SpaceX rocket upper stage expected to crash into the Moon unplanned in August

It is still unclear whether the impact will be visible from Earth. NASA manager William Cooke said on this: "I think it will be very, very hard to see, if not impossible." Planned impacts for research purposes have already occurred on the Moon multiple times in the past.

Observation by NASA

A few days before and a few days after the expected impact, NASA's "Lunar Reconnaissance Orbiter" probe is to fly over the expected impact site. This could provide more information about the event, the agency explained.

Comparable to the current case is an incident from around four years ago, when an unplanned collision of a rocket part with the Moon became known for the first time. NASA scientists at the time assumed, based on images from the "Lunar Reconnaissance Orbiter" probe, that it was a part of an old Chinese rocket, likely the launch vehicle of the "Chang'e 5-T1" mission, which had been launched into space from Earth in 2014.

Earlier unplanned collision on the Moon

China had however rejected these reports. The attribution of the object at that time therefore remains disputed. In the current case, however, the origin is clear: according to astronomers, it is the burned-out upper stage of a US rocket, which remained in space after deploying its payload and has since been uncontrollably leaving Earth's orbit.

Since the launch on January 15, 2025, the two lunar landers "Blue Ghost" and "Resilience" have been on their way or are already in operation. "Blue Ghost" is operated by the US company Firefly Aerospace, while "Resilience" comes from the Japanese start-up ispace. Both devices had been carried into space together by the same Falcon 9 upper stage.

Effects and risks

The expected impact is considered comparatively minor: since the upper stage will hit the lunar surface with a mass of about two tons and an impact velocity of around 2.5 kilometers per second, only a small crater of a few meters in diameter is expected. According to observers, there is no danger to the active lunar landers, as the impact site is expected to be in a little-visited region of the side of the Moon facing away from Earth.

The case does, however, raise questions about the space debris problem. Since more and more rocket launches are occurring and upper stages are often burned up in space or forgotten after separation, the risk of unplanned collisions with celestial bodies is increasing. International rules for the safe disposal of spent rocket stages so far exist only in rudimentary form.

Astronomers such as Bill Gray have been tracking such objects for years using self-developed software and publish their calculations to inform the scientific community. NASA, in turn, uses its lunar probe to document such events more precisely and to gather data about the composition of the lunar soil.

In the coming weeks, both private observers and NASA intend to further narrow down the exact time and location of the impact. Should the impact actually occur on August 5, initial images from the NASA probe could be expected a few days later.