Early Wednesday morning, a SpaceX Falcon 9 upper stage struck the moon near the Einstein Crater. The high-speed impact was detected by the European Southern Observatory's Very Large Telescope in Chile.
Sodium and lithium plumes detected by the Very Large Telescope
The European Southern Observatory's Very Large Telescope , situated at the Paranal Observatory in Chile, identified a distinct chemical signature following the collsiion. Using the Ultraviolet and Visual Echelle Spectrograph, astronomers detected spectral lines of sodium and lithium gas in the impact plume. As the report notes, the sodium likely originated from the lunar soil itself, whereas the lithium was likely a byproduct of the SpaceX rocket's composition.
This gas plume, which spanned several tens of kilometers, lasted for approximately five to ten minutes after the impact occurred. Scientists used the spectrograph to search for the specific spectral fingerprint of the rocket's chemicals being dispersed across the lunar surface.
A potential 90-foot crater near the Einstein Crater
The collision occurred at approximately 2:35 am ET near the moon's Einstein Crater, with the rocket trraveling at speeds exceeding 5,000 miles per hour. According to a preprint study authored by Dr. Benjamin Fernando and a group of NASA researchers, the high-velocity impact could have created a crater with a diameter ranging from 65 to 90 feet.
While the event was significant, it posed no danger to Earth, which remains roughly 225,623 miles away from the lunar surface. Although astronomers across the Americas aimed ground and space-based telescopes at the moon to witness the event, the impact was not visible to the naked eye and proved difficult to spot through standard equipment.
The January 15 Falcon 9 mission's disposal strategy
This incident is a direct result of the SpaceX Falcon 9 mission that lifted off on January 15, 2025, to carry two commercial lunar landers. While the rocket's first stage successfully returned to Earth, the second stage required a specialized disposal maneuver to comply with safety regulations for high-energy orbits.
For missions heading to low-Earth orbit, SpaceX and other operators typically allow the upper stage to burn up in the atmosphere. However, for high-energy missions, different protocols are required. SpaceX released a statement on social media following the crash, explaining that they worked closely with NASA to determine the optimal disposal solution for the upper stage.
What the Danuri orbiter's imagery will reveal
The Korean Pathfinder Lunar Orbiter, known as Danuri, captured critical imagery of the upper stage both immediately before and after the impact. Researchers are now beginning to process data from the Enhanced Resolution Imaging Spectrograph (ERIS) to find a matching visible signature. However, it remains unverified whether the ERIS data will provide a clear visual confirmation of the crater's final dimensions or the exact state of the impact site.
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