- By Geeta Pandey
- BBC News, Delhi
Last month, India made history when it became the first country to conduct a lunar mission near the Moon’s south pole.
Chandrayaan-3’s lander and rover, named Vikram and Pragyaan, spent about 10 days in the region, collecting data and images to send back to Earth for analysis.
Earlier this month, scientists put them to bed When the Sun began to set on the Moon, in order to function, the lander needed sunlight to charge its batteries. The country’s space research agency, Isro, said it expected them to wake up again “around September 22,” when the next lunar day dawns.
Isro has provided regular updates on their movements and findings and shared images taken by them.
These updates have excited many Indians, but others have been asking about the significance of these discoveries.
The BBC asked Mila Mitra, former NASA scientist and co-founder of Stem and Space, a Delhi-based space education company, to select some of the main findings from Chandrayaan-3 and explain their importance.
Distance traveled and craters avoided
Hours before the rover was laid down on September 2, Isro said Pragyaan “has traveled more than 100 meters (328 feet) and continues.”
That’s quite a long way to go for the six-wheeled rover, which moves at a speed of 1 cm per second.
What’s also significant, Mitra says, is that it has been able to stay safe and avoid falling into the craters that dot the Moon’s little-explored south polar region.
The rover, he says, has a special wheel mechanism, called a tilt bogie, which means that all its wheels do not move together, which helps it get up and down, but it may not be able to get out if it falls into a deep bottom. . crater. That is why it is important to make him go around the craters or even retrace his steps. And that, Mitra adds, is done by scientists at the command center who “observe the Moon through the eyes of the rover.”
“The rover is not automated and its movements are controlled from the command center, which acts based on the images it sends.
“There is a slight delay before they reach the command center due to the circuitous route they take: Pragyaan sends them to the lander which sends them to the orbiter to pass them to Earth.”
So when the command reaches the rover, it is a few steps closer to the threat.
But the fact that it managed to navigate safely around two craters shows that it is able to communicate very quickly with the command center, Mitra adds.
Blowing hot and cold
The first set of data collected from the top layer of lunar soil and to a depth of 10 cm (4 in) below the surface from a probe aboard the Vikram lander showed a marked difference in temperatures just above and below the surface.
While the temperature at the surface was nearly 60 °C, it dropped sharply below the surface, dropping to −10 °C 80 mm (about 3 in) below the ground.
The Moon is known for its extreme temperatures: according to NASA, daytime temperatures near the lunar equator reach 120°C (250°F), while nighttime temperatures can drop to -130°C (-208°F). And temperatures of -250°C (-410°F) have been recorded in craters that never receive sunlight and remain permanently in shadow.
But, Mitra says, this wide temperature variation is significant because it shows that the Moon’s soil, called lunar regolith, is a very good insulator.
“This could mean it could be used to build space colonies to keep heat, cold and radiation out. This would make it a natural insulator for the habitat,” he says.
It could also be an indicator of the presence of water ice beneath the surface.
A clue about the evolution of the Moon
When a laser detector mounted on the rover measured chemicals present on the lunar surface near the south pole, it found a large amount of chemicals such as aluminum, calcium, iron, chromium, titanium, manganese, silicon and oxygen.
But the most important findings, according to scientists, relate to sulfur. The instrument’s “first in situ measurement – in the original space” “unequivocally confirms” the presence of sulfur, Isro said.
The presence of sulfur on the Moon has been known since the 1970s, but scientists say the fact that the rover measured sulfur on the lunar surface itself – and not within a mineral or as part of a crystal – makes it becomes “a tremendous achievement.”
Mitra says the presence of sulfur in the soil is significant for several reasons.
“Sulfur normally comes from volcanoes, so it will expand our knowledge of how the Moon formed, how it evolved and its geography.
“It also indicates the presence of water ice on the lunar surface and since sulfur is a good fertilizer, this is good news as it can help plants grow if there is a habitat on the Moon.”
Was it really a lunar earthquake?
The Vikram lander carries an instrument that measures vibrations emanating from its own studies and experiments, as well as those of the rover and its activities.
Isro said that while the Lunar Seismic Activity Instrument (Ilsa) was keeping an eye on the ground, it also recorded “an event that appeared natural” and was investigating its source.
This event had a much larger amplitude, meaning it was much stronger, Mitra says, adding that there could be several explanations for this.
“It could be space debris, like a meteorite or asteroid, hitting the surface. Or it could be a seismic earthquake, which would make it the first lunar earthquake recorded since the 1970s. In that case, this could lead to a explanation of what is happening underneath.” the surface of the Moon and its geography.”
What is lunar plasma?
When Isro posted on They asked what it meant.
Ms Mitra explains that plasma refers to the presence of charged particles in the atmosphere that could hinder the radio wave communication used by Chandrayaan-3.
“The fact that it is very sparse or thin is good news as it means it will disrupt radio communication much less.”
When the lander jumped
The last thing the Vikram lander did before being launched in early September was what Isro called a “jump experiment”.
The agency said the lander was “ordered to start its engines, rose about 16 inches (40 cm) and landed 30 to 40 cm away.”
This “successful experiment” means the spacecraft could be used in the future to bring samples back to Earth or for human missions, he added.
Now, could this short jump mean a big leap for India’s future space plans?
Mitra says that “the jump was tested by restarting the engine after a moon landing to make sure it still works well.”
It also demonstrated that the spacecraft has “takeoff capability in a lunar soil environment, since until now the tests and actual takeoff have only been carried out from Earth,” he adds.
BBC News India is now on YouTube. Click here to subscribe and watch our documentaries, explanations and articles.