Chandrayaan-3 Now At Critical Juncture As Lander Attempts To Auto-Correct Course And Soft-Land On The Moon

India's third attempt at achieving a soft landing on the Moon crossed an important milestone yesterday as the Vikram lander, housing the Pragyan rover, separated from the main rocket. Now the mission has entered its most critical part of the journey.

The Vikram lander is no longer the payload and has become the propulsion and delivery spacecraft that will attempt to land on the Moon and release its payload, the Pragyan rover. Here's why this is the most important and risky part of the entire mission.

Chandrayaan-3 Now Two Missions After Releasing Vikram Lander and Pragyan Rover

ISRO announced the Chandrayaan-3 spacecraft's Vikram Lander Module has successfully separated from the primary Propulsion module (ISRO rocket's third stage) that ferried it to the lunar orbit. The Lander module will now lower itself and further reduce the orbital distance to eventually attempt a soft landing on the Lunar surface.

The Vikram Lander will now undergo a "De-boosting" process wherein it will gradually slow down, and place itself in an optimum orbit between 30 Km (Perilune orbit) and 100 km (Apolune orbit) from the Moon.

The Propulsion module will continue orbiting the Moon, taking in data, and relaying the same to ISRO. Its mission doesn't have an end date and may continue as long it remains operational.

However, the Vikram Lander and Pragyan Rover have an operational lifespan of just one Lunar Day, which translates to 14 Earth days. Even before completing the mission, the duo will have to achieve a soft landing, a feat that the Chandrayaan-2 mission couldn't achieve.

Chandrayaan-3 Will Succeed Where Chandrayaan-2 Failed?

There's little doubt that the Vikram Lander is now in the most critical zone as its predecessor failed in this stage. The most critical part of the landing is the process of bringing the velocity of the lander from 30 km height to the final landing, confirmed ISRO Chairman S Somanath.

There's horizontal velocity and then there's vertical velocity of the Lander in relation to the Moon. The Vikram Lander has been built by taking into consideration its predecessor's limitations. Still, there are many challenges the lander will have to overcome, on its own.

Both the Lander and the Rover have individual jobs, missions, and experiments to conduct. However, for these to begin, the orbital distance reduction and the soft landing have to be achieved without any major glitches.

The final descent of the Lander is expected to begin on August 23, 2023. In other words, Vikram Lander's soft landing on the Lunar south pole should take place on Wednesday, next week.