Chandrayaan-3: When will lunar mission launch and why does India want to explore the Moon?

The previous mission, Chandrayaan-2 in 2019, crashed when trying to land on the Moon

Chandrayaan-3 being prepared for Friday's launch. Photo: Isro

India is ready to launch its ambitious third lunar mission, Chandrayaan-3, on Friday as it plans to send a rover to the surface of the Moon after its previous mission, Chandrayaan-2, crashed as it was landing.

Chandrayaan means Moon-vehicle or lunar spacecraft in Hindi.

The Indian Space Research Organisation (Isro) – the country’s national space agency – is to launch the 3,900kg spacecraft from the Satish Dhawan Space Centre in Sriharikota, an island in the Bay of Bengal.

The Geosynchronous Satellite Launch Vehicle Mark III, the vehicle carrying the spacecraft Chandrayyan 3, will take off from the launch station at 2.35pm local time.

How important is the Chandrayaan-3 mission?

The success of the mission is viewed as a demonstration of India’s spacefaring ambitions. It will be the first spacecraft to land on the South Pole of the Moon, so far unexplored by human beings, in attempts to provide valuable scientific data on Earth.

Nasa says the mission will make numerous scientific measurements on the surface and from orbit.

The lunar mission is a follow-up to Chandrayaan-2, which was launched in September 2019 but crashed on the Moon’s surface when the soft-landing attempt failed because of issues with the onboard computer and propulsion system.

The mission is primarily a landing and roving mission, unlike the previous lunar mission which carried an orbiter.

The budget for the Chandrayaan-3 mission is 6.15 billion rupees (about $74 million).

The cost of the Chandrayaan-2 mission was about 8.5 billion rupees ($124 million) while the first mission, Chandrayaan-1, cost 5.41 billion rupees ($79 million).

Chandrayaan-2 lifts off from Sriharikota in July 2019. The lander crashed trying to touch down on the Moon. AFP

What is the objective of Chandrayaan-3?

“Chandrayaan-3 consists of an indigenous lander module, propulsion module, and a rover with an objective of developing and demonstrating new technologies required for interplanetary missions,” Isro said.

The main objective of Chandrayaan-3 is to demonstrate a safe and soft landing on the lunar surface as well as the capability to place a rover on the Moon to conduct scientific experiments.

This is India’s second mission to the Moon's South Pole. It launched Chandrayaan-1 in 2008, which intentionally crashed into the lunar surface and led to the discovery of frozen water.

While Chandrayaan-2's aim was to explore the areas combining the exosphere – the very thin and tenuous atmosphere of the moon – Chandrayaan-1 and 3 were set to explore the South Pole.

Launch preparation for Chandrayaan-3. Photo: Isro

Chandrayaan-3's components

The spacecraft is made up of a lander/rover and a propulsion module. The lander/rover will be similar to that used on Chandrayaan 2, with improvements to help ensure a safe landing.

It will be carried to lunar orbit by the propulsion module, which will remain in orbit around the Moon and act as a communications relay satellite.

The rover is expected to land on the Moon on either August 23 or 24, while Chandrayaan-3 will enter lunar orbit approximately a month after its launch.

The vehicle is made up of the following components.

Lander module: A space vehicle designed to land on the surface of the planet or moon. It has the capability to soft land at a specified lunar site and activate the rover, which will carry out chemical analysis of the surface during the course of its mobility. It is box-shaped, with four landing legs and four landing thrusters of 800 newtons each.

Propulsion module: This unit carries the lander and rover from launch vehicle injection to the final 100km lunar orbit.

It includes a payload – an electronic subsystem or experiment board comprising sensors that monitor factors such as temperature, humidity and radiation levels (called spectro-polarimetry of habitable planet Earth) – to study the spectral and polarimetric measurements of Earth from lunar orbit.

Lander payloads: The lander will carry payloads such as Chandra’s Surface Thermophysical Experiment to measure thermal conductivity and temperature. It also has an instrument for lunar seismic activity, which measures the seismicity, or frequency of earthquakes, around the landing site.

The lander includes the Langmuir Probe, used to estimate the electron temperature and electron plasma density in the ionosphere – where Earth's atmosphere meets space.

Rover payloads: The rover is a device designed to explore planetary surfaces. The rover will carry loads such as an alpha particle X-ray spectrometer and laser-induced breakdown spectroscope for establishing the elemental composition near the landing site.

Isro is using several advanced technologies in the lander, including altimeters, velocimeters and an accelerometer. There is also a navigation, guidance and control system, and a hazard detection and avoidance camera to ensure the safety of the vehicle when landing.