The South Korean probe Danuri confirmed the impact near Einstein Crater and documented changes in the ground and the scattering of material. The incident did not endanger anyone, but the large number of missions to the Moon requires planning in advance for the disposal of launch stages.
NASA and SpaceX are exploring how to dispose of upper stages of high-energy orbiting rockets in the future, after a Falcon 9 stage hit the moon's surface on August 5, 2026. The impact was unplanned and did not jeopardize an active mission, but it illustrates the need to define in advance what will be done with rocket stages after they complete their mission in the space between the Earth and the Moon.
The stage hit the moon near Einstein Crater on its western edge at 06:34 Universal Time, 09:34 Israel. The impact velocity was approximately 2.43 kilometers per second, which is approximately 8,700 km/h. The stage's mass was estimated at approximately four tons.
The South Korean spacecraft Danuri photographed the impact area before and after the event. The Korean Space Agency said the photographs showed changes in the surface and traces of the dispersion of material ejected during the impact. The data is still being analyzed, so precise and agreed-upon dimensions of the new crater have not yet been released.
Denuri made eight observations: one about thirty minutes before impact and seven more after. The orbiter passed within 340–350 kilometers of the site and operated both the LUTI high-resolution camera and a polarization camera designed to detect changes in the light-reflecting properties of the ground.
NASA's Lunar Reconnaissance Orbiter (LRO) is also expected to photograph the site. Comparing its photographs with those taken before the event will allow for more precise measurements of the crater's dimensions and the distribution of material around it.
Two landers and one remaining in orbit
The upper stage, designated 2025-010D, launched on January 15, 2025, carrying two private lunar landers: Firefly Aerospace's Blue Ghost and Japan's ispace's Resilience lander. Blue Ghost landed successfully, while Resilience crashed during its landing attempt.
After releasing the two landers, the upper stage had no fuel left to return it to Earth. It continued to move in a high, elongated orbit, which was affected for about a year and a half by the gravity of the Earth, the Moon, and the Sun, and by the pressure of solar radiation. The accumulation of these effects finally brought it into an impact orbit with the Moon.
Julianna Shaiman, SpaceX's director of science and Dragon programs, said in a NASA briefing that the company had passivated the stage in accordance with accepted rules and procedures. Passivation involves emptying or venting fuel residues and discharging energy sources to reduce the risk of the stage exploding and breaking into pieces.
However, passivation does not remove the object from space or control its trajectory for the long term. In low Earth orbit launches, the stage can usually be fired again and re-entered the atmosphere, where most of it burns up. In a high-energy mission to the Moon, much of the fuel is used to accelerate the payload, and there is not always enough maneuverability left for a controlled ejection.
According to Shaiman, SpaceX is working with NASA and other agencies to determine the appropriate disposal method for future missions operating in the Earth-Moon-Sun system. She did not specify which solutions are being tested.
Engineering options may include saving fuel for a final maneuver, directing the stage for a controlled impact in a remote area, sending it into orbit around the sun, or designing a trajectory that allows for reentry into the atmosphere. Each option has a cost in fuel and payload capacity, and therefore must be incorporated into the mission planning at an early stage.
The risk is small, but not zero.
The Moon is a very large area, and only a few robotic facilities are currently operating on it. Therefore, the probability that a random launch stage will hit an active spacecraft is extremely small. However, in the coming years, many landing attempts, robotic missions, and plans to establish manned infrastructure are expected, especially near the South Pole.
As landers, rovers, scientific instruments, and habitats accumulate on the lunar surface, even a small hazard could become a problem that requires attention. An impact doesn't have to occur directly on the facility: Rocks and dust ejected rapidly from an impact site could be scattered far and wide, damaging nearby equipment.
Another problem is tracking. Objects in low Earth orbit are usually monitored using radar arrays and telescopes. The space between the Earth and the Moon is much larger, and their orbits are affected by a number of gravitational forces. An object can remain in a complex orbit for months or years before its fate is determined.
The phase that hit the moon was detected and tracked by astronomer Bill Gray and other researchers. Their calculations predicted the time and location of the impact with such precision that it allowed both the spacecraft and ground-based observers to prepare in advance. In the future, as the number of objects in this space increases, a more organized catalog and coordination system will be needed.
Not the first artificial injury
Launch stages and spacecraft have hit the moon before, sometimes intentionally. During the Apollo program, several third stages of Saturn V launchers were aimed at the moon's surface. Seismometers left behind by the astronauts measured the seismic waves, helping researchers learn about the moon's interior.
In 2009, the Centaur stage of the Atlas 5 launcher intentionally impacted the Moon as part of the LCROSS mission. The spacecraft tracked the cloud of material ejected from the impact before it also crashed. Analysis of the material provided important evidence for the existence of water ice in the south polar region.
In 2022, a launch stage attributed to the Chinese launch of the Chang'e 5-T1 mission in 2014 hit the Moon. Photographs revealed two adjacent craters, likely due to the distribution of mass between the engines at one end of the stage and equipment or an adapter at the other end.
The main difference is between a planned impact, in a pre-selected area and for a scientific purpose, and an uncontrolled impact. In the first case, the impact point can be moved away from sensitive sites and observations can be coordinated. In the second case, the trajectory develops over a long period of time as a result of a combination of gravitational forces and solar radiation, and control over the target is limited or nonexistent.
A scientific opportunity born from space debris
Despite its unplanned nature, the impact also provides a research opportunity. Since the object's mass, velocity, structure, and trajectory are approximately known, the crater and the material distribution can be compared to predictions from physical models.
Data from Denuri and LRO could help researchers calibrate crater-forming models and better interpret natural meteorite impacts. They will also allow them to examine how materials from the stage itself mix with the lunar soil and how the dust cloud disperses in a nearly atmosphereless environment.
However, scientific utility does not eliminate the need for orderly disposal planning. As activity in the Earth-Moon space becomes a collection of individual missions into a permanent infrastructure, it will not be possible to leave the fate of large objects to gravity and chance.
External sources:
- Original article by Jeff Faust at SpaceNews
- NASA statement on the impact tracking
- Korean Space Agency statement on Danuri observations
- Bill Gray's trajectory calculations
More of the topic in Hayadan:
- Falcon 9 stage likely hit the moon at 8,700 km/h
- The amount of space debris in Earth's orbit and on the moon will increase – but no one is responsible for it
- NASA photographed the Genesis spacecraft crash site
- LCROSS discovered water on the moon
- The LRO spacecraft has completed the preparation of a high-resolution topographic map of the Moon
Questions and Answers
Why didn't they re-enter the atmosphere of the Falcon 9 stage?
The mission required a lot of energy to send two landers towards the moon. After the payload was released, the stage did not have enough maneuverability for a controlled re-entry into the atmosphere.
Has the moon strike been confirmed?
Yes. The South Korean probe Danuri photographed the area before and after the impact and identified changes in the ground and traces of ejected material. The exact dimensions of the crater are still being investigated.
Was there any danger to the astronauts or spacecraft?
Not in this case. The impact occurred in an area far from human activity. However, the risk will increase as more manned spacecraft, instruments, and infrastructure are placed on the moon.
How can future injuries be prevented?
A disposal trajectory must be planned in advance and fuel or propulsion assigned to it. Options include re-entry into the atmosphere, transiting into orbit around the sun, or a controlled impact in a pre-selected and coordinated lunar region.
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