Astronomers may soon witness an unusual celestial event that could be observable from parts of Earth using ground-based telescopes. The upper stage of a SpaceX Falcon 9 rocket is expected to collide with the Moon on August 5 at approximately 09:35 Kyiv time (2:35 a.m. ET). The impact is predicted to occur near Einstein crater. The projected date and impact location were calculated by Bill Gray, the developer of the Project Pluto software, who used available tracking data to model the rocket stage’s orbit and forecast its trajectory.
The upper stage expected to impact the lunar surface is the one left over from the SpaceX launch that carried the Firefly Blue Ghost mission on January 15, 2025. During that mission, a Falcon 9 delivered Firefly Aerospace’s Blue Ghost lunar lander and ispace’s Hakuto-R lunar lander into space. After deploying both spacecraft, the rocket stage exhausted its remaining propellant and was unable to perform a controlled return, leaving it to drift through space.
The upper stage is approximately 12 meters long, 4 meters in diameter, and has a mass of around 4,000 kilograms. It is expected to strike the Moon at a speed of roughly 8,750 km/h. According to a research paper by Bill Gray and his colleagues, the impact is not expected to produce any significant consequences. Although the Falcon 9 upper stage is larger than most natural objects that collide with the lunar surface, it is essentially a hollow metal structure traveling at a relatively low impact velocity by cosmic standards. It is expected to break apart on impact, creating a crater approximately 20 to 30 meters in diameter while ejecting a substantial plume of lunar dust.
This is precisely what astronomers will be watching. The event offers a rare opportunity to observe a lunar impact in real time, allowing researchers to study how dust and ejecta are displaced following the collision. The observations could also improve understanding of the hazards posed by impacts involving space debris. The impact is expected to be most visible from South America and from low- and mid-latitude regions of North America. Viewing conditions will depend largely on the Moon’s position in the sky at the time of impact – the higher it is above the horizon, the greater the chances of observing the event through ground-based telescopes.
Source: engadget
