Near-Earth Objects Discovered to Date | Here's the Count | NASA 360 FriendsofNASA.org: June 30 may be International Asteroid Day, but at NASA, every day is asteroid day! So, what do we know about the asteroids that are in Earth's neighborhood? A whole lot. Planetary defense — which includes finding, tracking, and characterizing near-Earth objects—is part of our mission at NASA. Here's the count of what we've discovered so far. Information about NASA's planetary defense efforts: https://www.nasa.