A discarded SpaceX Falcon 9 rocket stage will collide with the Moon in the early hours of Wednesday, Aug. 5 [5].
The event provides a rare opportunity for astronomers and planetary scientists to observe a fresh impact in real time. Studying the resulting crater allows researchers to better understand the physics of lunar impacts and the composition of the Moon's surface.
Reports indicate the rocket stage is traveling at speeds between 5,000 [1] and 5,400 mph [4]. The mass of the debris is estimated to be between three [4] and five tonnes [5]. Due to the velocity and mass of the object, the impact is expected to leave a crater approximately 16 feet deep [6].
While the collision is inevitable due to the stage's orbit, there is conflicting information regarding its visibility. Some reports suggest the impact may be visible from Earth to the naked eye [2], while other data indicates it will not be visible without specialized equipment [6].
Scientists intend to use the event to study crater formation. Because the object's mass and speed are known, the resulting damage serves as a controlled experiment for lunar geology. This differs from natural asteroid impacts, where the exact mass and velocity of the object are often unknown until after the strike occurs.
SpaceX said nothing on the trajectory of the discarded stage, but the orbit has made the collision certain [1]. The event marks one of the few times a man-made object of this size has struck the lunar surface in a predictable timeframe.
“The event provides a rare opportunity for astronomers and planetary scientists to observe a fresh impact in real time.”
This event transforms a piece of space debris into a scientific tool. By observing a collision with a known mass and velocity, researchers can calibrate their models of how craters form, which helps in dating the lunar surface and understanding the history of impacts across the solar system.
