A defunct SpaceX rocket is set to collide with the moon this Wednesday, with the power of more than three tons of TNT.
The impact is expected to carve out a new crater and send a plume of dust and rubble miles into space, an event scientists and skygazers are keen to observe.
The rocket has been floating in space for more than a year, after it was used to launch a pair of lunar landers.
Space tracking expert Bill Gray estimates the rocket's upper stage will strike the lunar surface at an astonishing 5,400 mph (8,700 kph) – seven times the speed of sound – near the Einstein Crater on the moon’s sunlit western limb.
While the action unfolds in the early hours, observers in the eastern parts of the U.S. and Canada, along with much of South America, are anticipated to have the best views.
Though this particular piece of space junk is not causing significant alarm, its trajectory underscores a growing concern about the increasing amount of debris in Earth's orbit and beyond.
"Things are getting crowded up there," noted Gray, who plans to monitor the aftermath from New Brunswick, Canada. This incident marks only the second known accidental rocket crash into the moon, following a Chinese rocket segment that created craters on the lunar far side in 2022.
The collision, fortunately occurring on the moon’s near side, offers a unique opportunity for scientific study. While the initial impact flash will likely be too dim and brief to observe, the resulting stream of ejected material could extend for several miles and remain visible through telescopes for tens of minutes.
Benjamin Fernando of Los Alamos National Laboratory highlighted the unique lunar environment: "The gravity on the moon is low and there is no wind to blow the dust away."
He added that understanding such events is crucial for assessing "how much of a hazard debris impacts pose to future astronauts." Fernando predicts the impact will create a crater approximately 90 feet across and 16 feet deep, too small for Earth-based observation but detectable by spacecraft.
NASA’s Lunar Reconnaissance Orbiter and South Korea’s Danuri lunar orbiter are poised to capture before-and-after images of the crash site. Danuri is expected to pass within a mile or two of the SpaceX rocket just two minutes prior to impact, according to Fernando and his team.
The abandoned rocket segment, measuring about 40 feet and weighing around 10,000 pounds, originally launched two private lunar landers on January 15, 2025. One, Firefly Aerospace’s Blue Ghost, achieved a successful lunar touchdown, while the other, from Japan-based ispace, unfortunately failed.
Scientists emphasize that observing well-tracked strikes by human-made objects provides invaluable data, unlike unpredictable meteoroid impacts. NASA intentionally crashed rocket sections and lunar modules during the Apollo era for seismic measurements, and in 2009, its LCROSS spacecraft was deliberately crashed to search for ice.
With the moon becoming a new frontier for exploration, experts stress the importance of improving debris monitoring and traffic control before more robots and astronauts arrive. The United States and China are currently in a race to land astronauts on the moon in the coming years, with companies like Elon Musk’s SpaceX and Jeff Bezos’ Blue Origin competing to provide landers for NASA's future Artemis IV missions.
Retired astrophysicist Jonathan McDowell offered a pragmatic view, stating in an email, "This impact will not be a problem."
However, he cautioned, "But in a future where there are long-term bases on the moon, similar impacts would be an issue and we need not to leave rocket stages in chaotic orbits of this kind."
