Robert Jastrow earned a Ph.D. in theoretical physics from Columbia in 1948 and pursued post-doctoral studies at Leiden, Princeton (Institute for Advanced Studies), and the University of California at Berkeley before becoming an assistant professor at Yale in 1953-1954. He then served on the staff at the Naval Research Laboratory from 1954-1958. In the latter year he was appointed chief of the theoretical division of the Goddard Spaceflight Center. He became director of the Goddard Institute of Space Studies in 1961 and stayed at its helm for 20 years before becoming professor of earth sciences at Dartmouth. He specialized in nuclear physics, plasma physics, geophysics, and the physics of the moon and terrestrial planets.