One of NASA’s spacecraft could reenter the atmosphere at approximately 7:45 P.M. EDT tonight. The agency has warned that there is a one-in-4,200 risk of harm to people as a result of potential debris.
When the 600-kilogram Van Allen Probe A reenters Earth’s atmosphere, it will largely burn up, but there are some parts that NASA expects to survive the journey, the agency announced on Monday. The exact timing of the event is unclear: the space agency says the 7:45 P.M. EDT estimate has a window of uncertainty of plus or minus 24 hours.
The spacecraft’s orbit is highly elliptical, so its exact “reentry time is still very uncertain,” says Jonathan McDowell, an astrophysicist who tracks satellites and space launches. “Based on latest Space Force data, it might already be down, or it might not be down until late Wednesday night.”
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The probe is one of two sister spacecraft that were launched in 2012 to study the “Van Allen belts”—bands of protons and electrons that cocoon Earth and protect our planet from harmful space weather and radiation. The mission ended in 2019 when the probes ran out of fuel.
The Van Allen belts are a harsh region and can be damaging to spacecraft and astronauts alike. Remarkably, the probe wasn’t expected to return to Earth until 2034, NASA said, but because of a “far more active than expected” solar cycle, it’s coming down ahead of schedule.
It’s unclear from NASA’s note where Probe A will enter the atmosphere—or where any debris may fall. Both NASA and the U.S. Space Force are tracking its path.
“Almost all the object is expected to burn up during reentry. There is no targeted area for the landing if any components survive,” a NASA spokesperson said in an e-mailed statement.
But the agency has emphasized that the risk of any danger to humans is “low,” or about one in 4,200. Most of Earth’s surface is covered with water, so the probe’s parts are most likely to hit the ocean—minimizing the risk to humans. For context, however, the one-in-4,200 risk of danger to anyone is higher than the chances of a single person being struck by lightning in their lifetime or of a scuba diver or surfer getting bitten by a shark.
The probes have served researchers well during their time in orbit: they helped in the discovery of an entire radiation belt that was previously unknown to scientists.
“The Van Allen Probes rewrote the textbook on radiation belt physics,” said Sasha Ukhorskiy, a project scientist at the Johns Hopkins Applied Physics Laboratory, who worked on the mission, in a 2019 statement when the probes retired. “The spacecraft used uniquely capable instruments to unveil radiation belt features that were all but invisible to previous sensors, and discovered many new physical mechanisms of radiation belt acceleration and loss.”
Editor’s Note (3/10/26): This is a breaking news story and may be updated.