Chandrayaan-3: Another feather in India\’s space odyssey

Prachi Mishra

Chandrayaan-3, India\’s lunar mission, successfully launched on July 14, 2023 in the afternoon from the Satish Dhawan Space Center in Sriharikota. The launch was carried out using the powerful Launch Vehicle Mark-III (LVM3) rocket. The Indian Space Research Organisation (ISRO) is responsible for managing the mission and overseeing the launch. With its origins dating back to 1962, ISRO has a rich history in space exploration, and it officially came into existence in 1969. Since then, ISRO has played a significant role in India\’s space endeavors.

In June 2023, just prior to the planned launch of Chandrayaan-3, India joined the Artemis Accords led by NASA. These accords focus on fostering peaceful exploration of the Moon by humans and robots. While the primary advantages of the accords pertain to human spaceflight, the White House stated that the data obtained from Chandrayaan-3 could also prove valuable for future Artemis missions involving human landings.

According to the Times of India, the estimated cost of Chandrayaan-3 is approximately $77 million USD. The official website states that Chandrayaan-3 has three main objectives: to achieve a safe landing on the lunar surface, to demonstrate rover operations, and to conduct scientific experiments on-site. As per the scientists involved in building and launching of the Moon mission the anticipated landing is expected to occur around August 23 or August 24.

The mission involves a propulsion module that will transport the lander and rover to the Moon\’s south pole. Once in lunar orbit, the module will adjust its trajectory to form a circular path roughly 60 miles (100 km) above the lunar surface. Subsequently, the lander will separate from the module and endeavor to make a soft landing on the Moon. During its 14 Earth-day surface mission (equivalent to a single lunar day), the lander and rover will conduct scientific investigations. Meanwhile, the propulsion module will observe Earth as part of its own scientific experiment.

ISRO has incorporated advanced technologies into the spacecraft package, which includes the rover, lander, and propulsion module. These technologies encompass hazard detection and avoidance capabilities for the rover, a landing leg mechanism designed for a gentle touchdown, as well as altimeters and velocity instruments to estimate altitude and speed above the lunar surface. ISRO has conducted numerous technology tests to simulate lunar conditions, placing instruments in cold temperatures resembling the Moon\’s environment and performing lander leg tests on simulated surfaces under various landing conditions. The agency has emphasized the importance of these tests in preparing for the mission.

The scientific payload of the Chandrayaan-3 mission is divided among the lander, rover, and propulsion module. The lander is generally box-shaped and equipped with four landing legs and four landing thrusters. Its total mass of approximately 3,900 pounds (1,752 kilograms) includes 57 pounds (26 kilograms) allocated for the rover. The lander incorporates several instruments and experiments, including:

1. Chandra\’s Surface Thermophysical Experiment (ChaSTE) to measure thermal conductivity and temperature on the lunar surface.
2. Instrument for Lunar Seismic Activity (ILSA) to detect moonquakes.
3. Langmuir Probe, which estimates the density and variation of plasma (superheated gas) in the lunar environment.
4. A Laser Retroreflector Array, provided by NASA, used for measuring distances using laser ranging.

As for the rover, it is a rectangular chassis mounted on a six-wheel rocker-bogie wheel drive assembly. The rover communicates with Earth through the lander. Its instrument suite includes:

1. Alpha Particle X-ray Spectrometer (APXS) for analyzing elements in lunar soil and rocks.
2. Laser Induced Breakdown Spectroscope (LIBS) to examine the chemical and elemental composition of the lunar surface.

The propulsion module is a box-like structure, features a large solar panel mounted on one side and a cylindrical structure on top serving as a mounting platform for the lander. With a mass exceeding 2.2 tons (2 tonnes), the propulsion module contributes significantly to the mission\’s overall weight. The module\’s primary experiment is the Spectro-polarimetry of Habitable Planet Earth (SHAPE) investigation, which supports exoplanet searches. This experiment involves collecting data on the polarization of light reflected by Earth, aiding in the search for other planets with similar characteristics, as reported by Nature.

Today, the Indian Space Research Organisation (ISRO) is embarking on its second endeavor to achieve a successful moon landing with the launch of Chandrayaan-3. With Chandrayaan-3, India has once again proven to the world that with indigenous capabilities and domestic talent, it can very well drive its space odyssey.