- About PSI
Arecibo Observatory is home to the world's largest, most sensitive single-dish radio telescope, with a diameter of 305 meters in the northern karst region of Puerto Rico. This facility dedicates hundreds of hours a year of its telescope time to improving our knowledge of near-Earth asteroids and comets with planetary radar. Built in 1963 to study the ionosphere, scientists use the facilities for radio astronomy and planetary radar as well as atmospheric work. Radar observations can spatially resolve near-Earth asteroids (NEAs) with up to 3.75-m resolution, revealing a wide variety of shapes, surface features, and sizes, as well as many binary objects. I will discuss recent scientific results from the Arecibo planetary radar system, including shape modeling asteroid 1998 QE2, surface polarization properties of the NEA population, and observations of NEA 2014 HQ124 and comet 209P/LINEAR. I will also discuss some of the engineering challenges involved in the Arecibo planetary radar system, as well as upcoming spacecraft missions to asteroids.