NASA spacecraft arrives at ancient asteroid, its 1st visitor

After a two-year chase, a NASA spacecraft has arrived at the ancient asteroid Bennu, its first visitor in billions of years.

The robotic explorer Osiris-Rex pulled within 12 miles (19 kilometers) of the diamond-shaped space rock Monday. It will get even closer in the days ahead and go into orbit around Bennu (BEN-oo) on Dec. 31. No spacecraft has ever orbited such a small cosmic body. Bennu is estimated to be 1,600 feet (487 meters) across.

About the size of an SUV, the spacecraft will shadow the asteroid for a year, before scooping up some gravel for return to Earth in 2023.

A Japanese spacecraft, meanwhile, has been hanging out at another asteroid since June, also to collect samples. A previous Japanese spacecraft brought back tiny particles from an asteroid.