The Critical 20 Minutes: How Chandrayaan-3's Vikram Lander Will Make A Soft Landing On The Moon

On Wednesday, the nation will collectively hold its breath for an intense twenty minutes as the Vikram lander of Chandrayaan-3 endeavors to perform a soft landing on the lunar surface in the evening. This pivotal moment in India's space exploration has been aptly coined "twenty minutes of terror," akin to the suspenseful finale of a T-20 cricket match.

Chandrayaan-3's Remarkable Journey and Landing Process

After a remarkable liftoff, ISRO's Mark-3 rocket propelled Chandrayaan-3 into orbit, where it traversed elliptic orbits around Earth, gradually gaining velocity.

On August 1, Chandrayaan-3 embarked on its 384,000-kilometer journey towards the moon. By August 5, the satellite comfortably nestled into the moon's orbit, and in the following days, Chandrayaan-3 was meticulously stabilised.

A significant and intricate maneuver occurred on August 17, as the propulsion module and Vikram lander with the Pragyaan rover detached from each other while the satellite was in a 153 km by 163 km orbit. The propulsion module continued orbiting the moon in this path.

Subsequently, the Vikram lander transitioned into a 134 km by 25 km elliptical orbit, approaching the moon's surface for the commencement of its powered descent. This procedure had been successfully executed during Chandrayaan-2.

The Nail-Biting Landing Day

The critical "twenty minutes of terror" begin on the landing day, setting off a heart-pounding climax. After receiving commands from Bengaluru, the Vikram lander will begin its descent from an altitude of 25 kilometers above the lunar surface.

During this powered descent, the lander hurtles towards the moon at a velocity of 1.68 km per second, equivalent to nearly 6048 km per hour - approximately ten times the speed of an airplane.

The Vikram lander subsequently reduces its velocity by firing its engines, although it remains almost horizontal to the moon's surface. This phase, known as the rough braking phase, extends for approximately 11 minutes.

Through meticulous maneuvers, the Vikram lander aligns vertically with the lunar surface, initiating the "fine braking phase."

It must be noted that during the final braking phase of Chandrayaan-2, the Vikram lander had lost control and crashed.

At an altitude of 800 meters above the moon's surface, both horizontal and vertical velocities cease, and the lander hovers over the lunar terrain, surveying the landing area.

Continuing its descent, the Vikram lander halts again at 150 meters above the surface, capturing images for hazard detection and identifying the optimal landing spot.

Eventually, the lander will achieve a soft landing on the moon's surface, utilising only two engines. The lander's legs are designed to endure an impact of up to 3 meters per second or roughly 10.8 km per hour.

Once the leg sensors detect contact with the lunar surface, the engines cease, concluding the intense twenty minutes of tension.

As the lunar dust, or regolith, settles, the ramp opens, allowing the Pragyaan Rover to gracefully descend.

Upon the Pragyaan Rover's successful landing, it gains freedom to explore the lunar surface, capturing significant scientific data.

A Pivotal Moment and the Beginning of Exploration

The climactic moment transpires when the Vikram lander captures images of the Pragyaan rover, while the rover reciprocates by photographing the lander. These images, India's first selfies from the moon's surface, are transmitted back to the country.

Subsequently, the Vikram lander and the rover commence their solar-powered scientific pursuits, designed to endure one lunar day, equivalent to 14 Earth days.

In the event of success, India will join an elite group as the fourth country to achieve a soft landing on a celestial body. This achievement marks a monumental leap for ISRO and a profound stride for India in the realm of space exploration, often referred to as the 'Amrit Kaal' or auspicious time. Truly, it is a celestial leap akin to the legendary 'Hanuman' jump for a nation of 1.4 billion individuals.