A piece of human technology, far from its initial mission, will carve a new scar on the face of our satellite. This is the upper stage of a rocket Falcon 9a remnant of a launch carried out in January 2025.
This massive object, after having accomplished its task by propelling two lunar landers, was abandoned in a very elliptical Earth orbit. A complex orbital billiards table ultimately placed it on a direct collision course, an event predicted for the August 5 around 6:44 UTC.
What is this object that will crash into the Moon?
The object in question is perfectly identified: it is the upper stage of the Falcon 9 rocket, bearing the international number 2025-010D. It was used for the launch of the mission Blue Ghost of Fireflywhich successfully landed, and the Japanese lander Hakuto-Rwhich unfortunately crashed.
Unlike a previous incident where a piece of debris was incorrectly attributed to SpaceX before being re-identified as Chinese, the traceability of this object this time is unequivocal. It has been followed without interruption since its launch.
Cet rocket stage weighs around 4 tonnes empty for a size of almost 14 meters. It will impact the lunar surface at a dizzying speed of 2.43 kilometers per second.
The astronomer’s calculations Bill Graycreator of the tracking software Project Plutopredict that the impact will occur near Einstein crateron the western edge of the visible side (the limb) of the Moon. The precision of the impact zone will be refined as the deadline approaches.
Will the impact of this rocket stage be visible from Earth?
Despite the violence of the collision, astronomers, led by Bill Gray, strongly tempered hopes of observing a bright flash. Several factors are working against us.
The impact will occur on a illuminated portion of the Moon by the Sun, thus drowning the faint glow of the event in the brilliance of the surface. Additionally, since the Moon has no atmosphere, the debris will not burn up in a spectacular streak like a shooting star.
This event is reminiscent of a NASA mission, LCROSSwho deliberately threw a rocket stage onto the Moon in 2009. The objective was to analyze the plume of debris.
Despite an impact zone chosen in the shadows to maximize contrast, nothing had been visible from terrestrial telescopes. The conditions being even less favorable this time, it will undoubtedly be necessary to count on lunar orbiters like the Lunar Reconnaissance Orbiter (LRO) of NASA to perhaps, retrospectively, photograph the new crater.
Does this lunar impact represent a danger?
In the short term, the danger is non-existent. The Moon is a dead, desert world and the impact zone is very far from any active or historic lunar landing site. No rover or scientific instrument will be threatened.
In the lunar immensity, the risk of such lunar impact affecting an installation is statistically almost zero. The only effect will be the creation of a artificial crater around ten meters in diameteran event that could even be of minor scientific interest for studying the composition of freshly excavated regolith (surface dust).
However, this event is above all a symptom of a larger problem. Bill Gray speaks of a “ some negligence » in the way we manage our space waste.
For the moment, this does not pose a major problem, but what will it be in a few years, when Chinese and American manned bases will be established near the South Pole?
The multiplication of missions will mechanically increase the probability of these uncontrolled falls, posing a threat to future infrastructures and astronauts.
How can we prevent the Moon from becoming a space dump?
The solution to this emerging problem is, however, relatively simple and within our technical reach. The company SpaceX is not the only one concerned, it is a practice common to many agencies.
It would be enough to allocate a small reserve of fuel in the upper stages of the rockets to carry out a final maneuver after separation of the payload. This final push would place the debris on a “ cemetery orbit ».
This end-of-life trajectory, generally a heliocentric orbit (around the Sun), would ensure that the stage never crosses paths with the Earth or the Moon again.
If this practice is not yet systematic, it is a question of cost and mass. Every additional gram of fuel is one gram less for payload.
But faced with the security challenges of future lunar operations, this disposal procedure will undoubtedly become a mandatory standard. It is wiser to plan our waste management before the sky actually falls.
