An abandoned upper stage of a SpaceX Falcon 9 rocket is expected to crash into the moon on Wednesday, in an unintentional collision that will carve a new crater into the lunar surface. The four-metric-ton piece, traveling at roughly 5,400 miles per hour, poses no danger to Earth, but scientists consider the impact a valuable opportunity to study how large objects affect airless worlds.
The object is the second stage of the Falcon 9 that launched Firefly Aerospace’s lunar lander toward the moon in January 2025. After the lander was sent on its way, the rocket stage was left floating in space. It has been there for more than a year, and its orbit has now lined up with the moon. The piece is about the size of a school bus, making it a particularly large piece of debris to end its journey on another celestial body.
Because the moon has no atmosphere, the incoming stage will not be slowed as it approaches the surface. It is expected to strike at full speed, blasting away lunar dust and rock and opening a fresh impact crater. The size and shape of the crater will depend on the exact angle and density of the object, but it is expected to be visible from lunar orbit.
NASA has said it will attempt to observe the event. Using available lunar observation tools, the agency hopes to capture data about the crash and the crater it leaves behind. That information could help scientists learn more about how the surface of the moon responds to high-speed impacts and how material ejected during a collision spreads across the surrounding area.
Although the crash is accidental, it is not a threat to Earth. The moon is distant enough that the debris will simply become part of the lunar landscape. Uncontrolled impacts by large human-made objects are uncommon, which makes this event different from the deliberate crashes that have been used in previous lunar science missions.
For researchers, the episode is useful because the object’s mass, speed, and origin are known in advance. Comparing that information with the crater will help refine models of impact physics and improve understanding of how the moon and other bodies without atmospheres record the history of collisions. Each observed impact adds another reference point for future studies.
The crash is also a reminder that hardware left in space after a mission can remain active for years. A piece of a routine commercial launch is about to become a permanent feature of the lunar surface, closing a journey that began more than a year and a half ago with liftoff from Earth.
