A double mystery on the hidden side of the Moon
An unexpected double crater photographed on the moon is further complicating an already very
mysterious affair that began when Bill Gray, a U.S. astronomer and astronomy software developer,
predicted in early 2022 that the remnant of a rocket would hit the far side of the
moon within a few months. This was the beginning
of an affair marked by a mystery within a mystery. Follow me if you want to know more!
The object (which was given the temporary name WE0913A) had first been photographed
by the Catalina Sky Survey, a series of telescopes near Tucson dedicated to wide-field searches for
comets, asteroids, and near-Earth objects whose orbit could dangerously intersect that of Earth.
However, WE0913A was not orbiting the Sun but was instead orbiting the Earth.
Which is strange for an asteroid! Going back in time, it was discovered
that the object had passed close to the Moon just two days after SpaceX launched its Deep
Space Climate Observatory mission on a Falcon 9 rocket, so Gray understandably thought it might
be the second stage of the Falcon X rocket launched by Elon Musk's Space X in 2015.
But later observations and analysis made him change his mind, so much so that he was convinced
that the object must rather be the third stage of a Long March 3C rocket, which had launched China's
Chang'e 5-T1 mission to the Moon on Oct. 23, 2014; carrying a probe that was supposed to test the
technology needed for the Chang'e-5 mission that, in 2020 was supposed to land on the Moon, collect
some lunar soil samples and return to Earth. The probe reached our satellite on Oct. 27,
transited about 12,000 km from its surface, and then returned to Earth, landing as planned
in Inner Mongolia, while the third stage of the rocket was abandoned in a highly unstable orbit.
After extensive research, Gray managed to calculate that the wreckage of the
third stage would impact the far side of the Moon on March 4, 2022, at 12:25 UT.
The identification of the debris was also confirmed by some students from
the University of Arizona, who were able to examine the image of the object and conduct
a spectral analysis of the outer paint, which turned out to be identical to that of similar
Chinese boosters and completely different from that of a Falcon 9.
Furthermore, a small amateur cubesat satellite had been in contact with
the Chang'e 5-T1 for the first 19 days of its flight, and the trajectory data sent
by that satellite perfectly matched the trajectory calculated by Gray.
So far, so good... except on February 21, 2022, an official denial came from
the Chinese Ministry of Foreign Affairs, stating that "The debris from the rocket
destined to hit the moon next March does not come from the Chang'e-5 T1 mission in 2014.
According to our monitoring, the upper stage of the rocket related
to the Chang'e-5 mission reentered the Earth's atmosphere in 2015 and completely burned up."
What was the mystery? Gray was absolutely certain about his calculations,
and therefore the Chinese government was lying. But for what reason?
To preserve China's good faith, one could possibly hypothesize a
possible confusion regarding the mission mentioned in the denial.
Both the Chinese and English transcriptions, as well as the Chinese language video of the
press conference, referred to the "Chang'e-5 mission," rather than the Chang'e-5 T1 mission!
Chang'e-5 T1 was, in fact, only a test mission, which was supposed to be followed by Chang'e-5,
which would have attempted to bring lunar samples back to Earth. Chang'e-5 was launched
in November 2020, and indeed, the upper stage of that mission reentered the Pacific Ocean
a week after launch, disintegrating. Was there an innocent misunderstanding
on the part of the Chinese between the very similar names of the two missions?
Even today this is highly doubtful, but the fact remains that the Chinese authorities have always
refused to acknowledge their mistakes, even in the face of indisputable facts.
And it is hard to understand why, given that in the history of space exploration the Moon
has been the target of many other probes and other instruments launched from Earth,
sometimes to assess lunar seismic features, and in other cases as a result of technical
problems and failed controlled lunar landings. The first impact of a man-made object on the
Moon occurred on September 13, 1959, when the then Soviet Union launched the Luna 2 probe
toward our natural satellite, which crashed west of the Sea of Tranquility. Thirty minutes later,
the third stage of the rocket that carried the small probe also hit the Moon.
In the years that followed, the Saturn V upper stage boosters of the Apollo 13, 14, 15, 16,
and 17 missions all crashed on the Moon to study the vibrations from the impact.
Sometimes the missions even intentionally sent boosters to the Moon for scientific reasons.
However, many other unintentional impacts have likely occurred in the
past - but we never knew about them because boosters that leave Earth
for low-Earth orbit missions often stay in space instead of re-entering the atmosphere.
For example, according to a study by Arizona State University, there have been at least 47
U.S. rockets that have crashed on the moon... But there are at least 50 objects that were
left in low Earth orbit in the 1960s, 1970s, and 1980s. Many of them can't be
found…and at least some of them likely hit the moon by accident and we didn't know it.
Be that as it may, Bill Gray knew his stuff. He went so far as to calculate that the wreckage of
the Chinese rocket would hit the lunar surface at a speed of about 3 kilometers per second,
or 11,000 kilometers per hour, even venturing to the point of impact: the far side of the Moon,
near the large Hertzsprung crater, Data was also used by Mark Robinson,
professor at Arizona State University and principal investigator of the Lunar
Reconnaissance Orbiter camera, to explain that at that speed the four tons of metal would have
carved a crater 20 meters wide: widely observed by some of the probes then in lunar orbit,
such as NASA's Lunar Reconnaissance Orbiter and the Indian Space Agency's Chandrayaan-2.
Thus came the fateful day of March 4, but no one would ever be able to confirm
or otherwise that the impact had occurred. Since the impact had been predicted to occur
on the opposite side of the Moon, observers on Earth had no chance to see the event,
and the lunar orbital probes were not in a favorable position for filming that day.
But the same thing would have happened even if the collision had occurred on
the near side because our satellite was in close conjunction with the Sun that day.
Now, some of you will immediately ask, how could anyone be sure that the impact actually occurred?
Well, you couldn't, and that was that.
The near certainty that the third stage of Long March 3C must have disintegrated in the
regolith of the lunar terrain came only from the last direct observations of the wreckage,
made about four weeks earlier. Observations that confirmed Gray's predictions.
Official confirmation of what had happened did not come until May 22, when the Lunar
Reconnaissance Orbiter was able to locate and photograph the crash site for the first time.
And this was the moment of the greatest surprise and mystery of the whole affair!
Right on the edge of Hertzsprung Crater, almost exactly where Gray's calculations had
placed the event, were clearly visible not one, but two new impact craters!
The two craters overlap, one 16 meters wide and the other 18 meters wide, together forming a
crater about 28 meters in diameter. By comparison, a tennis court is about 24 meters long.
A single object hitting the moon should generally leave a single crater. Many
double craters are known, probably from binary asteroids - two rocks
orbiting each other that strike almost simultaneously - or from a single object
that breaks in two just before impact. But the latter is something that only
happens on re-entry into the atmosphere. And that is certainly not the case here.
So why did this object do it? That is still a mystery.
A booster is essentially a long tube with very heavy rocket motors and nozzles at one
end and fuel tanks along its length. Once the fuel is gone, those tanks are pretty light.
Most of the force capable of digging a crater therefore comes from the impact of the engines,
and the rest of the booster could at best change the shape of the crater by stretching it.
A first hypothesis is that the booster may have come in at a very low angle of incidence,
making a double jump on the ground like rocks thrown on water, but Gray's calculations assure
that the angle of impact was very little off vertical, so this cannot be the explanation.
To our knowledge, no other lunar impact of the rocket body has ever produced two craters,
and this incredible oddity suggests that whatever hit the Moon had a peculiar structure,
with two large, massive protrusions at each end.
Another hypothesis is that of tidal forces. An object approaching a large body such as
the Moon could be distorted and then broken when it reaches the so-called Roche limit.
What is the Roche limit? Well, it is the minimum distance from the center of a celestial body
below which a second smaller body in free fall will be broken up by tidal forces, that is,
by the distortion caused by the difference in the gravitational force acting on the part
of the smaller body closest to the larger body as opposed to the part farthest away.
But this may apply to very large objects, certainly not to a booster only 12 meters long...
In short... the mystery remains as such, and it is at this point that doubt begins
to creep into the minds of those who cannot get their heads around all these oddities...
Could there be a willingness on the part of government space agencies,
and now private ones, to hide the truth about what is being sent into space?
The question comes as a growing number of analysts and experts fear that space could become the next
battleground. For example, Russia and China have recently conducted anti-satellite missile tests,
and the United States has long possessed similar capabilities.
Even though since 1965 the Outer Space Treaty has obligated nations to use space only for
peaceful purposes, most technologically advanced states are now developing a decidedly strategic
view of space resources. Even if there is no official declaration of the presence
of weapons systems aboard satellites. But are we to believe this? Are we to
believe that experiments of a dubious nature are not being carried out in space, with satellites
and probes launched in absolute secrecy? All these missions, even if we do not want
to think about the worst-case scenario, that of a conflict, would be completely classified and
would thus escape any possibility of cataloging the remnants left in high orbits, those that
include the space between the Earth and the Moon. For everything orbiting the Earth (low orbit or
geostationary orbit), there is an internationally valid registry of launched objects, but nothing
has yet been done to address the need to begin cataloging dozens of pieces of space junk,
such as spent rocket bodies, defunct satellites, and debris from missions to cislunar space.
Since the 1960s, beginning with the launch of the Apollo program and then with the advent of
the space race between the United States and the Soviet Union, space debris has also been
widely distributed around the Moon. Scientists do not know the location or orbit of the vast
majority of lunar debris, its presence, or what remains in orbit around the Moon or in
cislunar space; these objects are likely to remain in place for at least decades.
If action is not taken soon, the current debris and what will be produced and launched in the
coming years will become an emerging problem that could create dangerous conditions for astronauts
and spacecraft in the lunar environment. The problem is twofold, just as the crater
left by that single booster is twofold: to establish some form of absolute control over
everything that is launched into space, and to prevent space, understood as a
kind of new "Wild West", from turning into a new race, not for gold, but for armaments.