This is the first soft landing on another celestial body for India, which became the fourth country that was able to implement such a thing on an Earth satellite. In addition, this is the first landing in the circumpolar region of Selenium, where the soil is rich in water ice.
At 15:33 Moscow time on August 23, 2023, the Chandrayan-3 lander with a six-wheeled lunar rover landed on the natural satellite of our planet. A soft landing was provided by four engines of low variable thrust.
Unlike the Luna-25 that crashed four days ago, the Indian spacecraft is noticeably more massive, so its soft landing system is more complex, allowing it to gently land in a very small square of four by four kilometers. The landing site is located at the 69th degree of the southern latitude of the Moon, that is, also in the circumpolar zone, where Earthlings' vehicles have never landed before. The lunar landing in the circumpolar zone is more difficult than in low and middle latitudes, where automatic stations of the USSR, the USA and China landed before.
The scientific instruments on the Indian landing platform are noticeably smaller than those of the deceased Russian apparatus: one probe for studying lunar plasma, one device for determining the thermal conductivity of the upper ten centimeters of soil and a seismograph.
There is also a small, 26-kilogram lunar rover on board the lander. It has two forward-facing cameras, a laser spectrometer to determine the composition of regolith on the moon's surface, and an alpha X-ray spectrometer for the same purposes. The operating time of the lunar rover is limited to 14 days, because due to its compactness there is no heating radioisotope generator on it, as on Soviet lunar rovers or "Curiosity".
The key objective of the Indian mission was a successful soft landing. The point is not only that nine of the 12 vehicles sent to the Moon earlier in five years could not work properly, but also that specifically the Indian Chandrayan-2 crashed in 2019 while attempting a soft landing, destroying its lunar rover at the same time (the same thing happened with Luna-25). The success of the landing in the circumpolar zone, which is very difficult for this, is a significant step forward for the Indian lunar program.
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| Chandrayan-3. |
| Source: © ISRO |
Unfortunately, its budget and the energy capabilities of Indian carriers are significantly limited. Therefore, on "Chandrayan-3", unlike "Luna-25", there are no devices capable of analyzing the water content in the lunar soil at a depth of one or two meters, as well as a manipulator that can crumble even "permafrost" lunar rocks to a depth of 40 centimeters. This means that the data on lunar water from the Indian mission will be limited.
Water, the presence of which on the Earth's satellite was first established as a result of the analysis of the lunar soil back in the 1970s, for a long time did not have a theoretical basis for astronomers who believed that Selenium was anhydrous. Due to this, such data was rejected until the XXI century both in the USSR and in the USA (although water was found in samples of both American manned and Soviet unmanned lunar programs).
In the XXI century, hypotheses appeared that allow us to understand where water comes from on the moon. In the next ten years, scientists will have to receive confirmation from programs for studying the Earth's satellite — apparently, mostly manned
