INDIA, MOON BOUND!

ISRO’s third mission to the moon, Chandrayaan-3 aims to land on the lunar South Pole, a feat yet to be achieved by any nation.

By AYUSHEE CHAUDHARY

The world turned its gaze toward the sky on July 14, 2023 as Chandrayaan-3, India’s third lunar exploration mission, embarked on its extraordinary journey toward the moon. Propelled by the robust Launch Vehicle Mark-3 (LVM3) of the Indian Space Research Organisation (ISRO), this mission aims to make history by landing on the lunar South Pole, a feat yet to be achieved by any nation. If successful, India will become the fourth country to softly touch down on the moon’s surface, following the United States, the former Soviet Union, and China.

This venture is India’s second attempt at a lunar landing, following the Chandrayaan-2 mission in 2019. The first mission, Chandrayaan-1, discovered the presence of water molecules at the lunar South Pole using its orbiter. While Chandrayaan-2 could not achieve a soft landing, its orbiter continued to observe the moon. Now, Chandrayaan-3 seeks to build upon the accomplishments of its predecessors, leveraging the knowledge gained from over a decade of lunar exploration.

WHAT DOES CHANDRAYAAN-3 CONTAIN?

Chandrayaan-3, weighing 3,900 kg and with a cost of about

6.1 billion rupees ($75 million; £58 million), shares the same objectives as its previous iteration. Its primary goal remains to achieve a soft landing on the surface of the Moon, as emphasised by ISRO. The lander, named Vikram in honor of the founder of ISRO, Vikram Sarabhai, has a weight of approximately 1,500 kg. Within its payload lies the rover, Pragyaan, weighing 26 kg, aptly named after the Sanskrit word for wisdom.

Chandrayaan-3 consists of an indigenous Lander module (LM), a Propulsion module (PM), and a Rover with the objective of developing and demonstrating new technologies required for Interplanetary missions. The Lander will have the capability to soft land at a specified lunar site and deploy the Rover which will carry out in-situ chemical analysis of the lunar surface during the course of its mobility. The Lander and the Rover have scientific payloads to carry out experiments on the lunar surface. The main function of the PM is to carry the LM from launch vehicle injection to the final lunar 100 km circular polar orbit and separate the LM from the PM. Apart from this, the Propulsion Module also has one scientific payload as a value addition which will be operated post-separation of the Lander

Module. The launcher identified for Chandrayaan-3 is GSLVMk3 which will place the integrated module in an Elliptic Parking Orbit (EPO) of size ~170 x 36,500 km.

The propulsion module plays a vital role in carrying the lander module from the launch vehicle injection orbit to the point of separation. It will accompany the lander and rover configuration until they reach a lunar orbit of 100 km. Notably, the propulsion module is equipped with the Spectro-polarimetry of Habitable Planet Earth (SHAPE) payload, enabling the study of Earth’s spectral and polarimetric characteristics from the lunar orbit.

Unlike its predecessor, Chandrayaan-3 does not include an orbiter. However, the propulsion module responsible for transporting the lander to lunar orbit is equipped with a scientific instrument designed to observe Earth as if it were an exoplanet. This valuable data will contribute to future studies of exoplanets.

Lander Payloads: Chandra’s Surface Thermophysical Experiment (ChaSTE) to measure the thermal conductivity and temperature; Instrument for Lunar Seismic Activity (ILSA) for measuring the seismicity around the landing site; Langmuir Probe (LP) to estimate the plasma density and its variations.

A passive Laser Retroreflector Array from NASA is accommodated for lunar laser ranging studies.

Rover payloads: Alpha Particle X-ray Spectrometer (APXS) and Laser Induced Breakdown Spectroscope (LIBS) for deriving the elemental composition in the vicinity of the landing site.

A passive experiment called the LASER Retroreflector Array (LRA), contributed by NASA, will also be running in the background on the lander, collecting data that could help scientists better understand the dynamics of the moon system.

THE CHANDRAYAAN-3 ROCKET

Chandrayaan-3 was put into an elliptical orbit around the Earth by the Indian Space Research Organisation’s (ISRO’s) heaviest rocket — the Geosynchronous Satellite Launch Vehicle (GSLV) Mark-III. LVM3 is the operational heavy-lift launch vehicle of ISRO and has a spectacular pedigree of completing 6 consecutive successful missions. This is the 4th operational flight of LVM3, which aims to launch the Chandrayaan-3 spacecraft to Geo Transfer Orbit (GTO).

LVM3 has proved its versatility to undertake most complex missions like:

• Injecting multi-satellites.

• Mission planning to ensure safe relative distance among separated satellites through re-orientation and velocity addition maneuvers.

• Multi orbit (LEO, MEO, GEO) and execute interplanetary missions.

• India’s most prominent and heaviest launch vehicle ferrying Indian and international customer satellites. LVM3-M4 will be launched from the Second Launch Pad (SLP), SDSC, SHAR.