A discarded SpaceX rocket's upper stage is on a collision course with the moon, with impact expected on Wednesday. Space tracking expert Bill Gray predicts the rocket will strike the moon at approximately 5,400 mph (8,700 kph) near Einstein Crater on the moon’s western limb. The event is anticipated to create a crater and eject dust and rubble, which scientists are keen to observe.
This unintentional lunar impact highlights concerns about the growing amount of space debris in orbit. "Things are getting crowded up there," Gray commented. He noted that the crash could have been avoided if the rocket's upper stage had been nudged into a solar orbit after its mission.
This incident marks the second known instance of a defunct rocket accidentally impacting the moon. In 2022, a Chinese rocket segment created craters on the lunar far side. The upcoming impact will occur on the moon's near side, releasing energy equivalent to three tons of TNT.
While the impact flash itself is expected to be too dim to be visible, the resulting plume of ejected material could extend for miles and remain observable by telescopes for an extended period. "The gravity on the moon is low and there is no wind to blow the dust away," said Benjamin Fernando of Los Alamos National Laboratory. He encouraged both professional and amateur astronomers to observe the event.
Fernando anticipates the impact will create a crater approximately 90 feet across and 16 feet deep, a size not visible from Earth but observable by spacecraft. NASA's Lunar Reconnaissance Orbiter and South Korea's Danuri lunar orbiter are scheduled to capture images of the impact site before and after the event. The Danuri orbiter is expected to pass within a few kilometers of the impact zone shortly before the collision.
The SpaceX rocket segment, measuring about 40 feet long and weighing around 10,000 pounds, was originally launched on January 15, 2025, to deliver two private lunar landers. One of the landers, Firefly Aerospace's Blue Ghost, successfully touched down on the moon, while the other, from Japan-based ispace, was lost.
Scientists view such well-tracked human-made impacts as valuable opportunities to learn about the potential hazards of debris impacts for future lunar missions. Historically, NASA has intentionally impacted rocket sections and lunar modules on the moon for seismic studies, and in 2009, intentionally crashed its LCROSS spacecraft to search for ice near the lunar south pole.
With increased activity and planned missions to the moon, including crewed landings by the United States and China in the coming years, experts emphasize the need for improved debris monitoring and traffic management systems. "This impact will not be a problem," said retired astrophysicist Jonathan McDowell. "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."