Chinese rocket junk may have just smashed into Moon

A chunk of Chinese space junk today crashed into the far side of the Moon, according to a maker of astrometry software.

The trash is believed to be a spent Long March 3C rocket booster from the launch of Chang'e 5-T1, a Chinese experimental robotic spacecraft that lifted off in 2014. The leftover component was estimated to have smashed into the Moon at 1225 UTC on Friday, after hurtling through space at 5,800 miles per hour.

We're not sure of the timing because debris at such altitudes isn't usually tracked by agencies, such as the US Space Force, according to Bill Gray, who develops software for professional astronomers and first predicted the impact. Gray said he started tracking the debris in 2015 but an astronomer at NASA alerted him a few weeks ago to something that seemed, in Gray's words, "suspiciously large."

"We're quite sure it hit, just based on the trajectory data we got from telescopic observations," Gray told The Register. The impact time is probably good to within a minute and the impact point to within a few kilometers. Unless the object was removed by an occult hand it hit the Moon."

The collision probably created a crater on the Moon, though it'll be tricky to confirm this since there are only NASA's Lunar Reconnaissance Orbiter and India's Chandrayaan-2 covering the natural satellite's far side. A non-peer-reviewed paper that appeared in the American Astronomical Society's research notes, however, said it may be possible to see the cloud of dust kicked up during the impact from ground-based observatories.

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At first, the junk, tracked as object WE0913A or 2014-065B, was thought to be a component of a Falcon 9 SpaceX rocket that launched NASA's Deep Space Climate Observatory. This was revised by Gray to be an upper-stage booster from the Chinese space program. After more than six years in space, it's likely that it started floating further and further away from Earth and reached a distance where it could be captured by the Moon's gravity. 

Wang Wenbin, a spokesperson for China's Ministry of Foreign Affairs, denied that the rogue part was from its space agency. "According to China's monitoring, the upper stage of the Chang'e-5 mission rocket has fallen through the Earth's atmosphere in a safe manner and burnt up completely," he said in a statement last month. The Chang'e 5 mission launched in 2020 Wang referred to is not the 2014 Chang'e 5-T1, however, according to Gray.

Also curiously, the US Space Force lists the Chang'e 5-T1 booster as having entered Earth's atmosphere in October 2015. However, Gray believes the force did not and could not fully track the rocket, and that asteroid watchers instead continued to follow the object years after its lift off. Hence his confidence that whatever hit the Moon today was the Chang'e 5-T1 booster.

We've asked Space Force for comment. The military wing's debris-tracking squadron now believes the booster did not actually reenter the atmosphere as listed, and is reconsidering its status, The Verge reported.

The surface of the Moon has been disturbed by artificial objects before, such as when NASA's Lunar Crater Observation and Sensing Satellite was sent to smash into the ground to find hydrogen in pockets of lunar water in 2009.

Gray argued that scientists should start paying attention to junk further out into space: "Many more spacecraft are now going into high orbits, and some of them will be taking crews to the Moon," he said. "Such junk will no longer be merely an annoyance to a small group of astronomers." ®