A spent SpaceX Falcon 9 upper stage is expected to crash into the Moon on August 5, in what researchers say could be the first impact flash ever recorded on the sunlit face of the Moon. According to a report by Wired, the impact is forecast for around 6:34 am UTC near the Einstein crater, at a speed of more than 5,400 mph, roughly seven times the speed of sound.
The stage, which carried two landers to the Moon in January 2025, has been abandoned in orbit. The crash could throw up a plume of debris bright enough to be seen from Earth with the right equipment. No impact flash has ever been recorded on the sunlit side of the Moon, making the event a potential first for skywatchers.
The forecasts are based on two new preprint studies. One, posted July 27 to arXiv and led by William Jo, a doctoral candidate at the University of Texas at Austin’s Cockrell School of Engineering, ran a high-resolution physics simulation of the crash. The study, co-authored with professor David B. Goldstein and Philip L. Varghese, predicts how the hollow 3,900-kilogram metal shell will behave on impact.
“It’s like an empty eggshell, because it had all the fuel in it, and there is a rocket engine at one end that’s denser,” Goldstein said. Rather than burrowing in like a cannonball, the shell is expected to collapse from its edges inward, throwing up a broad curtain of soil spreading as far as 183 kilometers wide as well as a thin, faster spike nearly straight up. All told, the crash is forecast to displace about 12,700 kilograms of debris.
Laurence Trafton, an astronomer at UT Austin, said a plume reaching 50 kilometers past the limb would span about 28 arc seconds, roughly one-sixtieth of the Moon’s apparent width. “It can be easily resolved by a small telescope,” he wrote. The plume is expected to be 30 to 300 times fainter than the Moon itself and should peak about 90 seconds after impact, “long enough for an observer to witness.” Observers in the US Southeast would have the best odds of spotting it.
Scientists have previously slammed objects into the Moon to learn from the debris. In 1999, NASA drove the Lunar Prospector probe into a crater in a search for water, and a 2009 mission detected water ice in a plume after a spent rocket hit the south polar region. A 2022 impact widely billed as a Falcon 9 turned out to be a discarded Chinese booster, according to astronomers led by Bill Gray of Project Pluto, who also flagged the upcoming crash.
Researchers say the collision offers a preview of hazards for a more active era of lunar exploration. “We’re going to be colonizing the moon apparently pretty soon,” Jo said, noting that particles thrown up at 300 to 400 meters per second could put astronauts in harm’s way. Goldstein said dust control during lunar operations will be one of the biggest problems faced, a lesson from the Apollo era. NASA plans to return astronauts to the Moon within a few years and eventually build bases.
Sources: Wired, arXiv: Predicted Ejecta Dynamics and Observability of the 2026 Falcon 9 Upper Stage Lunar Impact, arXiv: Observational Planning for the 2026 August 5 Falcon 9 Upper Stage Lunar Impact
Author: Technology Desk
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