Case study: Apophis

(99942) Apophis was briefly rated Torino 4 in December 2004, with a 2.7% chance of impact in 2029. Additional observations (including pre-discovery images) ruled out 2029 within days, but small chances for 2036 and 2068 kept it on both risk lists for years. Radar observations during its March 2021 approach removed the last 2068 solutions, and NASA took it off Sentry.

The archive starts in 2018, after the 2004 drama, so it picks Apophis up as a long-term, low-probability entry and records its 2021 exit. See the object page.