Pinging space rocks: a radar story of asteroids and comets

Short of sending a spacecraft, radar observations have proven to be the most effective technique to study Near-Earth asteroids (NEAs) and occasionally, comets.  The two most powerful radars in the world are the Arecibo Observatory in Puerto Rico and the Goldstone Solar System Radar in the Mojave desert in California. To date, these radars have observed more than 700 NEAs and 20 comets. Radars play an important role in the physical characterization of these small bodies because of their high-resolution (several meters) imaging capability. Radar images directly display an object’s shape, size, satellite(s) when present, and prominent surface features. Furthermore, radar measurements of line-of-sight velocities and positions provide powerful orbital constraints and frequently add decades to centuries to how far in the future we can reliably calculate an orbit. This is of particular importance when assessing the impact probabilities of potentially hazardous asteroids (PHAs). In this talk, I will discuss radar contributions to the field of planetary science and showcase some of the best radar imaging targets that we observed recently.