Named in honor of Gordon H. Pettengill, planetary physicist at the Massachusetts Institute of Technology and currently director of the MIT Center for Space Research. Pettengill pioneered the development of planetary radar astronomy, beginning in the late 1950s with the first application of coherent Earth-based radar to lunar studies. In 1965 he led delay-Doppler observations that revealed the 3/2 spin-orbit resonance of Mercury. Since then his observations have helped characterize the physical and dynamical properties of the inner planets, the Galilean satellites, Saturn’s rings, and several asteroids and comets. Pettengill was principal investigator for the Pioneer Venus radar mapper experiment, which during 1978–1981 provided the first global maps of Venus topography, radar reflectivity and surface slope. He is also PI for the radar experiments on the Magellan Mission to Venus. (M 13610) _ _.