A roughly five-ton piece of a SpaceX Falcon 9 rocket is on a collision course with the moon, with its impact expected around 2:34 a.m. ET on August 5. The upper stage of the rocket, which was used to deliver two lunar landers, will strike the lunar surface at approximately 5,400 miles per hour near the crater Einstein on the western limb of the moon.
Bill Gray, who operates Project Pluto and develops software for tracking astronomical objects, first calculated the impending collision and has been monitoring the rocket stage since. He co-authored a study on the impact with an international team of researchers, which has been made available on the preprint server arXiv but has not yet undergone peer review.
According to Benjamin Fernando, a postdoctoral researcher at Los Alamos National Laboratory and the study's lead author, the impact is expected to vaporize the booster, produce a flash of light, and create a plume of ejected material, resulting in a new crater on the moon's surface.
Scientists view this event as a valuable calibration opportunity. While meteoroid impacts on the moon are frequently observed, their mass and speed are often unknown. For this event, researchers know both variables, allowing them to use the impact to refine techniques for studying natural, unpredictable impacts. The researchers also aim to analyze the composition of the ejected plume to learn more about the moon's makeup.
With NASA's plans for returning astronauts to the moon by 2028 and establishing a permanent base, the impact also presents a chance to assess the risks posed by such events to future lunar missions and infrastructure. Fernando highlighted the importance of understanding both direct risks, such as debris or flashes of light, and indirect risks, like being hit by ejected material that could interfere with spacecraft operations.
The Falcon 9 rocket was launched on January 15, 2025, carrying Firefly Aerospace's Blue Ghost 1 lander and ispace's Resilience lander. The Blue Ghost lander successfully landed on March 2, 2025, but the Resilience lander crashed after losing communication prior to landing. The upper stage of the rocket was left in a lunar-crossing orbit and is now destined for impact.
The collision itself will likely be too faint to be observed with the naked eye, even with a telescope. No impact flash has ever been recorded on the sunlit side of the moon, where this impact will occur. However, researchers are encouraging amateur astronomers with small telescopes to observe the event and report any visible flashes or plumes of debris, as the rarity of these events makes predicting the exact outcome uncertain.