JPL Sentry: Impact Risk Surveillance Table
Automated collision hazard assessment for confirmed Near-Earth Asteroids
JPL Sentry continuously evaluates the orbits of all known asteroids against high-precision planetary ephemerides, calculating potential impact trajectories over the next century. Most entries represent minuscule statistical probabilities (e.g. 1 in 100,000) stemming from slight positional uncertainties that narrow with every new telescope observation.
Public impact hazard scale. 0 means No Hazard (normal/zero collision risk). 1 is routine discovery. Values 2–4 merit attention by astronomers. Values 8–10 represent certain collisions.
Logarithmic scale comparing detected risk to the natural background impact frequency. Values below -2 indicate events of no practical consequence. Values from -2 to 0 merit monitoring. Positive values indicate situations of concern.
Removed from Sentry List (100 Objects)
Objects officially removed from the NASA/JPL Sentry impact monitoring database
NASA/JPL publishes removed objects with designation and removal date without per-object rationale. See NASA/JPL's explanation of the Sentry list.