Officials prepare to recover the landing module of the Chang’e-6 moon probe after it landed in Inner Mongolia, in northern China on June 25, 2024.
| Photo Credit: AFP

On June 25, Chinese personnel picked up a 300-kg cannister from the Inner Mongolian Autonomous Region; it contained two fistfuls of soil and rocks. The event made international headlines because the cannister had started its journey on the moon’s far side — the side permanently facing away from the earth — and the soil and rocks it carried came from there, a place in the Solar System only Chinese robots have visited thus far.

The mission, called Chang’e 6 (named after a mythological moon goddess), was part of the Chinese lunar exploration programme and the country’s most important yet. A sample-return mission is more complicated than other types of robotic missions to the moon — including orbiters, landers, and rovers — because of the number of moving parts and stronger time constraints.

For Chang’e 6, the China National Space Administration (CNSA) sent a lander to the moon’s surface, like India did with the Vikram lander of Chandrayaan 3. There, a drill and scooper extracted some material samples from and just below the moon’s surface and deposited them in the cannister. The cannister was then placed in an ascender module that lifted off from the lander to orbit, where it rendezvoused with the orbiter. The cannister was here moved to a returner spacecraft. This spacecraft flew to within 5,000 km of the earth and ejected the cannister. The cannister finally made its way to the ground after a bounced atmospheric re-entry manoeuvre.

The lander landed on the moon’s far side, which doesn’t have line of sight from the earth, so no signal from the earth’s surface could reach it. The CNSA instead had ground stations communicate with the lander by sending signals to a satellite it had already installed in orbit around the moon. When this satellite came in view of the lander, it relayed the signals to the lander, collected the replies, and later beamed them to the earth. The mission lasted 53 days.

Once the capsule landed, officials flew it to the Chinese Academy of Space Technology in Beijing. There, experts of the Chinese Academy of Sciences would have taken the samples out and placed them in storage, in preparation for research and analysis. The world’s first mission to the moon’s far side was Chang’e 4, which in 2019 delivered a lander and a rover there. In Chang’e 5, the CNSA executed a sample-return mission from the near side, and followed it up with Chang’e 6.

Also read | China launches lunar probe mission to collect samples for first time from far side of moon

Two leaders

Various countries of the world have made ‘returning’ to the moon a priority of their respective national space programmes. Two vague leaders have emerged in this race: one led by the U.S. and the other by China. The U.S. is currently focusing on sending payloads built by private companies to the moon and on a major programme to regularly land humans on the moon from the early 2030s.

If the moon is to have room for everyone, we need to understand both its sides. The far side is little like the near side. It is more covered by rocky terrain, has had less volcanism and, not being shielded by the earth like the near side, receives more solar radiation on its surface. The far side is scientifically important for two reasons. One, it’s an important part of the spatial and temporal map of the Solar System scientists are piecing together to reveal its evolution and guide future exploration. Two, Yung Kai-leung, a Hong Kong Polytechnic University professor and member of a team that contributed to the moonstuff collection system, told the Chinese national broadcaster the far side suffers more meteor strikes, and which future moon bases must be protected against. The Chang’e 6 lander also descended in the Apollo Basin, an ancient crater where materials from the moon’s deep crust or mantle could have been pushed out.

Researchers will now study the 1.93 kg of moonstuff in the hopes of learning something about the moon and the early solar system. The CNSA has said China’s researchers will have first crack at the returned samples, followed by researchers from abroad who applied for access. We don’t yet know if any Indian groups did. The results of these studies will be more valuable than gold.

A screenshot presentations a illustration of Chandrayaan-3’s a hit touchdown at the Moon’s floor, Wednesday, Aug. 23, 2023.
| Picture Credit score: PTI

The managed descent of the Vikram lander of Chandrayaan-3 made it one of the most closest approaches of a lunar undertaking to the moon’s South Pole. Then again like many of the lunar-landing missions prior to, Vikram too landed at the close to facet, making the Chinese language Chang’e 4 undertaking the one one to have landed at the some distance facet.

What are the moon’s ‘near’ and ‘far sides’ and is there a ‘dark’ facet?

The close to facet refers back to the portion of the moon — about 60% — this is vision to us. It’s at all times the similar facet this is vision from Earth since the moon takes the similar day to rotate about its axis because it does to circle across the Earth. Then again this doesn’t suggest that the part the moon is in perpetual darkness.

The ‘new moon’ or when the moon is secret from Earth is the day when the alternative ‘far side’ of the moon is bathed in daylight and continues to obtain brightness for just about a fortnight. The ‘dark side’ is thus unlit best within the sense that it used to be undisclosed and its diverse topographical options secret till the Soviet spacecraft Luna 3 in 1959 photographed it and the Soviet Academy of Sciences absolved an atlas of those pictures. Astronauts boarded the Apollo 8 undertaking of 1968 have been the primary people to look the some distance facet of the moon.

Is the unlit facet very other from the close to facet?

The main residue between the 2 facets is that the close to facet is moderately smoother and has many extra ‘maria’ or massive volcanic plains in comparison to the some distance facet. At the some distance facet on the other hand, there are excess craters, hundreds of kilometres vast, that have most probably resulted from collisions with asteroids. Occasion each side of the moon in its formative section have been in a similar fashion bombarded, the crust at the close to facet is thinner as a result of which, over hundreds of thousands of years, the volcanic lava within the lunar crust has flowed extra broadly into the thinner facet and crammed up its craters. The ensuing plains that experience thus shaped are way more conducive to territory missions as a result of they grant a moderately flat landscape for landers and rovers. Chandrayaan-3 known an section 2.4 km vast and four.8 km lengthy that had spots of 150 m areas that may be conducive to a safeguard descent. China’s Chang é-4 lander extra the one one to have effectively landed at the some distance facet. This car landed at the Von Karman crater positioned inside of a bigger 2,500 km vast crater referred to as the South Pole Aitken basin.

What’s particular in regards to the Chandrayaan-3’s touchdown?

The Chandrayaan-3 mission, life nonetheless at the close to facet, has controlled to land Vikram the nearest ever to the lunar South Pole. The coordinates of Chandrayaan-3 at 69.36 S and 32.34 E produce it about 600 km clear of the South Pole. The selection of being as related as imaginable to the South Pole used to be to get nearer to a “permanently shadowed region” or the place negative daylight ever reaches, A.S. Kiran Kumar, former Chairman, Indian Area Analysis Organisation, informed The Hindu. This may cruel expanding the probabilities of encountering frozen water-ice at the side of a number of “interesting deposits” that may divulge extra in regards to the moon and its harvestable sources. The Vikram lander “wasn’t exactly in a shadowed region” because it used to be important to glimmer daylight at the lander and rover to rate their sun batteries to store them powered. The undertaking’s guiding objective used to be to kill a a hit managed or ‘soft landing’ and the probabilities of doing that perfect life being close to the South Pole have been perfect served through protecting it within the close to facet, stated Mr. Kumar. Crucially, touchdown at the some distance facet would have intended negative direct, line-of-sight verbal exchange with the Earth, important for ordinary near-real-time updates. “In such a situation you will need a relay — something that will communicate with the rover and then transmit to the Earth (and vice versa). While the Chandrayaan-2 orbiter (from the 2019 mission) is still functional you would have to reorient its orbit to function as a relay. This would not only mean moving it further away from the moon in a different elliptical orbit but also delays of up to half a day in transmitting and receiving information. It’s always the objectives of the mission that determine the choice of landing locations,” he added.

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