He studies the origin and ultimately the diversity of asteroids, comets, terrestrial planets and their moons, and icy worlds. He uses numerical simulations (SPH with strength) to simulate planetary collisions and accretionary events. He is on the science team of the Psyche, MMX and Hera missions, and works on radar and seismology techniques to explore small planetary bodies from orbit. His first faculty position was in an Earth Sciences department, so he feels at home in a planetary science program anchored in geology! He is currently Professor in the Lunar and Planetary Laboratory at the University of Arizona, where he leads the Planetary Formation Lab.