A five-ton chunk of a SpaceX Falcon 9 rocket is days away from slamming into the lunar surface, and researchers say the unplanned collision could teach us something about the risks ahead as NASA pushes to put astronauts back on the moon.
The abandoned upper stage, left drifting in a high orbit after a January 2025 launch, is expected to strike near the crater Einstein on the moon's western edge on Aug. 5 at roughly 2:34 a.m. ET. It will be traveling at approximately 5,400 miles per hour. Bill Gray, who runs Project Pluto, a small operation that develops software for tracking objects in space, first calculated the collision course and has been monitoring the rocket stage ever since.
Gray and an international team of researchers, led by Benjamin Fernando, a postdoctoral researcher at Los Alamos National Laboratory in New Mexico, recently published a study on the coming impact through arXiv, an open-access server where scientists post papers before formal peer review. The study has not been peer-reviewed, but it lays out both the predicted trajectory and the scientific opportunity the crash presents.
The Falcon 9 rocket launched on Jan. 15, 2025, carrying two lunar landers: Firefly Aerospace's Blue Ghost 1 and ispace's Resilience. Blue Ghost successfully touched down on the moon on March 2, 2025. Resilience was not as fortunate, communications with the vehicle dropped out 90 seconds before landing, and it crashed.
After the upper stage finished its job delivering those payloads toward the moon, SpaceX left it in what researchers describe as a "moon-crossing high-Earth orbit." That orbit put it on a path where a lunar collision was at least possible. Whether SpaceX knew the impact was coming is an open question.
Fernando told ABC News he could not say for certain what the company knew or when it knew it:
"I don't think we know from SpaceX exactly to what degree they were in the know that this was going to happen. Certainly, the fact that it was used to deliver hardware to the moon meant that it was probably left in an orbit where there was a possibility of this happening. Whether they knew that it was going to happen and didn't say anything, or they simply hadn't run the calculation, I couldn't tell you."
That ambiguity matters. NASA plans to return astronauts to the lunar surface as early as 2028 and eventually build a permanent base there. If discarded rocket stages are crashing into the moon and nobody is tracking them until an independent software developer catches it, the question of accountability gets harder to dodge the closer we get to a crewed presence.
Fernando described the impact in blunt physical terms. The collision should vaporize the booster, produce a flash of light, kick up a plume of dust and regolith, the loose, rocky material covering the lunar surface, and carve out a fresh crater.
"We expect that to vaporize the booster, create a flash of light, probably a plume of ejecta -- dust, regolith, other stuff mixed into it -- and of course excavate a fresh crater on the lunar surface."
No one has ever recorded an impact flash on a sunlit part of the moon. That makes Aug. 5 a first-of-its-kind observing opportunity, if anyone is watching.
Fernando encouraged amateur astronomers with backyard telescopes to look and report what they see. Bigger telescopes and better conditions improve the odds of catching something, but the rarity of these events means scientists do not have firm expectations for what the flash or debris plume will actually look like.
"But because these events are so rare, we don't have a good expectation of exactly what we're going to see, which is exactly one of the reasons why we're asking people to take a look."
Beyond the spectacle, Fernando framed the collision as a preview of a problem that will only grow. More rockets are heading to and past the moon. More hardware will be left behind. And if NASA follows through on its 2028 timeline, astronauts and lunar infrastructure will be in the line of fire.
"These sorts of things are going to happen more and more often. And as we have more astronauts on the lunar surface, more lunar infrastructure habitats, for example, we need to understand how much of a risk these impact events actually pose."
He added that the Aug. 5 event offers a chance to study both direct risks, being struck by debris or blinded by a flash, and indirect ones, like clouds of ejected material interfering with spacecraft in lunar orbit.
If the plume's composition can be measured, Fernando said, it could also reveal something about the makeup of that part of the moon itself. "If we can measure the composition of that, that tells us something about the composition of that part of the moon," he said.
The scientific upside is real. But so is the underlying problem: a five-ton piece of rocket hardware is about to gouge a new crater into the moon, and the company that left it there has not publicly addressed whether it saw this coming. As the United States spends billions to build a sustainable presence on the lunar surface, the question of who tracks, and who answers for, the junk we leave in orbit is not academic. It is operational.
Washington has spent decades writing rules for debris in low-Earth orbit. The moon, apparently, is still the Wild West.
