A discarded SpaceX Falcon 9 upper-stage rocket is expected to collide with the Moon on Wednesday, Aug. 5 [3].
The event marks a rare instance of a large piece of human-made debris impacting the lunar surface at high velocity. Because the impact is predicted to create a massive plume of debris, it offers a unique opportunity for astronomers to study lunar soil displacement using Earth-based telescopes.
The rocket stage originally launched from Cape Canaveral, Florida [1]. It was left in a heliocentric orbit after it successfully deployed a pair of lunar landers [1]. Over time, natural orbital decay caused the stage to intersect with the Moon's path, placing the hardware on an uncontrolled trajectory [1].
The discarded stage has a mass of 4,500 kg [2]. It is traveling at an estimated speed of 5,400 miles per hour [1]. Experts said the rocket will strike the near side of the Moon, specifically near the lunar south-pole region [1].
While the exact impact point has not been disclosed, the collision is expected to be energetic. The resulting dust plume is projected to reach a height of 62 miles [3]. This plume should be visible to observers using telescopes on Earth [3].
SpaceX has not provided a statement regarding the trajectory of the discarded stage. The event is a result of orbital mechanics rather than a failure of the rocket's primary mission to deliver the landers to their intended destination [1].
“A discarded SpaceX Falcon 9 upper-stage rocket is expected to collide with the Moon on Wednesday, Aug. 5.”
This incident highlights the growing challenge of orbital debris in deep-space missions. As commercial entities like SpaceX increase the frequency of lunar-bound launches, the likelihood of uncontrolled re-entries or impacts increases. This specific collision provides a natural experiment for scientists to observe how high-velocity impacts affect the lunar regolith without the need for a planned kinetic impactor mission.
