It is critical to know the orbit of Bennu because recent calculations produced a cumulative probability of 1 in 1410 ( or 0.071 % ) of impact with Earth in the period 2169 to 2199 . Part of the OSIRIS-REx mission is to refine understanding of non-gravitational effects ( such as the Yarkovsky effect ) on this orbit, and the implications of those effects for Bennu's collision probability.
