What are the Chang’e missions?
China’s moon missions are called Chang’e, named for the goddess of the moon in Chinese mythology
The China National Space Administration (CNSA) launched the Chinese Lunar Exploration Programme (CLEP) in 2003, and the first Chang’e mission happened in 2007.
Chang’e 1 created a map of the moon’s surface.
With Chang’e 2, CLEP launched phase I of its moon missions, and equipped the orbiter with a better camera.
The images taken by this camera were used to prepare the Chang’e 3 mission’s lander and rover for their descent on the moon, which they successfully achieved on December 14, 2013, and started CLEP’s phase II missions.
Chang’e 4 was a precursor to Chang’e 6: in 2019, it carried the first lander and the rover to descend on the moon’s far side and explore this relatively more mysterious region.
Achieving this first required another spacecraft around the moon that could ‘talk’ between ground stations on the earth and the moon’s far side.
Phase III began with the Chang’e 5 mission. In late 2020, it deployed a lander on the moon’s near side.
It included a mission component called an ascender, which, after collecting and stowing soil samples (specifically, the youngest volcanic lunar soil samples yet), launched itself into orbit.
There, an orbiter collected the samples, transferred them to a returner, and the returner brought them to the earth.
CLEP’s second phase III mission, Chang’e 6 is attempting to replicate its predecessor’s feat — except from the moon’s far side.
What is the far side?
The moon is tidally locked to the earth: the lunar hemisphere facing the earth will always face the earth, and the hemisphere facing away will always face away.
The far side has rockier terrain and fewer smooth plains than the near side.
Scientists believe this is because of heat released by the earth when the moon was forming and thermochemical characteristics of the moon’s near-side surface.
In effect, it’s harder to land a spacecraft on the far side — and more so since it’s impossible to communicate directly from the earth with a spacecraft here: there’s no line of sight.
The far side is also expected to be a good place to install large telescopes, which would have a view of the universe unobstructed by the earth.
ISRO and scientists at the Raman Research Institute, Bengaluru, are currently working on such a telescope, called PRATUSH.
What is the status of Chang’e 6?
CNSA launched the 8.3-tonne Chang’e 6 orbiter-lander assembly on May 3, and it entered a lunar orbit on May 8.
On May 30, the lander complex split from the orbiter and descended over a large crater called the Apollo Basin on June 1.
Apollo itself lies within the much larger South Pole-Aitken Basin.
Once down and operational in the Apollo Basin, a drill plunged into the soil, and with help from a scoop extracted about 2 kg of far-side material, and transferred it to the ascender.
On June 4, the ascender took off for moon orbit, where it’s expected to rendezvous with the orbiter, transfer the samples to a capsule in the returner, which is finally expected to return to the earth, crashing somewhere in Inner Mongolia on June 25
What might the samples reveal?
Scientifically, the far-side samples are expected to inform insights about why the moon is the way it is and the formation of planets.
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