Click to Watch in HD > NASA Planetary Defense: The Asteroid Hunters

Watch Two unique ground telescope operations, at the Catalina Sky Survey in Mt. Lemmon, Arizona, and the Panoramic Survey Telescope and Rapid Response System, or PanSTARRS, located at Haleakala, Hawaii, are responsible for about 90 percent of all near-Earth object discoveries. Find out more about how NASA finds, studies and tracks near-Earth asteroids and comets by visiting .

Youtube Channel / NASA Jet Propulsion Laboratory