The Lunar Reconnaissance Orbiter (LRO) – NASA’s eye in orbit around the moon – has found the crash site of the mysterious launch vehicle that impacted on the far side of the moon on March 4, 2022.
The LRO images taken on May 25 showed not just a single crater but a double crater formed by the rocket’s impact, leaving astronomers with a new mystery to solve.
Why a double crater? Although somewhat unusual – none of the Apollo S-IVBs that hit the moon created double craters – it’s not impossible to create them, especially when an object hits at a low angle. But that doesn’t seem to be the case here.
Astronomer Bill Gray, who first spotted the object and predicted its moonset back in January, explains that the booster “came in at about 15 degrees from vertical. So that is not the explanation for this one.”
The impact site consists of an 18 meter wide east crater overlying a 16 meter wide west crater. Mark Robinson, lead researcher on the LRO camera team, suggests that this double crater formation could result from an object with different, large masses at each end.
“Typically, a spent rocket has a concentrated mass at the motor end; the rest of the rocket stage consists mostly of an empty fuel tank. As the origin of the rocket body remains uncertain, the dual nature of the crater can help indicate its identity,” he said.
So what is it?
That is a long story. The unidentified rocket first caught the attention of astronomers earlier this year when it was identified as the SpaceX upper stage that launched NASA’s Deep Space Climate Observatory (DSCOVR) to the Sun-Earth Lagrange point L1 in 2015.
Gray, who develops software that detects space debris, was alerted to the object when his software reported an error. He said That Washington Post on January 26 that “my software complained because it couldn’t project the orbit beyond March 4, and it couldn’t because the rocket had hit the moon.”
Gray broke the news, and the story made the rounds in late January — but a few weeks later, he received an email from Jet Propulsion Lab’s (JPL) Jon Giorgini.
Giorgini pointed out that DSCOVR’s trajectory should not have brought the booster close to the moon. To reconcile the conflicting trajectories, Gray began digging through his data, where he discovered he had misidentified the DSCOVR booster back in 2015.
SpaceX wasn’t the culprit, after all. But there was definitely still an object hurtling towards the moon. So what was it?
A bit of detective work led Gray to determine that it was in fact the upper stage of China’s Chang’e 5-T1 mission, a 2014 technology demonstration mission that laid the groundwork for Chang’e 5, which will successfully launch in 2020 returned a lunar sample to Earth (By the way, China recently announced that it will follow this sample-return mission with a more ambitious Mars sample-return project later this decade).
Jonathan McDowell provided some corroborating evidence that seemed to support this new theory for the object’s identity.
The riddle has been solved.
Just days later, China’s foreign minister claimed it wasn’t their booster: It crashed out of orbit shortly after launch and plunged into the ocean.
As it stands now, Gray remains convinced that the Change 5-T1 booster hit the moon, claiming that the Secretary of State made an honest mistake by linking Chang’e 5-T1 to the Chang’e 5 of the same name (whose booster did) mistaken for actually sinking in the ocean).
As for the new double crater on the moon, the fact that the LRO team was able to find the impact site so quickly is an impressive achievement in itself. It was spotted just months after impact, with a little help from Gray and JPL, who independently narrowed the search area to a few dozen miles.
For comparison, the Apollo 16 S-IVB impact site took more than six years of diligent searching to find.
Bill Gray’s account of the booster identification saga is here, as is his take on the double crater impact. The LRO images can be found here.
This article was originally published by Universe Today. Read the original article.