Current NASA Assessment of Apophis Impact Probability
NASA's Center for Near Earth Object Studies lists Apophis as a near-Earth asteroid with a cumulative impact probability far below the threshold for public concern. The Sentry impact monitoring system, which tracks potential Earth impacts over the next 100 years, currently shows no viable impact solutions for Apophis through the foreseeable future. The Palermo Technical Impact Hazard Scale, used by NASA to prioritize risks, rates Apophis at a negative value, meaning the risk is well below the background risk from undiscovered objects. For the latest orbital solution and uncertainty parameters, see the official CNEOS page on Apophis.
ESA's Near-Earth Object Coordination Centre and NASA JPL's Small-Body Database maintain the most recent radar and optical observations that define Apophis's orbit. The latest radar ranging campaigns, conducted with the Goldstone Deep Space Communications Complex and the Green Bank Telescope, have reduced the orbital uncertainty to a level where the 2029 and 2036 keyholes are precisely mapped. The 2029 close approach, known as a close approach rather than an impact scenario, will occur at a distance of about 32,000 kilometers from Earth's center, or roughly 6% of the Earth-Moon distance. The 2036 scenario, once considered a potential impact year, is now ruled out by these high-precision astrometric measurements.
Next Close Approach Dates and Keyhole Details
The next close approach of Apophis to Earth is scheduled for April 13, 2029, when the asteroid will become visible to the naked eye from parts of Europe, Africa, and western Asia. During this 2029 flyby, Apophis will pass within the geosynchronous satellite belt, at an altitude of approximately 32,000 kilometers above Earth's surface. The 2029 encounter is a key observational opportunity for radar and optical telescopes to refine the orbit further and eliminate any remaining uncertainty. The 2036 close approach, previously flagged in some media reports as a potential impact date, is now assessed as a safe flyby with no impact corridor.
A keyhole is a narrow region in space where Earth's gravity could alter Apophis's trajectory just enough to set up a future impact on a subsequent pass. For Apophis, the 2029 keyhole that would have led to a 2036 impact is now known to be missed by a margin of several thousand kilometers based on the latest orbital solution. The 2068 keyhole has also been evaluated, with current data showing no impact scenario for that date. The next major ground-based radar campaign is planned for 2029, using facilities such as the Arecibo Observatory replacement capabilities and Goldstone, to refine the post-2029 orbit.
Orbital Tracking, Historical Risk Revisions, and Scientific Missions
Apophis was discovered in 2004 and initially carried a Torino Scale rating of 4, the highest ever assigned to an asteroid, before subsequent observations ruled out the 2029 and 2036 impact scenarios. The Yarkovsky effect, a subtle thermal recoil force from anisotropic heat emission, was a key factor in early uncertainty about the orbital drift. Modern thermal modeling and radar measurements have now constrained the Yarkovsky acceleration to a level that eliminates the 2068 impact corridor as well. The OSIRIS-APEX mission, a follow-up to the OSIRIS-REx asteroid sample return mission, is planned to rendezvous with Apophis after its 2029 flyby to study the asteroid's surface and interior structure.
The Planetary Society and NASA's Planetary Defense Coordination Office use Apophis as a benchmark case for planetary defense exercise