Researchers at the University of Arizona simulated the formation of a large crater on metal-rich asteroid 16 Psyche to predict its internal structure ahead of NASA's arriving spacecraft. The study highlights the role of porosity in crater shapes and tests two possible compositions: a layered metallic core with rocky mantle or a uniform metal-silicate mix. Findings, published in JGR Planets, will aid interpretation of mission data expected in 2029.
Asteroid 16 Psyche, located in the main asteroid belt between Mars and Jupiter, is the 10th-most massive asteroid and the largest known primarily metallic object, measuring about 140 miles across. Discovered over two centuries ago, its origin remains debated: it could be the exposed core of a failed planet stripped by collisions, a fragment that lost its rocky shell, or a primordial metal-rich body shaped by impacts. NASA's Psyche spacecraft, set to arrive in 2029, aims to resolve these questions by measuring its surface, gravity, magnetic field, and composition. The mission is led by Arizona State University, with Lindy Elkins-Tanton as principal investigator; NASA's Jet Propulsion Laboratory manages operations, and it launched under the Discovery Program from Kennedy Space Center. The mission is led by Arizona State University, with Lindy Elkins-Tanton of the University of California, Berkeley, serving as principal investigator. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, manages mission operations, system engineering, and testing. The spacecraft platform was built by Maxar Technologies (now Intuitive Machines) in Palo Alto, California. Psyche is the 14th mission selected under NASA's Discovery Program, managed by the agency's Marshall Space Flight Center in Huntsville, Alabama. NASA's Launch Services Program at Kennedy handled the launch. Scientists at the University of Arizona's Lunar and Planetary Laboratory modeled a crater near Psyche's north pole, roughly 30 miles wide and three miles deep, formed by a three-mile-wide impactor at three miles per second. Their simulations, detailed in the Journal of Geophysical Research: Planets (2026; 131(3), DOI: 10.1029/2025JE009231), incorporated Psyche's shape from telescope data and internal porosity—the empty spaces affecting impact energy absorption, crater depth, steepness, and debris scatter. > Large impact basins or craters excavate deep into the asteroid, which gives clues about what its interior is made of. By simulating the formation of one of its largest craters, we were able to make testable predictions for Psyche's overall composition when the spacecraft arrives. — Namya Baijal, doctoral candidate at LPL and lead author > One of our main findings was that the porosity—the amount of empty space inside the asteroid—plays a significant role in how these craters form. — Namya Baijal The models tested two structures: a layered one with metallic core and thin rocky mantle, or a uniform mixture like some Earth meteorites. Both fit the crater, but spacecraft data on density variations and metal debris will distinguish them. > We found that an impactor about three miles across would create a crater of the right dimensions. The crater's formation is consistent with both scenarios of Psyche's makeup. — Namya Baijal Co-authors include Erik Asphaug, who likened asteroids to remnants of planet formation 'pizzas,' and others like Adeene Denton, who called the work a 'watershed moment' for simulating unique asteroids. These predictions give the Psyche team a head start for 2029 observations.