I study giant impacts that dominate the late stage of planet and satellite formation, such as that which formed the Moon. I want to understand how planets got to be so diverse; that is one of the subjects of my book, When the Earth Had Two Moons" HarperCollins 2019) I also study the geophysics of asteroids, comets and small moons, which are left over from accretion. Are they rubble piles? What causes their activity and surface patterns? How can we explore their interiors? I study the size-varying strength properties of meteorites as they relate to asteroids, and the origin of chondrules which I have proposed are the outcome of early planetesimal mergers. Motivated students have led me to study such interesting topics as crater lakes and patterned ground on Mars, the delivery of volatiles to the lunar surface, and Saturn's rings. I am committed to deespace exploration and am on the science teams of upcoming missions to asteroids Psyche and Didymos and to the Martian moons. I lead a NASA Discovery proposal, Comet Radar Explorer, that would obtain a high definition medical-like scan of a primitive object's interior. I work closely with a team in AME that is developing innovative low cost approaches to exploration, and cubesat laboratories that will rotate to mimic the low gravity environment of asteroids.