Astronomers say that a rocket section set to crash into the Moon in March did not come from Elon Musk’s space exploration company as they first thought.
Instead they believe it is probably a Chinese rocket stage launched for a lunar mission in 2014.
The impact of the collision with the Moon will be minor, scientists say.
Astronomers first identified a piece of machinery on course to crash into the Moon on 4 March in January.
Machinery left in space that doesn’t return to the Earth’s atmosphere after completing missions is known as space junk.
Data analyst Bill Gray identified the object as a Falcon 9 booster from a 2015 launch by billionaire Elon Musk’s space exploration programme SpaceX.
It was subsequently reported by journalist Eric Berger.
Mr Musk’s company ultimately aims to get humans living on other planets.
But now Mr Gray says he made an error and instead he believes it is a rocket launched in October 2014 as part of China’s Chang’e 5-T1 mission that sent a small spacecraft to the Moon.
Prof Jonathan McDowell from the US-based Harvard-Smithsonian Center for Astrophysics told BBC News he agrees with Mr Gray’s re-assessment.
He explained that there is a lot of “intrinsic uncertainty” in identifying space debris far from Earth and that mistakes happen.
There are limited resources for tracking space debris, he explained: “We rely on a small handful of volunteers who do it on their own time.
So there is limited scope for cross-checking.”
Objects close to Earth are tracked by a team at the US military’s Space Force, but junk further out in deep orbit is left unobserved.
The European Space Agency commented: “This still-evolving finding underscores the need for enhanced space tracking, and greater data sharing between spacecraft operators, launch providers and the astronomy and space surveillance communities.”
Prof McDowell said he is 80% certain that the object on course to hit the Moon is from the 2014 Chinese rocket launch.
When the object was first identified, Prof McDowell told BBC News it will be the first known uncontrolled collision of a human-made object with the Moon.
The rocket stage will explode as it makes contact.