed by Kang et al., that links penetrometry data to geotechnically relevant quantities such as the angle of internal friction, test this model using our own laboratory experiments, and compare this to known values as well as triaxial test results. We identified that for silica glass beads the effects of grain size and tip shape are very pronounced, with similar values of internal friction found in other sources and our triaxial tests. We observed that penetrometry can indicate similar angles of internal friction comparable to laboratory values for more irregular and angular sample materials such as the Phobos simulant used to prepare for JAXA's MMX mission. Our results suggest that a penetrometer could be used as a ‘poor man's triaxial test’ in planetary exploration.
SN - 0035-8711
SN - 1365-2966
ER -