Journal Article

The bearing capacity of asteroid (65803) Didymos estimated from boulder tracks

Ernst, C. M., Sunday, C., Daly, R. T., Pajola, M., Lombardo, P., Scheeres, D. J., Zhang, Y., Rivkin, A. S., Barnouin, O. S., Murdoch, N., Vincent, J. B., Lucchetti, A., Vivet, D., Sunshine, J., Campo-Bagatin, A., Michel, P., Chabot, N. L., Bigot, J.

2024

Overview

The bearing capacity - the ability of a surface to support applied loads - is an important parameter for understanding and predicting the response of a surface. Previous work has inferred the bearing capacity and trafficability of specific regions of the Moon using orbital imagery and measurements of the boulder tracks visible on its surface. Here, we estimate the bearing capacity of the surface of an asteroid for the first time using DART/DRACO images of suspected boulder tracks on the surface of asteroid (65803) Didymos. Given the extremely low surface gravity environment, special attention is paid to the underlying assumptions of the geotechnical approach. The detailed analysis of the boulder tracks indicates that the boulders move from high to low gravitational potential, and provides constraints on whether the boulders may have ended their surface motion by entering a ballistic phase. From the 9 tracks identified with sufficient resolution to estimate their dimensions, we find an average boulder track width and length of 8.9 ± 1.5 m and 51.6 ± 13.3 m, respectively. From the track widths, the mean bearing capacity of Didymos is estimated to be 70 N/m 2 , implying that every 1 m 2 of Didymos’ surface at the track location can support only ~70 N of force before experiencing general shear failure. This value is at least 3 orders of magnitude less than the bearing capacity of dry sand on Earth, or lunar regolith. Bearing capacity, the ability of a surface to support applied loads, is a critical property in planetary exploration to understand a surface’s response to landing or roving. Here, the bearing capacity of the asteroid Didymos is estimated using DART images of suspected boulder tracks on its surface.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 639/33/445/848 / 704/445/848 / Asteroids / Astrophysics / Bearing capacity / Boulders / Earth and Planetary Astrophysics / Gravity / Humanities and Social Sciences / Load / Lunar landing / Lunar surface / Mars / Moon / multidisciplinary / Regolith / Science / Science (multidisciplinary) / Sciences of the Universe / Space exploration / Surface motion