Chandrayaan-3 Mission: Why ISRO wants to explore the Moon’s south pole

• India’s space agency, ISRO is soon going to launch Chandrayaan-3 mission which is India’s third lunar mission.
• 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

Previous and Future landings

• 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 of the moon at 70 degrees latitude.
  •  If everything goes well, the Chandrayaan-3 will become the world’s first mission to soft-land near the lunar south pole.
• All the previous spacecraft to have landed on the Moon have landed in the equatorial region, a few degrees latitude north or south of the lunar equator.
• Earlier NASA Surveyor 7 spacecraft, made near 40 degrees south latitude moon landing way on January 10, 1968.

Chandrayaan-3 Mission:

• It is a follow-on mission to Chandrayaan-2 to demonstrate end-to-end capability in safe landing and roving on the lunar surface.
• Configuration: It consists of Lander and Rover configuration.
• It will be launched by LVM3 from SDSC SHAR, Sriharikota.
• Lander payloads: 
  • Radio Anatomy of Moon Bound Hypersensitive ionosphere and Atmosphere (RAMBHA)
  • Chandra’s Surface Thermo physical Experiment (ChaSTE)
  • Instrument for Lunar Seismic Activity (ILSA)
  • Laser Retroreflector Array (LRA) Rover:
  • Alpha Particle X-Ray Spectrometer (APXS)
  • Laser Induced Breakdown Spectroscope (LIBS) Propulsion Module:
  • Spectro-polarimetry of HAbitable Planet Earth (SHAPE)
• Mission objectives:
  • To demonstrate Safe and Soft Landing on Lunar Surface
  • To demonstrate Rover roving on the moon and
  • To conduct in-situ scientific experiments

Why hasn’t any spacecraft ever landed near the dark side/ lunar south pole?

• Because of geographical conditions, it is easier and safer to land near the equator.
  • That’s 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.
• 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.
• On the other hand, 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.
  •  Lack of sunlight and extremely low temperatures create difficulty in the operation of instruments.
  • 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.

Reasons for curiosity over 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 some parts of the lunar polar regions don’t 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.
• In a 2019 report, NASA said, “Water that happens to find its way into PSRs may remain there for long periods of time.
  • Data from the Diviner instrument onboard LRO (Lunar Reconnaissance Orbiter, robotic spacecraft currently orbiting the Moon) which measures temperatures across the Moon, including PSRs, indicate that some surfaces are cold enough so that water is stable at the surface.”

Conclusion

Chandrayaan-3 is follow up mission of Chandrayaan-2 mission which aims to demonstrate ISRO’s capabilities and advancement in space for safe landing in south pole of moonTherefore, it will help in  further space exploration programme of India.

Lunar Missions so far