Upper stage impacting the moon on 2026 August 5
Upper stage impacting the moon on 2026 August 5
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On 2026 August 5, within a few minutes of 06:35 UTC, an upper stage<br>(section) of a rocket used for a lunar mission will hit the moon. This<br>may be of some (probably minor) scientific interest, and we may learn<br>some things from it. It doesn't present any danger to anyone, though it<br>does highlight a certain carelessness about how leftover space hardware<br>(space junk) is disposed of.
This is the<br>second time I've identified a piece of junk as being about to hit the moon.<br>That event got considerably more attention than I'd expected, including<br>from non-astronomers. I'm hoping the following will answer most of the<br>questions people are apt to have about this new event.
What is this object?
Who observed this object?
How was the impact predicted?
Where and when will it hit the moon?
What else do we know about the object?
How fast will it be going when it hits the moon?
Will the impact be visible from earth?
Might we see the ejecta plume?
Where is the object now?
Will we get pictures of the resulting crater?
Why worry about this?
Should we worry about space junk in general?
Are there ways to avoid lunar impacts?
News articles about this impact
Contact info
What is this object?
This is the upper stage of a<br>Falcon 9 rocket. The Falcon 9 is SpaceX's workhorse rocket.<br>These rockets have<br>two stages. The first, larger stage gets the payload (and upper stage)<br>most of the way to orbit, and then comes back to earth and lands on a<br>barge, and can be re-used. The upper, smaller stage goes into orbit<br>and can't be re-used. As you can see in the above image, it's still<br>quite a large object, roughly the height of a five-story building.
Over 600 Falcon 9 rockets have been launched. Most of the upper stages<br>are either in orbits close to the earth or have already re-entered the earth's<br>atmosphere. A few are orbiting the sun. The object that will be hitting the<br>moon has been orbiting the earth for a little over a year.
The object doesn't have a name, just an official catalog designation of<br>2025-010D. That tells you that it was on the tenth rocket launched<br>into orbit in 2025,<br>on January 15 of that year, and was the fourth bit of hardware to be tracked<br>from that launch. The purpose of the mission was to launch the<br>Blue Ghost<br>and<br>Hakuto-R landers to the moon. Those were designated 2025-010A and 2025-010B.<br>They were held together by 2025-010C, a "payload canister".
2025-010D was the Falcon 9 upper stage, a rocket that propelled everything<br>else from a low orbit around the earth into an orbit that could reach the moon.<br>Once it had done that, all four objects separated from each other.
Over the following weeks and months, all four pieces were<br>tracked by the telescopes of asteroid surveys and amateur astronomers. Blue<br>Ghost landed on the moon on 2025 March 2. Hakuto-R took a much more circuitous<br>route to save on fuel, and attempted to land on 2025 June 5. Unfortunately,<br>contact with it was lost about 90 seconds before landing, and it crashed.
The payload canister, 2025-010C, kept orbiting the earth and
re-entered the earth's atmosphere at 12:06 UTC on 2025 March 15, near the<br>border between Argentina and Chile. I don't know if anybody actually saw it.<br>If they did, it would have looked like a fairly bright meteor.
The upper stage, 2025-010D, also kept orbiting the earth, but was a<br>bit higher and didn't re-enter. It's had a few close passes by the moon and<br>earth, but nothing that was close enough to look like a possible impact.<br>The asteroid surveys observed it whenever it wasn't too close to the sun or<br>moon to see. As of 2026 February 26, we had accumulated 1053 observations<br>of it.
Who observed this object?
This object has spent almost all of its time at distances similar to that of<br>the moon. Generally speaking, such objects are very poorly tracked.<br>The US military mostly tracks objects using radar. That does a superb job<br>of tracking low-orbiting junk; they've tracked gloves and tool bags that<br>astronauts have lost over the years. But the moon, and objects like<br>2025-010D, are about 400 times further away; the radar signals are<br>about 25.6 billion times fainter.
(If an object is 400 times further away,<br>it receives 1/400 squared, or 1/160000, as much radar energy. And of<br>that, only 1/160000 as much is returned to earth.)<br>Basically, the radar works well for "close" stuff, and the<br>telescopes work better for more distant objects.
However, these objects are entirely observable by the asteroid<br>surveys, and even by amateur astronomers with suitably advanced gear and<br>techniques. You can click here to see<br>observational data gathered by amateur observers and the resulting orbit<br>and impact prediction. (This is in a somewhat opaque form that is<br>quite familiar to asteroid observers.) This includes observations from<br>five observatories in<br>Mississippi, Utah, Beijing, and...