With its launch on July 14, 2023, followed by a successful first-orbit and second-orbit raising manoeuvre, Chandrayaan-3 is India’s third lunar mission which is scheduled to land on the lunar South Pole on August 23.

By Indian Space Research Organisation (GODL-India), GODL-India,

India’s moon missions over the years

India has been a major player in the field of space exploration for many years, and its moon missions have been particularly impressive. The first Chandrayaan mission was launched in 2008, and it was the first mission to successfully orbit the moon and send back high-resolution images. The second Chandrayaan mission, launched in 2019, was even more ambitious, and it included a lander and rover that attempted to touch down on the lunar surface.

The Chandrayaan-2 mission used a Geosynchronous Satellite Launch Vehicle Mark III (GSLV Mk III) to launch the orbiter, lander, and rover into space. The GSLV Mk III is a three-stage rocket that is capable of lifting heavy payloads into orbit. The orbiter is powered by a liquid-fueled engine, while the lander and rover are powered by batteries. The propellant used for the GSLV Mk III is a mixture of liquid hydrogen and liquid oxygen.

The mission objective of Chandrayaan-2 was to study the moon’s surface and atmosphere. The orbiter carried a number of scientific instruments, including a spectrometer, a camera, and a magnetometer. The lander and rover were designed to collect samples of the lunar soil and analyze them for signs of water ice.

The Chandrayaan-2 mission was a partial success. The orbiter is still in operation and has been sending back valuable data about the moon. However, the lander and rover were not able to successfully land on the lunar surface due to a last-minute software glitch.

How is it different from Chandrayaan-2?

It is similar to Chandrayaan-2, but with some key differences:

  1. Chandrayaan-2 comprised of an orbiter, Vikram lander, and Pragyan rover, while Chandrayaan-3 consists of a lander module (LM), propulsion module (PM), and a rover.
  2. Chandrayaan-3 will use the orbiter already hovering above the Moon launched with Chandrayaan-2 for its communications and terrain mapping requirements.
  3. The Vikram lander in Chandrayaan-3 will have stronger legs than in its previous version to enable withstanding landing at greater velocities than earlier. The landing velocity has been increased from 2m/second to 3m/second.
  4. Another change is the addition of more fuel to Vikram so it has more capability to travel or handle dispersion.
  5. The Chandrayaan-3 lander mission is equipped with “lander hazard detection and avoidance cameras” for coordination with the orbiter and the mission control during the landing process on the surface of the Moon. While Chandrayaan-2 had just one such camera, Chandrayaan-3 has been fitted with two such cameras.

Chandrayaan – 3

The main objective of Chandrayaan-3 is to achieve a soft landing on the lunar surface. The mission will also carry out experiments to study the lunar environment and develop new technologies for future planetary missions.

Chandrayaan-3 is a significant mission for India, as it will be the country’s first attempt to soft land on the lunar South Pole. The South Pole is a region of the Moon that has not been extensively explored, and it is thought to be a potential source of water ice. India’s first lunar mission – Chandrayaan-1 was launched in 2008, and it made a number of significant discoveries including finding evidence of water ice on the Moon, and it also mapped the Moon’s surface in unprecedented detail.

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Chandrayaan-3 consists of a lander, a rover and a propulsion module. The lander, called Vikram (Sanskrit for “Valor), is named after Dr. Vikram Sarabhai – the father of India’s space program and the rover is called Pragyan, which means “wisdom” in Sanskrit.

Lander

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It is about 1.4 meters (4.6 feet) tall and 1.5 meters (4.9 feet) wide, weighing about 1,400 kilograms (3,100 pounds).

The lander has four legs that are designed to absorb the impact of landing. It also has a parachute and retrorockets that will help to slow the lander down as it approaches the Moon.

The lander has three payloads:

  • Chandra’s Surface Thermophysical Experiment (ChaSTE) which will measure the thermal conductivity and temperature of the lunar surface.
  • Instrument for Lunar Seismic Activity (ILSA) will measure the seismicity around the landing site.
  • Langmuir Probe (LP) will estimate the plasma density and its variations.
  • The Laser Retroreflector Array (LRRR) from NASA, which will be used to measure the distance between the Earth and the Moon.

Rover

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The rover is a small, mobile vehicle that will be deployed from the lander. It will explore the lunar surface for up to 1 lunar day (14 Earth days). The rover has a mass of about 26 kilograms (57 lb) and is equipped with a variety of instruments, including a camera, a spectrometer, and a drill.

The mission is also significant because it will be the first time that India has attempted to land a rover on the Moon. The rover will be able to travel up to 500 meters on the lunar surface, and it will collect data that will help scientists to better understand the Moon’s history and evolution.

The rover will carry two payloads to study the lunar surface:

  • The Alpha Particle X-ray Spectrometer (APXS), which will identify the chemical composition of the lunar soil.
  • The Laser Induced Breakdown Spectroscopy (LIBS) instrument, which will identify the chemical composition of the lunar surface by analyzing the light emitted when a laser is fired at it.

Propulsion module

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It is a box-like structure that will carry the lander and rover configuration until the spacecraft is in a 100 km lunar orbit i.e. the main function of PM is to carry the LM (Lander module) from launch vehicle injection till the final lunar 100 km circular polar orbit and separate the LM from PM. The propulsion module also has a Spectro-polarimetry of Habitable Planet Earth (SHAPE) payload to study the spectral and Polari metric measurements of Earth from the lunar orbit.

The propulsion module has a mass of about 500 kilograms (1,100 lb) and is equipped with four liquid-fueled engines. The engines will be used to propel the spacecraft into lunar orbit and to land the lander on the Moon.

Conclusion

Chandrayaan-3 is indeed a challenging mission, but it is also a very important one. India’s success will make it the fourth country to have achieved a soft landing on the Moon, so far – with the US, the former Soviet Union and China.

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