Published June 2026
A spent Falcon 9 upper stage, drifting through space since SpaceX launched NASA’s Deep Space Climate Observatory (DSCOVR) in February 2015, is about to end its decade-long journey by crashing into the moon. Trajectory calculations place the impact around August 5, 2026, with the spent rocket body striking the lunar far side at roughly 2.5 kilometers per second, about 5,600 miles per hour. The object’s estimated mass is approximately four metric tons, though public sources do not specify whether that figure refers to the dry mass of the stage or includes residual propellant. No one on Earth will see it happen. But the collision will leave a fresh scar on the moon and sharpen an uncomfortable question: who is responsible for the growing cloud of abandoned hardware drifting between Earth and lunar orbit?
What tracking data shows
The object is cataloged under the provisional designation A11hSI1, though because provisional labels can change as objects are re-cataloged, that identifier may have been updated since it was first assigned. Its orbit and predicted trajectory are published through NASA’s CNEOS Scout system, a tool operated by the Jet Propulsion Laboratory that flags newly detected objects and computes where they are headed. Ground-based telescopes have collected positional measurements over multiple observation arcs, and the resulting orbit fit points squarely at a lunar intercept in early August.
Those calculations can be independently checked using the JPL Horizons System, NASA’s open-access ephemeris platform. Horizons lets any researcher plug in the positions of the Earth, moon, and tracked objects at a given time and verify whether the predicted collision geometry holds. Additional astrometry for A11hSI1 appears in the University of Arizona’s NEO Fixer tool, which coordinates follow-up observations. The overlap between these three independent systems gives the prediction a strong foundation: multiple groups can audit the same data and arrive at the same answer.
“This is a well-constrained trajectory,” said Bill Gray, the independent orbit analyst who first flagged the object’s lunar collision course using his Project Pluto software. “The orbit fit is solid enough that we can be quite confident about the date and the general area of impact, even if the exact coordinates on the far side still carry some uncertainty.”
Why a Falcon 9 stage was left out there
When SpaceX launched DSCOVR on a Falcon 9 rocket in February 2015, the second stage completed its job by placing the satellite on a trajectory toward the Sun-Earth L1 Lagrange point, about 1.5 million kilometers from Earth. After separation, the stage lacked enough residual propellant to perform a controlled deorbit burn, a common situation for early Falcon 9 missions before SpaceX refined its disposal procedures. Instead of reentering Earth’s atmosphere, the empty stage was stranded in a high, chaotic orbit influenced by the gravitational pull of the Earth, moon, and sun.
For more than a decade, those competing gravitational tugs have slowly reshaped the stage’s path. By mid-2026, that reshaping will steer it directly into the moon.
What is still uncertain
SpaceX has not publicly commented on the identification. That silence is consistent with the company’s general practice of not issuing statements about spent upper stages once a mission’s primary objectives are complete. The link between A11hSI1 and the DSCOVR launch rests on backward orbital reconstructions, not on telemetry from the rocket itself. Analysts matched the object’s trajectory to known launch histories through a process of elimination, and the fit is strong given the small number of objects in similar orbits. But without SpaceX releasing post-launch tracking data, the attribution remains highly probable rather than confirmed beyond doubt.
Pinpointing exactly where on the far side the stage will hit also carries uncertainty. The moon’s far side faces away from Earth at the moment of impact, and as of June 2026, no spacecraft has been assigned to image the predicted crash zone beforehand. Confirming the collision after the fact will likely fall to NASA’s Lunar Reconnaissance Orbiter (LRO), which has the resolution to spot fresh craters. LRO performed exactly this task in 2022, when it found a previously undetected double crater near the lunar equator.
The 2022 precedent
That 2022 event is the closest parallel to what is expected in August. On March 4, 2022, a rocket body slammed into the moon and carved out two overlapping craters, the larger roughly 18 meters across. The impact was initially attributed to a Falcon 9 stage, but subsequent analysis by independent trackers and JPL researchers re-identified the object as likely a Chinese rocket booster connected to the Chang’e 5-T1 lunar mission. The misidentification highlighted how difficult it is to track and catalog debris in cislunar space, where objects are faint, observations are sparse, and no single agency maintains a comprehensive catalog.
The August 2026 impact differs in one important respect: the tracking community identified the incoming object months in advance. That lead time gives researchers a window to plan observations and, potentially, to task LRO or other assets to survey the impact zone before and after the collision.
What it means for lunar traffic
The collision arrives at a moment when cislunar space is getting busier. NASA’s Artemis program aims to return astronauts to the lunar surface, commercial landers under NASA’s Commercial Lunar Payload Services (CLPS) program are flying with increasing frequency, and China’s Chang’e series continues to target the moon for robotic exploration. None of these missions are threatened by the August impact, but the event underscores a gap in space governance: there is no binding international requirement for operators to deorbit or dispose of upper stages sent beyond low Earth orbit.
In low Earth orbit, guidelines from the Inter-Agency Space Debris Coordination Committee (IADC) call for satellites and rocket bodies to reenter within 25 years of mission completion. No equivalent standard exists for cislunar space. As launch rates climb and more hardware is sent toward the moon, the population of uncontrolled objects in high orbits will grow unless operators adopt disposal practices voluntarily or regulators step in.
How the August orbit fit will sharpen before impact
For now, the most useful thing anyone can do is watch the data. Each new round of telescope observations between now and August will tighten the predicted impact time and location. If the orbit fit holds through the final weeks, the Falcon 9 stage will become one of a handful of documented cases where human-made hardware has struck another world, and the first where the tracking community saw it coming with enough lead time to turn the collision into a science opportunity rather than an after-the-fact surprise.
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*This article was researched with the help of AI, with human editors creating the final content.
