Chandrayaan-3 mission: Why ISRO wants to explore the Moon’s south pole
Context- Chandrayaan-3 was successfully launched on Friday (July 14) at 2.35 pm from the Satish Dhawan Space Center (SDSC) in Sriharikota. It is a follow-up to the 2019 Chandrayaan-2 mission, which partially failed after its lander and rover couldn’t execute a soft-landing on the Moon.
(Credits- Indian Express)
According to Isro officials, the Chandrayaan-3 will reach the lunar orbit almost a month after its launch, and its lander, Vikram, and rover, Pragyaan, are likely to land on the Moon on August 23. Notably, the landing site of the latest mission is more or less the same as the Chandrayaan-2 : near the south pole
Why hasn’t any spacecraft ever landed near the lunar south pole?
- There is a very good reason why all the landings on the Moon so far have happened in the equatorial region. Even China’s Chang’e 4, which became the first spacecraft to land on the far side of the moon — the side that does not face the earth — landed near the 45-degree latitude.
- It is easier and safer to land near the equator. The terrain and temperature are more hospitable and conducive for a long and sustained operation of instruments. The surface here is even and smooth, very steep slopes are almost absent, and there are fewer hills or craters. Sunlight is present in abundance, at least on the side facing the earth, thus offering a regular supply of energy to solar-powered instruments.
- The polar regions of the Moon, however, are a very different, and difficult, terrain. Many parts lie in a completely dark region where sunlight never reaches, and temperatures can go below 230 degrees Celsius.
- In addition, there are large craters all over the place, ranging from a few centimetres in size to those extending to several thousands of kilometres.
Why do scientists want to explore the lunar south pole?
- Due to their rugged environment, the polar regions of the Moon have remained unexplored. But several Orbiter missions have provided evidence that these regions could be very interesting to explore.
- There are indications of the presence of ice molecules in substantial amounts in the deep craters in this region — India’s 2008 Chandrayaan-1 mission indicated the presence of water on the lunar surface with the help of its two instruments onboard.
- In addition, the extremely cold temperatures here mean that anything trapped in the region would remain frozen in time, without undergoing much change. The rocks and soil in Moon’s north and south poles could therefore provide clues to the early Solar System.
Why don’t some parts of the lunar polar regions receive any sunlight?
- Unlike the Earth, whose spin axis is tilted with respect to the plane of the Earth’s solar orbit by 23.5 degrees, the Moon’s axis tilts only 1.5 degrees. Because of this unique geometry, sunlight never shines on the floors of a number of craters near the lunar north and south poles.
- These areas are known as Permanently Shadowed Regions, or PSRs.
Syllabus- Prelims; Current Affairs
Source- Indian Express