I study giant impacts that dominate the late stage of planet and satellite formation, such as that which formed the Moon, that can explain why planets are so diverse and sometimes hemispherically dichotomous. I also study the geophysics of asteroids, comets and small moons, the 'small bodies' left over from accretion. I study the strength properties of meteorites and the origin of chondrules. Motivated students have led me to study other topics such as lakes and patterned ground on Mars, the delivery of volatiles to the lunar surface, and Saturn's rings. I am on the science team of NASA's Psyche mission, and ESA's Hera mission to Didymos, and JAXA's MMX mission to the Martian moons. I am Science PI of the SpaceTREx laboratory at U Arizona that is advancing miniaturized space exploration and small cubesat laboratories for low-gravity research.