An 8,800-pound (4,000 kilograms) Falcon 9 rocket stage hit the moon last Wednesday (Aug. 5), stirring lunar regolith in a massive plume of dust observable all the way from Earth.

The rocket joined some 3,000 manmade objects scattered on the surface of our planet's companion. Some experts think it's about time we start treating the pristine lunar environment with a bit more respect.

Around 200 tons of Earth stuff have been either deliberately left on or crashed into the moon since the beginning of the space age. Some of this material has a prominent place in history books: The descent modules from all six Apollo landing missions, Soviet Lunakhod rovers from the 1970s and China's 2010s Yutu 1 and 2 robots still sit where they had been left or ran out of power.

But there is also a lot of stuff on the moon that wasn't really meant to end up there. Astronomer and space historian Jonathan McDowell says that many rocket stages and other objects left in orbit between Earth and the moon since the first lunar missions in the 1960s may have ended up on the gray dirt. Four years before the Falcon 9 upper stage crashed near Einstein Crater, for example, part of a Chinese Long March 3C rocket slammed into the moon's far side. And experts think such incidents could become increasingly common in the coming years, as exploration of the moon intensifies.

"We're in a transitional moment," McDowell told Space.com. "From the era when there was rare lunar exploration mostly by the U.S. and the Soviet Union, we've seen over the past decade other nations landing on the moon and the beginning of commercial missions. But governance has not kept up with this. We don't have an international set of agreements on how to operate near the moon, how to coordinate activities near the moon, and we're really going to need it because, not only is the amount of activity at the moon increasing, but the number of different players is greatly increasing, too."

Human activities on the moon are governed by the 1967 United Nations Outer Space Treaty, Marieta Valdivia Lefort, a policy officer at the Royal Astronomical Society in the U.K., told Space.com. Article IX of that treaty binds countries to "conduct the exploration of outer space in a way that avoids harmful contamination," she said. But what exactly constitutes such contamination is unclear, she added.

"There are international legal frameworks that apply to activities on the moon and include obligations concerning harmful contamination, but there is no dedicated international 'waste law' or comprehensive 'rubbish-management' system for it," Lefort wrote in an email. "The Outer Space Treaty does not define when contamination becomes 'harmful.' It does not set numerical waste limits, create approved disposal sites or require every object on the moon to be removed."

The moon is big. Its surface area, around 14.7 million square miles (38 million square kilometers) rivals that of Asia, Earth's largest continent, which covers 17 million square miles (44 million square km). But the moon's low gravity — around 17% that of Earth — means the dust that an impact stirs up travels a long way and takes a long time to settle, McDowell said.

"It's not just a local event," he said. "It's an equivalent to a continental-level event. In the future, when you have permanent human bases and scientific experiments on the moon, you don't want rocket stages smashing into the moon on a regular basis, creating big plumes of dust that could contaminate instruments or disturb gravitational wave detectors."

Moreover, the artificial material introduced and the craters that arise when heavy rocket stages smash into the lunar surface are altering the lunar environment, potentially erasing yet unexplored scientific material.

"The moon is naturally struck by meteoroids, and those impacts form part of the geological record that scientists are trying to understand," Lefort wrote. "The main concern is the alteration of the moon's physical and chemical environment, particularly where repeated disturbances could damage or obscure valuable scientific evidence."

Gregory Radisic, a space law expert at Australia's Bond University, told Space.com that the Falcon 9 crash was timely, as it can stir debate about responsible behavior in space before the moon gets too busy.

"It's not by good planning that this didn't hit something important," he said. "It's by pure luck that we're only having a conversation about theoretical problems down the line and that this did not destroy a million-dollar experiment or an important site of scientific study."

He added that spaceflight companies may start paying attention to the risks only after human lives are lost or expensive infrastructure suffers, resulting in tangible fines and consequences.

"When there is a loss of life or a loss of investment, the industry will start to care," Radisic said. "As long as things are losing aesthetic or scientific value, the industry is not likely going to care."

The Falcon 9 rocket stage that hit the moon was left in a high-altitude orbit around Earth in January 2025, after it propelled Firefly Aerospace's Blue Ghost and ispace's Resilience landers to the moon.

McDowell explained that, as the rocket stage was left relatively close to the moon, it got repeatedly influenced by lunar gravity, eventually spiralling into its surface.

"If you leave [an object] in an orbit that's in this middle region that is far enough that the moon's gravity is affecting it but not far enough out to go into orbit around the sun, then that orbit is very hard to predict," McDowell said. "The orbital uncertainties multiply over many passes and, eventually, if you get unlucky, the moon tugs it into an orbit where it's going to hit either the moon or Earth in a completely unpredictable way."

McDowell said that, since the January 2025 launch, SpaceX has been pushing its moon-mission rockets farther out into orbit around the sun.

"I hope that we're going to see a new norm evolve, and that what we have seen now is not how you dispose of your rocket stages in the future," he said. 


The moon dust has settled after a 4.5-ton SpaceX rocket body slammed into terrain near Einstein Crater on Aug. 5.

That impact site was imaged by South Korea's moon-orbiting Danuri spacecraft, as well as by NASA's Lunar Reconnaissance Orbiter (LRO). Reportedly, a Chinese commercial space debris monitoring satellite tracked and recorded the 5,400-mph (8,690-kph) moon punch, too.

Wandering through space for over a year, the leftover Falcon 9 upper stage had sent Firefly Aerospace's Blue Ghost-1 lander on its way to the moon back on Jan. 15, 2025. Also sent moonward on that flight was the Hakuto-R Mission 2's Resilience, a robotic lunar lander developed by the Japanese company ispace. While the moon has reclaimed its serenity, the implications of the uncontrolled collision continue to reverberate.

Close encounter

Interestingly, there was also the prospect of a too-close-for-comfort conjunction of the Falcon 9 upper stage and Danuri.

"We noticed roughly late June that there is an incoming Falcon 9 upper stage toward the moon, and also knew that it would be close to Danuri," Eunhyeuk Kim, a senior researcher at the Korea Aerospace Research Institute (KARI), told Space.com.

There was a huge uncertainty in the predicted trajectory of the upper stage, Kim said, while the orbit information of South Korea's Danuri lunar orbiter was quite accurate. "Therefore, we could not neglect the probability of an incoming and close encounter."

Spacecraft maneuver

However, around mid July, the KARI/Danuri team performed a maneuver of the spacecraft in preparation of a near-total lunar eclipse on Aug. 28, said Kim. That eclipse will see 96% of the moon's visible surface passing through Earth's dark umbral shadow.

Kim said that the orbiter's maneuver brought a slight change in the phase of the spacecraft's orbit, which canceled the probable conjunction between the upper stage and Danuri.

At the time of the Aug. 5 impact, Danuri was flying over the moon's south pole area, far away from the hit zone, said Kim.

High-speed ejecta

Dean Sladen is a quality manager and aerospace engineer in the United Kingdom for Accu Components, a high-precision manufacturing firm.

"As space agencies and private companies build out permanent lunar infrastructure, uncontrolled rocket stages evolve from a minor nuisance into a tangible operational risk," Sladen told Space.com. "A direct hit is the obvious worst-case scenario, but distant impacts also generate ground shocks and high-speed ejecta that can degrade sensitive equipment over time."

Sladen noted that lunar impacts have been a constant throughout history, with meteorites and comets bombarding the surface unhindered by an atmosphere. "Over the past 65 years, artificial objects have added a new dynamic to these events," he added.

Genuine hazard

Even modest hardware impacts permanently alter the lunar landscape, said Sladen. Given the moon's lack of a substantial atmosphere, there is no air resistance to slow debris down. An impact therefore hurls high-speed ejecta (fine regolith and rock fragments) across vast distances at bullet-like speeds.

"While this isn't a major threat to isolated missions today, as we establish permanent lunar infrastructure, high-velocity ejecta poses a genuine hazard to surface habitats, solar arrays and working astronauts," Sladen said.

To mitigate this issue, Sladen suggested that the industry will likely need designated impact zones or strictly controlled, targeted de-orbit protocols to ensure that spent hardware lands far from active installations.

"That said, human-made debris is only half the equation," Sladen continued. "Natural meteorites remain an ongoing background threat, and, while massive natural strikes are rare, they hit at significantly higher speeds and carry far more energy," Sladen said. "Controlling our own hardware is simply the part of the risk profile we actually have the power to manage."

Plume detections

In the meantime, while the Falcon 9 impact was tough to see from Earth, several observations from our planet reported the detection of sodium and lithium gas above the crash site.

The European Southern Observatory's (ESO) Very Large Telescope (VLT) in Chile, for example, saw the aftermath of the impact. The ESO reported that a chemical fingerprint of the impact was visible for five to 10 minutes, with an enormous plume of lunar material stirred up due to the hard-hitting hardware.

"I'm happy that ESO recorded some evidence of it through VLT, and Danuri has found the exact impact location," said William Jo, a graduate research assistant at the University of Texas, Austin who performed some pre-strike computer simulations.

"What we've learned so far is that the plume was too faint to see against the bright lunar surface, and only a large observatory telescope could pick some parts of it out against the dark sky, which is exactly what happened," Jo told Space.com. "The plume must have shot out high," he said, "and I'd like to know how high, or even whether we can replicate the signals."

Targets of opportunity

"Telescopes make the best spaceships," pointed out Elaina Hyde, director of the Allan I Carswell Observatory at York University in Canada. "We are always on the lookout for 'targets of opportunity' like this event."

Hyde organized a livestream event, training the observatory on the collision locale. They were unable to spot the impact, however.

"The lunar collision was not on our regular research program, but when it happened, we put it as a high-priority item to observe if the weather was clear," Hyde said. "Anything that happens quickly like this is often a target of opportunity, because you do not get a long time to plan the observation."

"However, since it was not visible from our location in Toronto, our 'null' or non detection can actually help to limit the estimates on how big the dust plume was and perhaps some of its properties," said Hyde.

Impact response

Also on the moon impact watch were observers using Lowell Observatory equipment in Arizona.

These researchers managed to measure a response from the rocket stage impact, spotting a sizable sodium and lithium gas plume that lasted between five and 10 minutes after impact, reported Carl Schmidt, an assistant research professor at Boston University's Center for Space Physics.

Observers at the 4.3-meter Lowell Discovery Telescope (LDT) in Happy Jack, Arizona used a long slit spectrograph to detect the plume. Graduate students from Boston University continue to analyze data gleaned from the moon wallop.

Bright lithium plume

"At LDT, we saw a bright lithium plume from the rocket body and fainter sodium [signature], likely from the surface itself," Patrick Lierle of Boston University told Space.com. "The bright lithium plume extends more than halfway up our field of view." The LDT results are also credited to Emma Lovett, a Boston University graduate student.

William Jo said he's looking forward to the release of observational data about the impact before he and colleagues can refine their lunar ejecta simulation model.

"That data, combined with our simulations, could tell us things like the composition of the lunar material, what orientation the impact hit at, and so on," Jo said.

The final resting place of SpaceX's moon-smashing rocket has been found.

The Korea Pathfinder Lunar Orbiter, known as Danuri, has captured imagery of the crater blasted out by the Falcon 9 upper stage that slammed into the moon early on Wednesday morning (Aug. 5).

"Danuri began observations about 30 minutes before the collision and, through orbit control, passed over the impact site multiple times, conducting a total of 8 imaging sessions," officials with the Korea Aerospace Research Institute (KARI) said via X this morning (Aug. 6). "Through this observation, changes in the terrain around the impact site and traces of ejecta spread were confirmed."

"Danuri secured both pre-collision and immediate post-collision footage, enabling analysis of changes caused solely by the collision and providing important research data," they added in the X post, which shared several before-and-after images of the impact site.

The Falcon 9 in question launched on Jan. 15, 2025, sending two private robotic moon landers — Firefly Aerospace's Blue Ghost and ispace's Resilience — to a high, moon-crossing Earth orbit. The duo then made their own way to the moon; Blue Ghost landed successfully on March 2 of that year, but Resilience crashed during its touchdown attempt.

The Falcon 9's first stage came back to Earth shortly after liftoff for recovery and reuse, as such boosters commonly do. Falcon 9 upper stages, by contrast, are expendable. SpaceX usually disposes of them in Earth's atmosphere, but the upper stage on the Blue Ghost-Resilience mission used almost all of its fuel getting its payloads to their distant destination. So the 8,800-pound (4,000 kilograms) rocket body remained up there, orbiting Earth — until solar activity and gravitational forces pushed it on a collision course for the moon.

That collision occurred at 2:34 a.m. EDT (0634 GMT) on Wednesday, according to KARI officials — right in line with predictions. Scientists calculated some other parameters ahead of time as well. For example, the rocket body probably hit the moon at about 5,400 mph (8,690 kph), gouging out a crater up to 89 feet (27 meters) wide.

The new observations by Danuri, as well as future work by other lunar probes, will help verify such predictions.

"The observation data secured by Danuri will be linked with follow-up observations from NASA's Lunar Reconnaissance Orbiter (LRO) and utilized in international collaborative research," KARI officials said in the X post.

It may be that some ground-based telescopes caught the impact as well. Astronomers at the Instituto de Astrofísica de Andalucía in Spain believe they captured a video of ejected material blasting off of the lunar surface around the predicted time of impact:

The Falcon 9 upper stage wasn't the first rocket body to slam into the moon. The third stage of a Chinese Long March 3C crashed into the lunar surface on March 4, 2022, for example. And the third stage of NASA's Saturn V rocket gouged out craters during multiple Apollo moon missions.

Danuri is South Korea's first lunar probe. The spacecraft launched on Aug. 4, 2022 atop a Falcon 9 and began circling the moon four months later. It carries six payloads, five of them provided by Korean universities and research organizations. The sixth is a NASA instrument called ShadowCam, which hunts for signs of water ice in permanently shadowed regions at the lunar poles.

This rocket wasn't supposed to die so dramatically.

On Wednesday (Aug. 5) at about 2:35 a.m. EDT (0635 GMT), the upper stage of a SpaceX Falcon 9 rocket will slam into the moon, blasting out a crater about 89 feet (27 meters) wide.

The rocket body has been loitering lazily high above Earth for more than 18 months. What jolted it out of its unremarkable senescence and put it on a kamikaze course for the moon?

It didn't take much, as the rocket regularly crossed into the moon's neck of the woods.

The Falcon 9 launched in January 2025, carrying aloft two private robotic lunar landers — Firefly Aerospace's Blue Ghost and Resilience, which was built by the Tokyo-based company ispace. (Blue Ghost landed successfully and carried out its historic mission, but Resilience crashed during its touchdown attempt.)

Falcon 9 first stages are famously reusable, but the vehicle's upper stages fly just once. SpaceX usually deorbits these rocket bodies shortly after launch, guiding them back for controlled destruction in Earth's atmosphere. That wasn't possible on the Blue Ghost-Resilience launch, however, as getting the lunar probes to their distant deployment point used up almost all of the upper stage's fuel.

As a result, the 8,800-pound (4,000 kilograms) rocket body "was abandoned in a moon-crossing high-Earth orbit," according to a recent study about the coming impact led by Benjamin Fernando of Los Alamos National Laboratory in New Mexico.

SpaceX performed "a different maneuver [than deorbiting] to ensure that the second stage itself is safe per the appropriate rules and regulations," Julianna Scheiman, director of NASA science and Dragon programs at SpaceX, said today (Aug. 3) during a press conference discussing the company's Crew-13 astronaut launch to the International Space Station, which is targeted for Sept. 12.

That maneuver did not lock the hunk of space junk into a stable location, however; natural forces still acted upon it and, it turns out, changed its trajectory.

"What has happened is, essentially, a mixture of solar activity and gravity forces have put it on a path towards the moon," Scheiman said.

Astronomers and lunar scientists are looking forward to the upcoming impact, even though it will occur on the sunlit side of the moon and therefore likely won't be visible to most observers here on Earth (though skywatchers with good telescopes might be able to catch a glimpse of the resulting ejecta plume).

The event "provides an opportunity to test pipelines for measuring flash properties to locate impact events seismically, and to better understand the multi-modal hazards posed to future lunar infrastructure and astronauts from space debris impacting the moon," Fernando and his colleagues wrote in their paper.

Those hazards won't be purely hypothetical for much longer, if all goes to plan: NASA aims to build a base near the moon's south pole over the coming decade via its Artemis program, and to keep that outpost staffed over the long haul. Scheiman said that SpaceX is looking into ways to minimize the chances that spent rocket bodies could rain down on an occupied moon in the future.

"It's one of the things that we're working in partnership with NASA and the other appropriate agencies," she said. "What is the best future disposal path for high-energy missions that are in the sun-Earth-moon system?"

This Falcon 9 won't be blazing an entirely new trail to the moon. The third stage of NASA's Saturn V moon rocket struck the lunar surface on multiple Apollo missions, for example. And, on March 4, 2022, a mysterious rocket body slammed into the moon, blasting out a weird double crater.

That shape revealed the impactor's identity — the upper stage of the Long March 3C rocket that sent China's uncrewed Chang'e 5-T1 mission around the moon in October 2014.

On Aug. 5, Earth's moon is due for a human-made, high-speed impact from an identified flying object: a spent SpaceX Falcon 9 upper stage. The event will lead to a literal "dust up" on the lunar landscape.

That Falcon 9 upper stage is a leftover from the launch that sent Firefly's Blue Ghost-1 lander to the moon on Jan. 15, 2025. Onboard the same flight was the Hakuto-R Mission 2, called Resilience, a robotic lunar lander developed by the Japanese company ispace.

And according to a new study by an international team published on the open-source arXiv server, the resulting impact plume may briefly be bright enough to see against the dark sky near the moon's edge. That means it might be visible to moongazers with sufficiently sensitive telescopes.

This head-on collision of the errant stage is expected to occur near the Einstein and Bell craters near the western lunar limb. It may well be visible to ground and space-based assets. Indeed, putting aside all the unknowns and modeling uncertainties, some specialists suggest if you've got the time and observational prowess, it might be worth a look.

Visible ejecta spike

Using special physics simulations to model the impact, William Jo, a graduate research assistant at the University of Texas, Austin and colleagues predict the debris plume from the impact will have the central ejecta spike reaching roughly 47 miles to over 60 miles (75 kilometers to 100 kilometers) altitude.

"Our calculations suggest the plume should be several orders of magnitude brighter than the dark-sky background for the first few minutes after impact," Jo told Space.com. "So the plume should be visible, though I'd stress this is a single nominal case. The real one will look different, and the numbers are on the optimistic side. But the point worth making is that the flash isn't really the story here."

Jo emphasized that there's great slam-dunk science to be had. "Watching this one gives us a rare chance to open up ejecta-plume science and calibrate those models against a real event, which matters for every future thing we deliver to the moon," Jo said.

Implications for future moon missions

According to new research led by Benjamin Fernando of the Los Alamos National Laboratory in New Mexico, the impact flash and resultant ejecta plume are "potentially observable" from ground- and space-based observational facilities.

"This event provides an opportunity to attempt the recording of an artificial impact in real-time; although many of the properties of the event (such as visual magnitude) are imprecisely predicted at present," Fernando and colleagues report.

Moreover, this rocket stage meets moon occasion yields an opportunity to test a pipeline for localizing impacts on the lunar surface for future seismic experiments, investigating the dust and plume dynamics from impact events on the moon, and considering hazards from artificial space debris impacts that future astronauts on the lunar surface might have to avoid, Fernando and team members point out.

"The maximum ballistic range of resolved particles is found to be slightly under 1,000 km, which is far enough to be significant from the perspective of presenting a hazard to future astronauts or infrastructure across much of the lunar surface," Fernando et al wrote in the study.

Before and after

Brent Garry is a project scientist for NASA's Lunar Reconnaissance Orbiter (LRO) at Goddard Space Flight Center in Greenbelt, Maryland. LRO will be passing over the projected rocket stage crash site about seven days prior to the impact and about seven days after the impact, Garry explains.

"After the impact we might have a little bit more knowledge of where it is. We can do some additional targeting about a week after the impact and get some targeting over where the site is," said Garry, as noted in earlier Space.com reporting.

Meanwhile, Jo at the University of Texas, Austin underscores the fact that a spent rocket stage is a hollow, spacecraft-like body, and there are very few impact models for human-made objects like it. They seem to produce very different plumes than natural impactors, like asteroids or comets do. But Jo stresses that the real scientific contributions will come by studying the moments after the impact.

"My concern is that most observers will stop at the sub-second flash and never track down the ejecta, which is the part that should actually be visible, and where the science is."

The lunar crash site from an meteorite strike on the moon is taking center stage in cosmic crime scene investigation and you can see the space rock impact zone online in a free webcast tonight (May 22).

The asteroid strike on the moon occurred on March 17 and marked the brightest lunar impact explosion seen since 2005, NASA scientists have said. The space agency announced the discovery of the impact last week.

Tonight, the online Slooh Space Camera will broadcast live views of the meteorite's impact site and you can watch the moon webcast on SPACE.com starting tonight (May 22) at 9 p.m. EDT (0100 GMT).

NASA scientists estimate that a 1-foot-wide (0.3 meters) meteoroid slammed into the moon at 56,000 mph (90,000 k/h) to carve a 65-foot (20 m) crater into the lunar surface. The resulting explosion would have been visible from Earth without a telescope and had the power of about 5 tons of TNT, NASA officials said.

"This is an unprecedented, first-time-ever event," astronomer and Slooh commentator Bob Berman said in a statement. "Apparently, a number of brilliant fireballs tore through Earth’s atmosphere just as the lunar surface received a visible impact bright enough to create a one-second point of light, seen by anyone watching the moon at that moment. This suggests that a fairly dense swarm of meteoroids zipped through our orbit at that time, two months ago."

During tonight's webcast, Slooh will stream in feeds from their observatory site in the Canary Islands off the coast of Africa while Berman and other experts will provide information about other near-Earth objects and meteorite impacts like the Feb. 15 meteor explosion in Siberia.

NASA scientists suspect the small asteroid that hit the moon weighed about 88 pounds (40 kilograms) at the time of the impact.

While the Earth's atmosphere prevented those space rocks from slamming into the planet, the atmosphere-less moon has no protection from these kinds of impacts.

Other scientists are also keeping an eye on the new moon crater. NASA's Lunar Reconnaissance Orbiter might take photos of the impact site, and researchers will continue to keep track of other moon- crashing space rocks.

To watch the Slooh webcast directly through the Slooh Space Camera website visit: http://events.slooh.com

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