Chandrayaan 3 Trivia: How Many Countries Have Successfully Soft-Landed On Moon?

Chandrayaan 3 Landing: With the soft landing procedure drawing closer by every hour and minute, there is an increasing curiosity among Indians and people abroad who are eagerly waiting for the final journey of the Chandrayaan-3 mission.

India's ambitious lunar mission Chandrayaan 3 is scheduled to soft land on the moon's surface on Wednesday around 6:04 PM IST.

As India prepares for this momentous occasion let's look at some trivia around this step called - Soft Landing on Moon.

Let's understand - What is a soft Landing, What do '17 minutes of terror' mean in the context of a soft landing and which countries have successfully pulled this off?

A Moon landing or lunar landing is the process of arrival of a spacecraft on the surface of the Moon. 

A soft landing is any type of aircraft, rocket or spacecraft landing that does not result in significant damage to or destruction of the vehicle or its payload, as opposed to a hard landing.

In Chandrayaan 3 mission, the spacecraft consists of an indigenous Lander module (LM), a Propulsion module (PM) and a Rover. 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. 

Soft landing, is a lunar landing procedure that requires a control descend of the spacecraft for its own safety and the gradual touchdown. The lander uses reverse thrust as a counterweight to gravity, decreasing the speed at which it descends to ensure a soft landing.

This critical process of soft-landing has been dubbed by ISRO officials as "17 minutes of terror" when the lander has to fire its engines at the right times.

At a height of 30 km, it will have a velocity of 1.68 km/second after which the thruster engines will have to be retro-fired so that the speed will be reduced to zero by the time it reaches the moon. There are four thruster engines attached to the lander module - initially, it will travel from a 30 km range to a 7.5 km range then to a 6.8 km after which that engine will be shut off and will work on a reverse thrust mechanism. Using the lander cameras and sensory equipment the lander will scan the lunar surface for any obstacles or hills or craters before finally touching down.

This entire process takes around 17 minutes 21 seconds which is the minimum time required and the maximum time will be 17 minutes 32 seconds. Hence it is dubbed as '17 minutes of terror'.

Although this can change basis the real-time analysis of the spacecraft and the landing procedure.

Watch: Director of Space Applications Centre (ISRO) Nilesh M Desai explains the significance of these “17 minutes”.

Hard-landing on the other hand is a lunar landing procedure performed at a higher rate of descent speed. These landings typically end in the spacecraft’s imminent destruction. Hard landings serve a purpose when the spacecraft’s mission is already fulfilled.

A recent example is Luna-25, Russia's first attempt to land a spacecraft on the Moon, which ended in failure with the spacecraft crashing onto the lunar surface.

As of August 2023, only three countries namely Russia, United States Of America and China have achieved this remarkable feat.

If successful, India will become the fourth country in the world to perform soft landing on the moon. In doing so India will also become the first ever country in the world to land on the lunar south pole.

Here's some more information on how these countries achieved this feat.

Russia:

• In 1959, Russia became the first country to achieve a successful lunar landing.

• In 1966, Russia became the first country to achieve a successful soft lunar landing.

• In 1970, it successfully retrieved lunar samples through an unmanned mission.

USA:

• In 1966, US achieved its first soft landing a few months after Russia.

• As of 2022, US already has 11 soft landings which is the most in the world and it is also the only country to land humans on the moon.

China:

• In 2013, Chang'e 3 lander touched down, marking the first moon landing since the USSR's Luna 24.

• In 2019, Chang'e 4 completed the first soft landing on the dark side of the moon becoming the first country to soft land a spacecraft on the 'dark' side.

• In 2008, Chandrayaan-1 which was designed for impact rather than a soft landing, had successfully reached the lunar surface.

• In 2019, Chandrayaan-2's lander crashed during a landing attempt with the orbiter remaining operational.

• On August 23, 2023 - Chandrayaan-3 will attempt to soft land on the South Pole of the moon.

ISRO's ambitious Moon mission Chandrayaan-3's Lander Module (LM) comprising the lander (Vikram) and the rover (Pragyan) is all set to land on the lunar surface on Wednesday evening at 6.04 pm IST.

The live telecast of the landing operation will begin at 5:20 pm IST on Wednesday. Live streaming of the landing sequence will be available on the ISRO website, its YouTube channel, as well as its social media profiles.

You can also watch the live broadcast on DD National TV on August 23.

You can watch it live through the video link below.