The landing module of the Indian mission to the Moon Chandrayaan-3 entered a state of hibernation yesterday, as planned. A few days before, last Sunday, the small Pragyan rover had also done it. This is an operation to protect the equipment from the cold and long lunar night, a night that lasts the equivalent of two Earth weeks and in which temperatures of -175C are reached which, in the deepest areas of the poles, can even reach at -250C.
The mission had been designed to survive on the surface of the Moon, near the south pole, and complete its investigations during the lunar daylight period (also equivalent to two weeks). The Indian space agency (ISRO), just before sending the hibernation order, announced that the main objectives of the mission had been achieved.
On its twitter account (now X), ISRO explained that, at the time hibernation began, the rover's battery was fully charged and its solar panel was facing the direction in which the Sun would rise again on the day. September 22 awaiting a possible reactivation. In the event that this revival does not take place, Pragyan "will remain there forever as an ambassador of India on the Moon" added the ISRO in its statement.
For its part, the moon landing module, called Vikram, was conducting experiments until almost the last moment. It also performed a short hop on the lunar surface, briefly firing its engines and moving about 16 inches toward its rover. As the ISRO specified, it was a test that could be useful for future missions.
On August 23, India became the fourth country to land on the Moon (the United States, the former Soviet Union and China had previously done so) and the first to do so relatively close to the desired lunar south pole. A couple of days earlier, the Russian Luna-25 mission had attempted it, but the ship had lost control during the maneuver to prepare for descent and had crashed into the surface.
The south pole of the Moon became one of the priority objectives of the main space agencies when, in 2018, the presence of water ice, probably of cometary origin, was confirmed inside some of its craters. Water is a strategic component to power future lunar bases, as well as to generate fuel for ships.
Since its landing on the Moon, the Indian mission has sent to Earth numerous scientific data collected by its instruments, data among which, for the moment, the confirmation of the presence of sulfur on the surface of the lunar south pole stands out.
The instrument called LIBS, installed in the Vikram module, used a laser to vaporize soil samples and analyze their components. The results have shown the expected presence of chemical elements such as aluminium, calcium, chromium, iron, manganese, oxygen, titanium and silicon. But instruments aboard satellites have never before detected sulfur in this region from lunar orbit.
It also highlights the detection made by the Vikram seismograph, on August 26, of a tremor of still unknown origin. Likewise, the temperature data collected by the sensors that the Pragyan rover has introduced under the lunar surface, and which show a drop of 60C at only 8 centimeters depth, have been surprising.
But without a doubt, the data that is most awaited is the one that should confirm the presence of hydrogen, which would be a possible indication of the abundance of water ice in this location.