March 20, 2013
Deep Space Network Radar Snaps Images Of Asteroid 2013 ET
April Flowers for redOrbit.com - Your Universe Online
On March 10, 2013, NASA scientists obtained a sequence of radar images of asteroid 2013 ET using the 230-foot Deep Space Network antenna at Goldstone, California. At the time the images were captured, the asteroid was about 693,000 miles from Earth, or approximately 2.9 lunar distances.
For improving the calculation of asteroid orbits or to study an asteroid's size, shape, rotation state, surface features and roughness of an asteroid, radar is a powerful technique. Scientists often use radar measurements of asteroid distances and velocities to enable computation of asteroid orbits much farther into the future than would be possible if radar observations weren't available.
NASA uses both ground- and space-based telescopes to detect, track and characterize asteroids and comets passing close to Earth. The Near-Earth Object Observations Program discovers these celestial objects, characterizes a subset of them and plots their orbits to rate their potential for causing harm to the Earth.