You know you live in the space age when a rocket hits the moon, and the industry as a whole points to the sky and, like an angry teacher holding up a paper airplane, asks, “Who launched this?” That is really what happened this week when an unidentified rocket stage (!) Affected the moon’s surface, formed a new and interesting crater and left us all wondering how it is possible not to know what happened.
The short version of this story is that skywatchers led by Bill Gray had been tracking an object for several months that, based on their calculations, would soon affect the moon. It was obviously a piece of rocket garbage (rockets produce lots of garbage), but no one went up to say “yes, it’s ours, sorry about that.”
Based on their observations and discussions, these amateur (but by no means lack of expertise) object trackers decided that it was most likely a SpaceX launch from 2015. But SpaceX failed, and after a while Gray and others, including NASA, decided that it was more likely to be a 2014 launch from China. China denied that this was the case, and said that the launch vehicle in question burned up upon re-entry.
Maybe they are telling the truth; they may not want to be responsible for the first completely unintended lunar impact in history. Other spacecraft have hit the moon, but it was intentional or part of a wrong landing (in other words, the impact was intentional, just a little harder than expected) – not just a stubborn piece of space junk.
Maybe we’ll never know, and it’s really the weirdest thing of all. With hundreds of terrestrial telescopes and radars, space-based sensor networks and cameras pointing in every direction – and that’s just space surveillance we know about! – It seems incredible that an entire rocket scene managed to sit in orbit for six or seven years, and eventually get all the way to the moon, without being identified.
I thought someone at LeoLabs, who has built a new network of debris tracking radars around the world, might have some insight. Darren McKnight, senior technical fellow there, had the following answers to my questions.
How is it possible that we did not know the identity and path of such a large and relatively recently launched object?
Tracking abandoned objects in a sislunar orbit is probably not a high priority for public sensors when they can spend that time observing satellites or space debris closer to Earth. However, tracking and monitoring of operational satellites in sislunar orbit is crucial for strategic intelligence, as it is a new highlight.
Would confusion like this be possible for an object being launched now?
Yes, this can happen again now as the technology used by US authorities to track space objects has not changed in many years.
Is it likely that more of these “mysterious objects” will make an impression here and there over the next few years?
It is possible that an unintentional lunar attack like this could happen again in the future, depending on the number of missions that put rocket bodies into these orbits and given enough time (years or decades). But incidents like this should generally be very rare.
And as Bill Gray notes in his article:
… Garbage at high altitudes has not been a concern for anyone outside the asteroid surveys, and even we have not been so concerned about it. Objects of this type are not tracked by the US Space Force; they use (mostly) radar, which is ‘myopic’: it can track objects four inches / 10 cm across in low orbits, but cannot see large rocket stages like this when they are as far away as the moon. You need telescopes for that.
How strange it seems (to me at least), paths for objects of this type are calculated only by me, in my spare time.
It’s remarkable in a way, but as everyone in the space surveillance world will tell you, there’s a lot to look at up there and you have to choose your goals. An object the size of a rocket halfway to the moon is not simple or easy to get a good picture of.
Our best clue to the object’s identity may actually be the crater it left when it hit. The impact site was depicted shortly after, and it has a strange double O-shape: two overlapping craters, one 18 meters across and the other 16 meters. Here are the before and after:
“The double crater was unexpected and may indicate that the rocket body had large masses at each end. Usually a used rocket mass is concentrated at the engine end; the rest of the rocket stage consists mainly of an empty fuel tank “, wrote NASA’s Mark Robinson.
While it is a tempting mystery, the truth is that there does not seem to be much reason to dedicate any serious resources to finding out. Stranger things are happening in space than part of a rocket that flies away at exactly the angle and speed needed to eventually hit the moon. And for all we know, someone out there is well aware of what this weird, double-sided space junk is, but would rather keep it quiet.