A SpaceX rocket upper stage that has been drifting through space for more than a year is set to slam into the Moon this Wednesday, creating a new crater and offering scientists a rare opportunity to observe a tracked lunar impact.

The abandoned rocket segment — measuring roughly 40 feet (12 meters) long and weighing approximately 10,000 pounds (4,500 kilograms) — originally launched two private lunar landers on January 15, 2025. One of those landers, Firefly Aerospace's Blue Ghost, became the first private spacecraft to achieve a fully successful lunar touchdown. The other, built by Japan-based ispace, crashed during its descent. Both missions reflected a broader shift in lunar exploration, with private companies increasingly carrying payloads to the Moon under NASA's Commercial Lunar Payload Services program and independent commercial ventures.

Space tracking expert Bill Gray predicts the upper stage will strike the lunar surface at 5,400 mph (8,700 kph) — seven times the speed of sound — near Einstein Crater on the Moon's sunlit western limb. The impact is expected to occur in the early morning hours, meaning the eastern United States and Canada, along with much of South America, should have the most favorable viewing conditions.

Gray, who plans to observe the aftermath from New Brunswick, Canada, noted the broader implications of the event. "Things are getting crowded up there," he said.

While the crash was never SpaceX's intention, space experts said it could have been avoided had the upper stage been steered into a heliocentric orbit. It will mark only the second known instance of a derelict rocket accidentally striking the Moon; in 2022, a Chinese rocket segment created a pair of craters on the lunar far side. Unlike Earth orbit, where debris-mitigation guidelines have existed for years, there are currently no binding international regulations governing the post-mission disposal of rocket stages in cislunar space.

Fortunately for astronomers, the upcoming impact will occur on the Moon's near side, releasing energy equivalent to roughly three tons of TNT. According to experts, the impact flash — lasting less than a second — will likely be too dim to observe directly. However, the ejected material could extend several miles (kilometers) into space and remain visible through telescopes for tens of minutes.

"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, who is encouraging both professional and amateur astronomers to make observations.

"Part of the reason for our interest in this event is to figure out how much of a hazard debris impacts pose to future astronauts," Fernando added in an email.

Fernando anticipates the impact will carve out a crater approximately 90 feet across and 16 feet deep (27 meters across and 5 meters deep) — too small to be seen from Earth but detectable by orbiting spacecraft. NASA's Lunar Reconnaissance Orbiter and South Korea's Danuri lunar orbiter are expected to capture before-and-after imagery of the crash site. According to Fernando and his team, Danuri will pass within a mile or two (a few kilometers) of the SpaceX rocket just two minutes before impact.

Scientists see value in studying well-tracked impacts of human-made objects, given that meteoroids and other natural bodies typically strike the Moon with little or no advance warning. During the Apollo era, NASA intentionally crashed rocket sections and lunar modules into the surface for seismic measurements, and those experiments helped reveal the Moon's internal structure. In 2009, NASA deliberately impacted its LCROSS spacecraft and upper stage near the lunar south pole in search of water ice.

As lunar activity intensifies, researchers emphasize the need for improved debris monitoring and traffic management. Most space surveillance infrastructure was built to track objects in Earth orbit, and detecting and cataloguing debris across the far larger volume of cislunar space remains a developing capability. The United States and China are both working to land astronauts on the Moon within the next few years. Elon Musk's SpaceX and Jeff Bezos' Blue Origin are competing to build the lander for NASA's Artemis IV mission, whose crew will follow in the footsteps of the 12 Apollo astronauts who walked on the lunar surface.

"This impact will not be a problem," said retired astrophysicist Jonathan McDowell in an email. "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."