“The best resolution of the radar images was 7.5 meters [25 feet] per pixel,” said JPL radar astronomer Lance Benner. “When 2005 YU55 returns, we intend to image it at 4-meter resolution with our recently upgraded equipment at the Deep Space Network at Goldstone, California. Plus, the asteroid will be seven times closer. We’re expecting some very detailed radar images.
Radar astronomy employs the world’s most massive dish-shaped antennas. The antennas beam directed microwave signals at their celestial targets — which can be as close as our moon and as far away as the moons of Saturn. These signals bounce off the target, and the resulting “echo” is collected and precisely collated to create radar images, which can be used to reconstruct detailed three-dimensional models of the object. This defines its rotation precisely and gives scientists a good idea of the object’s surface roughness. They can even make out surface features.
“Using the Goldstone radar operating with the software and hardware upgrades, the resulting images of YU55 could come in with resolution as fine as 4 meters per pixel,” said Benner. “We’re talking about getting down to the kind of surface detail you dream of when you have a spacecraft fly by one of these targets.”
At that resolution, JPL astronomers can see boulders and craters on the surfaces of some asteroids, and establish if an asteroid has a moon or two of its own. (Note: the 2010 Arecibo imaging of YU55 did not show any moons). But beyond the visually intriguing surface, the data collected from Goldstone, Arecibo, and ground-based optical and infrared telescopes are expected to detail the mineral composition of the asteroid.”
“On November 8, asteroid 2005 YU55 will fly past Earth and at its closest approach point will be about 325,000 kilometers [201,700 miles] away,” said Don Yeomans, manager of NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. “This asteroid is about 400 meters [1,300 feet] wide – the largest space rock we have identified that will come this close until 2028.”