Jet Propulsion Laboratory scientists hit the desert this week to get eyeball to eyeball with a passing asteroid, using a massive satellite dish to ping microwaves off the huge space object and gain a sense of what it is made of and when it is coming around again.
Scientists at NASA's Goldstone Deep Space Communications Complex 30 miles north of Barstow were just 200,000 miles or so from asteroid 2005 YU55.
Lance Benner, the lead scientist on the project, said the close encounter “significantly refined [understanding of] the asteroid's orbit, allowed us to compute its motion 64 years farther into the future than we could previously, revealed another close encounter with Earth in 2075 that we didn't know about, and provided considerable information regarding the shape, size and features on the asteroid's surface.”
The asteroid is roughly spherical, about 1,300 feet wide and made primarily of several large boulders. “Put in simple terms, 2005 YU55 resembles a gigantic meatball comparable in size to the Empire State Building,” Benner said.
Benner’s team fired radio waves at the asteroid with the 70-meter wide dish. The echoes were collected by another dish and then converted into digital images for scientists to study.
Benner said the effort brought back “the most detailed radar image of a near-Earth asteroid ever obtained.”
Scientists continued to study the asteroid from Goldstone and another site in Puerto Rico throughout the week. “We'll utilize the radar images to estimate the asteroid's rotation period, north pole direction and three-dimensional shape,” Benner said. “One important byproduct of the shape estimation is that we will also estimate the asteroid's center of mass very precisely, which we'll use to improve the orbit even more.”
Next time scientists will get as good a look is 2075, when 2005 YU55 may come even closer to earth.
“To date, we've seen less than half of the surface in detail, so there are probably more surprises awaiting us,” Benner said.