The unusual craters were observed in new images taken by NASA's Lunar Reconnaissance Orbiter on June 24. The unknown collision resulted in two overlapping impact sites — an eastern crater measuring 18 meters across and a western crater spanning 16 meters.
Astronomers made the discovery after they found an unidentified piece of space junk on a collision course with the Moon in 2021. But "the double crater was unexpected," NASA stated in a press release. "No other rocket body impacts on the moon created double craters."
The space agency added that two large masses on each end of the rocket may have caused the two craters, but that would be unusual, since spent rockets tend to have a heavy motor at one end and a lighter empty fuel tank at the other.
"Since the origin of the rocket body remains uncertain, the double nature of the crater may indicate its identity," NASA stated, adding that "No other rocket body impacts on the Moon created double craters".
According to Business Insider, 2016 data from Arizona State University, at least 47 NASA rocket bodies have created "spacecraft impacts" on the moon.
Bill Gray, the astronomer who first discovered the mysterious object and alerted NASA about its eventual collision, wrote on his blog Project Pluto, "I must confess that I'd naively thought it would be easier to find and would have been located shortly after impact." Gray he uses software to track near-Earth objects.
So far, however, no nation has acknowledged landing the mysterious rocket on the Moon, Universe Today reported.