The target asteroid for landing is Aphobis, an asteroid of about 400 m length, which will come close in 2029, missing the earth by about 30,000 kilometers. In 2012, China’s second lunar probe, Chang’e-2, after successfully completing its mission, rendezvoused with the asteroid Toutatis at a distance of 770 meters which passed the earth at a distance of about 7 million kilometers.
CAS news release, March 1, 2017