Why in the News?

India's Chandrayaan-3 mission made an indelible mark in history with its successful lunar landing. Achieving a 'soft landing' at the Moon's south pole, India now stands as the sole nation to have accomplished this remarkable feat.

Nearly sixty years after the Soviet Union’s Luna 9 mission made history as the first soft landing on the Moon, a lunar landing remains elusive for many countries. Russia’s Luna-25 mission failed earlier this week, in the same year that the Japanese Hakuto mission crash-landed. In 2019, Chandrayaan-2’s crash was preceded by Israel’s Beresheet facing a similar fate.

What is Soft Landing?

• A 'soft landing' refers to the precise and controlled landing of a spacecraft at a gentle speed, ensuring minimal or no damage to the craft.
• This achievement highlights the technical prowess of the spacecraft.
• During a soft landing, the spacecraft executes a sequence of maneuvers and braking procedures aimed at diminishing its velocity and aligning it with the chosen landing area.
• Typically, this involves activating retro-rockets or thrusters to gradually reduce descent speed and maintain a carefully managed approach.
• The ultimate objective is to guide the spacecraft to the surface in a manner that avoids significant damage, showcasing the precision and expertise of the mission.

But why is it so difficult?

•  The Moon has an extremely thin atmosphere. This means that spacecraft cannot rely on atmospheric friction to slow down considerably ahead of a landing which means that they will have to rely heavily on their propulsion systems to make a safe landing.
• Also, there is no GPS on the Moon, unlike here on Earth.
• This means that onboard computers will have to make quick calculations and maneuvers to land at a safe location without guidance from a massive network of satellites.

Why is ISRO Aiming for the Southern Pole?

• All of the spacecraft that have landed on the Moon previously have landed in the equatorial region, either a few degrees of latitude north or a few degrees south of the lunar equator.
• NASA’s Surveyor 7 is the mission that went farthest from the equator in history, landing as far away as 50 degrees south of the equator.
• It is not without reason that so many missions land near the equator.
• The terrain and temperature there are more welcoming, making the long and sustained operations of instruments easier.
• Also, the surface there is relatively smooth with very few steep slopes, hills, and craters.
• Due to the difficult environment, the polar regions of the Moon have largely remained unexplored.
• But if the data from many previous orbiter missions is anything to go by, these regions could be very interesting to explore.
• Chandrayaan-1 observed some evidence of the presence of ice molecules in the deep craters in the region.
• Also, the cold temperatures of the region mean that things trapped there would remain frozen for a long time.
• Essentially, that part of the Moon could act as a “time capsule.”
• This could help scientists discover clues about the early history of the solar system, including how the Earth and the Moon formed.

Why the South Pole of the Moon Holds Significance?

• Abundant Water Resources: Compelling evidence suggests the presence of water ice within the perpetually shadowed craters at the moon's south pole.
• This water resource holds immense value for future human lunar exploration, serving potential uses such as drinking water, food cultivation, and the production of rocket fuel.
• Various Volatiles: Beyond water ice, the moon's south pole may house other volatiles like methane and ammonia, offering additional resources for prospective lunar missions.
• Geological Fascination: The lunar south pole boasts intriguing geological features, notably the South Pole-Aitken basin, the moon's largest impact basin.
• Studying this basin could yield valuable insights into the moon's formation and evolutionary history.
• Prime for Astronomical Observations: The permanently shadowed craters at the moon's south pole provide an excellent vantage point for astronomical observations.
• Shielded from the Sun's radiation, these craters offer ideal conditions for studying radio waves and other forms of radiation that Earth's atmosphere tends to block.

What Has Changed Since the Chandrayaan-2 Setback?

• Enhanced Landing Gear: Chandrayaan-3's landing legs have been fortified to guarantee stability and secure touchdown, even at a velocity of 3 meters per second, equivalent to 10.8 kilometers per hour.
• Expanded Landing Flexibility: Unlike wheeled vehicles, a lunar lander employs stilts or legs to land.
• The potential landing area has been broadened, with Chandrayaan-3 now programmed to touch down safely within a 4-kilometer by 2.4-kilometer zone, rather than aiming for a specific 500-meter by 500-meter patch as previously targeted by Chandrayaan-2.
• Ample Fuel Reserves: Chandrayaan-3 carries an increased fuel load compared to Chandrayaan-2.
• This surplus fuel is on standby for last-minute adjustments to the landing site if required.
• Enhanced Solar Panels: The Chandrayaan-3 Lander is equipped with solar panels on all four sides, a significant upgrade from Chandrayaan-2's two-sided configuration.
• This design ensures the Lander can harness solar power consistently, even if it lands incorrectly or experiences tumbling.
• At least one or two sides will continually face the Sun, ensuring uninterrupted power generation.

What Next After Chandrayaan-3 successfully lands on the Moon?

• Payloads in Action: Typically, spacecraft carry specialized instruments and experiments, known as payloads, to observe and record events in space.
• Data Transmission to Earth: The data collected by these payloads is then transmitted back to Earth, where scientists analyze and study it for valuable insights.
• Consistent Payloads: In Chandrayaan-3, the six payloads on the Vikram lander and rover Pragyan remain consistent with the previous mission.
• Scientific Payloads on Lander: The lander hosts four scientific payloads that focus on various aspects, including the study of lunar quakes, thermal properties of the lunar surface, changes in the plasma near the surface, and a passive experiment aimed at precise measurements of the Earth-Moon distance. One of these payloads comes from NASA.

Rover Payloads: The rover carries two payloads designed to examine the chemical and mineral composition of the lunar surface. They are tasked with determining the presence and composition of elements like magnesium, aluminum, and iron in lunar soil and rocks.