The Chinese probe Chang’e-6 is returning to Earth with a very valuable cargo: the first soil samples ever collected on the far side of the Moon.
The robot collected around 2 kg of material after descending into the South Pole’s Aitken Basin (APS), one of the largest known craters in the Solar System.
Chang’e-6 spent two days collecting rocks and dust, using a mechanical arm and a drill, in a feat celebrated by the international scientific community.
The capsule with the samples is expected to land in the deserts of Inner Mongolia around June 25.
China is the only country that has reached the far side of the Moon. It achieved this for the first time in 2019, on the fourth of six Chang’e lunar exploration missions (name of the lunar goddess in Chinese mythology).
Several countries have already undertaken lunar missions, mainly the United States with its manned Apollo program and subsequent NASA unmanned probes. But all of them occurred on the observable side of the Moon.
The China National Space Administration described its latest achievement as an “unprecedented feat in human lunar exploration.”
He added that the Chang’e 6 mission involved “many engineering innovations, high risks and great difficulties,” especially the high temperatures on the far side of the Moon.
What, then, is the difference between the visible and non-visible sides of our natural satellite and why is exploring the latter so problematic?
A dangerous and mysterious hemisphere
From our perspective, the Moon has two sides or hemispheres, one visible and the other hidden, also called the “dark side”, although this one is also bathed in sunlight but we cannot see it.
The reason why the Moon only shows us one side is due to a phenomenon known as “synchronous rotation”, in which the satellite takes the same time to rotate on its own axis as it does to rotate around the Earth.
Sending a spaceship and landing it there is fraught with risk, because it is very difficult to communicate with it once it crosses over to the hidden side.
Upon reaching the far side of the Moon, the module runs out of signal.
“As we cannot communicate directly with the hidden side from Earth, another spacecraft has to go into orbit around the Moon to transmit orders from the control center and receive data,” explained Professor Martin Barstow, from the University from Leicester, to the British newspaper Guardian.
To do this, the CNSA used the Queqiao-2 satellite, which it had previously placed in lunar orbit.
Likewise, the descent module had to put into operation an autonomous visual obstacle avoidance system, equipped with a camera that automatically selected safe landing areas according to the brightness or darkness of the lunar surface.
different geology
The dark side, or rather the most remote hemisphere of the Moon, looks quite different from what we see from Earth.
Scientists explain that it has an older and thicker crust, with many more craters. There are also few of those “seas” or dark basalt plains created by the lava flow that are evident on the more visible side.
It is believed that a powerful impact in the Aitken Basin may have penetrated the crust into the lunar mantle. The Chang’e 6 capsule is expected to bring samples of that layer to Earth.
“Everyone is very excited that we can take a look at these rocks that no one has seen before,” Professor John Pernet-Fisher, a specialist in lunar geology at the University of Manchester, told the BBC.
Pernet-Fisher has analyzed other lunar rocks brought back by the US Apollo missions and by Chinese spacecraft.
Most of them are of volcanic origin, similar to those that we could find in Iceland or Hawaii.
But the material on the other side of the Moon could have a different chemistry.
Pernet-Fisher said the opportunity to analyze rocks from a completely different area of our natural satellite could answer fundamental questions about the formation of planets.
The south pole of the Moon is the next frontier for missions to our natural satellite: several countries are interested in understanding that region because there is a good chance that it has ice.
Access to water would significantly increase the odds of successfully establishing a human base on the Moon.
Major goals
In addition to enthusiasm for scientific research, the Chang’e-6 missions also reveal China’s ambitions beyond the Moon.
This program is useful practice for another possible goal: collecting samples from Mars.
While lunar material promises great scientific benefits in unlocking the secrets of the Solar System, samples from the Red Planet could potentially provide new clues about whether Mars could be habitable or not.
Another notable fact is that the Chang’e-6 mission requires a complex rendezvous maneuver between the probe carrying the samples and an orbital module that will bring them back.
This procedure is not necessary to recover the material, but it is necessary to take astronauts to the lunar surface and return them safely to Earth.
The added complexity appears to be a stepping stone toward manned lunar missions.
China announced last year that it plans to launch its first manned lunar mission before 2030.
Their idea is to take a couple of astronauts to the surface who hours later will meet a colleague in orbit. This is very similar to what was done with the descent/ascent and orbital modules of NASA’s Chang’e-6 and Apollo missions.
China is not considering a mere short-term presence, planting flags and leaving footprints on the Moon.
Its ambition is more similar to the Artemis program than NASA’s Apollo: it wants to launch two separate missions to the APS basin in 2026 and 2028, which include experiments with lunar soil to 3D print bricks that can be used to build a lunar base.
“The south pole of the Moon is the destination we will go to prepare for when we send humans to the Moon again,” explained Katherine Joy, professor of Lunar and Planetary Science at the University of Manchester.
“Along with Chang’e-7 and 8, several planned NASA missions will also land to determine where and how many volatile elements, including water and water ice, are found in the polar soil.
“This material could be useful for future human explorers, so it will be very interesting to see what diversity will be found in all the robotic lunar landing modules planned for the coming years.”
Keep reading:
* NASA photographed a strange object flying over the Moon and generated debate on social networks
* Hidden Earth force could be generating water on the Moon, according to study
* Mission Luna-25: The Russian mission that crashed created a new crater on the Moon
Click here to read more stories from BBC News Mundo.
You can also follow us on Youtube, instagram, TikTok,X, Facebook and in our new whatsapp channelwhere you will find breaking news and our best content.
And remember that you can receive notifications in our app. Download the latest version and activate them.
- What is China looking for on the far side of the Moon?
- Why it took so long to explore the far side of the Moon (and why it is essential to do so)
- The gigantic impact that explains the mystery of the difference between the two sides of the Moon