Toutatis,as an Apollo near-Earth asteroid in an eccentric orbit,was successfully visited by Change-2 on December 13,2012 after the spacecraft completed its lunar exploration and an extended mission of space-environment exploration at the Sun-Earth Lagrangian point.This flyby as close as a distance of 770 m away from the asteroids surface,reveals abundant geological features on Toutatis surface,like concavities,boulders,lineaments and regolith,particularly an approximately 800 m depression at the end of the large lobe as well as a sharply perpendicular silhouette near the neck region,indicating that Toutatis is probably a rubble-pile asteroid (Huang et al.2013).