An 8,800-pound Falcon 9 upper stage that had drifted since January 2025 slammed into the moon on Aug. 5, kicking up a dust plume visible from Earth and renewing scrutiny of lunar debris.
Lunar gravity gradually pulled the stage out of its unstable high-altitude Earth orbit, experts said, after SpaceX left it in cislunar space following the Blue Ghost and Resilience lander launch.
Around 200 tons of human-made material and roughly 3,000 objects already litter the lunar surface, while low gravity lets impact dust travel far enough to threaten future instruments, bases and scientific sites.
The 1967 Outer Space Treaty requires states to avoid harmful contamination, but experts said it sets no clear waste limits, disposal rules or definition of when lunar contamination becomes harmful.
Researchers and space-law specialists say such accidental impacts could become more common as national and commercial moon missions accelerate, increasing pressure for shared rules on lunar operations and disposal.