On April 13, 2029, an asteroid named for an ancient Egyptian god of chaos will pass roughly 20,000 miles above Earth’s surface, closer than many of the geosynchronous satellites that relay television signals and weather data from about 22,236 miles up. Apophis will not touch that satellite belt directly, but its path slices in underneath it, a distance NASA has confirmed carries no impact risk for at least the next 100 years.
The asteroid is roughly the length of an NFL football field and about as tall as the Eiffel Tower, made of the same stony material geologists call S-type. What makes its 2029 flight memorable is not size or composition but proximity: nothing this large is expected to come this close to Earth again for decades.
Roy Tucker’s team lost it after two days and found it again by accident
Apophis was discovered on June 19, 2004, by astronomers Roy Tucker, David Tholen, and Fabrizio Bernardi working at Kitt Peak National Observatory in Tucson, Arizona. Technical problems and bad weather limited the team to just two nights of observations before they lost track of the object entirely, according to NASA’s account of the discovery. A separate team at Siding Spring Observatory in Australia picked it back up later that same year, allowing astronomers to calculate an orbit precise enough to flag the asteroid as one of the more hazardous-looking objects catalogued at the time.
Apophis carries a name borrowed from Egyptian mythology’s god of evil and destruction because of that early hazard rating, a label chosen before further tracking ruled out any realistic chance of a strike. The scare was brief but real: on December 27, 2004, Apophis reached a level 4 on the Torino Scale, the international 0-to-10 system astronomers use to communicate impact risk, a rating no other object has matched before or since, tied to an estimated 2.7 percent chance of an Earth impact on the very April 13, 2029 date now set for the harmless flyby. Additional observations within days brought that number down sharply, though a narrower concern lingered until 2006, when astronomers ruled out the small chance that the 2029 pass would bend Apophis’s orbit through a gravitational keyhole and set up a strike in 2036.
Refined orbital calculations over the following two decades steadily shrank the uncertainty around its path until NASA could rule out impact entirely for at least a century, a conclusion the agency’s Apophis overview page now states without qualification.
20,000 miles: closer than the satellites that keep phones and TVs running
Geosynchronous satellites, the ones that broadcast television and relay weather imagery from a fixed point in the sky, orbit at roughly 22,236 miles above Earth’s surface. Apophis will pass about 2,000 miles inside that altitude, a gap NASA describes as closer than the distance of many satellites in that belt without the asteroid ever intersecting the orbital plane those satellites occupy. The flyby will be visible without a telescope across parts of the Eastern Hemisphere, and the hours immediately after closest approach will actually be the hardest to observe from the ground, since Apophis will sit too near the Sun in the sky for optical telescopes to pick it up.
That blind spot is part of why NASA and the European Space Agency both committed spacecraft to the encounter rather than relying solely on ground-based tracking. Earth’s gravity is expected to tug on Apophis during the pass, potentially altering its spin rate and triggering quakes or landslides across its surface, changes that would be far easier to catch from a spacecraft parked nearby than from a telescope waiting for the asteroid to reemerge from the Sun’s glare.
OSIRIS-APEX will already be trailing it when the flyby happens
NASA’s contribution is a repurposed spacecraft. After delivering a sample from asteroid Bennu to Earth in September 2023, the mission formerly known as OSIRIS-REx was renamed OSIRIS-APEX and redirected toward Apophis. The OSIRIS-APEX spacecraft will pass Earth about an hour behind Apophis during the 2029 encounter, using the planet’s gravity to settle onto a course parallel to the asteroid’s, then catching up to rendezvous with it in June for an 18-month survey. Once there, it will orbit from about half a mile away so its Canadian-built laser altimeter can map Apophis’s shape, and it may repeat a maneuver from the Bennu mission by dipping within 15 feet of the surface and firing its thrusters downward to kick up material for a closer look, without collecting a physical sample this time.
The European Space Agency is sending its own spacecraft, called Ramses, on a tighter schedule: a launch planned for April 2028 and arrival at Apophis in February 2029, two full months before the close approach, giving European scientists a chance to measure the asteroid’s condition before Earth’s gravity has a chance to reshape it. Between two spacecraft and a global network of ground telescopes, 2029 is shaping up as the most closely monitored asteroid flyby in NASA’s history, largely because an object the size of a football stadium will spend a few hours closer to Earth than the satellites people rely on every day.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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