Determining the Relative Cratering Ages of Regions of Psyche’s Surface

Abstract

The study of the cratering history of asteroid (16) Psyche is one of the investigations to be performed by the NASA Psyche mission. A dedicated Relative Ages Working Group will carry on these investigations using primarily imaging and topographic data, and complement the interpretation of these data with theoretical models (hydrocodes to simulate impacts) as well as laboratory experiments (impact experiments on relevant target materials). The Psyche Science Team will also rely on experience and lessons learned from prior space missions, such as NASA Dawn and ESA Rosetta.The main goals of the cratering investigations are to map craters and characterize their morphology across Psyche’s surface over a range of spatial resolutions. These data will then be used to constrain relative and absolute ages of Psyche’s terrains, and impact-related processes will inform other investigations, such as geological mapping, surface composition, and internal structure. Psyche’s cratering data will also be used to perform comparative analyses with similar data from other rocky asteroids. The present chapter provides a pre-launch view of the planned activities and methodologies of the Relative Ages Working Group.

A Post‐Launch Summary of the Science of NASA's Psyche Mission

“…It is plausible that impact craters may be deeper and have sharper rims than previously seen on rocky asteroids: Marchi et al (2020) conducted hypervelocity impact experiments into metal targets and measured a mean depth-to-diameter ratio of craters in those targets of 0.41 ± 0.01, compared to a depth-to-diameter ratio of 0.15-0.25 for craters in rocky targets. Second, a wide diversity of crater morphologies may exist depending on the local abundance of iron and its proximity to the surface (Marchi et al, 2020(Marchi et al, , 2022Raducan et al, 2020). Detection of crater degradation or erasure may hint at seismic shaking events from subsequent impacts (e.g., Baijal et al, 2023).…”

“…Psyche will be the largest asteroid ever visited in the 100–500 km diameter size range, which could mark the transition between bodies that are too large to be destroyed in collisions and those that are instead the fragments of catastrophic collisions (Ceres and Vesta, with diameters larger than 500 km, could represent objects too large to be catastrophically disrupted as may have happened for Psyche) (e.g., Bottke et al., 2005; Marchi et al., 2022). Large M‐types have main‐belt orbits that suggest that they interacted with ancient mean motion resonances of Jupiter (i.e., resonances that existed before Jupiter's final migration phase; Scott et al., 2015).…”

“…Based on past missions to other asteroids and Earth-based observations of Psyche's shape, it is expected that impact craters will be preserved on its surface in varying states of degradation (Russell et al, 2013;Shepard et al, 2021). In addition to better understanding the physics of impacts into metalrich bodies (e.g., target cratering strength and crater morphology), comparison of the size-frequency distribution of craters on Psyche's surface with main-belt crater chronology will enable estimates of the age of the surface and comparison with the geologic histories of other solar system bodies (Marchi et al, 2020(Marchi et al, , 2022. To address these questions, high resolution imaging of the surface will be provided by the Multispectral Imager to count craters with diameters larger than 1 km over at least 50% of the surface.…”